[Index]
Monthly Global Tropical Cyclone Summary February 1999
[Summaries and Track Data] [Prepared by Gary Padgett]
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Cyclones
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Monthly Global Tropical Cyclone Summary February 1999 [Summaries and Track Data] [Prepared by Gary Padgett] |
MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY
FEBRUARY, 1999
(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.)
TROPICAL CYCLONE REPORTS AVAILABLE
I have discovered that JTWC now has available on its new website
the complete Annual Tropical Cyclone Report for 1997 (1996-1997 season
for the Southern Hemisphere).
The URL is: http://199.10.200.33/jtwc.html>
Also, TPC/NHC has available on its webpage nice "technicolor"
tracking charts for the 1998 Atlantic and Eastern North Pacific
tropical cyclones; also, some of the preliminary storm reports are
now available.
The URL is: http://www.nhc.noaa.gov/1998.html>
***********************************************************************
FEBRUARY HIGHLIGHTS
--> New Caledonia and Queensland suffer cyclone strikes
***********************************************************************
ACTIVITY BY BASINS
ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico
Activity for February: No tropical cyclones
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NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180
Activity for February: No tropical cyclones
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NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180
Activity for February: 1 tropical storm **
** - This based upon JTWC's classification--JMA and PAGASA did not
classify Iris/Bebeng as a tropical storm.
NOTE: Most of the information on each cyclone's history presented in
the narrative will be based upon JTWC's advisories, and references to
winds should be understood as a 1-min avg MSW unless otherwise noted.
However, in the accompanying tracking document I have made comparisons
of coordinates with JMA (Japan) and the Philippines (PAGASA) when their
positions differed from JTWC's by usually 40-50 nm or more. Also, as
announced earlier in a separate posting, a column of 10-min avg MSW
is included--the values being obtained from either PAGASA's or JMA's
advisories. A special thanks to Michael V. Padua, owner of the Typhoon
'99 webpage, for sending me the PAGASA tracks.
In the title line for each storm I plan to reference all the cyclone
names/numbers I have available: JTWC's depression number and name (if
any), JMA's tropical storm numeric designator, and PAGASA's name for
systems forming in or passing through their area of responsibility.
Tropical Storm Iris/Bebeng (TC-02W)
15 - 19 February
------------------------------------
The second weak tropical storm to form in the Northwest Pacific
in 1999 can be traced to an area of convection which developed between
Pohnpei and Chuuk on 10 Feb. The disturbance appeared to be a
tropical wave propagating toward the west as it very slowly became
better organized. JTWC issued the first of three Formation Alerts
at 2330 UTC on 13 Feb when the disturbance was approaching the Palau
area. The system had the characteristics of a large monsoon depression
when PAGASA initiated advisories at 15/0000 UTC, naming it Bebeng.
Tropical Depression Bebeng was then located about 225 nm north-
northeast of Palau and had been quasi-stationary for a couple of days.
The depression began drifting westward, slowly increasing in
convective organization.
JTWC initiated depression advisories at 16/0000 UTC when the broad
center was estimated to be about 275 nm north-northwest of Palau.
There was evidence of multiple circulation centers and the depression
was undergoing light to moderate vertical shear. At 0300 UTC on
17 Feb the center was re-located to the south based on visible imagery.
This placed the low-level center under the deeper convection and JTWC
upgraded the depression to Tropical Storm Iris with 35-kt MSW at this
time. Iris' center was estimated to be about 325 nm northwest of
Palau. The 17/0900 UTC warning from JTWC noted that Iris had
developed an anticyclone and outflow appeared to be good. However,
six hours later vertical shear had increased and Iris appeared to
be weakening with multiple circulation centers apparent.
As it began to weaken Iris/Bebeng slowly turned to the northwest
east of the central Philippines. During its dissipation stages intense
convection would occasionally fire up but the low-level center became
increasingly disorganized. By 19/0000 UTC the low-level circulation
center had been absorbed into a pre-existing cyclonic environmental
shear zone and Iris/Bebeng was declared dissipated about 300 nm east
of Manila.
