[Index]
Monthly Global Tropical Cyclone Summary April 2006
[Summaries and Track Data] [Prepared by Gary Padgett]
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Monthly Global Tropical Cyclone Summary April 2006 [Summaries and Track Data] [Prepared by Gary Padgett] |
MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY
APRIL, 2006
(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.)
*************************************************************************
APRIL HIGHLIGHTS
--> Late season Northern Australian storm becomes one of the Southern
Hemisphere's most intense cyclones on record--fortunately makes
landfall in sparsely populated area
--> Intense Bay of Bengal cyclone makes destructive strike in Myanmar
*************************************************************************
ACTIVITY BY BASINS
ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico
Activity for April: No tropical cyclones
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NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180
Activity for April: No tropical cyclones
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NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180
Activity for April: No tropical cyclones
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NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea
Activity for April: 1 very severe cyclonic storm
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. Occasionally some
information may be gleaned from the daily tropical weather outlooks
and other bulletins issued by the Indian Meteorological Department
(IMD), which is the World Meteorological Organization's Regional
Specialised Meteorological Centre (RSMC) for the basin.
The reported maximum sustained winds (MSW) are based on a 1-minute
averaging period, which is used by all U. S. civilian and military
weather services for tropical cyclone warnings. For synoptic
observations in the North Indian Ocean region, both 10-minute and
3-minute average winds are employed, but IMD makes no attempt to
modify the Dvorak scale for estimating tropical cyclone intensity;
hence, a 1-minute average MSW is implied. In the North Indian Ocean
basin JTWC usually does not initiate warnings until a system has
become well-organized and likely to attain tropical storm status
within 48 hours.
VERY SEVERE CYCLONIC STORM MALA
(TC-02B / BOB0601)
24 - 29 April
---------------------------------------------------
Mala: contributed by Sri Lanka
A. Introduction
---------------
When JTWC numbers an April system in the Bay of Bengal as Tropical
Cyclone 02B--watch out! Dating back to 1981, there have been only two
April tropical cyclones in the North Indian Ocean, and both (in 1991
and 1994) were (1) numbered as TC-02B, (2) became very intense tropical
cyclones, and (3) made destructive strikes on the Asian mainland. And
this month's Cyclonic Storm Mala qualified in all three categories. It
was numbered as Tropical Cyclone 02B per JTWC (BOB0601 per IMD's nomen-
clature), became an intense cyclone, and made a destructive strike on
the mainland, in this case in Myanmar (formerly Burma).
This is as good a place as any to announce a change in the focus
of the monthly summaries. My time is extremely limited, and what time
I do have is often quite fragmented due to various commitments and the
time required to help care for my elderly mother. If the tropical
cyclone summaries are to continue, some time-reduction techniques are
necessary. Last year I discovered the online encyclopedia, Wikipedia,
and the storm reports which were being written and archived there. In
fact, I included links to the Wikipedia reports for Hurricanes Dennis and
Emily last year and perhaps for some others. Based on the fact that
reports for Atlantic hurricane seasons dating back into the 1950s have
been archived on Wikipedia, I perceive that the summaries will be
available there long-term.
Some of the Wikipedia reports are rather brief, and in some cases
(such as TCs Elia and Hubert following), I will write a more detailed
summary. But when the Wikipedia report is rather detailed (such as
for Mala and most of the Atlantic storms), I will for the most part just
reference the online report and include some supplemental information.
Since the May and June summaries will be rather brief due to few TCs
worldwide, I will explain there a little more fully how I plan to
structure the summaries in the future.
B. Links and Comments
---------------------
The online Wikipedia report may be accessed at the following URL:
http://en.wikipedia.org/wiki/Cyclone_Mala>
However, be advised that some of the links referenced in the report
were temporary and no longer work.
This report gives a fairly detailed overview of Mala. One minor
correction should be pointed out. As I understand things, IMD does
not issue a BOB number (or ARB number for Arabian Sea systems) until
a system has reached cyclonic storm (i.e., tropical storm) status. The
online report states that IMD designated it as BOB0601 when the deep
depression stage (30 kts) was reached. JTWC's first warning on Tropical
Cyclone 02B was issued at 24/1800 UTC when the system was located
approximately 600 nm southwest of Yangon (formerly Rangoon), Myanmar.
Regarding the intensity of Mala, JTWC's peak estimated MSW for the
cyclone was 115 kts in the warnings issued at 28/0600 and 28/1800 UTC.
