[Index]
Monthly Global Tropical Cyclone Summary March 2004
[Summaries and Track Data] [Prepared by Gary Padgett]
| Tropical
Cyclones
[Index] |
Monthly Global Tropical Cyclone Summary March 2004 [Summaries and Track Data] [Prepared by Gary Padgett] |
MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY
MARCH, 2004
(For general comments about the nature of these summaries, as well as
information on how to download the tabular cyclone track files, see
the Author's Note at the end of this summary.)
*************************************************************************
MARCH HIGHLIGHTS
--> Intense tropical cyclone makes devastating strike on Madagascar
--> Long-lived and erratic intense cyclone strikes Western Australia
--> Significant hybrid storm affects eastern Australia
--> First observed South Atlantic hurricane on record makes damaging
strike in southeastern Brazil
*************************************************************************
***** Feature of the Month for March *****
WESTERN HEMISPHERE TROPICAL CYCLONE NAMES for 2004
Tropical cyclones in the Atlantic Ocean, Gulf of Mexico, and
Caribbean Sea are assigned names by the Tropical Prediction Center/
National Hurricane Center in Miami, Florida. A separate alphabetical
set of alternating male/female names is used each year with the name
of the first tropical storm beginning with the letter "A". Names are
repeated every six years. The names of hurricanes which cause a lot
of damage and/or fatalities are usually retired from the list with
another name of the same alphabetical rank and gender replacing it.
Following the 2003 season, the names Fabian, Isabel and Juan were
retired. Fabian has been replaced with Fred, Isabel with Ida, and
Juan with Joaquin in the list of names for 2009.
The highest number of tropical storms named in one season in the
Atlantic was 19 during the very active 1995 season. The most active
Atlantic tropical cyclone season on record was 1933, in which 21 storms
were charted, but of course that season pre-dates the formal naming of
tropical cyclones. The active 1969 season is credited with 17 tropical
cyclones (plus one subtropical storm), but only 13 were actually named
operationally. Several of the systems began as hybrid/subtropical
storms and forecasters at the time were still debating how to classify
this type of storm system, and so they remained unnamed. A few years
later several tracks were added to the official Best Tracks database.
Two of these unnamed storms were hurricanes, thus giving 1969 a total
of 12 hurricanes--the current record for the Atlantic.
The list of names for 2004 is the same one used during the active
hurricane season of 1998 when fourteen tropical cyclones were named.
Georges and Mitch were the destructive hurricanes of 1998, and those
names have been replaced with Gaston and Matthew in the list for 2004.
TPC/NHC also has warning responsibility for the Eastern North
Pacific Ocean from the west coast of Mexico out to longitude 140W.
Six separate alphabetical sets of names are used for this basin in
the same manner as in the Atlantic. Initially, the Eastern Pacific
name sets contained only 21 names, omitting "Q" and "U" and ending
with the letter "W", as in the Atlantic. When the active 1985 season
threatened to exhaust the list, the names Xina, York and Zelda were
drafted to accommodate any additional storms which might develop.
(Hurricane Xina was named in late October, 1985.) The decision was
made sometime in the latter 1980s to extend the list with these three
names in odd-numbered years, and to add the names Xavier, Yolanda and
Zeke in even-numbered years (to preserve the alternating gender
scheme). During the Northeast Pacific's year of record activity in
1992, all 24 names were allotted to tropical cyclones forming east of
140W, ending with Tropical Storm Zeke in late October. Had more storms
developed, they would have been named with the letters of the Greek
alphabet (Alpha, Beta, etc), which is also the backup plan for the
Atlantic basin in case more than 21 tropical storms develop in a single
season.
The list for this year was last used in 1998 when thirteen tropical
cyclones were named, the last one being Madeline. However, six years
earlier, in 1992, all 24 names were used during the most active
Eastern Pacific on record since the advent of meteorological satellites.
The Central Pacific Hurricane Center, located in Honolulu, has
tropical cyclone warning responsibility for that portion of the North
Pacific Ocean lying between longitudes 140W and 180. The majority of
the tropical storms and hurricanes seen in that region are visitors
from east of 140W, but on the average about one tropical storm forms
in the Central Pacific each year, and when this happens, the storm is
given a Hawaiian name. The list consists of four sets of twelve
names each, using only the letters of the Hawaiian alphabet. All the
names are used--the first storm to form in a given year is assigned
the next available name on the list. No tropical cyclones were named
by CPHC in 2003. The last storm to form in Central Pacific waters
was Hurricane Huko in late October, 2002, so the next name to be
assigned will be Ioke.
Names for 2004 are (** indicates name has already been assigned):
ATLANTIC EASTERN PACIFIC CENTRAL PACIFIC
Alex Lisa Agatha Madeline Ioke
Bonnie Matthew Blas Newton Kika
Charley Nicole Celia Orlene Lana
Danielle Otto Darby Paine Maka
Earl Paula Estelle Roslyn Neki
Frances Richard Frank Seymour Oleka
Gaston Shary Georgette Tina Peni
Hermine Tomas Howard Virgil Ulia
Ivan Virginie Isis Winifred Wali
Jeanne Walter Javier Xavier Ana
Karl Kay Yolanda Ela
Lester Zeke Halola
UPDATED TABLES OF ATLANTIC NET TROPICAL ACTIVITY
For the past few years I have included tables of Atlantic and
Northeastern Pacific monthly net tropical activity (NTC). As part of
the monthly feature for March, I have included tables for the Atlantic
basin--the Northeast Pacific will follow in a later summary. When
breaking up a tropical cyclone season temporally (into months), some
decisions have to be made regarding inter-monthly cyclones. I have
previously explained in detail my reasoning here, and interested
persons can find this in the March, 2002, summary, which can be
obtained from any of the websites listed at the end of this summary.
The 2003 Atlantic tropical cyclone season has the distinction of
being the longest lasting season on record as measured from the
beginning of the first named cyclone to the dissipation of the final
storm. Subtropical Storm Ana was reclassified as a tropical storm
on 21 April, making it the first known Atlantic tropical storm to
have formed in the month of April. Tropical Storm Peter weakened
into a depression on 10 December--234 days after Ana had formed.
Tropical Storms Odette and Peter were the first Atlantic December
tropical cyclones since Hurricane Lili in 1984, and constitute the
first occurrence of two December tropical storms since 1887. The
first table below lists the monthly statistics for the individual
months as well as the seasonal totals. The second table lists the
monthly figures over the period 1950-2003, inclusive.
Atlantic Hurricane Season of 2003
---------------------------------
Month NS H IH NSD HD IHD NTC
APR 1 0 0 3.25 0.00 0.00 2.8
MAY 0 0 0 0.00 0.00 0.00 0.0
JUN 1 0 0 1.50 0.00 0.00 2.2
JUL 2 2 0 12.25 2.00 0.00 14.4
AUG 3 2 1 6.75 2.25 1.25 25.6
SEP 4 3 1 29.75 23.00 14.00 92.2
OCT 3 0 1 21.50 5.50 1.50 28.0
NOV 0 0 0 0.00 0.00 0.00 0.0
DEC 2 0 0 4.25 0.00 0.00 4.8
TOTAL 16 7 3 79.25 32.75 16.75 170
Atlantic Basin Monthly NTC Table
1950-2003
--------------------------------
Month NS H IH NSD HD IHD NTC
JAN 0 0 0 4.50 3.50 0.00 0.07
FEB 1 0 0 1.50 0.00 0.00 0.04
MAR 0 0 0 0.00 0.00 0.00 0.00
APR 1 0 0 3.25 0.00 0.00 0.05
MAY 5 2 0 18.50 6.25 0.00 0.45
JUN 28 10 2 73.75 13.25 0.75 2.32
JUL 44 19 1 135.25 34.25 0.50 3.78
AUG 144 81 31 625.25 298.75 64.50 24.25
SEP 189 132 67 1201.50 674.50 171.00 47.66
OCT 90 57 19 496.25 237.75 41.75 16.81
NOV 27 20 4 126.75 46.00 6.25 4.14
DEC 5 2 0 17.00 3.75 0.00 0.41
TOTAL 534 323 123 2703.50 1318.00 284.75
AVG 9.9 6.0 2.3 50.0 24.4 5.3
The following table contains the annual statistics for the Atlantic
basin for the period 1950-2003:
Atlantic Basin Annual NTC Table
1950-2003
--------------------------------
Year NS H IH NSD HD IHD NTC
1950 13 11 7 98.00 59.50 15.50 225
1951 10 8 2 57.75 36.25 5.00 113
1952 7 6 3 39.75 22.75 4.00 91
1953 14 6 3 64.50 18.00 5.75 113
1954 11 8 2 51.75 31.50 9.00 122
1955 12 9 5 82.75 46.75 14.25 185
1956 8 4 2 30.00 12.75 2.25 64
1957 8 3 2 38.00 21.00 5.25 79
1958 10 7 4 55.50 30.25 8.50 131
1959 11 7 2 40.00 22.00 3.75 92
1960 7 4 1 29.50 18.25 9.00 80
1961 11 8 6 70.75 47.50 21.50 207
1962 5 3 0 22.25 10.75 0.00 31
1963 9 7 2 52.00 37.25 5.75 109
1964 12 6 5 71.25 43.00 9.75 156
1965 6 4 1 39.50 27.25 6.25 79
1966 11 7 3 64.00 41.75 7.75 133
1967 8 6 1 58.00 36.25 5.75 99
1968 7 4 0 26.50 10.00 0.00 38
1969 17 12 3 83.25 40.00 6.25 158
1970 10 5 2 23.25 6.75 1.00 60
1971 13 6 1 63.00 28.75 1.00 89
1972 4 3 0 21.00 6.25 0.00 26
1973 7 4 1 32.50 10.00 0.25 48
1974 7 4 2 31.50 14.25 4.25 70
1975 8 6 3 42.50 20.50 2.25 87
1976 8 6 2 44.75 25.50 1.00 80
1977 6 5 1 13.75 6.75 1.00 43
1978 11 5 2 40.50 13.50 3.50 80
1979 8 5 2 44.25 21.50 5.75 89
1980 11 9 2 60.00 38.25 7.25 126
1981 11 7 3 59.75 22.50 3.75 106
1982 5 2 1 16.25 5.75 1.25 34
1983 4 3 1 13.50 3.50 0.25 30
1984 12 5 1 51.25 18.25 0.75 73
1985 11 7 3 51.25 21.25 4.00 103
1986 6 4 0 23.25 10.50 0.00 36
1987 7 3 1 37.25 5.00 0.50 44
1988 12 5 3 47.00 21.25 9.25 114
1989 11 7 2 66.00 31.75 9.75 126
1990 14 8 1 66.25 26.75 1.00 96
1991 8 4 2 22.25 8.25 1.25 56
1992 6 4 1 38.75 16.00 3.50 63
1993 8 4 1 30.00 9.50 0.75 50
1994 7 3 0 27.75 7.25 0.00 34
1995 19 11 5 121.50 61.75 11.50 217
1996 13 9 6 79.00 45.00 13.00 188
1997 7 3 1 28.75 9.50 2.25 50
1998 14 10 3 88.00 48.50 9.50 165
1999 12 8 5 78.50 41.00 14.25 177
2000 14 8 3 67.00 32.75 5.00 127
2001 15 9 4 64.25 25.50 4.25 131
2002 12 4 2 53.50 10.75 3.00 80
2003 16 7 3 79.25 32.75 16.75 170
AVG 9.9 6.0 2.3 50.0 24.4 5.3
*************************************************************************
ACTIVITY BY BASINS
ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico
Activity for March: No tropical cyclones
*************************************************************************
SOUTH ATLANTIC (SAT) - Atlantic Ocean South of the Equator
Activity for March: 1 hurricane
CYCLONE CATARINA
(TC-01T)
19 - 28 March
------------------------------------
A. Introduction
---------------
According to many old meteorological textbooks, many things just
don't happen. In particular, essentially all books dealing with the
global climatology of tropical cyclones unanimously state that tropical
cyclones do not develop in the South Atlantic Ocean. This assertion,
however, was proven false 13 years ago when a strong tropical depression
or possibly even minimal tropical storm formed just off the west
African coast a few degrees south of the equator in April, 1991. And
just a couple months earlier, in January, what appeared to be a minimal
tropical storm developed off the coast of Brazil around 15S. Yet neither
of these events grabbed the headlines as did a system which formed off
the southeastern Brazilian coast in late March. A system which had just
about all the essential features of a tropical cyclone evolved out of
an extratropical LOW and headed for the Brazilian coast. Satellite
intensity estimates indicated a strong Category 1 or weak Category 2
hurricane on the Saffir/Simpson scale, and the widespread damage which
occurred when the cyclone made landfall in the Brazilian state of Santa
Catarina was consistent with a storm in this intensity range.