***********************************************************************
NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea
Activity for February: 1 tropical cyclone of gale intensity
NOTE: The tracking and intensity information for North Indian Ocean
Basin tropical cyclones is based primarily upon operational warnings
from the Joint Typhoon Warning Center of the U.S. Air Force and Navy
(JTWC) at Pearl Harbor, Hawaii. For weaker systems not in warning
status by JTWC, information gleaned from the twice-daily issuances
of the Indian Meteorological Department (IMD) was used to complete
the tracks. These bulletins usually give analyzed center positions
at either 0300 or 0600 UTC and 1200 or 1500 UTC.
The MSW are based on a 1-min 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 region,
both 10-min and 3-min average winds are employed, but IMD makes no
attempt to modify the Dvorak scale for estimating tropical cyclone
intensity; hence, a 1-min avg MSW is implied. In the North Indian
basin JTWC usually does not initiate warnings until a system is
well-organized and likely to attain tropical storm status within
48 hours.
Tropical Cyclone (TC-01B)
1 - 5 February
--------------------------
The 1999 tropical cyclone season in the North Indian Ocean got off
to a very early start with a rare February cyclone. The system can
be traced back to a disturbed area in the south-central Bay of Bengal
first mentioned by JTWC on 27 Jan. The weak LOW drifted west-
northwestward over the succeeding days and gradually became better
organized. JTWC issued a Formation Alert at 0400 UTC on 31 Jan with
a second Alert issued 24 hours later. The first warning from JTWC,
issued at 0900 UTC on 2 Feb, located a 35-kt tropical cyclone about
325 nm east-northeast of Colombo, Sri Lanka, at 0600 UTC. Strongest
winds were in the western half of the storm due to asymmetric
convection and the storm's forward translational effects.
The cyclone, which had been moving west-northwestward due to the
steering effects of a subtropical ridge located to its northeast,
began to turn to the north-northwest as a trough moved through India.
The MSW reached a peak of 40 kts at 03/0600 UTC when the system was
centered about 275 nm east-southeast of Madras, India. Winds ahead
of the trough began to induce shearing over the tropical cyclone,
causing it to begin weakening. JTWC issued the final warning at
2100 UTC on 4 Feb, locating the low-level center, now devoid of any
deep convection, about 225 nm east-southeast of Madras.
***********************************************************************
SOUTH INDIAN OCEAN (SIO) - South Indian Ocean West of Longitude 90E
Activity for February: 1 tropical disturbance
1 tropical depression
1 moderate tropical storm
The primary sources of information upon which the narrative is based
are the warnings issued by the TCWC on La Reunion Island, associated
with Meteo France, and which is the RSMC for the South Indian Ocean
basin. However, cyclones in this region are named by the sub-regional
centres on Mauritius and Madagascar with longitude 55E as the dividing
line between their respective areas. La Reunion only advises these
centres regarding the intensity of tropical systems. References to
sustained winds should be understood as meaning a 10-min averaging
period unless otherwise stated. In the accompanying track file
some position comparisons have been made with JTWC's positions, and
warnings from JTWC were used as a source of 1-min avg MSW estimates.
(A special thanks to Philippe Caroff of the La Reunion TCWC for
sending me an analyzed Best Track File for Chikita and Tropical
Depression D19899. This data forms the basis for the tracking
information given for these systems in the accompanying track file.)
Tropical Storm Chikita (TC-17S)
29 January - 5 February
--------------------------------
JTWC began mentioning a disturbed area north of Cocos Island (in
the Australian Region) in their Tropical Weather Outlooks as early
as 24 Jan. During the following days the disturbance drifted generally
southwestward. By 1200 UTC on 29 Jan the poorly-defined center was
estimated to be about 175 nm southwest of Cocos. On 30 Jan the LOW
began to move at an accelerated pace westward and intensified. JTWC
issued the first warning at 31/0000 UTC with MSW (1-min) estimated
to be 30 kts. The depression continued to organize rapidly and was
named Chikita by the Mauritius TCWC at 1200 UTC. Chikita's center
was then located about 850 nm west-southwest of Cocos and MSW were
estimated at 37 kts, which was the highest during the storm's lifetime.
(JTWC's peak 1-min MSW of 40 kts is in close agreement with the Best
Track value from La Reunion.) The JTWC warning issued at 31/0900 UTC
reported some ship observations of winds to 35 kts.
Tropical Storm Chikita sailed rapidly westward to west-southwestward
at speeds of nearly 20 kts at times, following in the tracks of
Damien/Birenda. After the initial rapid intensification, however, the
storm did not strengthen any further, and slowly began to weaken.