There was no warning issued at the peak intensity time of 28/1200 UTC.
However, both JTWC and AFWA assigned Dvorak ratings of T6.5/6.5 at that
hour, so it seems likely that Mala reached a peak intensity of 125 kts
about that time while located approximately 200 nm west-southwest of
Yangon. Based on the JTWC warnings, the cyclone's intensity had dropped
to about 100 kts by the time of landfall near Gwa, Myanmar. The final
warning from JTWC, issued at 29/1800 UTC, placed the weakening 35-kt
center inland about 370 km north-northeast of Yangon.
A graphic depicting the track of Cyclonic Storm Mala may be found at
the following link:
http://www.tropicalcyclone2005.com/database/2006/I/BTI/2006-02B-MALA.gif>
C. Damage and Casualties
------------------------
According to the Wikipedia report, there were 22 deaths reported
in Myanmar with 6000 houses damaged and 351 completely destroyed. More
detailed information may be found in the online report.
D. The 1991 and 1994 April Cyclones
-----------------------------------
Since I mentioned the previous destructive April tropical cyclones in
the Bay of Bengal numbered TC-02B, I thought I'd include a little
information on them. The 1991 cyclone was one of the strongest storms
on record in the North Indian Ocean--the JTWC Best Track file assigns
it a peak MSW of 140 kts with an estimated CP of 898 mb. This deadly
cyclone struck Bangladesh with a lost of 139,000 lives, according to
the publication The World Almanac and Book of Facts.
A track of Tropical Cyclone 02B of 1991 may be accessed at the
following URL:
http://weather.unisys.com/hurricane/indian_oc/1991/index.html>
For information on the 1994 cylcone, I have turned to Jack Beven's
Weekly Tropical Cyclone Summaries, which of course were the predecessor
of the current monthly summaries. Jack began writing his weekly reports
in July, 1991, so missed covering the deadly Bay of Bengal storm of that
year by a few months. However, he did include a fair amount of
information on the 1994 cyclone. Tropical Cyclone 02B of 1994 hit the
coastline of Bangladesh near Cox's Bazaar with a peak MSW estimated at
135 kts. (The JTWC Best Track gives a peak intensity of 125 kts for
this cyclone, so it appears likely the intensity was adjusted downward a
bit in post-analysis.)
This storm was responsible for 139 deaths in Bangladesh with more
than 5000 persons injured. Also, at the time of Jack's report, 300
Thai fishermen, whose boats were wrecked by the cyclone, were still
missing.
A track of Tropical Cyclone 02B of 1994 may be accessed at the
following URL:
http://weather.unisys.com/hurricane/indian_oc/1994/index.html>
(Report written by Gary Padgett)
*************************************************************************
SOUTHWEST INDIAN OCEAN (SWI) - South Indian Ocean West of Longitude 90E
Activity for April: 1 moderate tropical storm
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 Tropical Cyclone Advisory Centres in Mauritius and
Madagascar with longitude 55E being the demarcation line between their
respective areas of naming 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.
TROPICAL STORM ELIA
(MFR-13 / TC-22S)
6 - 16 April
---------------------------------------
Elia: contributed by Madagascar
The origin of the tenacious Elia lay with an area of persistent
convection first noted approximately 830 nm east of Diego Garcia at 1800
UTC on 5 April. Vertical wind shear was low to moderate and upper-level
outflow was weak. MFR initiated advisories on the system as Tropical
Disturbance 13 at 0000 UTC 6 April, placing a weak 20-kt center roughly
650 nm west-northwest of the Cocos Islands. The LOW drifted westward
but remained weak and advisories were discontinued at 07/0000 UTC. A
JTWC satellite bulletin at 08/0600 UTC fixed a center several hundred
miles to the east, or approximately 425 nm west-northwest of the Cocos
Islands and within BoM Perth's area of warning responsibility. It seems
more likely that this was a new center forming within the larger area of
disturbed weather. JTWC assessed the potential for development as 'fair'
as the system moved farther to the east, reaching a point about 200 nm
north-northwest of the Cocos Islands by 1200 UTC on the 9th. Deep
convection was confined to the western semicircle and conditions were
only marginally favorable for further strengthening.