A word about the names, numbers, and nomenclature for this cyclone.
The name by which the storm came to be known--Catarina--appears to have
first been utilized by the Brazilian press. It seems likely that the
designation "Furacao Catarina" was intended to mean the furacao (hurri-
cane) threatening (Santa) Catarina (the state), but it was taken by the
international press to mean a name for the storm in the sense in which
tropical cyclones are normally named in the other oceanic basins. The
numerical designator '01T' was applied by the UK Meteorological Service
when a number-plus-suffix was needed for the UKMET modeling program.
The Monterrey NRL website for a time used the designator '01L' ('L' being
the suffix normally applied for Atlantic tropical systems). One other
name should be mentioned. Roger Edson of the University of Guam
suggested the old Portuguese name Aldonca for the cyclone (before
Catarina had become established as the somewhat official name), and this
name was widely used for a couple of days by some discussion groups and
websites.
All the available satellite data products and the damage incurred
onshore more or less prove that Catarina was a cyclone of hurricane
intensity. But should Catarina be classified as a tropical cyclone?
That is a question for which there is a significant divergence of
opinion among the world's foremost tropical meteorologists. This topic
will be discussed further after the storm's synoptic history and damage
have been covered. For purposes of the header above, I chose to simply
call the storm "Cyclone Catarina". All parties in the tropical vs sub-
tropical vs non-tropical debate would agree that Catarina was a cyclone.
B. Storm Origins
----------------
Much of the information in this section was taken from a discussion
by Dr. Lance Bosart of the University at Albany/SUNY. Lance's full
synoptic discussion can be accessed at the following link:
http://cimss.ssec.wisc.edu/tropic/brazil/other/synoptic.html>
Beginning around 12 March a quasi-stationary weak cold-core upper-
level trough became established east of southern Brazil. SSTs in the
area were around 24-25 C and deep layer (850-200 hPa) vertical shear
was generally less than 10 m/sec. The upper-level cyclone was isolated
from the westerlies by a persistent ridge that lay poleward of the
system. A series of troughs crossing the Andes during the period led
to weak surface baroclinic cyclone formation over central Argentina.
These systems would usually undergo modest re-intensification when they
reached the eastern coast of South America and moved offshore. Catarina
formed from the last of these baroclinic systems which crossed the coast
of South America and moved over SSTs of 24-25 C.
The transition to a tropical-like system appeared to occur beneath a
narrow ribbon of Amazonian moisture that turned westward and then north-
westward from the main column of moisture that swept poleward along the
eastern flank of the cut-off cyclone. Otherwise, the environment over
and to the west of the storm was quite dry in mid and upper levels. The
available evidence suggests that the precursor disturbance to Catarina
was an ordinary, small-scale system that formed through ordinary baro-
clinic processes within the envelope of a larger-scale upper-level
trough. Similar developments in the Northern Hemisphere have been
observed to occur in conjunction with polar LOW formation beneath high-
latitude cut-off cyclones, small-scale cyclone formation beneath cut-off
cyclones over the Mediterranean Sea, and cyclogenesis beneath cut-off
cyclones over the western Atlantic Ocean.
C. Synoptic History
-------------------
Information relating to the track and intensity of Catarina in this
section is based upon the track supplied by Roger Edson and which was
included in the March global tropical cyclone tracks file prepared by
the author.
At 1800 UTC on 19 March a weak 25-kt LOW was located near the east
coast of Brazil near the city of Florianopolis. After an initial
northerly jog (or relocation), the LOW moved in an east-southeasterly
direction for the next three days, reaching a point approximately
775 nm east-southeast of Florianopolis by 22/1800 UTC. The maximum
winds were estimated at 30 kts. This was the easternmost point in the
system's track--it subsequently began to move very slowly toward the
west. Gales were estimated to have developed by 23/1800 UTC, and the
LOW began to exhibit increasing subtropical/hybrid characteristics on
the 24th. At 24/0000 UTC the LOW was located approximately 550 nm
east-southeast of Florianopolis and was moving slowly but steadily
westward. Roger's track suggests that the system had become a 45-kt
tropical storm by 0600 UTC on 25 March when it was centered roughly
425 nm east-southeast of Florianopolis, and a minimal hurricane 24 hours
later when located about 300 nm east-southeast of the same city.
The estimated MSW reached 70 kts at 26/1200 UTC and then leveled off
for about 18 hours before undergoing a modest intensification. The
system had by this time been dubbed Catarina by the Brazilian media,
and, guided by a persistent ridge to the south, continued inexorably
westward toward the coastline of Santa Catarina state. As it approached
the Brazilian coastline, Cyclone Catarina passed over a strip of slightly
warmer SSTs and responded by intensifying yet further. Roger estimates
that the peak 1-min MSW reached about 85 kts shortly before landfall
around 0600 UTC on 28 March. Catarina's eye crossed the coast about
25 nm north of Torres and just south of Ararangua. The final data point
of Roger's track at 28/1800 UTC places a weakening 45-kt tropical storm
inland about 165 km north of the city of Porto Alegre. Catarina began to
rapidly weaken after making landfall in the manner of a normal tropical
cyclone.
D. Meteorological Observations
------------------------------
There were few meteorological observations available from near the
center of Catarina. The only strong wind report I'm aware of was an
unofficial report of a gust to 82 kts, but the time and location and
other particulars are unknown. Based on a couple of reports from
one coastal site near the landfall point and another from a station
about 100 km inland, David Roth has estimated that the SLP in the eye
at landfall was probably at least down to 991 hPa.
E. Damage and Casualties
------------------------
In the state of Santa Catarina approximately 32,000 homes were
damaged with 393 fully destroyed. Two persons lost their lives with
11 reported missing. About 75 persons were severely injured, and over
400 persons were injured after the storm while making repairs (from
falls and other construction-related accidents). The total damage
was estimated at around US $350,000,000. In the state of Rio Grande
do Sul 31,500 people were adversely affected with 4500 homes damaged.
Also, one health center and 16 schools were damaged, and 150,000 square
metres of streets had to be re-paved.
Agriculturally speaking, the banana crop in the region suffered
an 85% loss, while other tropical fruit crops experienced losses of up
to 60%. Rice plantations experienced crop losses of around 40%.
A special thanks to Alexandre Aguiar of Sao Leopoldo and Luiz Gava
or Porto Alegre for sending the above information. More information
can be obtained from the following websites:
http://www.emater.tche.br/>
http://www.defesacivil.sc.gov/br/>
http://www.defesacivil.rs.gov/br/>
Additionally, Julian Heming of the UK Meteorological Office supplied
a list of links containing further information on Catarina:
http://www.metoffice.com/sec2/sec2cyclone/catarina.html>
http://www.metoffice.com/sec2/sec2cyclone/tcbulletins/2004/
march.html#01t>
http://www.metoffice.com/sec2/sec2cyclone/tcimages/Misc/>
http://www.ncdc.noaa.gov/oa/climate/research/2004/mar/
brazilcane.html>
http://www.drdisk.com.hk/aldonca.htm>
http://cimss.ssec.wisc.edu/tropic/brazil/brazil.html>
http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.
php3?img_id=12037>
http://tenkimap.com/tc/slant/>
http://users.qldnet.com.au/~carls/2003-2004/aldonca-catarina/
aldonca-catarina.htm>
http://www.ssd.noaa.gov/PS/TROP/catarina.html>
F. Discussion
-------------
I have in my files many, many e-mails discussing the nature of Cyclone
Catarina, i.e., whether or not the system in its later stages should be
classified as a tropical cyclone. I had intended to try to summarize
many of the opinions and comments, but I have decided against that. It
would make the report unduly long, and furthermore, many of the comments
were made by professional meteorologists on a non-public discussion list,
and I don't have the time to try to contact all of them asking for
permission to air their opinions in this summary, which is available to
the public. So I intend to just hit a few of the high points here, and
perhaps quote a few persons whom I know would not mind.
The debate over whether or not Catarina should be called a tropical
cyclone at times seemed almost as stormy as the cyclone itself. What is
interesting is that almost everyone is in agreement over the salient
characteristics of the system:
(1) It was definitely of baroclinic origin, but once fully developed,
appeared to be essentially completely isolated from any
baroclinic systems.
(2) It had well-organized convection surrounding a well-defined
eye in the manner of a tropical cyclone, even though the
convection was somewhat more shallow than what is typically
seen in association with cyclones in the deep tropics.
(3) It was warm-core in the mid and upper-levels.
(4) It had a tight wind core similar to tropical cyclones.
(5) It exhibited anti-cyclonic outflow.
(6) It spent most of its life, especially the latter portion, moving
over SSTs of around 24-25 degrees Celsius.
(7) It definitely had winds exceeding hurricane intensity, as
evidenced by the magnitude of damage when it moved onshore.
Sound like a tropical cyclone? Just about all U. S. tropical cyclone
forecasters and researchers would (and did) answer that question with an
unequivocal and resounding "yes". But there were a few dissenting, at
least questioning, voices also, primarily coming from the Australian
sector of the globe. What it really boils down to, in essence, is not
so much a disagreement about the characteristics of Catarina, but about
the application of the label 'tropical cyclone' to systems of baroclinic
origin forming and moving over waters cooler than the traditional
empirical threshold of 26 degrees Celsius.
For more than 30 years, such systems in the North Atlantic basin have
routinely been classified as tropical storms or hurricanes; hence, it is
no surprise that the U. S. tropical cyclone community was all but
unanimous in considering Catarina a tropical cyclone. During its latter
stages the cyclone certainly did not appear to be frontal, and with a
warm core, well-organized moderately-deep convection, an eye and anti-
cyclonic outflow, it possessed all the essential characteristics of a
tropical cyclone as defined by TPC/NHC's operational policy. Regarding
the SST issue, systems forming over sub-27 C waters have many times been
classified as tropical cyclones. In November, 1980, small Hurricane
Karl formed near the center of a large, weakening, occluded extratropical
cyclone over SSTs near 20 degrees Celsius.
The Australian experience, however, has been somewhat different. In
the Coral Sea and South Pacific waters off southern Queensland and
northern New South Wales, many subtropical/hybrid and even extratropical
systems have been noted to form at fairly low latitudes, i.e., a whole
continuum between severe extratropical cyclones and severe classic
tropical cyclones occurs. Deciding at what point to make the decision to
declare a named tropical cyclone has often proved to be very problematic.