Chikita passed about 40 nm north of Rodrigues Island early on 3 Feb as
either a strong depression or a minimal tropical storm. Rodrigues
(which belongs to Mauritius) reported maximum wind gusts to 50 kts
when the center was nearest. Rodrigues, which had been experiencing
drought conditions, had some very welcome rainfall from Chikita.
Coastal stations recorded around 75-80 mm while one location in the
hills measured 113 mm.
The low-level center had become exposed by this time, but Chikita's
windfield remained strong, especially on the south side, due to the
rapid forward motion even after most of the convection had decreased.
Winds to gale force extended out only 30 nm to the north but out to
200 nm to the south. The weakening system passed around 100 nm north
of Mauritius and La Reunion on 4 Feb and was dissipating off the east
coast of Madagascar by 0600 UTC on 5 Feb. Mauritius reported peak
wind gusts around 38-40 kts, while on La Reunion, gusts to 44 kts
were experienced on the northern and southern coasts. A gust to
57 kts was recorded on the volcano La Fournaise at an elevation of
2250 m.
On Mauritius an average rainfall of 86 mm in 24 hours was recorded
on the 4th with a maximum of 160 mm measured at Mare-Aux-Vacoas, a
reservoir in the southwestern portion of the island. Like Rodrigues,
Mauritius had been experiencing a drought so the rainfall was very
welcome. (Thanks to Arvind Mungur of London for passing along this
information he'd gleaned from _L'Express_, a local daily newspaper.)
On La Reunion Chikita brought the first episode of heavy rainfall
since mid-December with the heaviest amounts falling in a 6-hour period
early on 4 Feb before the remnant of Chikita made its closest approach.
However, the rain continued for more than 48 hours so that significant
amounts were recorded:
. maximum of 119 mm in 48 hrs at Saint-Benoit (eastern coast) with
73 mm during the first 6 hrs
. 100 mm at Saint-Denis (main city on the north coast)
. more than 200 mm in 48 hrs over the central and eastern heights
. maximum of 436 mm at Bellecombe's lodging (elevation 2250 m) with
132 mm during the first 6 hrs
(Thanks to Philippe Caroff of the La Reunion TCWC for sending me the
wind observations and rainfall amounts for Rodrigues and La Reunion.)
Tropical Depression "D1" (TC-21S)
11 - 17 February
----------------------------------
This system, classified as a tropical depression by Madagascar but
carried as a tropical storm by JTWC, formed and remained in the
Mozambique Channel throughout its existence. The Mozambique Channel
has indeed been a "hot spot" of development for the South Indian Ocean
since early January with two systems forming in January and two in
February. A weak LOW was mentioned by La Reunion just off the coast
of Mozambique near Quelimane on 11 Feb. The system drifted slowly
southward in the Channel for a couple of days, slowly becoming better
organized. JTWC began issuing warnings at 1500 UTC on 13 Feb when
the depression was located in the southern portion of the Channel east
of the southern Mozambique coast. JTWC's estimated peak MSW (1-min)
was 45 kts on 14 Feb, based in part on ship synoptic observations
of 35 kts. The maximum sustained 10-min avg winds reported by the
La Reunion TCWC were 33 kts at 14/1800 UTC--just under tropical storm
strength.
The system drifted slowly to the east-northeast on 14-15 Feb as
it reached its peak intensity, then turned back to the north as it
weakened. By the 15th about all the convection had been sheared away,
although the low-level center was still well-organized. The
weakening system continued north-northwestward and had dissipated near
its point of origin by 17 Feb.
Tropical Disturbance "D2" (TC-23S)
23 February - 4 March
-----------------------------------
The second disturbance of the month to form in the Mozambique
Channel was first mentioned by JTWC in a Tropical Weather Outlook on
21 Feb. The system had moved offshore into the Channel and was
associated with the tail end of a passing shear line. La Reunion
began issuing bulletins on 23 Feb, locating a weak LOW just off the
Mozambique coast south of Beira. Over the succeeding days the
disturbance remained quasi-stationary with MSW estimated at 25 kts.
The LOW was classified as a subtropical cyclone on 25 Feb but
designated as a tropical disturbance on 26 Feb as central convection
increased.