Over the next couple of days the LOW wandered erratically on a
generally southerly track, thence curving back to the west and passing
about 100 nm northwest of the Cocos Islands. The system appeared
somewhat better organized on the 11th with JTWC's satellite estimates
suggesting that it was near tropical storm intensity. Perth initiated
shipping bulletins on the LOW at 11/1800 UTC with the center located
approximately 325 nm west-northwest of the Cocos Islands, and JTWC
followed with their first warning on TC-22S at 12/1200 UTC. The system
was then located about 400 nm west of the Cocos Islands and was moving
southwestward at 10 kts. Significant strengthening was not expected
as the system was forecast to remain in an unfavorable vertical shear
environment.
TC-22S re-entered MFR's area of warning responsibility at 0000 UTC
on 13 April and was classified as a 30-kt tropical depression. At
13/1200 UTC the depression was upgraded to a tropical storm and assigned
the name Elia by the Meteorological Services of Mauritius. The south-
westerly motion continued and Elia reached its peak intensity of 45 kts
at 14/0600 UTC while centered roughly 550 nm west-southwest of the Cocos
Islands. (JTWC's estimated peak 1-min avg MSW was 55 kts.) Vertical
shear had not lessened, but Elia's poleward outflow had increased
significantly. By the 15th the LLCC was becoming decoupled from the
convection and the tropical storm accordingly began to weaken in a high
shear environment. JTWC issued their final warning at 15/1200 UTC, and
MFR downgraded Elia to a tropical disturbance at 16/0600 UTC. Six hours
later that agency issued the final advisory on ex-Elia, placing the
center approximately 870 nm southeast of Diego Garcia.
A graphic depicting the track of Tropical Storm Elia may be found at
the following link:
http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-22S-ELIA.gif>
A brief report with a satellite picture of Elia may be accessed at
the following URL:
http://en.wikipedia.org/wiki/Cyclone_Glenda#Moderate_Tropical_Storm_Elia>
No damage or casualties are known to have resulted from Tropical
Storm Elia.
(Report written by Gary Padgett)
*************************************************************************
NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (AUW) - From 90E to 135E
Activity for April: 1 tropical cyclone
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 April
------------------------------------------
Two tropical cyclones traversed Southern Hemisphere waters between
135E and 90E during the month of April. The first one, Tropical Cyclone
Hubert, formed to the north of Western Australia early in the month and
moved generally southward toward the coastline, but encountered strong
vertical shear and weakened dramatically upon approaching the coast.
A short report on Hubert follows.
The other, and much more significant cyclone, was a visitor from east
of 135E. Tropical Cyclone Monica, which had formed in the Coral Sea,
moved westward across the Cape York Peninsula into the Gulf of
Carpentaria where it deepened into one of the most intense tropical
cyclones ever noted in the Southern Hemisphere. Following a track
remarkably similar to intense Tropical Cyclone Ingrid in March, 2005,
Monica swung west-northwestward in the Gulf, clearing the northeastern
tip of the Northern Territory before resuming a westerly track. However,
Monica did not go as far west as Ingrid had moved and suddenly swung to
the southwest and inland about 15 nm west of Maningrida on 24 April.
The peak MSW (10-min avg) of 135 kts assigned by BoM Darwin is among the
highest, if not the highest, ever assigned operationally by an Australian
TCWC. An excellent report on Monica, written by Simon Clarke, follows in
the next section of this summary covering the Northeast Australia/
Coral Sea region.
TROPICAL CYCLONE HUBERT
(TC-21S)
4 - 7 April
-------------------------------------------
A. Storm History
----------------
The daily Tropical Weather Outlook issued by the Perth TCWC on 1 April
mentioned a weak tropical LOW near 14.0S/115.0E, but the system was not
forecast to develop into a tropical cyclone over the next three days.
JTWC first mentioned the disturbance in the STWO issued at 02/1800 UTC,
noting that deep convection was cycling near a broad but symmetric LLCC.
Vertical shear was low to moderate and the LOW was situated under the
western extent of a 200-mb anticyclone. By the next day the system's
chances for development were looking better, and BoM Perth initiated gale
warnings for shipping interests at 0300 UTC on 4 April, placing the
center approximately 475 nm north of Onslow, Western Australia. The
system's organization continued to improve and JTWC issued a TCFA at
2100 UTC. Shear was low to moderate and outflow was good and improving.
BoM Perth upgraded the LOW to Tropical Cyclone Hubert at 1200 UTC on
5 April, placing the center about 300 nm north-northeast of Onslow. The
cyclone, which had initially moved southeastward during its developmental
stages, commenced on a south-southwesterly trajectory as it was steered
by a mid-level ridge over Western Australia. Hubert was expected to
follow a more southwesterly track, but a weak upper-level LOW to the
south of the cyclone did not fill as anticipated. This created a
weakness in the ridge, allowing Hubert to move on a more southerly
track toward the Western Australian coastline.