Jeff Callaghan points out that early on 28 March Catarina seemed to be
straddling an increasing low to mid-level thermal gradient between a warm
thermal HIGH over land to its southwest and a cold 700 to 500-hPa cold
LOW near and northeast of the center. Jeff further indicates that about
all systems in the Brisbane AOR (tropical cyclones and otherwise)
straddle such thermal gradients, but with tropical cyclones the shear
and vertical tilt are usually much weaker. In summary Jeff states that
in his opinion Catarina was similar to the hybrid systems located towards
the tropical cyclone end of the spectrum; operationally, it would likely
have been named as a tropical cyclone.
Greg Holland, a leading Australian tropical cyclone researcher, is not
in favor of classifying Catarina as a tropical cyclone. With Greg,
however, it is not a question of the cyclone being frontal. He sees a
continuous spectrum of warm-core, convectively-driven cyclones ranging
from polar LOWs through Mediterranean cyclones to hybrid systems like
Catarina. In his opinion, the term 'tropical cyclone' is best restricted
to systems actually forming in the tropics over SSTs 26 C or higher.
Generally speaking, NHC forecasters years ago rather liberalized the
definition of a tropical cyclone to include systems of subtropical
origin, as long as they were not frontal, in the interest of reducing
confusion in public warnings. Australia, on the other hand, seems to
have somewhat restricted the definition of a tropical cyclone, likely
after Dvorak analysis became the primary intensity estimation tool, in
order to weed out some of the numerous hybrids (and possibly monsoon
depressions) which were not handled too well by the Dvorak method.
In the western Atlantic, 26 C SSTs extend northward to latitude 40N
with even warmer waters in the Gulf Stream just off the U. S. East Coast,
so hurricanes from the deep tropics often maintain their intensity to
latitudes well outside the tropics. So with systems of baroclinic origin
sometimes forming over these same waters and acquiring most (if not all)
of the features of cyclones forming in the deep tropics, it is not
surprising that NHC forecasters in the main opted for classifying these
systems as tropical cyclones, even if a few systems lacked some of the
characteristics of classic tropical cyclones. However, off eastern
Australia true tropical cyclones rarely affect the coastline south of
latitude 25S, and almost never beyond 30S, but hybrid storm systems tend
to be rather abundant in those latitudes. The subtropical storms,
though, while occasionally capable of producing hurricane-force winds,
rarely attain the intensity of even a moderately intense tropical
cyclone, so it does seem to make sense to try to differentiate between
those storms from the deep tropics which can upon occasion become very
intense as opposed to those from the subtropics which rarely strengthen
beyond storm intensity.
I recently checked the official definitions of the term 'tropical
cyclone' in several of the WMO regions, and there are subtle differences
which, if interpreted very literally, would admit such systems as
Catarina in some basins and not in others. In short, there is no
universally agreed-upon, detailed definition of a tropical cyclone;
hence, it is not surprising that there would be major differences of
opinion regarding a system like Catarina.
G. Another Possible Subtropical System
--------------------------------------
For an ocean which is not considered a tropical cyclone basin to have
had two possible tropical cyclones in the same season is remarkable, but
there was yet a third system which deserves mention. This system
occurred several days before the pre-Catarina LOW formed. I received an
e-mail from David Roth at HPC on the morning of 15 March regarding a
LOW which was developing off southern Brazil. To quote part of David's
message: "It looks subtropical in satellite pix due to the shear present
and weak frontal tail extending NNW of the LOW despite the convection
pulsing SE of the center (there is a broad, weak 5 C gradient across the
frontal feature)...but when looking at 500 hPa the temps are up to -5 C
and the SSTs are near 25 C, so it appears to be warm core. It could
merely be a sheared TC...but that weak front keeps me from thinking that
it's fully tropical.
"A buoy a bit south of the center has had sustained winds of 20-30 kts
since midday Sunday (14 March), and pressures a bit west of the center
are down to 1009 hPa at 1000 UTC, so the subtropical definition might be
a better fit. The satellite imagery looked best at 0300 UTC, when
convection entirely covered the center and a weak feeder band attempted
to form on the convection's north side."
H. Link to Further Information
------------------------------
Chris Velden at the University of Wisconsin and his associates have
made available a webpage devoted to coverage of Cyclone Catarina. Many
satellite images, as well as graphs of data from other sensors, may be
found. The link to this outstanding compendium of Catarina data is:
http://cimss.ssec.wisc.edu/tropic/brazil/brazil.html>
(Report written by Gary Padgett)
*************************************************************************
NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180
Activity for March: No tropical cyclones
*************************************************************************
NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180
Activity for March: 1 tropical storm **
** - Classified as a tropical storm by JTWC and PAGASA only
Northwest Pacific Tropical Activity for March
---------------------------------------------
One tropical cyclone formed during the month of March in the Northwest
Pacific basin. JTWC assigned the designator 02W to the system when
warnings were initiated, and PAGASA named the system Butchoy when it
trespassed into that agency's AOR. These also were the only TCWCs to
upgrade 02W/Butchoy to tropical storm intensity--all the other Asian
warning centres classified the system as only a tropical depression. A
report follows on Tropical Storm 02W/Butchoy, written by Kevin Boyle. A
special thanks to Kevin for his assistance.
TROPICAL STORM
(TC-02W / BUTCHOY)
16 - 23 March
--------------------------------------
A. Storm Origins
----------------
Tropical Storm 02W formed from an extensive area of cloudiness
associated with a near-equatorial trough. It was to become the third
unnamed system on the trot, the previous being Tropical Storm 27W
(December, 2003) and Tropical Storm 01W (February, 2004). JTWC began
issuing STWOs on a persistent area of convection within the trough at
1130 UTC on 14 March located near 3.0N/142.6E, or approximately 460 nm
southeast of Yap. Earlier, at 14/0812 UTC, a QuikScat pass showed a
very large and elongated LLCC consolidating under the large area of
convection which was situated south of the circulation near the
strongest winds. The environment was assessed as moderately favourable
with good diffluence and weak to moderate wind shear.
The potential for development at this point was judged to be poor,
but this was upgraded to fair at 14/1400 UTC. The area of convection
at this time was relocated to a position closer to Yap Island,
approximately 350 nm to the southeast. The development potential
remained fair through the 15th, and then was upgraded to good at 16/0900
UTC. A TCFA was issued as animated multi-spectral imagery revealed a
better-defined LLCC associated with the system. The first warning on
Tropical Depression 02W was issued three hours later.
B. Storm History
----------------
At 1200 UTC on 16 March Tropical Depression 02W was moving westward
at 6 kts, located approximately 150 nm east-southeast of Palau. The
system continued to consolidate and was upgraded to tropical storm
intensity at 16/1800 UTC. The third warning (issued at 17/0000 UTC)
placed the centre 18 nm east of Palau, but the combination of visible
and microwave satellite images and synoptic data from Palau indicated
that the LLCC was further to the southeast than previously advertised.
Tropical Storm 02W was thus relocated to a position 150 nm southeast of
Palau. It was now moving somewhat faster (at 10 kts) towards the west-
northwest, embedded in the steering flow of a mid-level ridge to the
north. However, the LLCC soon separated from its associated area of
deep convection, and TS-02W was downgraded to a depression at 17/0600
UTC. The earlier relocation meant that Palau had to endure a second
approach, but this time not so close. By 17/1200 UTC the centre of
the cyclone had passed the island to its south and was located 70 nm to
the south-southwest. (PAGASA had initiated bulletins by this time,
naming the system Butchoy.)
At 0000 UTC 18 March Tropical Depression 02W was moving west-
northwestward at 17 kts from a position roughly 180 nm west of Palau.
Animated multi-spectral imagery at this time depicted a complex system
with up to three fully-exposed, weak LLCCs. An 18/0413 UTC AMSU pass
gave the best indication of where the main LLCC was located, near
9.0N/130.0E, or approximately one degree southeast of the displaced deep
convection. The synoptic situation with TD-02W began to improve as the
system turned northwestward, and after the convection began to redevelop
over the LLCC, the MSW was upped to 30 kts at 1200 UTC, and further to
35 kts (tropical storm status) at 18/1800 UTC.
At 19/0000 UTC Tropical Storm 02W/Butchoy was moving northwestward
some 425 nm east-southeast of Manila with 35-kt sustained winds. At
this time, animated multi-spectral imagery once again suggested the
presence of multiple centres, and the 0000 UTC position was based on
the LLCC nearest the deep convection. Forward motion fluctuated from
4 to 9 kts over the next couple of days as the difficult-to-pinpoint
centre of TS-02W continued trekking to the northwest. A 19/2202 UTC
AMSU pass showed the LLCC to be exposed on the south side of the deep
convection.
By 0000 UTC on 20 March Tropical Storm 02W/Butchoy had closed the
distance to Manila down to 295 nm (to the east-southeast). Initially,
forecast models were predicting the system to cross the Philippines,
but the 20/0000 UTC Prognostic Reasoning message called for a change
to a northward track east of the Philippines, through a weakness, and
finally recurving northeastward into the westerlies. But before that
was to happen, TS-02W had one last, final fling. A TRMM pass at 20/1641
UTC showed improved organisation of the deep convection and the formation
of banding features. The MSW was raised to 45 kts, and this was to be
the peak intensity.
Microwave imagery at 21/0000 UTC showed that the LLCC had become
partially-exposed again, indicating that shear was increasing from the
west. Weakening had begun, and TC-02W was barely holding on to tropical
storm status by 1200 UTC as it veered northeastwards, passing
approximately 260 nm east-northeast of Manila, Philippines. The MSW
fell below 35 kts and TS-02W was downgraded to a depression at 21/1800
UTC. At 0000 UTC 22 March the centre of the ailing tropical depression
was relocated to a position approximately 240 nm northeast of Manila
with the nearest deep convection sheared over 125 nm away to the north-
east. Movement had become sluggish towards the north-northwest at 2 kts.
As cool, dry air entrainment and high vertical wind shear were expected
to continue, the final warning was issued by JTWC at 22/0600 UTC,
locating the slow-moving and completely exposed LLCC of the dissipating
storm approximately 220 nm northeast of Manila.
(Editor's Note: PAGASA was the only one of the Asian TCWCs to upgrade
TC-02W to tropical status, assigning a peak MSW (10-min avg) of 45 kts.)
C. Damage and Casualties
------------------------
No damage or casualties are known to have resulted from Tropical
Storm 02W/Butchoy.
(Report written by Kevin Boyle)
*************************************************************************
NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea
Activity for March: No tropical cyclones
*************************************************************************
SOUTHWEST INDIAN OCEAN (SWI) - South Indian Ocean West of Longitude 90E
Activity for March: 2 tropical disturbances
2 severe tropical storms **
1 very intense tropical cyclone
** - Systems formed east of 90E and moved into basin
Sources of Information
----------------------
The primary sources of tracking and intensity information for
Southwest Indian Ocean tropical cyclones are the warnings issued by
the Tropical Cyclone Warning Centre on La Reunion Island, part of
Meteo France (MFR), and the Regional Specialised Meteorological Centre
for the basin. However, tropical cyclones in this region are named
by the sub-regional warning centres on Mauritius and Madagascar with
longitude 55E being the demarcation line between their respective
areas of warning responsibility. The La Reunion centre only advises
these agencies regarding the intensity of tropical systems. References
to sustained winds imply a 10-minute averaging period unless otherwise
stated.