The system began to move at a slightly increased pace to the east-
southeast on 27 Feb. JTWC initiated warnings at 1500 UTC on the 27th
but never upgraded the LOW to tropical storm intensity. The warning
indicated that the system appeared to be embedded in a frontal zone
and tracking off to the southeast. By 28/1500 UTC most of the
convection had been sheared away to 90 nm east of the low-level
center. For some reason of which I am not totally sure of the
cause, I was unable to access any bulletins from La Reunion between
28/0600 UTC and 0000 UTC on 4 Mar. JTWC's last warning at 0600 UTC
on 1 Mar placed the center about 100 nm south of Tulear on the
southeast coast of Madagascar and accelerating to the southeast.
However, I began receiving La Reunion's releases once more at 0000 UTC
on 4 March and discovered that they were still issuing bulletins on
Tropical Disturbance "D2", and that it was back in the Mozambique
Channel, just off the African coast and near its point of origin.
The disturbance continued drifting northward and was last located
near the Mozambique coast north of Beira at 04/1800 UTC. (After
Tropical Storm Davina was named in the central Indian Ocean on the
4th, bulletins on this system were re-designated as "E1"--indicating
that the next storm name would begin with the letter "E" and that
this was the first disturbance to be in existence after the "D" name
had been allotted.)
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AUSTRALIAN REGION (AUG) - From Longitude 90E Eastward to Longitude 160E
Activity for February: 1 tropical LOW (depression)
1 tropical cyclone of storm intensity
The primary sources of information for Australian Region tropical
cyclones are the warnings and bulletins issued by the three TCWC's
at Perth, Darwin, and Brisbane. Information gleaned from JTWC's
warnings is used as a supplement for times when it was impossible to
obtain Australian bulletins and for comparison purposes. Additionally,
some information came from the Monthly Report of the RSMC at Darwin,
Northern Territory. References to sustained winds should be
understood as being based on a 10-min averaging period unless
otherwise noted.
Mr. Matthew Saxby, a tropical cyclone enthusiast from Queanbeyan,
New South Wales, Australia, is going to assist me with collecting
information and preparing tracks for tropical cyclones in the
Australian Region. Some of the information contained in the narratives
is based upon information forwarded to me by Matthew. A special
thanks to Matthew for his assistance.
Tropical LOW (TC-18S)
31 January - 14 February
------------------------
A weak tropical disturbance south of Java was mentioned by both
JTWC and Perth in their daily Tropical Weather Outlooks beginning
around the end of January. Perth began issuing bulletins on the
system at 2200 UTC on 3 Feb when it was centered about 250 nm north
of Port Hedland, Western Australia. JTWC initiated warnings on the
LOW at 2100 UTC on 4 Feb. The depression moved west-southwestward
through around 1000 UTC on 5 Feb, then turned to more of a west-
northwesterly course at a slower pace. Perth issued the final
warning at 06/2200 UTC when the LOW was centered about 500 nm south-
southeast of Christmas Island. JTWC continued issuing warnings
through 09/0000 UTC as the system slowly weakened. A residual LOW
remained quasi-stationary in the general area for several more
days.
This tropical LOW experienced vertical shear throughout most of
its life. An upper-level anticyclone over Western Australia supplied
easterly shear which kept the convection sheared to the western side
of the circulation. Gales on the western side of the circulation did
accompany this depression, but in accordance with the definition of
a tropical cyclone utilized by WMO Region 5, the system was not
classified as a tropical cyclone and named. On the 6th scatterometer
data indicated winds of 35-40 kts out to 120 nm southwest of the low-
level center which was fully exposed about 90 nm northeast of the
nearest convection. By the 7th most of the deep convection had
dissipated due to increasing vertical shear and cold-air stratus
entrainment.
Tropical Cyclone Rona (TC-20P)
8 - 12 February
-------------------------------
A tropical LOW persisted for several days in the Coral Sea, near
the Cape York Peninsula, during the second week of February. Upper-
level conditions became favorable for tropical development, and the
system began to intensify quite rapidly on 10 Feb, becoming Tropical
Cyclone Rona at 1800 UTC. Both JTWC and Brisbane initiated warnings
at the same time, locating Rona about 175 nm east of Cooktown on the
Queensland coast. Rona initially moved southward, but soon turned
to the west-southwest under the steering influence of a subtropical
ridge to the southeast of the cyclone. The storm also accelerated
somewhat to a forward translational speed of about 10 kts by the
time it reached the Queensland coast.
