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Monthly Global Tropical Cyclone Summary March 1998
[Summaries and Track Data] [Prepared by Gary Padgett]
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Monthly Global Tropical Cyclone Summary March 1998 [Summaries and Track Data] [Prepared by Gary Padgett] |
MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY
MARCH, 1998
(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.)
HIGHLIGHTS
--> South Indian Ocean active but storms remain at sea
--> Vanuatu suffers damage from two cyclones
***********************************************************************
CORRECTIONS and UPDATES to Earlier Summaries
I have received some additional information from the South Indian
Basin on February cyclones, a correction to an observation reported
in the December summary, and some brief damage reports from French
Polynesia.
(1) Observations from Mauritius during Tropical Cyclone Anacelle
Arvind Mungur of London sent some information regarding the effects
of Anacelle as it passed about 65 nm east of Mauritius on 11 Feb. The
capital, Port Louis, recorded 125 mm of rain that day. Barometric
pressure fell to 986.1 mb, but wind gusts did not exceed hurricane
force. No details were given about the effects of this cyclone on
St. Brandon.
(2) Report on an unnamed tropical depression
Arvind Mungur also sent the following information (slightly edited):
A low-pressure area deluged Mauritius and especially Reunion in late
February. From 18-25 Feb Reunion recorded 1700 mm of rain with 572 mm
coming in 24 hrs on the 24th! This deluge caused severe flood damage,
landslides and powercuts--the worst rain damage in several years. The
peak rainfall in Mauritius occurred on 25 Feb (240 mm in 24 hrs).
According to news reports the depression passed about 80 nm southeast
of Mauritius on the 25th and caused mean winds of 20 kts with gusts
reaching 46 kts. The lack of warnings (the system was not classed as
a storm) caught the island by surprise, and there were many complaints
directed at weather forecasters and reporters for not warning the
public effectively--especially since conditions were as bad as during
Anacelle when warnings were in effect. Surface observations suggest
that this depression peaked at 25-30 kts on 25 Feb before heading
southward.
NOTE: I am not sure how this system was handled by the responsible
warning agencies in the South Indian Ocean. No warnings were issued
on this system by JTWC.
(3) Connection between TC-21S and TC-23S (Beltane)
Julian Heming of the Bracknell (UK) Meteorological Office sent the
following:
I thought you might be interested to know that the TC warning centre
at La Reunion considered TC-21S and TC-23S (Beltane) to be the same
system. I discussed this with Frank Wells of JTWC who thought there
was probably enough of a gap when the system was not clearly identi-
fiable to justify classifying TC-23S as a new TC. However, La Reunion
in their advisories continued to track the system back northward again
after JTWC had ended TC-21S. It crossed Madagascar a second time and
reformed in the Mozambique Channel when JTWC commenced advisories on
TC-23S.
(4) Tropical Cyclone Pam (SWP in Dec) observation dated incorrectly
Mark Kersemakers of the Fiji TCWC at Nadi uncovered an observation
from Rarotonga that had the wrong date. Reference the paragraph in
the December summary which begins with "Pam passed about 40 nm south-
west of Rarotonga at 0600 UTC on 9 Dec." The text subsequently
reports that the lowest pressure of 986 mb wasn't recorded until
10/0600 UTC--with a comment that this was rather strange. Mark sent
the following explanation:
CORRECTION: the 10/0600 UTC should have been 09/0600 UTC. The
information sent by me was wrong due to the forecaster who compiled
it not allowing for the dateline change--the barograph was in local
time. The time was converted but the date was not. This change no
longer makes the pressure strange.
(5) Damage report from French Polynesia
Steve Ready of the New Zealand Meteorological Service has sent a
little information regarding the effects of Tropical Cyclones Ursula
and Veli in the area of French Polynesia in early February. These
cyclones caused damage to three islands in the Tuamotu group: Mataiva,
Rangiroa, and Makatea. Mataiva was the worst struck with 39 houses
damaged, bridges down, roads washed away; Makatea had 5 houses damaged
while the airstrip on Rangiroa was inconvenienced by wash-up of coral
and sand. Ursula was the stronger of the two with damage due to pre-
cyclone swell rather than winds. Fortunately there was no loss of
life.
NOTE: A very special thanks to Arvind, Julian, Mark and Steve for
passing the above addenda/corrections on to me.