Hubert gradually intensified, reaching a peak intensity of 55 kts at
07/0000 UTC while centered approximately 115 nm north of Onslow. (JTWC
had upped the 1-min avg MSW to 55 kts as early as 1800 UTC on the 5th,
but noted that the LLCC remained partially-exposed due to moderate
northeasterly shear.) Shortly after peaking in intensity, Hubert made
a slight jog to the south-southeast toward the coastline. However, the
cyclone ran into atmospheric hostilities in the form of high vertical
shear and quickly began to weaken. The final advice from BoM Perth
at 07/1500 UTC downgraded Hubert to a tropical LOW and placed the
center near the coast about 20 nm east-northeast of Onslow and about
30 nm southwest of Mardie. The system subsequently moved inland and
dissipated.
A graphic depicting the track of Tropical Cyclone Hubert may be
found at the following link:
http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-21S-HUBERT.gif>
The track of Hubert in tabular format may be accessed at the following
link:
http://www.tropicalcyclone2005.com/database/2006/SOHEM/B-TRACKS/2006-21S-BT.txt>
A brief report on Hubert with a satellite image of the system may be
accessed at the following URL:
http://en.wikipedia.org/wiki/Cyclone_Glenda#Tropical_Cyclone_Hubert>
B. Meteorological Observations
------------------------------
Following are a few synoptic observations sent to the author by
Matthew Saxby. A special thanks to Matthew for sending the information.
(1) Wind
--------
At Karratha sustained winds (10-min avg) fell just shy of gale force,
reaching ESE 33 kts at 06/0130 UTC but remaining near 30 kts for over
24 hours. The peak gust of 45 kts was recorded at 06/0830 UTC.
The weather station on Bedout Island recorded a maximum 10-min avg
wind of NE 38 kts at 06/1900 UTC. At Barrow Island winds first exceeded
gale force at 06/1230 UTC and did so continuously through 07/0500 UTC.
Peak sustained winds of 41 kts were observed at 06/2130 UTC, 07/0400 UTC
and 07/0500 UTC from the ESE, ENE and NE, respectively. A peak gust of
51 kts was recorded several times between 06/1631 UTC and 07/0100 UTC.
(2) Rainfall
------------
In the 24 hours ending at 0100 UTC on 7 April, Barrow Island recorded
234 mm of rain. In the 24 hours ending at 08/0100 UTC, Coolawanyah
recorded 156 mm and Mt. Florance measured 132 mm.
D. Damage and Casualties
------------------------
No reports of damage or casualties resulting from Tropical Cyclone
Hubert have been received.
(Report written by Gary Padgett)
*************************************************************************
NORTHEAST AUSTRALIA/CORAL SEA (AUE) - From 135E to 160E
Activity for April: 1 over land tropical LOW
1 severe tropical cyclone
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.
Northeast Australia/Coral Sea
Tropical Activity for April
-----------------------------
Following a track very similar to the intense Tropical Cyclone Ingrid
of March, 2005, Severe Tropical Cyclone Monica became one of the most
intense tropical cyclones ever tracked in the Southern Hemisphere since
the commencement of the satellite era. The cyclone was one of the latest
on record to affect the Northern Territory and brought very heavy
rainfall to the region. Until Monica came along it was beginning to
look like this would be the first season since the 1988-89 season that
the Darwin TCWC would not see a named tropical cyclone anywhere within
their AOR. According to information from Mark Kersemakers, a forecaster
at BoM Darwin, the 1987-88 season was also stormless in Darwin�s AOR. An
outstanding report on Monica, authored by Simon Clarke, follows.