In the companion tropical cyclone tracks file, I occasionally
annotate positions from warnings issued by the Joint Typhoon Warning
Center (JTWC) of the U. S. Air Force and Navy, located at Pearl
Harbor, Hawaii, when they differ from MFR's coordinates by usually
40-50 nm or more. The JTWC warnings are also the source of the
1-minute average maximum sustained wind values included in the
tracks file. Additionally, information describing details of
satellite imagery and atmospheric circulation features included in
the narratives is often gleaned from the JTWC warnings.
Southwest Indian Ocean Tropical Activity for March
--------------------------------------------------
After a quiet February, tropical cyclone activity returned to the
Southwest Indian Ocean in March. The most intense cyclone of the season,
Gafilo, formed well to the northeast of Mauritius and trekked westward
toward a rendezvous with Madagascar. Striking the northeastern portion
of the island at peak intensity, Gafilo was very destructive and deadly
to the cyclone-prone island. After reaching the Mozambique Channel,
Gafilo re-intensified and struck Madagascar a second time along the
western coast. Severe Tropical Storms Helma and Itseng stirred up
waters in the eastern extremity of the basin, both having moved in
from the Australian Region where they were known as Nicky and Oscar,
respectively. (Reports on these two storms follow in the next section
of this summary, covering the Northwest Australia/Southeast Indian
Ocean region.)
There were a couple of other disturbances numbered by MFR. The first
of these, Tropical Disturbance 11, certainly wins the award for being the
most tenacious tropical system of the year. According to Huang
Chunliang, who monitored this system on a daily basis, it was very likely
a continuation of former Tropical Cyclone Evan, which formed on the first
day of the month in the northwestern Gulf of Carpentaria. Perth dropped
bulletins on ex-Evan on 6 March while it was located off the Western
Australian coast after it had failed to re-intensify. The daily Tropical
Weather Outlooks began mentioning a tropical LOW on the 13th about 65 nm
southwest of the Cocos Islands. The LOW had crossed 90E by the 15th and
MFR began issuing sporadic bulletins on the system, numbering it as
Tropical Disturbance 11. At 1200 UTC on the 15th it was located about
625 nm west-southwest of the Cocos Islands. JTWC issued a TCFA for the
disturbance at 0900 UTC on 16 March, but cancelled it a few hours later.
MFR estimated the peak 10-min avg winds at 25 kts during this period,
but by 1200 UTC on the 21st the system had weakened while located about
80 nm east-northeast of Agalega and bulletins were dropped for a few
days. Interestingly, during the period when MFR was not issuing
bulletins, JTWC upgraded the disturbance to TC-21S with the MSW (1-min
avg) estimated at 30 kts. Per JTWC's first warning, the center of TC-21S
was located approximately 225 nm south of the Seychelles at 23/1800 UTC.
However, a special warning (the third) was issued at 24/1200 UTC down-
grading the system. After JTWC had dropped the system, MFR on the 25th
issued their first bulletin in four days as convection flared once more
in the vicinity of the weak low-level center. During this last gasp of
Tropical Disturbance 11's life, the peak 10-min avg winds near the center
were estimated at no higher than 20 kts. The final MFR bulletin, issued
at 0600 UTC on 28 March, placed the weak LLCC approximately 225 nm
northeast of the northern tip of Madagascar.
On the 31st of March, MFR issued two bulletins on a system located
roughly 160 nm south-southeast of Agalega, designating it as Tropical
Disturbance 13. However, the system subsequently weakened and no more
bulletins were issued. A report on the very intense Tropical Cyclone
Gafilo follows.
TROPICAL CYCLONE GAFILO
(MFR-09 / TC-16S)
2 - 15 March
-------------------------------------------
Gafilo: contributed by Madagascar
A. Storm Origins
----------------
An area of convection developed approximately 360 nm south of Diego
Garcia on 29 February. Animated enhanced infrared satellite imagery
revealed cycling convection beginning to develop near an organizing
LLCC. An upper-level analysis indicated favorable divergence aloft
but marginal vertical wind shear. JTWC assessed the potential for
development over the next 24 hours as poor. This was upgraded to
fair at 0400 UTC on 1 March when the system was relocated about 60 nm
to the west of the previous day's position. A 01/0114 UTC QuikScat
pass depicted a well-defined LLCC with improving convective organization.
A 200-mb analysis indicated that the disturbance was equatorward of an
upper-level ridge axis with good diffluence and weak vertical shear.
The system was relocated to a position about 300 nm south-southwest
of Diego Garcia at 1800 UTC on 1 March. MFR issued the first bulletin
on Tropical Disturbance 09 at 0600 UTC on the 2nd, estimating the MSW
(10-min avg) at 25 kts. A couple of hours later JTWC issued a TCFA for
the system since deep convection was continuing to become better
organized. The first JTWC warning on TC-16S, locating the center about
740 nm east-northeast of Mauritius, was issued at 1800 UTC. The system
was moving west-southwestward at 12 kts, tracking along the equatorward
periphery of a mid-level steering ridge located to the southeast. MFR
upgraded the disturbance to a tropical depression (30 kts) at 03/0000
UTC, and at 03/0600 UTC Tropical Storm Gafilo was christened by the
Meteorological Service of Mauritius. Gafilo was located some 545 nm
to the northeast of Mauritius with 40-kt winds, and the storm's motion
had become west-northwesterly at a spiffy 20 kts.
(NOTE: According to Philippe Caroff, Chief Forecaster of Meteo France
La Reunion, the name of this particular cyclone is correctly pronounced
"gah-FEEL", i.e., the final 'o' is silent.)
B. Storm History
----------------
The rapid west-northwestward motion continued through 3 March, but
by 0600 UTC on the 4th Gafilo's translational speed had slowed to 7 kts
and the storm had turned more to the west. By 04/1800 UTC the cyclone
was moving west-southwestward from a position 415 nm north of Mauritius.
Intensification was steady once the system reached tropical storm
status, and an AMSU pass at 04/0616 UTC revealed the presence of a small,
symmetrical eye. MFR upgraded Gafilo to tropical cyclone (hurricane)
status at 1200 UTC on 4 March. (JTWC had done so 18 hours earlier.)
Throughout the 5th and 6th the rapidly intensifying cyclone trekked
steadily in the direction of northern Madagascar. Gafilo had reached
the "intense cyclone" stage (winds 90 kts or higher) by 1800 UTC on
5 May. Twelve hours later the cyclone had reached its peak estimated
intensity of 125 kts (10-min avg)--a "very intense cyclone" per MFR's
terminology. MFR estimated the minimum CP at a very low 895 hPa.
(JTWC's peak 1-min avg MSW of 140 kts is in excellent agreement with
MFR's reported peak intensity). SSM/I imagery revealed a very distinct
eye 20 nm in diameter during Gafilo's most intense stage. Storm-force
winds reached outward from the center 75 nm in all quadrants, and
gales covered an area over 350 nm in diameter.
The center of the very intense Gafilo made landfall near Antalaha,
Madagascar, shortly after 0000 UTC on 7 March with winds near the peak
intensity of 125 kts (10-min avg). The storm's winds dropped sharply
after landfall as the cyclone moved at a fairly good clip across
northern Madagascar. At 07/1800 UTC, MFR was reporting the intensity
at 45 kts, but JTWC's 1-min MSW estimate was 75 kts. By 1200 UTC on
the 8th Gafilo's center was back over water in the Mozambique Channel
roughly 200 nm west of Antananarivo. The storm by then was tracking
slowly south-southwestward along the western periphery of the mid-level
steering ridge located to the southeast. By 1800 UTC on 9 March Gafilo
had rounded the western extremity of the ridge and was moving south-
eastward at 10 kts back toward the southwestern coast of Madagascar.
The storm had slowly intensified and the MSW had reached 60 kts by
this time. (JTWC upgraded Gafilo to 65 kts for a 24-hour period
commencing at 08/1800 UTC.) Severe Tropical Storm Gafilo made landfall
a second time in Madagascar around 09/2300 UTC just north of the town of
Morombe with peak winds estimated at 60 kts. The 10/0000 UTC synoptic
observation from Morombe reported sustained winds of 27 kts and a MSLP
reading of 986.8 hPa.
Gafilo's center meandered around over southern Madagascar for over
three days. MFR downgraded the system to a depression at 11/1800 UTC,
and JTWC wrote their final warning at the same time. The center of
the weak tropical disturbance finally moved back over water around 0600
UTC on the 13th, but conditions did not favor re-intensification, so
MFR issued the final warning on Gafilo at 13/1200 UTC, placing the
center approximately 375 nm west-southwest of Reunion Island. However,
warnings were revived 24 hours later on the system as a subtropical
depression, located about 300 nm south-southeast of Reunion Island and
moving rapidly east-southeastward. The LOW, however, did not strengthen
significantly and had begun to weaken again by the 15th. The final
bulletin at 15/0600 UTC placed the center about 550 nm south of Rodrigues
Island.
C. Damage and Casualties
------------------------
Tropical Cyclone Gafilo was extremely destructive to Madagascar. A
report dated 30 March 2004 on the ReliefWeb internet site gave the death
toll at 237 with 181 missing. A ferry en route from the Comoros Islands
to Madagascar during the time the cyclone was located off northwestern
Madagascar never arrived and was presumed sunk. The ferry was carrying
113 passengers and crew, but it is not clear if these are included in
the above quoted death toll or number of missing persons, or either.
A majority of the deaths occurred in associated with extensive flooding
caused by the torrential rains. Over 300,000 hectares of productive
agricultural land were damaged, and an estimated 150,000 hectares of
crops were lost. The most heavily damaged crops were rice, corn and
vanilla. More than 200 schools and 200 health centers were either
damaged or destroyed.
The city of Majunga on the northwestern coast suffered heavy damage
and facilities along the waterfront were destroyed. The city reported
peak gusts of 88 kts during the storm. Morondava, a city prone to
coastal flooding, was almost 100% destroyed. Approximately 95% of
Antalaha was demolished, and the town of Maroantsetra located on
Antongil Bay was inundated. Gafilo passed overland to the south of
Majunga, but the storm maintained intensity rather well in passing
across the island. Morondava is located along the central western
coast of Madagascar near where Gafilo made its second landfall. However,
Antalaha is near the northeastern coast where the cyclone made its
initial and most intense landfall. This area suffered greatly in April,
2000, from the intense Tropical Cyclone Hudah, and was also affected
by intense Tropical Cyclone Hary in March, 2002, but with relatively
minor damage since that particular cyclone only brushed the coast and
the more intense left semicircle remained offshore.
One press report mentioned wind gusts of 179 kts in association with
Gafilo, but no information was given regarding time, location, and
whether or not they were recorded or estimated. In the author's
opinion, they were likely not reliably recorded, since this would indeed
probably be a world record for winds recorded in a tropical cyclone.
Another press report stated that wind gusts of 135 kts were recorded.
This value seems much more believable, although no information was given
regarding time and location.
Many articles about the effects of destructive Tropical Cyclone
Gafilo may be found at the following link:
http://www.reliefweb.int/w/rwb.nsf/vLND>
(Report written by Gary Padgett)
*************************************************************************
NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (AUW) - From 90E to 135E
Activity for March: 1 tropical cyclone
2 severe tropical cyclones (hurricanes)
Sources of Information
----------------------
The primary sources of tracking and intensity information for
Northwest Australia/Southeast Indian Ocean tropical cyclones are
the warnings and advices issued by the Tropical Cyclone Warning
Centres at Perth, Western Australia, and Darwin, Northern Territory.
References to sustained winds imply a 10-minute averaging period
unless otherwise stated.