By 11/0300 UTC synoptic data indicated that 35-kt winds were
already occurring just offshore near Cape Bowling Green. Tropical
Cyclone Rona continued to intensify until the eye made landfall just
north of the resort town of Port Douglas around midnight on 11-12
Feb. Just how intense did Rona become? The peak 10-min MSW reported
by Brisbane was 60 kts at 11/1200 UTC. However, the Tropical Cyclone
Advices had Rona classified as a Severe Tropical Cyclone (i.e., a
hurricane), and the peak estimated gusts of 180 km/hr, when reduced
to 10-min MSW by the standard reduction factor of 1.4, yields a
MSW of 70 kts. With an attendant estimated central pressure of 970 mb,
it seems likely that Rona perhaps did reach hurricane intensity
shortly before making landfall. The JTWC warning at 11/2100 UTC
estimated that peak winds (1-min MSW) reached 65 kts just prior to
landfall.
After making landfall, Rona weakened but the remnants hung around
in the coastal area for a few days, then drifted southward and eastward
back out into the Pacific. The renmant LOW subsequently moved
eastward and re-intensified, becoming Tropical Cyclone Frank in the
Fiji AOR. For a description of Tropical Cyclone Frank, see the portion
of this summary covering the Southwest Pacific Basin. (NOTE: This
Rona/Frank connection is based upon information taken from the Monthly
Tropical Diagnostic Statement from the Darwin TCWC. JTWC continued
tracking Rona's remnants westward south of the Gulf of Carpentaria.
However, it seems likely JTWC may have been tracking the upper-level
circulation while the low-level center remained near the coast. The
JTWC warning from 11/2100 UTC makes the observation: "TC-20P (Rona)
has slowed rapidly as it moved into the Great Dividing Range Mountains.
Satellite animation shows the convection weakening and continuing
across the mountains, but synoptic data indicates the low-level
circulation remains caught up in the mountain range.")
Although the eye moved inland just north of Port Douglas, newspaper
accounts stated that Cow Bay, an idyllic resort about 125 km north of
Port Douglas, took the brunt of the storm. Two houses were flattened,
12 others damaged, and a car crushed by a falling tree. Flooding was
a major concern, extending as far south as Ingham. About 2000 people
were evacuated from their homes near Cairns and Innisfail due to
rain-swollen streams. Highest 24-hour rainfall totals ending at
2200 UTC on 11 Feb were: Topaz - 531 mm; Greenhaven - 474 mm;
Kuranda - 420 mm; Cardwell - 369 mm; Ravenshoe - 354 mm; and Tully -
340 mm. Roads were cut in many districts, and powerlines were down
across a wide area.
Two potential marine disasters were narrowly averted. A 40-m
tourist vessel, Atlantic Clipper, was caught at sea and rode out the
cyclone with a crew of 13 and 26 passengers. Two elderly sailors were
rescued by helicopter from an isolated beach on South Molle Island in
the Whitsundays after their yacht hit rocks in the huge seas.
The Darwin Monthly Report mentions six fatalities due to the
flooding caused by Rona. Matthew Saxby, however, reports that he
monitored news accounts of the cyclone and heard of no fatalities
mentioned in connection with the cyclone. He did hear of six deaths
due to flooding on the evening (Australian time) of 10 Feb, but
Rona was only a fairly weak depression at that time. Perhaps this
discrepancy can be clarified later, and if so, will be reported on
in a future summary. There was a lot of flooding occuring in
portions of Queensland due to a couple of LOWS (possibly subtropical
or hybrid storms) which had struck the coast farther south in the
days preceeding Rona.
As far as agricultural losses go, the principal crop affected was
sugarcane. Cyclone Rona flattened cane crops between Mossman and
Townsville--a region which grows one-third of the state's sugarcane.
Winds gusting to 55 kts played havoc with the cane stalks (up to 3 m
in height), leaving them a tangled and matted heap. Other crops
hit hard by the high winds and torrential rains were bananas and
papaws. Banana farms around Innisfail, Tully, and Mission Beach
sustained major damage.
Much of the information presented above was taken from newspaper
accounts mailed to me by Matthew Saxby. A very special thanks to
Matthew for sending me the clippings.