***********************************************************************
ACTIVITY BY BASINS
ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico
Activity for March: No tropical cyclones
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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: No tropical cyclones
***********************************************************************
NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea
Activity for March: No tropical cyclones
***********************************************************************
SOUTH INDIAN OCEAN (SIO) - South Indian Ocean West of Longitude 90E
Activity for March: 1 tropical cyclone of gale intensity
1 tropical cyclone of storm intensity
1 tropical cyclone of hurricane intensity
NOTE: The only sources of information on South Indian cyclones I have
available for the time being are the warnings issued by JTWC. All the
winds reported in the narrative are 1-min average maximum sustained
winds.
Tropical Cyclone Donaline (TC-26S) 6-10 March
-----------------------------------------------
The Joint Typhoon Warning Center (JTWC) on Guam issued the first
warning on a developing depression in the west-central South Indian
Ocean at 1200 UTC on 6 Mar, locating the system about 250 nm northeast
of Rodrigues Island. (Rodrigues lies about 315 nm slightly north of
due east of Mauritius.) The depression had become a tropical storm
with 40-kt winds by 07/0000 UTC. Initially Donaline drifted generally
in an eastward direction, but by 0000 UTC on 8 Mar was moving to the
south. Peak intensity of 55 kts was reached at this time when the
cyclone was centered about 400 nm east of Rodrigues. Afterward
Donaline began to weaken and accelerate off to the south-southeast.
The low-level circulation center had become completely exposed due to
shear by 09/1200 UTC. The system had weakened to below gale force
12 hrs later, and the last warning, issued at 1200 UTC on 10 Mar,
located the center about 750 nm southeast of Rodrigues.
Tropical Cyclone Elsie (TC-27S) 12-17 March
---------------------------------------------
JTWC issued the first warning on a rapidly developing tropical
system in the central Indian Ocean at 0000 UTC on 12 Mar. The system
was located about 850 nm southeast of Diego Garcia. Scatterometer
data from a pass at 11/1720 UTC showed a narrow vortex of 35-kt winds
around a low-level center with a band of 30-kt winds in the southeast
quadrant. Concurrent satellite imagery showed spiral bands forming
west and east of the center. Elsie moved generally in a south-
southwesterly direction for the next five days, reaching a peak
intensity of 90 kts at 1200 UTC on 13 Mar, only 36 hrs after the first
warning was issued. The cyclone at this time was centered about
1000 nm east of Rodrigues Island.
Elsie weakened just as quickly as it had intensified--by 14/1200
UTC the storm was experiencing moderate shear and winds had decreased
to minimal hurricane force. The south-southwesterly motion came to a
halt after 0000 UTC on 17 Mar and the weakening system turned to the
southeast. The last JTWC warning, issued at 17/1200 UTC, placed the
center about 950 nm east-southeast of Rodrigues. The final warning
indicated that extratropical transition was expected to be complete
within 24 hrs.
Tropical Cyclone Fiona (TC-28S) 17-20 March
---------------------------------------------
JTWC issued the first warning on Tropical Cyclone 28-S (to be named
Fiona by the Mauritius TCWC) at 0000 UTC on 17 Mar. The center of
this rapidly developing cyclone was located about 150 nm northwest of
Rodrigues. The initial warning estimated the maximum sustained winds
at 40 kts, and mentioned that conditions were ripe for continued rapid
strengthening: poleward outflow was linked up with mid-latitude
westerlies, a small CDO feature was present, and spiral bands indicated
good cross equatorial flow in the north and east quadrants. But the
anticipated intensification never happened. A passing shortwave trough
inhibited further development and winds were decreased to 35 kts in
the next warning. During this time Fiona had drifted westward to a
position about 215 nm northeast of Mauritius.
The weak storm next moved to the southeast for about 24 hrs but then
curved back to the west. After the trough had lifted out Fiona gained
a little in intensity, but vertical shear never really lessened enough
to allow the cyclone to intensify further. Fiona passed about 75 nm
east of Mauritius at around 1500 UTC on 19 Mar with 40-kt winds.
Continuing on to the south, the system began to slowly weaken once more
with the last warning placing the center about 225 nm east-southeast
of La Reunion at 20/1200 UTC.
Newspaper reports stated that wind gusts up to 38 kts were recorded
in the eastern portion of Mauritius as Fiona passed by, but there were
no rainfall nor pressure observations mentioned. (Thanks to Arvind
Mungur for passing along this bit of information.)