In the companion tropical cyclone tracks file, I occasionally
annotate positions from warnings issued by the Joint Typhoon Warning
Center (JTWC) of the U. S. Air Force and Navy, located at Pearl
Harbor, Hawaii, when they differ from the Australian centres' coor-
dinates by usually 40-50 nm or more. The JTWC warnings are also the
source of the 1-minute average maximum sustained wind values included
in the tracks file. Additionally, information describing details of
satellite imagery and atmospheric circulation features included in
the narratives is often gleaned from the JTWC warnings.
Northwest Australia/Southeast Indian Ocean
Tropical Activity for March
------------------------------------------
Three tropical cyclones traversed waters off Western Australia and
the Southeast Indian Ocean during March. Two of these became intense
tropical cyclones (peak 10-min avg winds >= 90 kts) while the other
almost reached hurricane intensity (it was considered a minimal hurri-
cane by JTWC). Tropical Cyclone Nicky formed in the western extremity
of Perth's AOR and had almost reached hurricane status by the time it
crossed 90E into the Southwest Indian Ocean and was re-named Helma.
Severe Tropical Storm Nicky-Helma moved generally southward and main-
tained intensity for a couple of days before rapidly weakening.
Severe Tropical Cyclone Oscar formed during the fourth week of the
month and moved harmlessly westward over the open South Indian
Ocean. Oscar peaked at 95 kts (110 kts 1-min avg per JTWC) while
still in the Australian Region, but had begun weakening rapidly by the
time it crossed into the Southwest Indian Ocean basin and was renamed
Itseng by the Meteorological Service of Mauritius. The third cyclone,
Fay, was named by the Darwin TCWC but spent most of its life in Perth's
AOR. Severe Tropical Cyclone Fay was the most intense cyclone of the
season in the entire Australian Region, reaching Category 5 status on the
Australian scale. Fay moved slowly and erratically off the coastline
of Western Australia, and weakened to a Category 2 cyclone at one point,
but recovered and regained Category 4 status before making landfall
along a sparsely-inhabited stretch of coastline. Heavy rains attending
Fay's landfall caused widespread flooding in portions of Western
Australia.
Reports follow on Nicky-Helma, Oscar-Itseng, and Fay, all authored
by Simon Clarke.
TROPICAL CYCLONE NICKY-HELMA
(TC-17S / MFR-10)
8 - 13 March
------------------------------------------------
A. Storm Origins
----------------
Nicky was the fifth tropical cyclone of the 2003/2004 season named by
the Perth Tropical Cyclone Warning Centre. While Nicky formed in the
Australian basin, it moved into the Southwest Indian Ocean basin where,
according to convention, it was renamed Helma.
Nicky-Helma was first detected on 8 March 2004 within a persistent
area of convection. QuikScat imagery depicted an organised LLCC
approximately 370 nautical miles west of the Cocos Islands (near
13.4S/90.7E). The system was located within an environment of good
upper-air diffluence and moderate wind shear. The initial depression
was slow and erratic in movement due to the surrounding weak steering
environment. By 09/0400 UTC the developing tropical LOW was located
near 13.2S/90.7E and had deepened to 995 hPa. At this time the Perth
TCWC officially named the system Tropical Cyclone Nicky.
B. Storm History
----------------
Nicky soon commenced a southwesterly path along the western periphery
of a low to mid-level ridge located to its southeast. This south-
westerly path at a pace of between 7 and 10 knots was to be maintained
more or less for the remainder of the cyclone's life. Initially, upper-
level wind shear slackened, allowing Nicky to slowly intensify. By
10/1800 UTC Nicky had passed into the Southwest Indian Ocean basin near
16.5S and was renamed Helma. Peak intensity was attained at 11/0600
UTC with Helma (972 hPa) located near 17.8S/88.1E. Meteo France in La
Reunion estimated the maximum 10-min avg winds at 60 knots, while JTWC's
peak 1-min avg MSW was 70 knots.
Thereafter, increasing vertical wind shear, constricting upper-air
ventilation and cooler sea surface temperatures steadily weakened
Helma. By 12/1800 UTC Helma's LLCC was exposed on the northwestern
edge of the deep convection. Increasing westerly wind shear prevented
any further re-coupling of the LLCC with the deep convection and by
13/0600 UTC, Helma had lost tropical cyclone status approximately
1000 nautical miles southwest of the Cocos Islands (near 22.7S/84.2E).
C. Damage and Casualties
------------------------
Nicky-Helma remained over the open ocean for its entire life. The
Perth and La Reunion warning centres issued warnings for shipping.
However, there are no known reports of any incidents arising from the
cyclone.
Satellite imagery of the system can be found at the following web-
link:
http://www.nnvl.noaa.gov/cgi-bin/index.cgi?page=products&category=
Year%202004%20Storm%20Events&event=Tropical%20Cyclone%2017S>
(Report written by Simon Clarke)
SEVERE TROPICAL CYCLONE FAY
(TC-18S)
14 - 28 March
-----------------------------------------------
A. Storm Origins
----------------
Fay was the second tropical cyclone of the 2003/2004 season to be
named by the Darwin Tropical Cyclone Warning Centre. However, Fay
moved into Perth�s area of responsibility soon after naming and it
was in Western Australia that Fay had its greatest impact, reaching
Category 5 status on the Australia scale with wind gusts estimated to
be as high as 163 knots.
The pre-cursor of Fay was detected as early as 14 March 2004 in the
northern Gulf of Carpentaria as a tropical disturbance moving towards
the west at approximately 10 knots. After skirting offshore parallel
to the Top End of the Northern Territory, the tropical LOW had reached
the Timor Sea to the west of Darwin by 16 March 2004. Deep convection
had increased but remained at its strongest to the northwest of, and
slightly removed from, the LLCC. Under a favourable upper-level
environment of low vertical wind shear and fair diffluence, the tropical
LOW was officially named Fay at 16/1200 UTC.
At this time, Fay was located approximately 180 nautical miles west-
northwest of Darwin and 170 nautical miles north-northeast of Kalumburu
(near 11.7S/127.9E). The system was travelling in a west-southwesterly
direction at 6 knots along the northwestern periphery of a mid-level
steering ridge located to the southeast.
B. Storm History
----------------
Following naming, Fay travelled toward the southwest closer to the
Kimberley coast. However, the cyclone turned towards the west on
18 March (prior to making landfall) as it was steered by a mid-level
ridge to the south.
Fay then drifted out into the Indian Ocean and intensified at a near
climatological rate under favourable conditions of moderate upper-level
outflow and weak vertical wind shear. Fay reached its peak intensity
of 910 hPa at 21/1000 UTC while located approximately 150 nautical miles
north-northwest of Cape Leveque (near 14.1S/122.4E) with the peak MSW
estimated at 115 knots (120 knots 1-min avg per JTWC) near the centre.
Around this time the cyclone became quasi-stationary as a passing short-
wave trough began to weaken the mid-level steering ridge to the south.
Peak intensity was sustained only briefly. Fay abruptly turned to
the south-southeast toward the west Kimberley coast as a mid-level
trough extending northwest to southeast over central Australia filled
and the steering ridge to the northeast began to dominate. This path
was to be maintained for almost 48 hours, during which time Fay
weakened to a category 2 cyclone on the Australian scale as dry air
originating from the Great Sandy Desert was entrained into the system.
On 25 March animated water vapour imagery revealed that a poleward
outflow channel extending to the southeast of Fay was counterbalancing
the effects of the continental dry air entrainment. Accordingly, the
cyclone commenced re-intensification, reaching category 3 status as it
passed within 50 nautical miles of Broome before veering away on a more
west-southwesterly track. At 25/1000 UTC Fay was estimated to be
75 nautical miles north-northeast of Pardoo and 115 nautical miles
northeast of Port Hedland (near 18.9S/119.9E) and had re-intensified
into a Category 4 cyclone. Fay was about to commence on a track to the
south at 3-5 knots which would be maintained until landfall. Fay's
coastal crossing was in a remote part of the coastline between the
pastoral stations of Pardoo and Wallal at approximately 26/2200 UTC.
Fay possessed an estimated central pressure of 940 hPa just prior to
landfall with estimated peak 10-min avg winds of 90 knots (115 knots
1-min avg per JTWC) near the centre.
After making landfall, the cyclone began weakening as it moved to
the south-southeast farther inland, passing close to the Yarrie Mine.
The cyclone eventually lost cyclone status between Nullagine and
Telfer (21.6S/121.1 E) at 28/1000 UTC, approximately 36 hours after
moving onshore.
C. Warnings
-----------
The Darwin and Perth Tropical Cyclone Warning Centres issued a total
of 109 Tropical Cyclone advices for Fay collectively. Advisories were
discontinuous as Fay reached peak intensity well out in the Indian
Ocean. Shipping forecasts were issued on a regular basis, however,
during this period.
D. Meteorological Observations
------------------------------
The Perth Bureau of Meteorology has issued a report on Fay that can
be found at:
http://www.bom.gov.au/weather/wa/cyclone/fay/index.shtml>
This report provides a snapshot of the cyclone, including pictorial
representations of Fay�s track, satellite and radar imagery. As Fay
did not pass over any wind or pressure recording sites during its
life, other observations within this report are limited.
E. Damage and Casualties
------------------------
The body of an SES volunteer was found in a remote West Australian
gorge after he was swept to his death in a flash flood while trying
to save an injured tourist. This was the only reported casualty as a
result of Fay.
There was little damage of any consequence. The Manager of the
Kooljaman resort at Cape Leveque on the Peninsula reported to local
media that some of the resort's camping accommodation had been damaged.
Strong winds uprooted between 50 and 100 trees with some of the fallen
trees blocking the access road to the resort.
The resort town of Broome was all but shut down as the cyclone passed
by. Schools, shops and businesses were closed and flights were
cancelled. Broome experienced strong winds with gale-force gusts, some
heavy rain and heavy seas but escaped serious damage. The cyclone
uprooted trees and closed roads in the region, but left little in the
way of structural damage.
The BHP Billiton iron ore mine at Yarrie, 150 kilometres east-
southeast of Port Hedland, was shut down during the passage of the
cyclone. Some 200 workers were locked down for 8 hours in two squash
courts as accommodation units were overturned, water tanks "shredded"
and power lines cut as the cyclone passed by.
In the 24 hours to 0100 UTC on 28 March 2004, heavy rain was recorded
in the Pilbara, especially in the De Grey River catchment southeast
of Port Hedland. Highest registrations included 134 mm at Warrawagine,
230 kilometres east-southeast of Port Headland, and 111 mm at Mandora,
on the coast 250 kilometres east-northeast of Port Hedland. Wallal
Downs, about 30 kilometres from Mandora, recorded 197.6 mm in the
48 hours to 0100 UTC. These falls are considered to represent the best
rains in four years, if not a decade, in central and western parts of
the Pilbara and Gascoyne.
At Nullagine, 150 kilometres farther south, flooding in the Nullagine
River split the town into four sections, resulting in the evacuation
of the town's population of 140 to the police station, court house
and buildings on the outskirts of the town. Heavy rain in the Oakover
and Nullagine River catchments produced moderate flooding in the De Grey
River. The wind uprooted trees and disrupted phone and power services
throughout the area.
At the time of writing this report, there was no information
available regarding stock losses. However, the accruing benefits of
the useful rain will likely outweigh any immediate short-term losses.
