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Monthly Global Tropical Cyclone Summary March 2002
[Summaries and Track Data] [Prepared by Gary Padgett]
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Monthly Global Tropical Cyclone Summary March 2002 [Summaries and Track Data] [Prepared by Gary Padgett] |
MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY
MARCH, 2002
(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
--> Very intense tropical cyclone brushes Madagascar
--> First Northwest Pacific March super typhoon on record forms
--> Very quiet month in Australian Region
*************************************************************************
***** Feature of the Month for March *****
Tables of Monthly Net Tropical Cyclone Activity (NTC)
The idea for these tables originated with Eric Blake's tropical
cyclone forecast for the month of August, 2000, included in the
August update to the CSU 2000 Atlantic seasonal forecast. Eric
made reference to the percentage of the total NTC which was normally
contributed by the month of August, so I became interested in
calculating such a figure for all the months for the Atlantic and
Northeast Pacific (NEP) basins. (NOTE: I included these same tables
as a Feature of the Month in the March, 2001 summary. Here I have
just updated them through 2001, primarily to reflect the abnormally
active latter two months of the 2001 Atlantic hurricane season.)
In the discussion and in the tables, the following abbreviations
are used. These are the same ones used by Dr. Bill Gray and the
CSU forecast team, and the complete definitions can be found on
the CSU website in any of the Atlantic seasonal forecasts archived
there: http://tropical.atmos.colostate.edu/forecasts/>
NS - named storm (MSW > 33 kts, whether actually named or not)
H - hurricane (MSW > 63 kts)
IH - intense hurricane (MSW > 95 kts)
NSD - named storm day
HD - hurricane day
IHD - intense hurricane day
NTC - net tropical cyclone activity (avg of other 6 parameters)
For the Atlantic statistics I used the period 1950-2001. Even
though aerial reconnaissance of Atlantic cyclones began in 1944,
I began with 1950 since that year is the beginning point of Dr. Gray's
and the CSU forecast team's NTC calculations. For the NEP basin I
utilized the period 1971-2001. Extensive aerial reconnaissance of
these cyclones was performed during the 1971-1973 seasons before
being curtailed following the Arab oil embargo of late 1973. By 1974
the first edition of the Dvorak method had been developed and was
beginning to be used, so the MSW values can be considered somewhat
reliable from that point onward.
Calculating overall seasonal statistics for a tropical cyclone
basin presents no problem, but when dissecting a season temporally
some decisions have to be made. Some definitions and procedures I
followed include:
(1) A month was defined as beginning at 0000Z on the 1st day of the
month and ending at 1800Z on the final day of the month.
(2) The "days" parameters (NSD, HD, IHD) were accumulated for each
exact month per the definition in (1) above. A given storm or
hurricane day was counted in only one month--the month of origin had
no bearing on these parameters.
(3) The other main issue was how to count intermonthly cyclones for
the NS, H, and IH tallies. I decided that a given storm/category
should count in only one month; i.e., when the monthly totals are
added up, they should equal the totals for the season. For the NS
parameter a storm is counted in the month in which winds initially
reached 34 kts (or higher) and the storm type was tropical. A
similar procedure was used for the H and IH parameters. Admittedly
this can lead to some unusual-looking statistics at times. For
instance, Major Hurricane Keith of 2000 was named on 29 September,
reached hurricane intensity on 30 September, and winds reached 100 kts
at 0000Z on 1 October. Therefore, Keith is counted as a September
NS and H, but as an October IH. Similarly, Major Hurricane Opal of
1995 is counted as a September NS, but as an October H and IH.
Northeast Pacific Hurricane Ekeka in 1992 is counted as a January NS
and H but as a February IH. Since no other tropical cyclones
occurred in February during the period under consideration, February
is shown as having no NS or H but one IH. Similarly, in the Atlantic
basin, no cyclones began in January, but the month nonetheless has
some NTC due to Hurricane Alice, which originated and reached
hurricane intensity in December, 1954, but remained active until
5 January, 1955.
Another issue which needed to be addressed was the well-known
upward bias in Best Track MSW values for the Atlantic basin prior to
around 1970. Following the rule which Chris Landsea gave me years
ago, for the years 1950-1970, any MSW value of 100-115 kts was reduced
by 5 kts. Any MSW value of 120 kts or greater was reduced by 10 kts.
However, there were a few cases where I excepted this rule based upon
normal maximum wind/minimum pressure relationships--Carol of 1953,
Janet of 1955, Hattie of 1961, Camille of 1969--to name a few. Also,
I upped the MSW for Hurricanes Daisy and Helene of 1958 based upon the
central pressures and the MSW as given by Dunn & Miller in _Atlantic
Hurricanes_. It should be mentioned that there are quite likely some
MSW biases in the NEP Best Track file, but I did not attempt to correct
any of these as I had no guidance for doing so.
One final item--the various statistics for the NEP basin include
all systems which reached the various intensity levels east of
longitude 180, but the "days" parameters are accumulated only for the
time which a given system spent east of 180. A system which began east
of 180 but reached H or IH intensity west of 180 is counted only as a
NS (e.g., Paka of 1997). This is just my preference--there are other
methodologies which are equally valid. The Central North Pacific
(CNP) between 140W and 180 has such a low incidence of tropical cyclone
activity, especially formations, that it is difficult to consider it as
a separate basin. A majority of the NTC in the CNP is generated by
storms originating east of 140W, and while most tropical cyclones
originating in the CNP do not affect Hawaii, the two destructive
Hawaiian hurricanes of the past three decades (Iwa and Iniki) reached
tropical storm intensity in the CNP and shouldn't be ignored. On the
other hand, I did not want to skew NEP basin statistics by including
the NWP portions of such storms as Ruby of 1972 and Oliwa and Paka of
1997 which formed just east of the Dateline but went on to become long-
lived and/or very intense typhoons in the NWP basin.