***********************************************************************
AUSTRALIAN REGION (AUS) - From Longitude 90E Eastward to Longitude 160E
Activity for March: 1 tropical cyclone of storm intensity
1 former tropical cyclone (extratropical or hybrid)
NOTE: Some of the material presented on Tropical Cyclone Nathan is
taken from the March Darwin Tropical Diagnostic Statement. Thanks
to Sam Cleland for sending that report to me. Unless stated other-
wise, references to sustained winds imply a 10-min averaging period.
Tropical Cyclone Nathan (TC-30P) 21-31 March
----------------------------------------------
Tropical Cyclone Nathan developed from a LOW embedded in the weak
monsoon trough soon after Yali had reached tropical cyclone intensity
farther east. Although upper-level outflow was favorable, mid-level
shear restricted rapid development. Nathan developed rather quickly
initially--the first warning, issued at 0000 UTC on 21 Mar, classified
the system as a 40-kt tropical cyclone just east of the northern Cape
York Peninsula, or about 300 nm north-northwest of Cooktown on the
Queensland coast. During its early stages Nathan dropped up to 400 mm
of rain on the northern and eastern portions of the peninsula.
Being a small system in an environment of weak steering flow, Nathan
moved slowly and erratically--generally eastward away from the coast,
and then in a southerly direction, coming to within 100 nm of Cooktown
at 23/1200 UTC. The Brisbane TCWC consistently reported Nathan's
maximum 10-min average winds at 45-50 kts throughout most of its
life, but JTWC briefly elevated the storm to minimal hurricane status
at 65 kts (1-min avg) from 1200 to 1800 UTC on the 23rd. After
approaching the Queensland coast, Nathan came under the steering
influence of the broad monsoon flow that had been dragged south by
Tropical Cyclone Yali. The cyclone began moving in an east-
northeasterly direction at an accelerated pace, becoming more easterly
after 25/0000 UTC.
By 0000 UTC on 26 Mar Nathan was located about 275 nm southwest of
Honiara on Guadalcanal and was becoming sheared. This shearing
process was possibly related to the large extratropical (or hybrid)
system to the south which had been Yali. Nathan curved to the south
on the 27th and Brisbane downgraded the system to a depression and
ceased issuing advices. By 27/1200 UTC the cyclone was located about
200 nm north-northeast of the Chesterfield Islands and was showing some
signs of re-intensification. A CDO feature had regenerated and spiral
bands were wrapping into a well-defined center; therefore, JTWC upped
the winds to 45 kts and continued to issue warnings on Nathan. The
system then began to move back to the west and slowly weakened as it
approached Australia once more.
A scatterometer pass on 29 Mar indicated a small area possibly
containing 35-kt winds, and a 30/0000 UTC observation from Willis
Island reported 30-kt easterly winds. JTWC kept Nathan as a minimal
tropical cyclone until 0000 UTC on 31 Mar, when it was downgraded to
a weakening depression about 150 nm north-northwest of Cooktown.
Tropical Cyclone Yali (TC-29P) 25-27 March
--------------------------------------------
Tropical Cyclone Yali, which had spent most of its life in the Fiji
area of warning responsibility, moved westward across 160E around
1200 UTC on 25 March into the Australian region for a couple of days
before undergoing rapid deepening as an extratropical cyclone and
pommelling New Zealand with high winds and seas and heavy rains.
Yali was not a true tropical cyclone by the time it entered Australian
waters. It had been captured by an upper LOW and was somewhat like the
hybrid storm systems which are occasionally seen in North Atlantic
subtropical waters and usually referred to as subtropical cyclones.
Fiji and Brisbane regarded the system as extratropical while Guam
continued to issue tropical cyclone warnings until 27/0000 UTC. For
the complete history of Tropical Cyclone Yali, see the section of
this summary covering the Southwest Pacific Basin.
***********************************************************************
SOUTHWEST PACIFIC (SWP) - South Pacific Ocean East of Longitude 160E
Activity for March: 1 tropical depression
2 tropical cyclones of hurricane intensity
NOTE: Thanks to Steve Ready of the New Zealand Meteorological Service
at Wellington for passing along some information on Tropical Cyclone
Yali. Also, some of the material on Yali is taken from the March
Darwin Tropical Diagnostic Statement. Unless stated otherwise,
references to sustained winds imply a 10-min averaging period.
Tropical Depression 28 February-2 March
-----------------------------------------
A tropical depression had formed in the southeastern Solomon Islands
on 28 Feb near Santa Cruz Island. At 0000 UTC on 1 Mar the depression
was centered about 350 nm east-southeast of Honiara on Guadalcanal.