F. Further Information / Web Links
----------------------------------
Further information, including satellite imagery, track details and
photographs of the event can be found at the following web-links:
http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.ph
p3?img_id=12047>
http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_v2.ph
p3?img_id=12045>
http://www.redtailcanyon.com/items/40932.aspx>
http://www.broomecam.com/event/tcfay.htm>
Courtesy to Laurier Williams for part of the material contained
within this report. For further information please refer to Laurier
Williams excellent web page at:
http://www.australianweathernews.com/index.shtml>
(Report written by Simon Clarke)
SEVERE TROPICAL CYCLONE OSCAR-ITSENG
(TC-20S / MFR-12)
20 - 28 March
--------------------------------------------------------
A. Storm Origins
----------------
Oscar was the sixth tropical cyclone of the 2003/2004 season to be
named by the Perth Tropical Cyclone Warning Centre. Following on
from Nicky two weeks earlier, Oscar also moved into the Southwest
Indian Ocean basin where it was renamed Itseng.
Oscar-Itseng was first detected as a westerly moving depression on
22 March 2004, located approximately 285 nautical miles east-southeast
of the Cocos Islands (near 14.9S/100.9E). At the time, animated
infrared and microwave imagery depicted deep convection cycling over
a well-defined LLCC. Upper-level conditions were somewhat favourable
with weak to moderate vertical wind shear and good diffluence aloft.
By 23/2200 UTC, the developing depression was located near 14.8S/97.4E
and had rapidly deepened to 985 hPa. It was officially named Tropical
Cyclone Oscar by the Perth TCWC at this time.
B. Storm History
----------------
Oscar continued on a 6-knot westerly path under the steering
influence of a mid-level ridge to the south while steadily
intensifying in a favourable environment consisting of warm sea
surface temperatures and good upper-level outflow in the poleward
direction. A banding eye formed as the cyclone passed approximately
130 nautical miles to the south of the Cocos Islands on 25 March.
Peak intensity was attained at 25/2200 UTC with Oscar (935 hPa)
located approximately 375 nautical miles southwest of the Cocos
Islands (near 17.0S/92.1E). Perth estimated the maximum 10-min avg
winds at 95 knots while JTWC's peak 1-min avg MSW was 110 knots.
Satellite imagery depicted a well-defined eye. At this time, Oscar
was moving toward the south-southwest at approximately 5 knots in
response to a migratory short-wave trough that had weakened the
mid-level steering ridge to the south.
A mid-level ridge to the east eventually recurved Oscar toward the
south. However, by 27/1800 UTC Oscar had edged sufficiently to the
west to move into the Southwest Indian Ocean basin (near 19.4S).
Accordingly, Oscar was renamed Itseng. By this time Itseng had
encountered moderate to strong upper-level wind shear and cool sea
surface temperatures and as a consequence had weakened dramatically.
The cyclone lost deep convection over its LLCC and was soon
downgraded below cyclone status at 28/1200 (near 19.7S/89.2E). The
spectacular loss in structure is depicted at the following weblink:
http://www.eorc.nasda.go.jp/TRMM/typhoon/html/a/2004s/20S.OSCAR-
ITSENG_2004s_e.htm>
C. Damage and Casualties
------------------------
As with Nicky-Helma earlier in March, Oscar-Itseng remained in open
ocean for its entire life. The Perth and La Reunion warning centres
issued warnings for shipping. However, there are no known reports of
any incidents arising from the cyclone.
Satellite imagery of the system can be found at the following web-
links:
http://www.nnvl.noaa.gov/cgi-bin/index.cgi?page=products&category=
Year%202004%20Storm%20Events&event=Cyclone%20Oscar>
http://rapidfire.sci.gsfc.nasa.gov/gallery/?2004086-
0326/Oscar.A2004086.0735.1km.jpg>
(Report written by Simon Clarke)
*************************************************************************
NORTHEAST AUSTRALIA/CORAL SEA (AUE) - From 135E to 160E
Activity for March: 2 tropical cyclones
1 significant hybrid storm
Northeast Australia/Coral Sea
Tropical Activity for March
-----------------------------
The fairly inactive (at least in recent years) portion of the Southern
Hemisphere lying between east longitudes 135 and 160 produced three
rather noteworthy systems during the month of March, two of which brought
severe weather and/or very heavy rainfall to the coasts of Queensland
and northern New South Wales. A subtropical hybrid-type storm early in
the month brought damaging winds, heavy rainfalls and high seas to the
coastlines of the aforementioned states. A few weeks later, another
storm system took shape right along the tropical Queensland coast,
bringing extremely heavy rainfalls and gale-force winds. After moving
away from the coast, this LOW developed enough central convection and
typical tropical cyclone features to be designated Tropical Cyclone
Grace. After earning a name, Grace sped away from Australia, entering
the Fiji AOR east of 160E shortly before being downgraded.
The Gulf of Carpentaria was the spawning ground for a tropical LOW
which became a tropical cyclone. A LOW began showing signs of
strengthening on the last day of February, and on 1 March became the
ephemeral Tropical Cyclone Evan for a few hours before making landfall
in the Northern Territory. Evan's remnant LOW re-emerged into the Timor
Sea and was expected for a few days to re-intensify into a tropical
cyclone, but this never materialized. The system continued westward
across the South Indian Ocean, characterized by occasional convective
flare-ups. There is a possibility that the brief TC-21S in late March
northeast of Madagascar was related to the remnants of Evan. Another
tropical LOW formed in the Arafura Sea around mid-month and drifted
westward north of the Top End. This system ultimately became Severe
Tropical Cyclone Fay. (A report on Fay will appear in Part 2 of the
March summary.)
A special thanks to Simon Clarke, who was near the center of action
for the unnamed hybrid storm, for writing the report on that system, as
well as the summaries for Tropical Cyclones Evan and Grace. Also, many
thanks to Jeff Callaghan for sending observations and damage reports
related to these systems.
TROPICAL CYCLONE EVAN
(TC-15P)
29 February - 06 March
------------------------------------------
A. Storm Origins
----------------
Tropical Cyclone Evan, the second cyclone to be named by the Darwin
Tropical Cyclone Warning Centre, briefly attained tropical cyclone status
in the Gulf of Carpentaria. The initial depression formed in the north-
eastern Gulf on 29 February from a broad area of monsoonal activity
stretching from Tropical Cyclone Monty off the Pilbara Coast of Western
Australia across the Cape York Peninsula, Queensland, and into the
northern Coral Sea.
The tropical depression (TC-15P per JTWC) maintained a general west-
southwesterly track with convection initially displaced slightly to
the west of the LLCC. By 01/0630 UTC and despite continuing shear,
organization improved sufficiently for the depression to be upgraded
to tropical cyclone status.
B. Storm History
----------------
At the time, the newly-named Evan was centred in the Gulf of
Carpentaria about 70 nautical miles east of Alyangula and 110
nautical miles south-southeast of Nhulunbuy (13.9S/137.5E) and moving
west-southwestward at 10 knots. Evan maintained a central pressure
of 994 hPa with a MSW (10-min avg) of 40 knots until landfall
approximately three hours later on the eastern coast of Groote
Eylandt.
After crossing Groote Eylandt, Evan maintained a westerly path,
crossing the mainland Northern Territory coastline to the near north
of Numbulwar at 01/1530 UTC. Evan rapidly weakened to below tropical
cyclone intensity, but the remnant depression continued to track
westwards across the Top End at (or near) 10 knots, re-emerging over
water in the Joseph Bonaparte Gulf near Port Keats by 03/0030 UTC.
Evan moved overland again, clipping the far northern Kimberley
coastline of Western Australia, before final re-emergence into the
Indian Ocean at 04/0030 UTC.
Warnings were issued by the Perth Tropical Cyclone Warning Centre
for ex-tropical cyclone Evan at this time. However, the system
remained weak and poorly organised, suffering from dry air entrainment
that effectively stifled any further opportunity for redevelopment.
Convection was lost and the remnant tropical LOW moved out across the
Indian Ocean, showing varying degrees of convective bursts without
ever regaining sufficient momentum for redevelopment as a tropical
cyclone.
C. Damage and Casualties
------------------------
There were no casualties as a consequence of Evan and any damage
reported was inconsequential, being confined primarily to power loss
and flooding on Groote Eylandt. As Evan crossed Groote Eylandt, the
storm dumped a record 316 mm of rain on the island. The island's
previous 24-hour rainfall record was 158 mm. (Not a BoM source--from
EO Natural Hazards Website.)
Evan's main impact was to contribute further to the Australian Top
End's very much above-average wet season rainfall. The local media
reported that the Stuart Highway south of Katherine was closed for
several days due to these rains, and several businesses and homes
experienced localised flooding.
(Report written by Simon Clarke)
SUBTROPICAL STORM
2 - 5 March
-------------------------------------
A. Storm History
----------------
An unusual event was to unfold in the Coral Sea during the first
week of March, 2004, as a tropical LOW formed in the northern Coral Sea.
The LOW subsequently moved toward the south-central Queensland coast as
a hybrid system induced by a 500-hPa LOW near the Tropic of Capricorn.
This was not to be a typical tropical cyclone, but rather a sheared-type
hybrid with storm-force winds in its southern quadrant.
The first gale warning was issued by the Bureau of Meteorology,
Queensland, at 02/0648 UTC as a 1002-hPa tropical LOW near 14S/154E
slowly deepened in conjunction with a developing pressure gradient
associated with a large HIGH located over the Tasman Sea. By 03/0149
UTC, a complex area of low pressure with two centres had become
established in the Coral Sea with one LOW (1000 hPa) located near
14S/151E and another LOW (1002 hPa) located near 18S/159E.
These two LOWs gradually interacted with each other as a trough dug
southwards through the Coral Sea into the strong high-pressure system
to the south. Eventually a new 999-hPa low-pressure centre developed
on the trough line at 04/1334 UTC near 20.5S/157E (approximately 380 nm
northeast of Fraser Island). This LOW then commenced a southwestward
motion at approximately 22 kts while rapidly intensifying. Satellite
imagery at the time clearly showed a south to east bias in the upper-
level cloud structure, indicating a hybrid system with tropical
characteristics coupled to an upper-level system of more mid-latitude
characteristics.
At the time, Jeff Callaghan of the Bureau of Meteorology, Queensland,
explained to the local media that SSTs of around 28 C were fuelling the
storm and that it was being steered by an upper-level LOW centred near
Charleville, Queensland, giving the storm a fairly predictable south-
westerly path towards the Fraser Island area. Also at this time,
gales became established across the entire southern Coral Sea to
New Caledonia.
The subtropical storm was to remain a complex system and by 05/0600
UTC, the primary 994-hPa low was located near 23.0S/152.5E and moving
southwestward at about 20 kts, producing gales and storm-force winds in
the open east coast waters of Australia between Bowen and Coolangatta.
The storm eventually crossed the coast at approximately 05/0012 UTC in
the Hervey Bay area of southeast Queensland before tracking inland to
the west of Brisbane and dissipating soon thereafter.
In response to the serious nature of the storm, and in an unusual
move for Queensland, the emergency signal sirens normally assigned
exclusively to tropical cyclones were used in association with the
Bureau of Meteorology's Severe Weather Warnings issued for this sub-
tropical system as it approach the south Queensland coastline.
To add to this summary, the following comments are provided, courtesy
of Jeff Callaghan, in the following (slightly edited) insight:
"Dynamically this system was developing in a similar fashion to a
severe East Coast LOW except for the fact it was moving over waters
where the sea surface temperatures were 28 C. Often with these
systems QuikScat shows very tight circulations with at least storm-
force winds near the centre and gales right around the centre. If
this were to have happened we (i.e., BoM Brisbane) would have
considered naming it as a tropical cyclone. However, because of the
strong LOW near Willis Island, it developed as a very elongated system
with no tight focus, and as a result the strongest winds were well-
removed from the centre and so Severe Weather Warnings appeared to be
the way to go."