Also worthy of mention was a tropical LOW which meandered about over
the Northern Territory and adjacent Gulf of Carpentaria waters for almost
two weeks during the first part of April. While fairly well-organized,
this LOW was not nearly as significant as the one in late January which
brought sustained winds to near gale force with gusts to storm force
in some areas. It did, however, enhance monsoonal rainfall which caused
floods in the Katherine area, leading to large-scale evacuations of
people living in the area. Some information on these floods may be
found at the following link:
http://abc.net.au/news/newsitems/200604/s1611695.htm>
SEVERE TROPICAL CYCLONE MONICA
(TC-23P)
16 - 26 April 2006
--------------------------------------------------
A. Introduction
---------------
The Southern Hemisphere TC season kept its best for last. TC Monica
was not only the strongest cyclone of the season in the Southern
Hemisphere; but also one of the Southern Hemisphere�s strongest in
recorded history. While not causing as much destruction as TC Larry
from a month earlier, Monica is noted for bringing tremendous
rainfall across the north tropical coast of Queensland, Cape York
Peninsula and the Top End of the Northern Territory.
A brief preliminary report on Severe Tropical Cyclone Monica,
authored by the Australian Bureau of Meteorology is also available
on-line at the following URL:
http://www.bom.gov.au/announcements/sevwx/nt/nttc20060417.shtml>
An unofficial summary can also be found at the following URL which
also includes some impressive satellite imagery:
http://en.wikipedia.org/wiki/Cyclone_Monica>
Also of particular note about Monica is that the cyclone arrived
quite late in the season which is usually over in the last weeks of
April in the Southern Hemisphere.
B. Storm History
----------------
Monica developed from a cluster of tropical thunderstorms that was
identified as early as 15 April in the Solomon Sea. Under an upper-
level ridge over the northern Coral Sea, the consolidating area of
convection gradually developed a LLCC near 9.0S/152.5E. Development
continued in a favourable environment consisting of low vertical wind
shear, good divergence aloft and high SSTs.
On 16 April, the LOW rounded the SE tip of Papua New Guinea and
entered the northern Coral Sea, moving SW at approx. 8 kts. At
17/0000 UTC the developing 995-hPa LOW was located at 12.4S/150.0E
(approx. 330 nm NE of Cooktown, Queensland) and was officially named
Monica.
The advisories issued by BoM Queensland indicated that Monica was
expected to intensify and move on a general westward path toward Cape
York Peninsula due to the steering influence of the low to mid-level
ridge to the south. Monica followed this forecast track and by
18/1200 UTC reached hurricane status (65-kt winds 10-min avg)
approximately 125 nm E of Lockhart River (13.0S/145.6E) while
accelerating to 12 kts on a general W to WSW path toward Cape York.
At 19/0600 UTC, Monica made its first landfall as a 960-hPa, max
10-min avg 80-kt cyclone approx. 20 nm S of Lockhart River (13.1S/
143.3E). Just prior to landfall, Monica slowed slightly with the eye
appearing to loop south and then parallel to the coast for a while
prior to making landfall. Interestingly, Monica crossed the coast in
almost the exact same point as Ingrid from the previous 2004/05
season (see unofficial comparison at Link 4).
Comparisons between Monica and Ingrid were not to finish there.
Monica moved quite quickly westwards across Cape York Peninsula and
despite a substantial breakdown in core convection and fragmented
radial outflow, emerged as a Category 2 cyclone in the Gulf of
Carpentaria 20 nm S of Aurukun (13.6S/141.5E) at 20/0000 UTC.
Like Ingrid from the season before, Monica embarked on a general NW
path across the very warm Gulf waters in response to a subtropical
ridge anchored to the SW of the system and steadily intensified as
the surface inflow around the LLCC improved. Hurricane intensity was
regained at 20/1800 UTC near 13.6S/140.2E (220 nm ESE of Nhulunbuy,
Northern Territory and 90 nm W of Aurukun, Queensland) as the cyclone
continued to drift to the NW at 4 kts. Monica continued to intensify
under highly favourable conditions of high SSTs and weak vertical
wind shear.
The cyclone developed a regular and circular clear eye as it traveled
to the north of the NE tip of the Northern Territory. Category 5
status was achieved at 22/0600 UTC near 12.4S/139.2E (140 nm E of
Nhulunbuy) and this was maintained until landfall. The cyclone was
tracked by the Nhulunbuy (Gove) radar which showed the classic
concentric eye-wall characteristic of intense cyclones. The cyclone
continued to improve in structure with very deep convection expanding
even further with a very symmetrical warm eye which contracted to 20
nm in diameter surrounded by a ring of cold convective tops.