Atlantic Basin Monthly NTC Table
--------------------------------
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 0 0 0 0.00 0.00 0.00 0.00
MAY 5 2 0 18.50 6.25 0.00 0.47
JUN 27 10 2 72.25 13.25 0.75 2.39
JUL 41 17 1 121.25 32.25 0.50 3.64
AUG 138 79 30 613.50 296.50 63.25 24.80
SEP 177 125 65 1134.50 643.50 155.25 47.15
OCT 87 57 17 464.25 229.50 39.00 16.76
NOV 27 20 4 126.75 46.00 6.25 4.33
DEC 3 2 0 12.75 3.75 0.00 0.34
TOTAL 506 312 119 2569.75 1274.50 265.00
AVG 9.73 6.00 2.29 49.42 24.51 5.10
Northeast Pacific Basin Monthly NTC Table
-----------------------------------------
Month NS H IH NSD HD IHD NTC
JAN 1 1 0 3.25 2.00 0.00 0.15
FEB 0 0 1 3.00 2.25 0.50 0.21
MAR 1 0 0 1.00 0.00 0.00 0.04
APR 0 0 0 0.00 0.00 0.00 0.00
MAY 15 8 1 49.75 14.00 2.25 1.80
JUN 67 36 14 249.25 93.25 26.00 10.87
JUL 117 63 35 511.50 228.50 72.00 23.51
AUG 122 74 34 643.25 258.75 58.99 24.78
SEP 111 69 35 537.75 259.75 77.00 24.67
OCT 61 35 19 288.00 132.75 39.00 12.94
NOV 11 3 0 31.00 5.75 0.00 0.85
DEC 2 1 0 7.50 1.00 0.00 0.19
TOTAL 508 290 139 2325.25 998.00 274.75
AVG 16.39 9.35 4.48 75.01 32.19 8.86
The differences between the two basins in the seasonal pattern of
activity are striking. The Atlantic season is sharply-peaked with
almost half of the NTC occurring in the month of September alone; the
three-month period of August through October accounts for almost 90%
of the annual NTC. By way of contrast, the Northeast Pacific basin's
seasonal pattern of activity does not reach such a sharp peak, but
exhibits a plauteauing of NTC over the months of July, August, and
September with each month contributing about 25% of the annual NTC.
June and October make up the majority of the remaining amount.
One interesting and somewhat surprising fact apparent in the
Atlantic NTC table is that November has a higher level of activity
than July. November lags behind July in number of named storms, the
parameter usually used to judge activity, but has (at least in recent
decades) seen considerably more hurricane and intense hurricane
activity. Atlantic intense hurricanes are almost always confined to
the peak months of August, September and October, the only exceptions
during the previous half-century being:
June - Audrey (1957), Alma (1966)
July - Bertha (1996)
November - Greta (1956), Kate (1985), Lenny (1999), Michelle (2001)
NOTE: As time permits I plan to try to work up similar NTC tables for
the other tropical cyclone basins, so stay tuned.
*************************************************************************
ACTIVITY BY BASINS
ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico
Activity for March: No tropical cyclones
*************************************************************************
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 depression
1 super typhoon
Sources of Information
----------------------
Most of the information presented below is based upon tropical
cyclone warnings and significant tropical weather outlooks issued
by the Joint Typhoon Warning Center of the U. S. Air Force and
Navy (JTWC), located at Pearl Harbor, Hawaii. In the companion
tropical cyclone tracks file, I normally annotate track coordinates
from some of the various Asian warning centers when their center
positions differ from JTWC's by usually 40-50 nm or more. All
references to sustained winds imply a 1-minute averaging period
unless otherwise noted.
Michael V. Padua of Naga City in the Philippines, owner of the
Typhoon 2000 website, normally sends me cyclone tracks based upon
warnings issued by the Japanese Meteorological Agency (JMA) and the
Philippines' Atmospheric, Geophysical & Astronomical Services
Administration (PAGASA). Also, Huang Chunliang of Fuzhou City, China,
sends me each month tracks obtained from warnings issued by the
National Meteorological Center of China (NMCC), the Central Weather
Bureau of Taiwan (CWBT) and the Hong Kong Observatory (HKO). A very
special thanks to Michael and Chunliang for the assistance they so
reliably provide.
In the title line for each storm I have referenced all the cyclone
names/numbers I have available: JTWC's depression number, the
JMA-assigned name (if any), JMA's tropical storm numeric designator,
and PAGASA's name for systems forming in or passing through their
area of warning responsibility.
Northwest Pacific Tropical Activity for March
---------------------------------------------
A tropical depression which formed in late February west-southwest of
Pohnpei intensified and was christened Tropical Storm Mitag on the final
day of the month. Mitag subsequently strengthened into a typhoon, passed
very near Yap, then strengthened into a super typhoon as it recurved a
few hundred miles east of the Philippines--the first super typhoon on
record for the month of March, at least dating back to 1959.
The only other system during the month was Tropical Depression 03W,
which was named Caloy by PAGASA (a nickname for 'Carlos'). Like so many
tropical cyclones in recent months in both hemispheres, this system
formed at a very low latitude--well south of 10N. The first JTWC warning
on TD-03W, issued at 1200 UTC on 19 March, placed the center about 70 nm
west-southwest of Palau, or approximately 500 nm east-southeast of the
city of Surigao on the northern tip of Mindanao. TD-03W/Caloy moved
westward toward Mindanao. As it approached the island on the 21st, the
center turned toward the west-northwest, crossing Mindanao and the
islands of Bohol, Cebu, Negros and Panay before traversing the Sulu Sea
and clipping the northern tip of Palawan as it exited into the South
China Sea. After crossing the Philippine Archipelago, TD-03W/Caloy
meandered generally west-northwestward across the South China Sea,
weakening and dissipating off the Vietnamese coast about 330 nm east-
southeast of Hue City by 25/1200 UTC.
Heavy rains from the depression were responsible for damage and some
fatalities on Mindanao. A press report forwarded to me by Michael V.
Padua states that 28 persons were killed with two others reported miss-
ing in the two Surigao Provinces. The worst-hit area was Surigao del
Sur where the majority of the fatalities, mostly minors, occurred. Most
died from drowning, or were buried alive in a landslide in Barangay Libus
Sud in the town of San Miguel. More than 50,000 people in the two
Surigao Provinces were displaced by flash floods. Damage to infra-
structure, agriculture, fisheries and livestock amounted to more than
90 million pesos ($1.764 million US). (The above information was taken
from an article by Mr. Ben Serrano which appeared in the Philippine Daily
Inquirer on 28 March 2002--thanks to Michael for sending it to me.)
SUPER TYPHOON MITAG
(TC-02W / TY 0202 / Basyang)
26 February - 8 March
------------------------------------------------
Mitag: contributed by the Federated States of Micronesia, is a Yapese
woman's name meaning "my eyes"
A. Storm Origins
----------------
A weak LLCC developed just south of Pohnpei on 25 February. A STWO
issued by JTWC at 1200 UTC noted that a recent QuikScat pass had revealed
a weak LLCC embedded in a broad trough with poorly-organized convection.