B. Meteorological Observations
------------------------------
Jeff Callaghan also provided the following detailed material with
respect to observations:
(1) Waves and Storm Surge
-------------------------
Very large long-period waves were generated by the storm. Waves with
significant wave heights of almost 6 m and maximum heights of almost
12 m were recorded on the Mooloolaba wave rider buoy around 0600 UTC on
5 March. On the buoy off Stradbroke Island the corresponding readings
were 7.1 m and 14.3 m around 05/0700 UTC, coming from the east-northeast.
The peak height measured on the Tweed Buoy was just over 14 m and this
occurred at 1700 UTC on 6 March, when the significant wave height was
between 5 and 6 metres. The wave periods were almost 13 seconds and
approached from the east-northeast.
Even in Moreton Bay a maximum wave height of over 3.5 metres was
measured around 1500 UTC on 5 March.
The worst effect from storm surge appears to have been in association
with the Friday night's high tide at Currumbin on the Gold Coast when
cars were floating around the car park. This was not a big tide (0.74 m
below the Highest Astronomical Tide--HAT) and therefore the wave effects
appear to have added over a metre to the tide.
Northeasterly gales in Moreton Bay early on Saturday raised the level
of the Bay 0.6 metres. The winds eased somewhat but still water levels
almost reached HAT on the 05/2347 UTC. This, combined with waves,
caused inundation of low-lying areas.
(2) Wind Observations
---------------------
Cape Moreton's (WMO 94594) strongest winds were at 05/0500 UTC--
130/56 knots (10-min mean) and peak gust 67 knots. Note these Almos
automatic weather stations (AWS) appear to have very low gust factors
compared with the old Dynes anemometers. Cape Moreton reported storm-
force winds from 0057 to 0530 UTC on 5 March.
Double Island Point (WMO 94584) also reported storm-force winds from
0130 to 0330 UTC on 5 March from the south-southeast. The maximum
10-minute mean wind was 49 knots.
The Gold Coast Seaway reported south-easterly gales from 0400 to 1000
UTC on the 5th with maximum gusts to 50 knots, followed by easterly gales
from 05/1230 to 1600 UTC.
Moreton Bay South (AWS) reported southeasterly gales from 0555 to
0718 UTC on 5 March with maximum gusts to 49 knots, followed by east-
northeasterly gales around 05/1500 UTC.
Moreton Bay Central (AWS) reported southeasterly gales from 0200 to
0728 UTC on 5 March with maximum gusts to 56 knots. Easterly gales were
felt from 05/0949 to 05/1217 UTC, then turning north-northeasterly from
05/1411 to 05/1530 UTC. Maximum gusts on the 5th were 51 knots.
Moreton Bay North (AWS) reported southeasterly gales from 0304 to
0630 UTC on 5 March with maximum gusts to 46 knots.
Redcliffe (AWS) reported south to southeasterly gales from 05/0300
to 05/0733 UTC with maximum gusts to 49 knots, followed by easterly
and northeasterly gales from 1400 to 1522 UTC.
Heron Island (AWS) reported gales from the south-southwest from 0035
to 0600 UTC on 5 March with maximum gusts to 49 knots.
Rundle Island (AWS) reported southerly gales from 04/2130 to 05/0200
UTC with maximum gusts to 50 knots.
Cato Island (WMO 94394) AWS reported southeasterly gales from 1300 to
1800 UTC on 4 March.
Frederick Reef (WMO 94393) AWS reported southeasterly gales from 0500
to 1500 UTC on the 4th with a maximum 10-minute mean wind of 39 knots.
Gannet Cay (WMO 94379) AWS reported south to southwesterly gales from
04/2200 to 05/0200 UTC with a maximum 10-minute mean wind of 42 knots.
(3) Rainfall Observations
-------------------------
Twenty-four hour rainfall totals from 04/2300 to 05/2300 UTC
include:
TOMEWIN 284.0 mm
SPRINGBROOK 259.0 mm
MALENY 239.0 mm
O'REILLYS ALERT 236.0 mm
TAMBORINE 226.0 mm
MT MEE 225.0 mm
MT GLORIOUS 221.6 mm
TALLEBUDGERA CK 197.0 mm
CANUNGRA 196.2 mm
HINZE DAM 194.0 mm
MT NEBO 190.6 mm
COOROY 182.6 mm
FERNY HILLS 180.0 mm
LAKE MANCHESTER 176.0 mm
BEERBURRUM 169.6 mm
STRATHPINE 169.0 mm
MORAYFIELD 164.2 mm
EUMUNDI 161.0 mm
WOODFORD 157.0 mm
HIGHVALE 155.2 mm
PETRIE 154.0 mm
MITCHELTON 150.0 mm
EVERTON HILLS 148.0 mm
REDCLIFFE 144.0 mm
SAMFORD 134.0 mm
C. Casualties and Damage
------------------------
To this end, up to 106,000 customers lost power during the passage
of the subtropical storm through the greater Brisbane Metropolitan area,
the Sunshine Coast, and the Gold Coast with tree and associated minor
structural damage reported throughout the area and extending into
northern New South Wales.
Tragically, at the time of reporting two casualties are known as a
consequence of the subtropical storm (with possibly another person
missing) with all of the deaths associated with drowning in flooded
waterways. Other damage reports from local State Emergency Service
included minor roof damage and sandbagging requests.
Police also reported some cars bogged in flooded roadways. The
Warrego Highway at Cunningham's Gap, to the west of Brisbane, was also
closed due to rockslides.
On a more positive note, the subtropical storm contributed to very
beneficial drought-breaking rainfalls over the southeastern half of
Queensland, significantly easing the persistent drought over the Gold
Coast region.
An excellent summary and satellite interpretation, including
unofficial comments of the event, can be found at:
http://www.drdisk.com.hk/seq04.htm>
(Report written by Simon Clarke with significant contributions by
Jeff Callaghan)
TROPICAL CYCLONE GRACE
(TC-19P / TD-07F)
18 - 24 March
------------------------------------------
A. Storm Origins
----------------
Grace is mostly remembered for its effects prior to reaching cyclone
status rather than during its life as an officially named tropical
cyclone.
A multi-centred tropical LOW formed adjacent to the north Queensland
tropical coast near Cooktown as early as 20 March within a very active
monsoon trough that stretched across the northern Coral Sea and Cape
York Peninsula in an exaggerated northwest to southeast band across
the Coral Sea toward New Caledonia. Over the ensuing days, the
northernmost circulation became dominant and initially commenced a
path toward the east and then southeast of the equatorward ridge. The
tropical LOW struggled to develop an upper-level structure under a
relatively unfavourable upper-level wind environment. With hindsight
the storm may well have been a hybrid system rather than a classic
tropical cyclone. Gales were forecast well to the north and south of
the centre. The definition of a tropical cyclone in WMO Region V
requires that gales be present near the centre; hence, the storm
remained unnamed until there was evidence of gale-force winds near the
tropical LOW's centre.
However, by 21/1820 UTC the Bureau of Meteorology, Queensland,
deemed that the central circulation had consolidated sufficiently
enough to qualify as the second named tropical cyclone of Queensland's
2003/2004 season: Grace.
B. Storm History
----------------
Tropical Cyclone Grace formed in the open ocean near 20.0S/155.0E
(or approximately 330 nautical miles east-northeast of Mackay). At
this time Grace had a CP of 988 hPa and was moving toward the southeast
at 15 to 20 knots. This general motion was to continue for the
remainder of the cyclone's life. Grace peaked in intensity at 985 hPa
with a MSW of 50 knots (10-min mean) while centred near 20.3S/155.9E at
22/0000 UTC. This intensity was maintained for approximately 6 hours.
Thereafter, Grace began to undergo extratropical transition with an
increasingly asymmetric wind field due to a squeeze with a surface ridge
to the south. A vertical circulation remained present in the low levels
but was sheared away above 500 hPa by a 30 to 50-knot northwesterly
flow.
Grace rapidly lost its entire upper-level structure and was
downgraded at 23/1800 UTC from tropical cyclone status (by the TCWC
at Nadi, Fiji) when located approximately about 400 nautical miles
east-northeast of Sandy Cape (23.6S/162.3E). The remnant surface wind
field of the system meandered to the east and then to the east-northeast
over the following days, producing a very broad area of gales to its
south through the Tasman Sea. Fiji continued to issue warnings on
ex-tropical cyclone Grace for 24 hours in the event that it should
redevelop. However, after 24/1800 UTC, general gale warnings were
issued for a few more days for the extratropical remnants of Grace.
C. Meteorological Observations
-------------------------------
Many thanks to Jeff Callaghan at the Bureau of Meteorology, Brisbane,
for the following observations, summarised within this report:
(1) NORTH QUEENSLAND OBSERVATIONS
---------------------------------
(a) Rainfall
------------
Selected rainfall amounts from 2300 UTC 16 March to 2300 UTC
19 March (all amounts in mm):
Locataion To 18 March To 19 March To 20 March Total
--------------------------------------------------------------------
Tully-Saddle Mtn. Alert 163.0 201.0 231.0 595.0
Copperlode Dam Alert 163.0 256.0 222.0 641.0
Topaz 156.0 231.0 372.0 759.0
Daintree Tea 151.0 203.0 282.0 636.0
Mt. Sophia 150.0 222.0 279.0 651.0
Port Douglas 149.0 138.0 166.0 453.0
Bartle View Alert 147.0 147.0 248.0 542.0
Kuranda Qld 139.0 232.0 195.0 566.0
Babinda 128.0 224.0 334.0 686.0
Myola Alert 123.0 160.0 172.0 455.0
Cairns 116.0 178.0 162.0 456.0
(b) Storm Surge Observations
----------------------------
A 0.4 m storm surge was recorded at Cooktown on the morning high
tide (0.3 m above HAT) on 19 March. Many boats were upturned in the
harbour and washed away.
A 0.2 m storm surge was recorded at Cairns on the morning high tide
(just above HAT) on 19 March and a 0.3 m storm surge on the morning high
tide (at HAT) on 20 March. This caused the flooding around the northern
beach suburbs to build up and required the closing of some roads.
A 0.55 m storm surge was recorded at Clump Point on 20 March, and the
HAT was exceeded with a storm surge of 0.45 m at Lucinda on 20 March.