Monica maintained a westerly path at 8 kts approx. 75 nm off the
northern coastline, passing over the Wessel Islands. Peak intensity
of 905 hPa and max 10-min avg winds of 135 kts was achieved at
23/0600 UTC near 11.4S/137.4E (115 nm ENE of Elcho Island) and
maintained for a further 12 hours. Despite being more powerful than
Ingrid from the 2004/05 season, it is noted that Monica�s path was
slightly farther north, keeping its relatively larger, intense
circulation offshore as the storm tracked westward parallel to the
Top End.
(Also of note, the Joint Typhoon Warning Agency pegged Monica at a
peak of 155 kts with gusts to 190 kts, which is equivalent to a
moderate American Category 5 cyclone (Saffir/Simpson Scale). CIMSS
estimates at the time also placed Monica as a 170-kt/T8.0/868.5-mb
cyclone, which certainly would rank Monica in the top echelon of
cyclones in recorded history worldwide. It should be noted that
reliable records of cyclone intensity only go back to the mid-1980s
in the Southern Hemisphere.)
Finally the cyclone shifted to an 8-kt WSW track in response to a
weakening of the mid-level ridge to the south as a consequence of an
approaching major shortwave trough over Western Australia. This
brought the centre of Monica across the coastline near 11.8S/134.1E
(about 15 nm W of Maningrida or 190 nm ENE of Darwin) just prior to
24/1200 UTC as a 915-hPa cyclone.
The very destructive core of Monica with gusts to 350 km/hr (190 kts)
affected the coast between Maningrida and Goulburn Island while crossing
the coast. However, Monica weakened very rapidly over land, losing
hurricane intensity in a little under 12 hours and cyclone status
overland near Darwin (12.6S/131.4E) at 25/0000 UTC as the cyclone lost
all of its cold convective cloud tops. The LLCC remained evident to
400 hPa in Darwin vertical wind profiler data and the depression
moved WNW and then SSW into the Timor Sea. However, the remnant LOW
remained too close to the NT coastline for any significant re-
intensification with all deep convection developing over land well
away from the centre. The exposed LLCC moved inland over the SW Top End
east of Port Keats and dissipated soon afterwards.
C. Observations
---------------
No meteorological instruments recorded the full impact of Monica.
However, the following brief notes were available at the time of
report writing.
In Queensland, peak wind gusts recorded were 59 kts at 15:00 local
time (19/0400 UTC) at Lockhart River and 50 kts at 7:43pm local time
(19/0943 UTC) inland at Coen. The heaviest rain occurred well south
of the cyclone within the strong onshore flow in the area between
Cape Tribulation and Cairns.
A number of places around the Cairns region received more than 200 mm
as the cyclone made its way across Cape York Peninsula. On 20 April,
Copperlode Dam (11 km W of Cairns) recorded 340 mm in the 24 hours to
9 am and Cairns itself passed its monthly April rainfall record of
550 mm.
In the Northern Territory, Gove Airport recorded a gust of 44 kts as
Monica passed well to the north. This observation is the station�s
highest April wind in 21 years. Elsewhere the highest wind gusts
recorded were 55 kts at Milingimbi at 12:30 local time (24/0330 UTC),
80 kts at Maningrida at 18:31 local time (24/0931 UTC), and 52 kts at
Warruwi at 22:00 local time (24/1300 UTC). It is noted that the
Maningrida wind gauge became inoperative at 20:02 local time (24/1102
UTC).
The BoM reported very heavy rainfall in parts of the western Arnhem
district on 23 and 24 April, in the Darwin-Daly district on 25 April
and in the Victoria River District on 26 April. The highest 24-hour
totals included Ngayawili 190 mm on 24 April; Adelaide River East
225 mm, Elizabeth Valley 192 mm, Noonamah 186 mm, Darwin River Ridge
174 mm, Humpty Doo 166 mm and Channel Island 153 mm on 25 April; and
Kidman Springs 261 mm, Coolibah 216 mm and Dashwood Crossing 129 mm
on 26 April.
A graphic displaying the track of Severe Tropical Cyclone Monica may
be found at the following link:
http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-23P-MONICA.gif>
D. Preliminary Damage Reports
-----------------------------
Monica was a relatively compact cyclone. Similar to Ingrid from the
previous season, communities beyond a 50-nm radius of the track were
hardly affected by the cyclone�s winds. However, in contrast to
Ingrid, Monica brought some of the heaviest rains ever recorded for
April through parts of Northern Queensland and the Northern
Territory.