***********************************************************************
SOUTHWEST PACIFIC (SWP) - South Pacific Ocean East of Longitude 160E
Activity for February: 1 tropical depression
2 tropical cyclones of gale intensity
1 tropical cyclone of hurricane intensity
NOTE: Most of the information presented below was taken from the
operational warnings and advisories issued by the Fiji TCWC at Nadi
and from the Monthly Summary for February prepared by Alipate
Waqaicelua, Principal Scientific Officer and Chief of the forecasting
group. A special thanks to Alipate for sending the summary to me.
Also, a special thanks is due Steve Ready of the New Zealand
Meteorological Service for forwarding to me some damage reports on
Tropical Cyclones Ella and Frank which he had received from Claude
Gaillard, the Director of Meteo France in New Caledonia.
References to sustained winds imply a 10-minute averaging period
unless otherwise noted. Also, the basic definition of a cyclone in
WMO Region 5 (Australia and the South Pacific) has the unique
requirement that a depression must have gale-force winds more or less
completely surrounding the center before the system is named as a
tropical cyclone. Hence, often gales of 35-40 kts may be present in
one or two quadrants but the system is not considered a tropical
cyclone.
Fiji this season has initiated their own numbering scheme for
tropical disturbances (01F, 02F, etc) that form in the Nadi AOR.
Some of the numbered disturbances never warrant depression status.
Numbers 11F, 12F, 13F, and 15F were all weak, short-lived tropical
disturbances occurring over the first half of February which did not
reach tropical depression status.
Tropical Cyclone Ella (TC-14F / TC-19P)
9 - 14 February
----------------------------------------
JTWC mentioned a LOW in their Tropical Weather Outlook at 0600 UTC
on 9 Feb located near 13S, 160E, or about 75 nm south-southwest of
Rennell Island, the southernmost island in the Solomon group. The LOW
was located in a monsoon trough, and a better-defined center had
consolidated farther to the north by 10/0000 UTC. JTWC and Nadi both
initiated bulletins on the system at this time, placing the center
about 35 nm north of Rennell Island. The depression drifted slowly
eastward for a day or so, passing just south of San Cristobal Island,
then turned to the southeast and began to intensify. Nadi named the
system Tropical Cyclone Ella at 0400 UTC on the 11th when it was well
southeast of San Cristobal. After reaching cyclone intensity Ella
turned to more of a southerly to south-southeasterly course and
accelerated.
Tropical Cyclone Ella passed about 100 nm west of the northern tip
of the Vanuatuan island of Espiritu Santo around 1500 UTC on 11 Feb.
The cyclone reached its peak intensity of 45 kts also about this time.
An area of strong subsidence to the south of Ella and a southerly flow
entrained drier air into the system which hindered its development.
Also, as a subtropical ridge to the east steered Ella quickly
southward, the cyclone moved into an area of increasing vertical wind
shear. By early on 12 Feb the low-level center had become exposed,
but later in the day moved back under some deep convection and
re-intensified slightly. This was reflected in the MSW estimates
by both JTWC and Nadi.
Ella passed about 175 nm west of Port Vila, Vanuatu, at 12/0000 UTC
and continued on rather quickly to the south-southeast. The cyclone
passed through the Loyalty Islands lying to the east of New Caledonia;
passing over Ouvea around 1200 UTC and brushing the west coast of
Lifou a few hours later. Ella passed about 60 nm east-northeast of
Noumea around 1800 UTC and continued on southeastward, slowly
weakening. The storm was declared extratropical by Wellington at
0000 UTC on 14 Feb when it was located about 200 nm northeast of
Norfolk Island.
Tropical Cyclone Ella was moving at about 20 kts when it passed
through the Loyalty Islands. The estimated MSW at the time was 40 kts,
but the rapid translational motion augmented the winds on the lefthand
side of the storm. Lifou recorded a maximum 10-min wind of 46 kts at
12/1314 UTC with a peak gust of 65 kts. Some significant damage was
sustained by buildings and vegetation on the northern side of the
island of Lifou, but no casualties or fatalities have been reported.