(c) Wind Observations
---------------------
The strongest winds from Green Island AWS recorded on 18 March
were:
1220 UTC 130/37, G. 47 KTS
1230 UTC 120/41, G. 49 KTS
1300 UTC 120/37, G. 42 KTS
2000 UTC 130/38, G. 42 KTS
and on 19 March 2004:
1900 UTC 140/41, G. 47 KTS
1930 UTC 140/37, G. 43 KTS
2000 UTC 140/38, G. 43 KTS
and on 20 March 2004:
0300 UTC 160/37, G. 43 KTS
0330 UTC 150/40, G. 46 KTS
0400 UTC 160/39, G. 46 KTS
0630 UTC 170/38, G. 45 KTS
0900 UTC 170/38, G. 45 KTS
1130 UTC 180/37, G. 42 KTS
The strongest winds from:
Low Isle AWS at 18 March 2004 LWI 1311 UTC 140/39, G. 50 KTS
Bougainville Reef AWS at 20 March 2004 1900 UTC 220/32 KTS, 996.2 hPa
Holmes Reef AWS at 18 March 2004 0700 UTC 100/31 KTS, 999.8 hPa;
at 20 March 2004 1900 UTC 180/32 KTS, 994.5 hPa;
at 20 March 2004 2000 UTC 190/32 KTS, 996.0 hPa
Flinders Reef at 19 March 2004 1200 UTC 120/35 KTS, 999.5 hPa;
at 19 March 2004 1900 UTC 180/32 KTS, 994.9 hPa
(2) SOUTH QUEENSLAND OBSERVATIONS
---------------------------------
(a) Reef Wind Observations
--------------------------
Frederick Reef observations:
21/1200 UTC 140/36 knots MSLP 997.4 hPa
21/1300 UTC 140/34 knots MSLP 997.6 hPa
21/1400 UTC 140/37 knots MSLP 996.1 hPa
21/1500 UTC 140/43 knots MSLP 993.9 hPa
21/1600 UTC 140/40 knots MSLP 993.0 hPa
21/1700 UTC 150/40 knots MSLP 992.9 hPa
21/1800 UTC 130/41 knots MSLP 993.7 hPa
21/1900 UTC 140/45 knots MSLP 992.2 hPa
21/2000 UTC 130/43 knots MSLP 992.8 hPa
21/2100 UTC 130/43 knots MSLP 992.2 hPa
21/2200 UTC 130/44 knots MSLP 993.0 hPa
21/2000 UTC 130/43 knots MSLP 992.8 hPa
21/2300 UTC 130/46 knots MSLP 992.0 hPa
(AWS then failed)
(b) Island Observations
-----------------------
Heron Island:
22 March 2004 0801 UTC 180/35, G. 46 knots, and 0815 UTC 180/37,
G. 48 knots
Rundle Island:
21 March 2004 1730 UTC 170/34, G. 41 knots; 1800 UTC 170/35,
G. 39 knots; and 1830 UTC 170/34, G. 39 knots
(c) Coastal Wind Observations
-----------------------------
Cape Moreton - 21 March 2004 2230 UTC 140/45, G. 54 knots
Double Island Point - 22 March 2004 0330 UTC 160/41, G. 51 knots
(d) Waves
---------
On 24 March 2004, the wave rider buoys near Brisbane had the
significant wave height increasing to 4.8 metres (maximum heights to
9 metres) from the northeast. The main wind field offshore was from
the southeast or east-southeast, indicating that the swell arriving
here was subject to angular spreading and weakening. This is an
indication of the vast area of gales out to sea during the previous
24-hour period.
Beaches on the Gold Coast reported waves surging up through
vegetated dune areas on 24 March, with vertical scarping of up to
1.0-2.0 m in many places along the open beaches.
D. Damage and Casualties
------------------------
During its formative stages and due to its proximity to the coastline,
the initial tropical low-pressure complex that eventually consolidated
into Tropical Cyclone Grace caused widespread flooding and damage to
roads and property along the far north Queensland coast, mainly between
Cooktown and Cairns. Winds and waves brought tide levels above the
highest tides of the year (HAT) and this was particularly evident at
Cooktown. Floodwaters closed all major roads into Cairns.
In addition, a large section of one lane of the Captain Cook Highway
north of Cairns collapsed after a landslide consisting of nearly 20
metres of rock and boulders the size of cars destroyed the ocean-side
road. The scenic coastal highway and link between Cairns and Port
Douglas was closed for several days. Residents were evacuated from
the Whitfield range area due to landslides.
An estimated $20,000,000 (US) damage to the Cairns region is
attributed to pre-cyclone Grace. There were no casualties associated
with Tropical Cyclone Grace. However, the State Emergency Services (SES)
reported that impatient drivers were ignoring road closures. Several
roads were closed, including the Bruce Highway south of Cairns, where
the Tully River was in flood. On Saturday (19 March), SES workers were
rescuing motorists who had driven around the closure signs only to be
swept from the roads. Also, a man was rescued clinging to the roof of
his car in floodwaters north of Cairns after being trapped there for four
hours. Ergon Energy reported that more than 350 properties were without
power for some time as crews were unable to get access to repairs, a
problem caused mainly by fallen trees. However, there was no significant
damage to the overall network.
In combination with a strong high-pressure ridge to its south, Grace
produced a large area of gales and high seas in a broad swath across
the Coral Sea, particularly south of the St. Lawrence area. Large
swells battered the coast, forcing the closure of some Sunshine Coast
beaches. On 23 March a helicopter and coastguard rescued a stricken
craft near the Gold Cost Seaway. Following shortly after the South
Queensland subtropical hybrid (see separate report) some two weeks
earlier, Grace exacerbated significant coastal erosion along the
South Queensland and Northern New South Wales coastlines. Sandbagging
was required to protect the Currumbin Surf lifesaving club at high tide.
On a lighter note, experienced surfboard riders reported having a
'field day'.
Following the loss of tropical cyclone status, the remains of Grace
continue to have an impact. In New Caledonia, further strong winds,
heavy rains and flooding were experienced. A massive oil slick
threatened a popular tourist beach in New Caledonia. Officials in
the French Pacific territory put up barriers around the island of
Amedee, which was threatened by a toxic oil slick, estimated to cover
an area of 20 square kilometres. They said the oil had come from a
boat wrecked several decades ago on a coral reef off South Province.
F. Further Information/Weblinks
-------------------------------
A satellite shot of Grace can be found at:
http://earthobservatory.nasa.gov/NaturalHazards/natural_hazards_
v2.php3?img_id=12022>
G. Post-Note
------------
It is evident that the local media had grasped the name 'Grace' long
before a named cyclone was actually a fact. This might be due to its
destructive effects on the Queensland coastline prior to official naming,
which occurred when the storm was well out to sea and moving away from
the coast.
(Report written by Simon Clarke with significant contributions from
Jeff Callaghan)
*************************************************************************
SOUTH PACIFIC (SPA) - South Pacific Ocean East of Longitude 160E
Activity for March: 3 tropical depressions
1 tropical cyclone **
** - System formed west of 160E and moved into basin
South Pacific Tropical Activity for March
-----------------------------------------
No tropical cyclones graced the waters of the South Pacific east of
160E during March except for Grace (pun intended!), which moved into
Fiji's AOR from the Australian Region shortly before becoming extra-
tropical. (The report on Grace can be found above.) However, there
were a few tropical depressions which deserve mention. The first of
these was designated Tropical Depression 06F by Nadi. TD-06F was
first classified as a depression at 2100 UTC on 20 March when it was
located roughly 225 nm west-southwest of Port Vila, Vanuatu. The
system drifted generally southeastward over the next couple of days,
and the final bulletin at 22/1800 UTC placed the center approximately
475 nm south-southeast of Port Vila. Winds near the center were never
estimated greater than 25 kts, but there were peripheral gales reported
well to the south and east of the centre. Some of the islands of
Vanuatu experienced heavy rains and strong, gusty winds during the
passage of TD-06F. Natural disaster chaser Geoff Mackley from New
Zealand was on the island of Ambrym at the time filming the volcanoes
on the island. Heavy weather from the tropical LOW wreaked havoc on
Geoff's expedition, blowing down tents and damaging other equipment.
An interesting account of the team's woes can be found at the following
URL:
http://www.rambocam.com/archive/marum.html>
A weak tropical depression was analyzed at 1800 UTC on 28 March about
125 nm northeast of Fiji, or near 17S/180E. A QuikScat pass had
indicated winds of 30-40 kts under convection several degrees north of
the center, but these winds were believed to be overestimated due to
rain effects, and were also not corroborated by surface observations.
This LOW drifted southeastward and the final reference to it was in the
Tropical Disturbance Summary issued at 19/0600 UTC when it was located
near 19S/178W. No "F-number" was assigned to this weak depression, and
no track was given in the companion global tropical cyclone tracks file.
Another highly-sheared system formed on 30 March to the southeast of
Tonga. This LOW was designated Tropical Depression 08F, and like TD-06F,
had fairly weak winds near the center on the order of 15-25 kts, but
generated gales well to the south and southwest of the center. TD-08F
was diffuse and difficult to track, experiencing two significant
relocations. By 0600 UTC on 1 April the LOW was becoming extratropical
roughly 175 nm west-southwest of Rarotonga and was dropped from Nadi's
tropical weather outlooks.
*************************************************************************
EXTRA FEATURE
In order to shorten the amount of typing in preparing the narrative
material, I have been in the habit of freely using abbreviations and
acronyms. I have tried to define most of these with the first usage
in a given summary, but I may have missed one now and then. Most of
these are probably understood by a majority of readers but perhaps a
few aren't clear to some. To remedy this I developed a Glossary of
Abbreviations and Acronyms which I first included in the July, 1998
summary. I don't normally include the Glossary in most months in
order to help keep them from being too long. If anyone would like to
receive a copy of the Glossary, please e-mail me and I'll be happy
to send them a copy.
*************************************************************************
AUTHOR'S NOTE: This summary should be considered a very preliminary
overview of the tropical cyclones that occur in each month. The cyclone
tracks (provided separately) will generally be based upon operational
warnings issued by the various tropical cyclone warning centers. The
information contained therein may differ somewhat from the tracking and
intensity information obtained from a "best-track" file which is based
on a detailed post-seasonal analysis of all available data. Information
on where to find official "best-track" files from the various warning
centers will be passed along from time to time.
The track files are not being sent via e-mail. They can be retrieved
from the archive sites listed below. (Note: I do have a limited e-mail
distribution list for the track files. If anyone wishes to receive
these via e-mail, please send me a message.)
Both the summaries and the track files are standard text files
created in DOS editor. Download to disk and use a viewer such as
Notepad or DOS editor to view the files.
The first summary in this series covered the month of October,
1997. Back issues can be obtained from the following websites
(courtesy of Michael Bath, Michael V. Padua, Michael Pitt, and
Chris Landsea):
http://australiasevereweather.com/cyclones/>
http://www.typhoon2000.ph>
http://mpittweather.com>
ftp:// ftp.aoml.noaa.gov/hrd/pub/landsea/padgett/>
Another website where much information about tropical cyclones may
be found is the website for the UK Meteorological Office. Their site
contains a lot of statistical information about tropical cyclones
globally on a monthly basis. The URL is:
http://www.met-office.gov.uk/sec2/sec2cyclone/sec2cyclone.html>
TROPICAL CYCLONE REPORTS AVAILABLE
JTWC now has available on its website the complete Annual Tropical
Cyclone Report (ATCR) for 2002 (2001-2002 season for the Southern
Hemisphere). ATCRs for earlier years are available also. The report
for the 2002-2003 Southern Hemisphere season has also recently been
added.
The URL is: http://199.10.200.33/jtwc.html>
Also, TPC/NHC has available on its webpage nice "technicolor"
tracking charts for the 2003 Atlantic and Eastern North Pacific
tropical cyclones; also, storm reports for all the 2003 Atlantic
and Eastern North Pacific cyclones are now available, as well as
track charts and reports on storms from earlier years.
The URL is: http://www.nhc.noaa.gov>
A special thanks to Michael Bath of McLeans Ridges, New South Wales,
Australia, for assisting me with proofreading the summaries.
PREPARED BY
Gary Padgett
E-mail: [email protected]
Phone: 334-222-5327
Kevin Boyle (Eastern Atlantic, Western Northwest Pacific, South
China Sea)
E-mail: [email protected]
Huang Chunliang (Assistance with Western Northwest Pacific, South
China Sea)
E-mail: [email protected]
Simon Clarke (Northeast Australia/Coral Sea, South Pacific)
E-mail: [email protected]
*************************************************************************
*************************************************************************
|
Document: summ0403.htm
Updated: 26th October 2006 |
[Australian Severe Weather index] [Copyright Notice] [Email Contacts] [Search This Site] |