The following is a preliminary snapshot of the effects of Monica on
communities in the cyclone's path, collated from various sources:
(1) Northern Queensland
-----------------------
There were no immediate reports of injuries or damage, though rain
from Monica caused the worst floods in living memory in parts of far
north Queensland. Significantly, flooding isolated many parts of the
Cape, making it difficult to initially assess the damage.
The Lockhart River township (pop. 700) escaped serious harm, although
news reports say about 15% of the buildings were damaged. Many roads
were cut to traffic including extensive wash outs from major flooding
along the Peninsula Developmental Road. Several residents from a
Cape York Peninsula aboriginal community and at least three families
from cattle properties were airlifted to drier ground due to flooding.
Farther south in Cairns several air flights in and out were cancelled
on 19 April. All tourist trips to the Great Barrier Reef were also
abandoned. The Kuranda Railway, a popular tourist train which winds
through World Heritage protected tropical rain forest near Cairns was
also halted because of a landslide along the line.
As tropical cyclone Monica tracked west across the Gulf of
Carpentaria, many of the 75 prawn trawlers that fish the remote off-
shore regions took shelter in calmer waters to the south near Karumba
and the Northern Territory-Queensland border. The interruption to
the banana prawn harvest created at least one week of disrupted
fishing time and wasted fuel in less than ideal fishing grounds. One
of the largest companies, NewFishing Australia, estimated the
disruption will cost them tens of thousands of dollars alone.
(2) Top End, Northern Territory
-------------------------------
Monica was the strongest cyclone on record to affect the Northern
Territory. Destructive winds caused extensive defoliation and
felling of trees on Marchinbar Island as the cyclone passed directly
over the Wessel Island group. Just north of the island chain,
Martjanba outstation was completely destroyed. At Junction Bay,
Monica ripped mangrove forests from the ground and destroyed sand
dunes.
Monica ran over a fairly sparsely populated section of coastline.
However, several small aboriginal communities were in the cyclone�s
path. A 50-km wide swath of defoliation and major tree damage was
reported to the west of Maningrida (pop. 2600) that extended inland
over parts of the Kakadu National Park to the escarpment near
Oenpelli.
Jabiru and Maningrida were spared a direct hit by only a matter of
miles. In the Maningrida community, several houses and a local
school were reported as being unroofed or extensively damaged.
Houses were also damaged and power was lost in other small
communities including Milingimbi, Oenpelli, Jabiru and Ngayawili
(Elcho Island). Power lines were also damaged in Yirrkala,
Ramingining, Warruwi (Goulburn Island) and other smaller communities
and outstations.
The following URL provides more detail on the recovery operations
underway in these communities:
http://www.nt.gov.au/monica/update.html>
Grave fears were held that Monica might reach Darwin as a strong
Category 3 cyclone and some domestic and international flights in and
out of the city were cancelled as a consequence. The city�s ANZAC
Day rites had to be called off. However, Monica weakened dramatically
on its overland approach to Darwin and will be remembered there more
so for the tremendous late season rain that it bought rather than for
its wind damage. The heavy rains cut many roads including the Arnhem
Highway at the Adelaide River and Cox Peninsula Road at Berry Creek.
Fortunately, no casualties or serious injuries were reported as a
consequence of Monica.
E. Links
--------
Link 1:
=======
Satellite imagery � Monica developing in the North West Coral Sea
http://earthobservatory.nasa.gov/NaturalHazards/shownh.php3?img_id=13501>
Link 2:
=======
Satellite Imagery � Monica crosses Cape York
http://earthobservatory.nasa.gov/NaturalHazards/shownh.php3?img_id=13511>
Link 3:
=======
A selection of impressive satellite and radar images as Monica passes
close to the Top End, Northern Territory:
http://monica.infoaddict.net/main.php>
Link 4:
=======
Tidal Effects Environmental Protection Agency�s Comparison to Ingrid
(Cape York Crossing):
http://www.epa.qld.gov.au/publications/p01901aa.pdf/Tropical_cyclone_Monica.pdf>
(Report written by Simon Clarke)
*************************************************************************
SOUTH PACIFIC (SPA) - South Pacific Ocean East of Longitude 160E
Activity for April: 1 tropical depression
South Pacific Tropical Activity for April
-----------------------------------------
No tropical cyclones formed in the South Pacific basin during the
month of April. RSMC Nadi identified one system as a numbered tropical
depression, but it was weak. Tropical Depression 17F was first mentioned
at 1800 UTC on 20 April, located to the southeast of Fiji and just east
of the Dateline. The system was weak with an exposed center and with
isolated deep convection located to the south of the LLCC. TD-17F
meandered slowly around for a couple of days, but by the 23rd had moved
southward out of the tropics and was dropped from the Fiji Tropical
Disturbance Summaries. No track was included for Tropical Depression 17F
in the accompanying cyclone tracks file.