The LOW was situated beneath weak diffluent flow aloft in a region of
moderate vertical shear. The system continued to drift westward and by
0600 UTC on the 26th was located approximately 260 nm south-southwest of
Pohnpei. Convection had increased in organization near the LLCC so JTWC
upgraded the development potential to fair. A TCFA was issued at 1430
UTC and the first warning on Tropical Depression 02W was issued at 1800
UTC. The depression's center was located approximately 155 nm west-
southwest of Pohnpei--a relocation to the north from the position at
0600 UTC--and moving west-northwestward at 4 kts.
JTWC upgraded the depression to tropical storm status on the third
warning, issued at 27/0600 UTC, based on CI estimates of 25 and 30 kts
and some synoptic data. Tropical Storm 02W was then centered about
200 nm east-southeast of Chuuk, moving slowly west-northwestward as it
was steered by a low to mid-level ridge to the north. A 27/0948 UTC
SSM/I pass indicated that the center was partially-exposed with the deep
convection sheared west of the LLCC. The cyclone continued trekking in
the general direction of Chuuk with little change in intensity for the
next 24 hours. By 1200 UTC on 28 February the center was located only
around 15-20 nm southeast of Chuuk, moving westward at 11 kts, and CI
estimates had risen to 35 and 45 kts. JTWC upped the MSW to 40 kts, and
JMA and NMCC both upgraded the system to tropical storm status with JMA
assigning the name Mitag.
B. Track and Intensity History
------------------------------
At 28/1800 UTC Tropical Storm Mitag was located about 525 nm southeast
of Guam, moving westward at 9 kts with an estimated MSW of 45 kts. The
cyclone continued its westward motion on 1 March, steered by the mid-
level ridge in the Philippine Sea along latitude 19N. JTWC upgraded
Mitag to a 70-kt typhoon at 0600 UTC based on CI estimates of 65 kts.
The storm had earlier been undergoing some easterly shear, but a tightly-
curved banding feature had become evident in satellite imagery, accom-
panied by cycling bursts of deep convection. By 1800 UTC Typhoon Mitag
had reached a point 395 nm south of Guam, still tracking westward at
15 kts with the MSW pegged at 70 kts. At 0600 UTC on 2 March the storm
was located roughly 300 nm east-southeast of Yap and had turned to more
of a west-northwesterly heading. JTWC bumped up the intensity to 75 kts
while JMA and NMCC upgraded Mitag to typhoon status. A developing band-
ing eye feature had become evident by 1200 UTC, and at 1800 UTC, JTWC
increased the intensity to 100 kts. Typhoon Mitag at 1800 UTC was cen-
tered about 95 nm southeast of Yap and was moving west-northwestward at
a rather quick 17 kts.
The eye of Mitag passed a short distance to the south of Yap late on
2 March (UTC) and at 0000 UTC on the 3rd was centered about 40 nm south-
southwest of the island. A 02/2337 UTC SSM/I pass depicted a large round
eye 60 nm in diameter while water vapor imagery showed excellent outflow
in all quadrants. Synoptic observations from Yap indicated 30-kt sus-
tained surface winds with 76-kt easterly winds at an elevation of 300 m.
Mitag's intensity fluctuated somewhat on the 3rd but remained near
100 kts, based on CI estimates of 90 and 102 kts. JTWC increased the
MSW slightly to 105 kts at 1800 UTC with the typhoon centered about
480 nm east-northeast of the island of Mindanao, still moving west-
northwestward. As the 4th progressed the western extension of the
ridge to the north of Mitag eroded, resulting in a more northwesterly
track. JTWC upped the estimated MSW to 115 kts at 04/0000 UTC, based
on CI estimates of 115 kts. Visible animation depicted an irregular
eye 29 nm in diameter with colder cloud tops located over the western
quadrant. At 1200 UTC Typhoon Mitag was located approximately 370 nm
east of Samar island, moving northwestward at 7 kts. A 04/0929 UTC SSM/I
pass revealed that an eyewall replacement cycle was nearing completion
with bands of deep convection surrounding the eye. By 1800 UTC the
system was approaching the upper-level ridge axis, and one CI estimate
had reached 127 kts, although the MSW remained at 115 kts for the 1800
UTC warning. JMA's 10-min avg MSW at the time was 85 kts while NMCC's
estimate was 100 kts.
Around 0000 UTC on 5 March it appeared that Mitag had peaked at
115 kts and would likely slowly weaken. The JTWC warning for 05/0000 UTC
indicated that the system was beginning to experience some shear as it
entered upper-level westerlies to the north. However, by 0600 UTC Dvorak
estimates had reached T7.0 and JTWC correspondingly upped the MSW to
140 kts, making Mitag the first March super typhoon on record. The
storm was located about 330 nm east of Catanduanes Island at the time
and had turned to a northward course. NMCC and JMA increased their
10-min avg MSW estimates to the peak values of 110 kts and 95 kts, res-
pectively, at 0600 UTC (with PAGASA following suit at 1200 UTC). The
minimum central pressure for Mitag was estimated at 930 mb by JMA. It
appears that the reason for Mitag's unexpected intensification was that
the upper-level southwesterlies which had initially begun to impinge on
the storm retreated somewhat to the north, thereby enhancing the
typhoon's poleward outflow channel. A SSM/I pass around 1200 UTC
revealed a 25-nm diameter eye surrounded by a solid ring of deep convec-
tion. At its peak Super Typhoon Mitag was a fairly large typhoon. Gales
extended outward from the center 200 nm in the northern semicircle and
160 nm to the south, while the radius of storm-force winds was estimated
at 70 nm.
Mitag began to slowly weaken on the 6th. JTWC decreased the MSW to
130 kts at 0000 UTC, and to 125 kts at 0600 UTC. The typhoon was then
located about 375 nm east-northeast of Catanduanes Island, moving north-
northeastward at 7 kts. A low to mid-level ridge east of the storm was
still the primary steering influence, but was receding and Mitag was
becoming embedded in strong mid-level westerlies associated with an
approaching mid-latitude trough. Satellite CI estimates were still
127 kts at 1800 UTC, but JTWC dropped the intensity to 115 kts in antici-
pation of rapid weakening as the storm entered a region of strong vert-
ical shear. Typhoon Mitag did begin to weaken rapidly on 7 March. From
06/1800 UTC to 07/1800 UTC, the estimated MSW fell from 115 kts to
55 kts, and 24 hours later the storm had dissipated.