Tropical Cyclone Frank (TC-16F / TC-22P)
16 - 23 February
-----------------------------------------
Tropical Cyclone Frank had its origin in the Australian Region,
being a re-development of Tropical Cyclone Rona which had wreaked
havoc along the Queensland coast on 11 and 12 February. (See the
section of this summary covering the Australian Region for a
description of Rona.) After Rona weakened over the Queensland coast,
its remnant low- to mid-level circulation tracked southward,
re-emerging over water and then tracking to the east. By 0600 UTC
on 17 Feb the LOW was located about 300 nm east-northeast of
Rockhampton and moving eastward. By 18/1800 UTC the system had just
crossed into Fiji's AOR and had been named Frank. The cyclone was
centered at that time about 350 nm west-northwest of Noumea.
Steered by a mid-level ridge to its north, Frank continued on a
more or less due easterly course towards the northern tip of New
Caledonia and intensified. The cyclone reached hurricane force just
about the time it struck the extreme northern tip of the island
around 1800 UTC on 19 Feb. As a ridge to the east began to build
and with a trough approaching from the west, Frank turned to a south-
easterly course which took the center skimming along the eastern
coast of New Caledonia. Frank reached its estimated peak
intensity of 80 kts (100 kts 1-min MSW from JTWC) around 20/0000 UTC.
Even though very near the coast, the eye became much better defined.
After moving about halfway down the island, the cyclone turned to the
south and crossed right over the middle of the island, passing a
short distance to the west of Noumea around 20/1200 UTC.
After crossing over New Caledonia, Tropical Cyclone Frank began
to weaken due to the influence of increased northwesterly shear and
cooler SSTs. Fiji had downgraded Frank from hurricane force to storm
force by 20/2100 UTC, but JTWC kept the cyclone at hurricane strength
through 21/1800 UTC. By 0600 UTC on the 21st the low-level center
was fully exposed about 25 nm from the nearest deep convection. Ship
synoptic reports indicated that a broad 35-kt wind field existed
southeast to southwest of the cyclone.
Frank turned to the southwest after crossing New Caledonia, and
warning responsibility was passed to Wellington after 0600 UTC on
21 Feb. Wellington declared the storm extratropical at 1800 UTC
that day, but JTWC continued to issue warnings through 23/0000 UTC,
tracking the storm westward and then curving to the south-southeast.
The final JTWC warning located the extratropical center about 275 nm
west of Norfolk Island.
Frank possessed a very small radius of damaging winds, which meant
that Noumea experienced relatively light winds, even though the centre
of the cyclone passed only about 15 nm to the west. Some townships
in the north and west end of New Caledonia suffered power outages,
disruption to water supply and telecommunications, and there were some
landslides on coastal roads. Flooding caused some crop damage in the
northeast portion of the island, but there were no casualties or
serious damage to the infrastructure.
After the cyclone, Meteo France in New Caledonia alleged that the
actual maximum wind speeds were much lighter than the estimates
provided by Fiji and JTWC--that the highest MSW was closer to 65 kts
(Fiji's highest estimate was 80 kts--JTWC's was 100 kts 1-min avg).
Presumably this was based upon actual measurements from La Grande
Terre (New Caledonia's largest island) or else inferred from the
observed damage. But it should be pointed out that the island was
on the righthand (weaker) side of the storm with respect to its
direction of motion. With the translational speed being about 10 kts,
the MSW in the left semicircle could have easily been 15-20 kts higher
than in the right semicircle, especially considering that a
substantial portion of the right half of the cyclone's circulation
lay over the mountainous landmass.
Tropical Depression (TD-17F)
18 - 19 February
-----------------------------
A weak tropical depression was first identified on surface charts
at 17/1200 UTC, embedded along a monsoon trough over the southern parts
of Fiji and moving slowly eastward. By 0000 UTC on 18 Feb the LOW was
turning more to the southeast but had not become any better organized.
After 18 hours had elapsed some organization was beginning to appear
when the depression was just south of Tongatapu. Convection associated
with the system increased slightly but under increasing shear. The
first marine warning was issued at 2100 UTC, warning of gales in the
southern semicircle since it was moving into a surface ridge to the
south. The depression moved off to the southeast and the final warning
was issued at 19/1200 UTC when it was approaching Wellington's AOR.
Tropical Cyclone Gita (TC-18F / TC-24P)
27 February - 2 March
----------------------------------------
At 0000 UTC on 25 Feb a shallow depression was located just north
of the Southern Cooks, drifting slowly southward and embedded in the
SPCZ. Convection was quite disorganized though low-level cloud lines
were visible under the thick cirrus outflow, curving into the estimated
low-level center. The disturbance at this time was located in a
fairly strong shearing environment, but after 1800 UTC the upper-level
situation began to change to a slightly more favorable one, with
diffluence increasing and a weak ridge developing over the system.