Also, during the final days of April several more LOWs were referenced
simply as 'depressions' in the Fiji summaries. These systems were well
east of the Dateline and were never classified as 'tropical� depressions,
so it is assumed they were likely hybrid or subtropical in character.
*************************************************************************
SPECIAL FEATURE - SOURCES OF TROPICAL CYCLONE INFORMATION
The purpose of this section is to list some websites where many and
varied types of tropical cyclone information are archived. Many readers
will know about these already, but for the benefit of those who don't,
I wanted to include them.
(1) Aircraft Reconnaissance Information
---------------------------------------
Various types of messages from reconnaissance aircraft may be
retrieved from the following FTP site:
ftp://ftp.nhc.noaa.gov/pub/products/nhc/recon/>
Information regarding how to interpret the coded reconnaissance
messages may be found at the following URL:
http://www.nhc.noaa.gov/reconlist.shtml>
Links are also included to websites with further information about the
U. S. Air Force 53rd Weather Reconnaissance Squadron and the NOAA Air-
craft Operations Center.
(2) Archived Advisories
-----------------------
All the advisory products (public advisories, forecast/advisories,
strike probabilities, discussions, various graphics) issued by TPC/NHC
are archived on TPC's website. For the current year (using 2004 as an
example), the archived products can be found at:
http://www.nhc.noaa.gov/archive/2004/index.shtml>
Links to tropical products archives for earlier years are available at
the following URL:
http://www.nhc.noaa.gov/pastall.shtml>
JTWC warnings for past storms are archived on the NRL Monterry website:
http://www.nrlmry.navy.mil/tc_pages/tc_home.html>
On the NRL site, the link to past years can be found in the upper left
corner of the screen.
I am not aware at the moment of any other TCWC which archives all
its tropical cyclone warning/advisory products for public access, but
if I learn of any, I will add them to this list.
(3) Satellite Imagery
---------------------
Satellite images of tropical cyclones in various sensor bands are
available on the NRL Monterrey and University of Wisconsin websites,
courtesy of Jeff Hawkins and Chris Velden and their associates. The
links are:
http://www.nrlmry.navy.mil/tc_pages/tc_home.html>
http://cimss.ssec.wisc.edu/tropic/tropic.html>
On the NRL site, the link to past years can be found in the upper left
corner of the screen. For the CIMSS site, a link to data archives is
located in the lower left portion of the screen.
Additional tropical satellite imagery, along with looping ability for
composite microwave imagery for the Western Hemisphere north of the
equator, can be found at:
(1) For the Eastern North Pacific:
http://www.ssd.noaa.gov/PS/TROP/trop-epac.html>
(2) For the Atlantic, Gulf of Mexico and Caribbean Sea:
http://www.ssd.noaa.gov/PS/TROP/trop-atl.html>
I'm sure there are other sites with available imagery available, and
as I learn of them, I will add the links to this list.
*************************************************************************
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 August, 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, Chris
Landsea, and John Diebolt):
http://australiasevereweather.com/cyclones/>
http://www.typhoon2000.ph>
http://mpittweather.com>
ftp://ftp.aoml.noaa.gov/hrd/pub/landsea/padgett/>
http://www.tropicalcyclone2005.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.metoffice.gov.uk/weather/tropicalcyclone>
TROPICAL CYCLONE REPORTS AVAILABLE
JTWC now has available on its website the Annual Tropical Cyclone
Report (ATCR) for 2004 (2003-2004 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 2005 Atlantic and Eastern North Pacific
tropical cyclones; also, storm reports for all the 2005 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]
Simon Clarke (Northeast Australia/Coral Sea, South Pacific)
E-mail: [email protected]
*************************************************************************
*************************************************************************
|
Document: summ0604.htm
Updated: 6th August 2006 |
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