Mitag was moving east-northeastward at 9 kts at 0000 UTC on 7 March
with winds down to 95 kts. The storm continued to quickly weaken and
at 1800 UTC, JTWC downgraded Mitag to a 55-kt tropical storm located
about 515 nm southwest of Iwo Jima. The storm's motion had become more
easterly during the day, and the system was forecast to turn sharply to
the south in response to strong monsoon northeasterlies associated with
a high-pressure system located over the East China Sea. By 08/0000 UTC
Mitag's center was fully-exposed with remaining deep convection sheared
90 nm to the northeast. JTWC issued the final warning on Mitag at 0600
UTC, downgrading it to a 25-kt depression. The dying storm was centered
approximately 150 nm south of Parece Vela Island in the Philippine Sea,
moving southward at 6 kts. The LLCC was completely decoupled from the
upper-levels and was located roughly 125 nm southwest of the remaining
deep convection. Cool, drier air had entered the system, leading to
further weakening. JMA was still classifying Mitag as a 40-kt tropical
storm at this point, likely due to a recent QuikScat pass which had indi-
cated some gales in the northwest quadrant associated with the monsoon
surge. However, six hours later JMA downgraded Mitag to a depression and
discontinued bulletins.
C. Comparisons Between JTWC and Other Centers
---------------------------------------------
During Mitag's pre-typhoon and early typhoon stages, and during the
rapid decay phase, intensity estimates from the various warning centers
agreed rather well after conversion to the same time averaging period.
JTWC's intensity of 100 kts on the 2nd and 3rd as the storm passed Yap
is somewhat above the equivalent 1-min avg MSW implied by JMA's and
NMCC's 10-min avg MSW estimates. During the time of Mitag's peak inten-
sity on 5 March, NMCC's maximum 10-min avg MSW of 110 kts was reasonably
close to JTWC's peak of 140 kts. JMA's and PAGASA's peak intensity
estimates of 95 kts, however, are well under JTWC's peak, being equiv-
alent to a 1-min avg MSW of about 110 kts.
D. Damage and Casualties
------------------------
No deaths or serious injuries were reported on Yap, but destructive
winds and a tidal surge destroyed nearly all the food crops in low-lying
areas in the northern, northeastern, and southern parts of Yap Main
Island up to 400-500 metres inland. The tidal surge put many low-lying
areas, including parts of the main town of Colonia, under water for
several hours. Rumung Island, just off the northern part of Yap Main
Island, as well as the nearby atolls of Ifalik, Woleai, and Eauripik
were also reported to have sustained major damage. Many power lines were
downed and damage was reported to public facilities and roads. Some
150-200 persons lost their homes, and private property including boats,
vehicles, and merchandise in stores was destroyed. No monetary estimate
of the damage was available. (The information in this paragraph was
gleaned from a report by the Office for the Coordination of Humanitarian
Affairs located on the following website: http://www.reliefweb.int>.)
*************************************************************************
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: 1 intense tropical cyclone
1 very intense tropical cyclone
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
--------------------------------------------------
The trend for intense tropical cyclones in the Southwest Indian Ocean
during the current season continued in March. The most intense cyclone
of the season, Hary, formed southwest of Diego Garcia, moved westward,
then curved to the south, brushing the northeastern coastline of Mada-
gascar before recurving to the southeast. Hary was near its peak inten-
sity of 120 kts (10-min avg MSW from La Reunion) as it approached the
coast. JTWC also reported their peak 1-min avg MSW of 140 kts at the
same time. Later in the month Tropical Cyclone Ikala formed well east
of Diego Garcia and remained in the eastern portion of the basin. Ikala
briefly reached intense tropical cyclone status (10-min avg MSW greater
than or equal to 90 kts) on the 27th before weakening rapidly as it moved
into higher latitudes.
TROPICAL CYCLONE HARY
(MFR 11 / TC-18S)
5 - 15 March
-----------------------------------------
A. Storm Origins
----------------
A STWO issued by JTWC at 0800 UTC on 2 March indicated that an area of
convection had developed approximately 510 nm west-southwest of Diego
Garcia. Deep convection was cycling in intensity, and the disturbance
was situated beneath diffluent flow with an upper-level trough located to
the east-southeast. The potential for developing into a significant
tropical cyclone was assessed to be fair. However, by 1800 UTC a Quik-
Scat pass and sparse synoptic data indicated that the LLCC was quite weak
and embedded in a near-equatorial trough. Convection had weakened and
the development potential was downgraded to poor. Twenty-four hours
later the system was located approximately 475 nm southwest of Diego
Garcia, drifting east-southeastward. The LLCC was still weak and exposed
with associated convection decoupled to the southwest--moderate upper-
level westerlies were inhibiting development of the system. Little
change in intensity was noted on the 4th as the disturbance remained
quasi-stationary about 450 nm southwest of Diego Garcia.
Early on 5 March, however, animated satellite imagery depicted
increasing organization of deep convection near the center. The LLCC
was relocated to a point approximately 400 nm west-southwest of Diego
Garcia and the development potential was upgraded to fair. A TCFA was
issued at 1630 UTC, and at 1800 UTC, MFR upgraded the disturbance to
tropical depression status with maximum central winds of 30 kts (10-min
avg). JTWC issued their first warning on TC-18S at 0000 UTC on 6 March
with an initial intensity of 35 kts (1-min avg). At 0600 UTC Mauritius
upgraded the depression to Tropical Storm Hary, located about 600 nm
west-southwest of Diego Garcia or slightly less than 700 nm northeast of
Port Louis, Mauritius. Hary was moving slowly southwestward at 5 kts
under the steering influence of a low to mid-level ridge to the south-
east.
B. Track and Intensity History
------------------------------
Hary followed a fairly straight westward course for several days,
occasionally jogging slightly to the west-southwest or west-northwest.
During this time the storm intensified from a minimal tropical storm
into an intense cyclone. A 200-mb analysis around 1200 UTC on the 6th
indicated that Hary was located beneath a ridge axis with little shear.
Persistent deep convection was wrapping around a well-defined LLCC and
the storm's intensification was rather rapid. Winds had reached 60 kts
by 1200 UTC on 7 March when Hary was located about 500 nm north of Port
Louis. Even though the majority of the deep convection was in the south-
ern semicircle, a developing eye was evident and the storm exhibited good
outflow in all quadrants. (JTWC estimated the 1-min avg MSW at 65 kts
at this time.) Between 07/1200 and 08/0000 UTC, Hary intensified very
rapidly. At 0000 UTC, MFR upgraded Hary to a tropical cyclone (i.e.,
hurricane) with 85-kt winds, located about 550 nm north-northwest of
Mauritius. (JTWC upped their 1-min avg MSW estimate to 105 kts at the
same time.) Satellite imagery depicted a fairly well-defined 9-nm diam-
eter eye.
MFR increased the 10-min avg MSW estimate to 95 kts at 0600 UTC, and
at 1200 UTC, JTWC upped their 1-min avg MSW to 120 kts, based on CI esti-
mates of 115 kts. (MFR's intensity remained at 95 kts at 1200 UTC but
was increased to 110 kts at 1800 UTC.) At 08/1200 UTC the center of
Tropical Cyclone Hary was located approximately 250 nm east of Cape
D'Ambre, Madagascar. Deep convection had increased in all quadrants.