By 26/1200 UTC curved convective bands were beginning to form with the
overall organization greatly improved as the LOW moved out of the
Southern Cooks towards the southeast.
At 27/0000 UTC Dvorak classifications from Honolulu had reached a
weak T3.0, so Nadi issued the first gale warning but with gales
forecast only in the southeastern semicircle. The depression at this
time was centered about 175 nm southeast of Mangaia or about 275 nm
southeast of Rarotonga. Another gale warning was issued 6 hours later
as the system was nearing the border of the Wellington AOR. By 1200
UTC the system was clearly a tropical cyclone but had moved out of
Fiji's AOR. For procedural/policy reasons, it was named Gita belatedly
after it had entered Wellington's AOR. (The monthly summary from
Alipate states that, in retrospect, the system should have been
upgraded to a tropical cyclone at 27/0000 UTC.)
Tropical Cyclone Gita continued south-southeastward into the "no
man's land" of the South Pacific, reaching an estimated peak intensity
of 45 kts by 0600 UTC on 28 Feb. Although Gita was downgraded to
an extratropical gale by 28/1800 UTC, it continued to display
significant central convection until after 0600 UTC on 1 Mar. Atypical
of most tropical cyclones in this part of the South Pacific, Gita was
not picked up by a westerly trough and accelerated into higher
latitudes. In a relatively weak shearing environment with gradually
cooling SSTs, the cyclone spun down slowly, continuing to generate
some convection near the center until 2 Mar. This sort of slow
"spin down" is often seen in Eastern North Pacific tropical cyclones
which move out over cooler waters, protected from the westerlies by
a ridge to the north.
NPMOC issued only two warnings on Gita, with the highest estimated
1-min MSW being 35 kts; but Dr. Mark Lander of the University of Guam,
unaware that any agency was issuing warnings on the cyclone, posted
a couple of reports to an e-mail discussion list. Mark's estimated
MSW (presumably 1-min avg) was 50 kts, in excellent agreement with
Wellington's 45-kt MSW (10-min avg). A good bit of discussion ensued,
especially concerning at what point should Gita have been called
extratropical. TPC/NHC (and presumably JTWC also) usually does not
classify a tropical cyclone as extratropical until it has merged with
a distinctive baroclinic zone. Regarding the Eastern North Pacific
cyclones which spin down slowly over cooler waters, TPC/NHC normally
carries these as tropical depressions until they have been reduced to
a swirl of low clouds with no convection and little hope of
re-generation.
Steve Ready of the New Zealand Meteorological Service, in an e-mail
message, stated that likely the decision to downgraded Gita to an
extratropical gale was premature, but that marine warnings were
continued through 0500 UTC on 3 Mar for the benefit of any
"not-so-ancient" mariners (Steve's expression) who might have been in
the vicinity. According to Steve it is very rare in the South Pacific
for a tropical cyclone to be carried as such after it has crossed
30S. In New Zealand, if and when any tropical cyclone (or one which
has recently transformed into an extratropical cyclone) threatens,
the word "tropical" is dropped and the system is referred to as
Cyclone "So-and-so". This enables the weather service to highlight
the origin of the storm and to raise the level of public response.
***********************************************************************
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 included in the July summary.
I will include this glossary from time to time, primarily in "lean"
months without a lot of tropical cyclone activity to cover. But if
anyone missed receiving it and wishes to obtain a copy, send me an
e-mail privately and I'll forward 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
February as an example: feb99.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: feb99.sum, for
example.
Back issues can also be obtained from the following websites
(courtesy of Michael Bath, Michael V. Padua, Tom Berg, and Michael
Pitt):
http://australiansevereweather.com/cyclones/>
http://www.geocities.com/capecanaveral/6825>
http://www.hcane.com/tropcl.html>
http://www.qisfl.net/home/hurricanemike>
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>
Prepared by: Gary Padgett
E-mail: [email protected]
Phone: 334-222-5327 (nights & weekends) / 850-882-2594 (weekdays)
***********************************************************************
***********************************************************************
|
Document: summ9902.htm
Updated: 18th March 2008 |
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