The cyclone was situated on the western extension of a mid-level ridge
and was forecast to continue tracking westward for the next 12 to 18
hours followed by a sharp turn poleward as a longwave trough approached.
At 0000 UTC on 9 March, Hary's 24-nm diameter eye was centered about
200 nm east of Cape D'Ambre, moving west-southwestward at only 2 kts.
MFR's intensity estimate remained at 110 kts while JTWC increased their
1-min avg MSW to 125 kts based on a Dvorak rating of T6.5. At 1200 UTC
the cyclone was located 150 nm east of Cape D'Ambre, moving west-
southwestward at 7 kts. The storm's intensity leveled off for several
hours, perhaps weakening a bit. JTWC's 1-min avg MSW remained at 125 kts
while MFR decreased their MSW to 100 kts at 1200 UTC. However, by 1800
UTC Hary was intensifying once again as MFR upped the intensity to
115 kts.
Tropical Cyclone Hary reached its peak intensity around 0000 UTC on
10 March when it was centered approximately 175 nm south-southeast of
Cape D'Ambre. MFR estimated the intensity at 120 kts with a central
pressure of 905 mb, making the storm a "very intense" tropical cyclone
by their terminology--maximum 10-min avg winds greater than 115 kts.
(JTWC's peak 1-min avg MSW was 140 kts, in very close agreement with
MFR's intensity.) Gale-force winds reached outward 130 nm from the
23-nm diameter eye in all quadrants, while the radius of 50-kt winds
was estimated at 60 nm. Hary was moving south-southwestward at 10 kts
due to the steering influence of the strong mid-level ridge to the east
and a transient mid-latitude trough moving eastward to the south of the
storm. The eye of Tropical Cyclone Hary made landfall on the coast of
Madagascar around 1200 UTC on 10 March at a point approximately 30 nm
south-southeast of Antalaha (WMO 67025). MFR reported the intensity
at 95 kts while JTWC's 1-min avg MSW was estimated at 135 kts.
By 11/0000 UTC the center of Hary had moved offshore to a position
roughly 60 nm east-southeast of Mahavelona. The storm was moving south
at 11 kts, and had weakened due to interaction with the landmass of
Madagascar. MFR lowered the 10-min avg MSW to 85 kts, while JTWC
decreased their 1-min avg MSW estimate to 115 kts. The storm no longer
displayed a discernible eye but still showed tightly-curved convective
bands. By 1200 UTC Hary was located about 220 nm west of Reunion Island,
moving south-southeastward at 16 kts, and had maintained its intensity.
A SSM/I pass and multi-spectral satellite imagery indicated an eye fea-
ture with tightly-wrapped banding. A trough to the west was deepening
and beginning to create some northwesterly shear over the storm.
Tropical Cyclone Hary was located about 190 nm southwest of Reunion
Island at 12/0000 UTC, moving southeastward at 15 kts, and had more or
less maintained its intensity, although JTWC dropped their 1-min avg
MSW to 100 kts. At 1200 UTC the cyclone was located approximately
300 nm south-southwest of Reunion Island with deep convection confined
mainly to the southern semicircle. Dvorak numbers were still running at
T5.0 and T5.5 but began to drop soon afterward. JTWC issued an interim
warning at 1800 UTC, lowering the intensity to 80 kts. The Remarks noted
that convection was weakening in the western semicircle due to the north-
westerly shear and that Hary was nearing the mid-point of extratropical
transition. At 0000 UTC on the 13th Hary was centered about 455 nm
south-southeast of Reunion Island. Both MFR and JTWC lowered their
respective intensity estimates to 70 kts, based on CI estimates of 65
and 77 kts.
MFR downgraded Hary to a 55-kt tropical storm at 0600 UTC, and at
1200 UTC declared the system to be extratropical, although the intensity
was bumped up slightly to 60 kts. JTWC issued their final warning on
Hary also at 1200 UTC with the storm located approximately 515 nm south-
southeast of Reunion Island. The center was fully-exposed with the
remaining deep convection sheared about 30 nm to the southeast. MFR
continued to issue bulletins on the still-potent extratropical storm
for another couple of days as it moved generally southeastward, later
turning eastward. By 1200 UTC on the 15th the former very intense trop-
ical cyclone had weakened into a minimal gale about 800 nm southeast of
Reunion Island and the final bulletin was issued.
C. Comparisons Between JTWC and Other Centers
---------------------------------------------
For most of Hary's lifespan, the 1-min avg MSW estimates from JTWC and
the 10-min avg MSW estimates from MFR agreed rather well after conversion
to the same time averaging period, being usually within 5-10 kts. The
respective peak intensities--120 kts for MFR and 140 kts for JTWC--agreed
very closely. The biggest difference was at 10/1200 UTC when Hary had
just made landfall in eastern Madagascar. JTWC's value of 135 kts would
correspond to a 10-min avg MSW of 119 kts, whereas MFR was reporting
95 kts at the time. JTWC's estimates ran a little higher than MFR's
from that point until 12/0000 UTC when they once more fell in line.
In the interim warning issued at 12/1800 UTC, JTWC's MSW estimate was
lowered to 80 kts, equivalent to a 10-min avg MSW of 70 kts, while MFR's
reported intensity was 85 kts.
D. Damage and Casualties
------------------------
Damage in Madagascar appears to be relatively light--rather surprising
considering the intensity of Hary when its eye brushed the coast. In
the Antalaha district, no major damage was reported inside the city.
One death by electrocution was reported, and two bridges were destroyed
on the road to Cap Est to the south. Likewise, in the district of
Fenerive Est, no damage was reported inside the city. The road to
Toamasina was cut due a bridge being out. Hary was about the same
intensity as Tropical Cyclone Hudah, which struck near Antalaha in
April, 2000, claiming over 100 lives and almost destroying the city.
One mitigating factor was likely the fact that the more dangerous
left semicircle remained offshore. If any more information regarding
damage or casualties becomes available, I will include it in a future
summary.
TROPICAL CYCLONE IKALA
(MFR 12 / TC-20S)
22 - 31 March
------------------------------------------
A. Storm Origins
----------------
A persistent area of convection developed on 20 March about 675 nm
east of Diego Garcia. The convection was associated with a weak LLCC
located beneath diffluent flow aloft. By 1800 UTC on the 21st the
LOW was centered roughly 540 nm east of Diego Garcia. Visible and
enhanced infrared imagery depicted a broad circulation moving westward.
Convection had weakened some since the previous day. MFR issued the
first tropical disturbance bulletin at 1200 UTC on 22 March, and at 1300
UTC, JTWC issued an interim STWO relocating the LLCC eastward to a
point approximately 645 nm east of Diego Garcia. The system was located
just equatorward of the upper-level ridge axis and animated visible
imagery depicted improving organization of deep convection near the
center, hence, the development potential was upgraded to fair. The
regular STWO at 1800 UTC, however, once more relocated the disturbance
back to the west, to near its 21/1800 UTC position. Central convection
continued to improve in organization and at 22/2330 UTC, JTWC issued a
TCFA for the system--by then located about 500 nm east of Diego Garcia.
By 1800 UTC on the 23rd, the LLCC had reached a point approximately
300 nm east of Diego Garcia as it continued to push westward across the
South Indian Ocean. A temporary weakening trend was in progress with
earlier deep convection having dissipated and a large cirrus shield over
the system arresting development for the time being. However, CIMSS data
showed weak vertical shear with good divergence aloft. By the time JTWC
re-issued the TCFA at 2330 UTC, convection was increasing once again near
the center. At 0600 UTC on 24 March, JTWC issued their first warning on
TC-20S with an initial intensity of 30 kts, and MFR upgraded the system
to a tropical depression with a 10-min avg MSW also of 30 kts. The
center of the depression was then centered approximately 270 nm southeast
of Diego Garcia, moving west-southwestward at 9 kts under the steering
influence of the subtropical ridge to the southeast.
At 24/1800 UTC, JTWC upped the MSW to 40 kts (1-min avg). Satellite
intensity estimates were still 30 kts, and animated imagery depicted
various areas of convection developing and dissipating within a broad
LLCC. A QuikScat pass revealed a very large LLCC with winds of 20-25
kts around the periphery and a large area of 5 to 10-kt winds in the
center--highest winds were evident within the areas of deep convection.
Thus, the system had the characteristics of a large monsoon depression
at this juncture. At 0600 UTC on the 25th the system was centered
roughly 250 nm south of Diego Garcia, moving west-southwestward at 7 kts.
The center was partially-exposed with weak banding features attempting
to wrap into the LLCC from the northeastern and southeastern quadrants.
A recent QuikScat pass revealed an elongated LLCC with light winds of
10-15 kts within 90 nm of the center in the eastern quadrant. Satellite
CI estimates were 35 and 45 kts, so Mauritius upgraded the depression to
Tropical Storm Ikala.
B. Track and Intensity History
------------------------------
Throughout its formative stages, Ikala moved west-southwestward. The
storm reached the westernmost point of its track about the time it was
named as a tropical storm--shortly afterward the system made an abrupt
hook back to the southeast and followed a south-southeasterly trajectory
for the remainder of its life as a tropical cyclone. (During its later
extratropical stage Ikala moved back to the southwest.) By 25/1800 UTC
MFR had increased the intensity to 45 kts with the storm centered about
270 nm south of Diego Garcia. Animated satellite imagery indicated that
convection was increasing over the LLCC with a weak banding feature in
the southeastern quadrant. A recent QuikScat pass indicated an elong-
ated LLCC (or else the possibility of dual circulations). By 0600 UTC
on 26 March the winds had increased to 55 kts (65 kts 1-min avg MSW from
JTWC) and a ragged eye feature was seen to be developing. A QuikScat
pass indicated a well-defined LLCC with a symmetric wind field. MFR
upgraded Ikala to tropical cyclone status with 65-kt winds at 1800 UTC
when the storm was centered approximately 475 nm south-southeast of Diego
Garcia. A 26/1709 UTC SSM/I pass indicated that a banding eye had
developed.
Following the development of the eye Ikala intensified rather rapidly.
MFR increased the intensity to 85 kts at 27/0000 UTC, and JTWC upped the
1-min avg MSW estimate to 105 kts at 0600 UTC, based on a CI estimate
of 102 kts. A 27/0412 SSM/I pass revealed a 21-nm diameter eye. Gales
extended outward 180 nm to the southeast and from around 80-100 nm in
the other quadrants while the radius of storm-force winds was estimated
to be 30 nm. (The radii were taken from JTWC's warnings--MFR's gale
radius was slightly smaller but the radius of storm-force winds was the
same.) At 1200 UTC, MFR increased the 10-min avg MSW to its peak for
the storm of 90 kts, accompanied by an estimated central pressure of
940 mb. Tropical Cyclone Ikala was then centered approximately 625 nm
south-southeast of Diego Garcia. Ikala had barely reached its peak
intensity when the first signs of weakening began to be seen. A TRMM
pass at 27/1459 UTC revealed that there was no longer an eye feature and
that the LLCC had begun to decouple from the mid-level vortex. Animated
enhanced infrared imagery indicated that the mid-level circulation was
accelerating to the southeast while the LLCC continued to move slower
with a low-level ridge building to the south.
MFR decreased the intensity estimate to 85 kts at 27/1800 UTC, to
80 kts six hours later, and to 65 kts at 28/0600 UTC. Interestingly,
JTWC's 1-min avg MSW was even lower--60 kts--down from 105 kts twelve
hours earlier. Ikala was downgraded to a 50-kt tropical storm at 1200
UTC when centered roughly 825 nm southeast of Diego Garcia. JTWC issued
their final warning at 1800 UTC with the intensity estimated at 45 kts,
based on CI estimates of 45 and 55 kts. Satellite imagery showed a
cirrus shield extending to the southeast with deep convection confined
to the poleward semicircle. Ikala had linked up with a baroclinic
boundary extending to the southeast and JTWC classified the system as
extratropical. MFR continued to treat Ikala as a tropical storm for
another 24 hours--by 29/1200 UTC the system was moving southward at
6 kts. At 1800 UTC MFR also declared Ikala extratropical, moving
west-southwestward at 8 kts with maximum winds of 45 kts. The remnant
gale center continued moving generally southwestward, turning to the
south-southwest and accelerating. The final bulletin on the LOW, issued
at 31/1200 UTC, placed the center approximately 1200 nm east-southeast
of Reunion Island.
C. Comparisons Between JTWC and Other Centers
---------------------------------------------
The MSW estimates from JTWC agreed very closely with those from MFR
throughout most of Ikala's history. The respective peak intensity esti-
mates, 90 kts from MFR (10-min avg) and 105 kts from JTWC (1-min avg)
were in perfect agreement. JTWC's MSW values on the final two warnings
were 5 kts less than MFR's 10-min avg estimates.
D. Damage and Casualties
------------------------
No damage or casualties are known to have resulted from Tropical
Cyclone Ikala.
*************************************************************************
NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (AUW) - From 90E to 135E
Activity for March: No tropical cyclones
*************************************************************************
NORTHEAST AUSTRALIA/CORAL SEA (AUE) - From 135E to 160E
Activity for March: 1 tropical cyclone of gale intensity
Sources of Information
----------------------
The primary sources of tracking and intensity information for
Northeast Australia/Coral Sea tropical cyclones are the warnings
and advices issued by the Tropical Cyclone Warning Centres at
Brisbane, Queensland, and Darwin, Northern Territory, and on very
infrequent occasions, by the centre at Port Moresby, Papua New
Guinea. 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.
NOTE: Much of the information contained in the summary of Tropical
Cyclone Des, especially in sections (B) and (D), was obtained from a
report on the storm written and sent to me by Alipate Waqaicelua, Chief
Forecaster at the Nadi TCWC in Fiji. A special thanks to Alipate for
sending me the report.
Northeast Australia/Coral Sea
Tropical Activity for March
-----------------------------
The month of March was quiet in waters all around northern Australia
and in the Southeast Indian Ocean. The only tropical system to form in
the AOR of any of the Australian TCWCs was Des, which formed just inside
the eastern boundary of Brisbane's AOR on the 5th. In fact, just three
hours after Des was named it had moved eastward across longitude 160E
into Fiji's AOR.
TROPICAL CYCLONE DES
(TC-17P / TD-12F)
4 - 7 March
----------------------------------------
A. Storm Origins
----------------
A STWO issued by JTWC at 0600 UTC on 3 March noted that an area of
convection associated with a broad circulation had developed approxi-
mately 450 nm east-southeast of Port Moresby, Papua New Guinea. A 200-mb
analysis indicated weak to moderate divergence aloft associated with an
upper-level ridge over the Solomon Islands. Twenty-four hours later the
system was located about 670 nm north-northeast of Brisbane. Deep con-
vection was increasing, and at 04/1200 UTC the Brisbane TCWC initiated
bulletins on the LOW. JTWC issued an interim STWO at 1500 UTC, upgrading
the development potential to fair. Deep convection had continued to
increase over the eastern semicircle, and the LLCC was located poleward
of an upper-level ridge in a region of moderate divergence.
JTWC issued a TCFA for the system at 04/2130 UTC, then located about
550 nm north-northeast of Brisbane, and at 0000 UTC on 5 March, Brisbane
issued a gale warning for a zone of gales located in the southern semi-
circle. JTWC issued their first warning on TC-17P at 05/0600 UTC. The
system was located about 600 nm northeast of Brisbane, moving east-
southeastward at 7 kts. The initial 1-min avg MSW of 35 kts was based
upon CI estimates of 30 and 35 kts. A banding feature was wrapping
around the eastern side of the LLCC, and a 200-mb analysis indicated
that the system was situated beneath favorable outflow aloft. TC-17P
was tracking east-southeastward under the steering influence of a low to
mid-level ridge east of the system, and this motion was forecast to
continue. Strengthening continued, and at 0900 UTC Brisbane upgraded the
system to Tropical Cyclone Des with 40-kt winds, located a mere 30 nm
west of longitude 160E, which is the border between Brisbane's and Nadi's
respective areas of warning responsibility.
B. Track and Intensity History
------------------------------
RSMC Nadi took over the primary responsibility for warnings at 05/1200
UTC with the cyclone centered approximately 385 nm west-northwest of
Noumea, New Caledonia. Three hours later Des was located about 200 nm
west-northwest of the northern tip of New Caledonia. Intensity was
45 kts and the storm was tracking toward the east-southeast at 8 kts. At
this stage, convection and overall organisation had increased markedly,
due mainly to decreasing shear downwind of the cyclone. Spiral bands had
gained more curvature, and deep convective tops within the central dense
overcast and convective bands had steadily cooled through the night
hours. Hence, at 05/1800 UTC Des was upgraded to storm intensity with
winds estimated at 50 kts and forecast to increase to 55 kts during the
next 12 to 24 hours. By 06/0000 UTC Tropical Cyclone Des was located
approximately 275 nm west-northwest of Noumea, and due to a gradual
backing of the steering windfield, the storm began to turn southeastward.
With good outflow established and decreasing shear forecast, the
cyclone was basically being steered into a favourable region for further
intensification. However, Des was now slightly gaining speed towards the
southeast and was located closer to the rugged terrain of New Caledonia.
During the evening of the 6th, the cyclone began to gradually lose organ-
isation through friction induced by the volcanic landmass. Vertical
shear was also increasing, though gradually. But the damage to Des'
structure was already beyond rescue. At 06/1200 UTC the cyclone was
centered about 150 nm west of Noumea, and while the intensity was still
at storm force, it was forecast to decrease to 45 kts over the next 12 to
18 hours. Des had also begun to gradually accelerate to 12 kts toward
the southeast under the strengthening steering and toward a region of
stronger shear.
At 06/1800 UTC Tropical Cyclone Des was in a very strongly sheared
environment. The LLCC was exposed about 100 nm to the west of the deep
convection. Maximum intensity was 40 kts and the cyclone was further
accelerating to the southeast at 15 kts. At 07/0000 UTC the system was
located about 100 nm south of Noumea with the MSW estimated at 35 kts and
decreasing steadily. Des was downgraded to a tropical depression at
0600 UTC on the 7th when located approximately 145 nm southeast of
Noumea. Some peripheral gales remained, but well away from the centre
which was devoid of any deep convection. JTWC issued their final warning
on Des also at 0600 UTC, estimating the 1-min avg MSW at 35 kts. The
Wellington office assumed warning responsibility for the LOW as it
reached the 25th parallel and turned eastward. The final gale warning
from Wellington was issued at 07/2300 UTC with the center located about
325 nm northeast of Norfolk Island.
C. Comparisons Between JTWC and Other Centers
---------------------------------------------
JTWC's peak 1-min avg MSW estimate of 45 kts was a little under the
maximum 10-min avg MSW of 50 kts estimated by Nadi, which would be
equivalent to a 1-min avg MSW of 55-60 kts. Otherwise, intensity
estimates between the warning centers were basically in good agreement.
D. Damage and Casualties
------------------------
New Caledonia was spared from the destructive storm force winds
because Des made a turn to the southeast around 06/0000 UTC, maintaining
a good 90 to 100 nm distance from the southern coastline. No reports of
damage or casualties resulting from Tropical Cyclone Des have been
received from New Caledonia at the present time.
*************************************************************************
SOUTH PACIFIC (SPA) - South Pacific Ocean East of Longitude 160E
Activity for March: 2 tropical depressions **
1 tropical cyclone of storm intensity ++
** - one of these was treated as a minimal tropical storm by JTWC
++ - visitor from the Australian Region (Des)
Sources of Information
----------------------
The primary sources of tracking and intensity information for
South Pacific tropical cyclones are the warnings and advisories
issued by the Tropical Cyclone Warning Centres at Nadi, Fiji (for
waters north of latitude 25S), and Wellington, New Zealand (for
waters south of latitude 25S). 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 Southern Hemisphere
centres' 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.
South Pacific Tropical Activity for March
-----------------------------------------
For the third consecutive month, no tropical cyclones were named by
the Nadi TCWC, which covers the South Pacific north of latitude 25S
between longitudes 160E and 120W. The only named cyclone in the region
was Tropical Cyclone Des, which formed just west of 160E and was named
by Brisbane only about three hours before moving into Fiji's AOR. (See
the section of this summary covering the Northeast Australia/Coral Sea
region for a report on Des.)
Fiji numbered two other systems as tropical depressions during the
month. One of these, Tropical Depression 13F, was classified as a
tropical storm by JTWC (TC-19P); therefore, I am including a separate
short report on this system. The other depression (TD-14F), formed on
the 18th only about 65 nm southeast of Pago Pago, American Samoa. The
system remained quasi-stationary and was located about 100 nm south-
southwest of Pago Pago at 2100 UTC on 20 March. But at 0600 UTC on the
21st the center of the broad system was relocated about 300 nm to the
south-southwest of the 20/2100 UTC position. Another tropical disturb-
ance in that vicinity had been mentioned in the Tropical Disturbance
Summary (issued by Nadi) for 20/2100 UTC, and it seems likely that this
system was considered the dominant center for TD-14F from 21/0600 UTC
forward.
The depression continued to drift west-southwestward and was located
about 450 nm south-southeast of Fiji on the Dateline when last mentioned
by Nadi at 2100 UTC on 23 March. Gale warnings were issued from the
20th until early on the 22nd for some associated peripheral gales created
by the depression's proximity to a high-pressure system northeast of
New Zealand.
There was one other system in the South Pacific during March which
perhaps deserves mentioning. A subtropical-type LOW formed on 21 March
about 250 nm northwest of Dahurei Island. A 21/0230 UTC QuikScat pass
revealed a LLCC with some associated deep convection on the poleward
side. An upper-level LOW was in the vicinity, creating some moderate
vertical wind shear. JTWC assessed the disturbance to have a fair
potential for development, and at 22/1700 UTC a TCFA was issued for
the system, which by then was positioned approximately 125 nm north-
northeast of Dahurei Island. Deep convection was developing near the
LLCC and the LOW was situated beneath favorable diffluence aloft.
However, seven hours later the TCFA was cancelled--deep convection was
being sheared to the southeast and the system was moving into a region
of cooler SSTs, hence, tropical cyclogenesis appeared to be unlikely.
TROPICAL DEPRESSION
(TD-13F / TC-19P)
13 - 16 March
---------------------------------------
A STWO issued by JTWC at 0600 UTC on 13 March noted than an area of
convection located approximately 280 nm west of Vanuatu had persisted
for 24 hours. Animated satellite imagery showed deep cycling convection
associated with a weak LLCC which had been depicted by a recent QuikScat
pass. A 200-mb analysis indicated that the area was situated beneath an
upper-level ridge axis in a region of weak to moderate vertical shear
with moderately favorable poleward outflow. At 2000 UTC the system was
located approximately 450 nm northwest of Noumea. Convection was still
somewhat isolated but was increasing in organization, hence, the
development potential was upgraded to fair. In the Tropical Disturbance
Summary issued at 2100 UTC, Nadi classified the system as Tropical
Depression 13F.
JTWC issued a TCFA at 0800 UTC on the 14th for the LOW which was then
located about 380 nm northwest of Noumea. Animated visible imagery
depicted cycling deep convection displaced to the south-southeast of the
LLCC. The convection had increased in coverage, however, and satellite
intensity estimates ranged from 25 to 35 kts. The first warning on
TC-19P was issued at 14/1800 UTC, placing the center near the northeast
coast of New Caledonia, moving southeastward at 14 kts. The initial
warning intensity (1-min avg) of 35 kts was based on CI estimates of
25 to 45 kts. Convection near the center had increased in coverage and
organization. The system was being steered southeastward by a low to
mid-level ridge to the north-northeast, and by 0600 UTC on 15 March the
center of TC-19P was located about 160 nm east-northeast of Noumea,
moving east-southeastward at 26 kts. The system had passed poleward of
the upper-level ridge axis and deep convection had become sheared to the
southeast of the LLCC.
At 15/1800 UTC the system was centered approximately 365 nm southwest
of Fiji. JTWC still reported the MSW (1-min avg) at 35 kts, based on
CI estimates of 25 to 45 kts, but a recent SSM/I pass indicated that the
LLCC had decoupled from the convection. The final warning on TC-19P from
JTWC, issued at 0600 UTC on 16 March, placed the center about 320 nm
south-southwest of Fiji, moving east-southeastward at 15 kts. The MSW
was estimated at 30 kts, and the LLCC was dissipating rapidly under the
combined influence of moderate vertical shear and cooler SSTs. No damage
or casualties are known to have resulted from this tropical depression.
*************************************************************************
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
in the following manner:
(a) FTP to: hrd-type42.nhc.noaa.gov [140.90.176.206]
(b) Login as: anonymous
(c) For a password use your e-mail address
(d) Go to "data" subdirectory (Type: cd data)
(e) Set file type to ASCII (Type: ascii)
(f) Transfer file (Type: get remote_file_name local_file_name )
(The files will be named with an obvious nomenclature--using
March as an example: mar02.tracks)
(g) To exit FTP, type: quit
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. If anyone wishes to retrieve any of the previous summaries,
they may be downloaded from the aforementioned FTP site at HRD. The
summary files are catalogued with the nomenclature: mar02.sum, for
example.
Back issues can also be obtained from the following websites
(courtesy of Michael Bath, Michael V. Padua and Michael Pitt):
http://australiasevereweather.com/cyclones/>
http://www.typhoon2000.ph> OR http://66.40.4.61>
http://mpittweather.com>
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 2001 (2000-2001 season for the Southern
Hemisphere). ATCRs for earlier years are available also.
The URL is: http://199.10.200.33/jtwc.html>
Also, TPC/NHC has available on its webpage nice "technicolor"
tracking charts for the 2001 Atlantic and Eastern North Pacific
tropical cyclones; also, preliminary storm reports for all the 2001
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 Wollongbar, New South Wales,
Australia, for assisting me with proofreading the summaries.
Prepared by: Gary Padgett
E-mail: [email protected]
Phone: 334-222-5327
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Document: summ0203.htm
Updated: 27th December 2006 |
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