Over the next couple of days the system drifted generally in an
easterly to southeasterly direction without significant strengthening.
By 02/0600 UTC the last bulletin issued by Nadi located the depression
about 250 nm northeast of Port Vila in Vanuatu. Winds in the eastern
semi-circle were forecast to possibly reach gale force on 2 Mar but
the system did not develop into an organized tropical cyclone.
Tropical Cyclone Yali (TC-29P) 18-27 March
-------------------------------------------
A well-defined low pressure system was identified in the Southwest
Pacific on 18 Mar and drifted to the west between Vanuatu and the
Solomon Islands while slowly strengthening. Yali was named by the
Nadi TCWC at 1800 UTC on 19 Mar when located about 350 nm due north-
west of Port Vila, Vanuatu. The first JTWC warning at 18/1200 UTC,
centering the LOW about 350 nm north-northwest of Port Vila, classified
the system as a minimal tropical cyclone with 35-kt (1-min) winds. Up
to this time Yali had been tracking to the southwest, but by 0600 UTC
on 20 Mar the cyclone had begun moving on a southeasterly track due to
a strengthening of the northwest monsoon flow to the north of the
storm.
For the next two-and-a-half days Yali moved on a southeastward
course, passing west of the main islands of Vanuatu but finally coming
close enough to brush the southernmost islands of Tanna and Aneityum.
Yali reached hurricane force at 21/1200 UTC when located about 100 nm
west-northwest of Port Vila. The center of the hurricane passed
about 60 nm west of Port Vila around 0000 UTC on 22 Mar but no strong
winds were reported. Peak intensity of 70 kts (10-min avg) with an
estimated central pressure of 965 mb was attained at 22/0600 UTC when
Yali was centered about 80 nm south of Port Vila, which reported winds
of only 11 kts and a pressure of 992 mb. (It is possible that the low
wind reading was due to poor exposure of the instrument.)
By 1800 UTC on 22 Mar Tropical Cyclone Yali had reached its eastern-
most position about 200 nm southeast of Port Vila. The upper ridge to
its north had intensified, increasing shear and restricting convection;
consequently Yali began to weaken, dropping below hurricane force. At
the same time a mid-level subtropical ridge to the south began to
impact its motion with easterly flow forcing a westward component to
its track. As Yali moved to the southwest and slowly weakened,
the wind field was becoming quite asymmetric. At 23/0000 UTC gales
were reported 90 nm to the north but 150 nm to the south. Matthew
Island, about 130 nm southeast of the center, reported east winds of
40 kts. The main convection at this time was about 140 nm south of
the center.
At 1200 UTC on 23 Mar Yali was located about 125 nm east of Noumea,
New Caledonia with 45-kt winds. The weakening cyclone passed just
south of New Caledonia late on 23 Mar (UTC) as it continued on its
southwesterly track. By 25/0000 UTC an upper LOW had captured the
cyclone with cold air cumulus working around the west and north sides
of the circulation. Yali had become a hybrid-type cyclone of the
type often referred to in the North Atlantic as a subtropical cyclone.
Fiji downgraded the system to an extratropical system and discontinued
advisories. JTWC continued to track Yali southwestward in the general
direction of Australia.
The semi-tropical Yali slowed and moved more on a westerly track
as it approached and crossed 160E on 24 and 25 Mar. By 26/1200 UTC
the center of the large cyclone was about 300 nm east-northeast of
Brisbane. Some convection was noted re-developing about 90 nm south
of the elongated center with gales likely affecting the Australian
coast on 26 and 27 Mar. By 0000 UTC on 27 Mar the cyclone was moving
more quickly to the south with the final JTWC warning placing the
center about 325 nm east-southeast of Brisbane.
Yali underwent a transformation over the Tasman Sea. It came under
the influence of a double jet structure (equatorward entrance of one,
polar exit of another) and strong cyclonic vorticity advection at
500 mb. The system deepened and moved rapidly towards the southern
end of New Zealand's South Island. Its central pressure lay between
970-975 mb as it crossed the coast on 29 Mar. Wind damage was reported
over a wide area--roofs lifted, flying debris, trees toppled, power
lines down. Heavy rain was experienced in the western and southern
portions of the South Island over a 6-12 hr period, but fortunately
the fast-moving nature of the storm prevented any significant rain
flooding. The passage of Yali coincided with exceptionally high
tides, causing sea flooding near Nelson and Westport. One youth was
washed into the sea near New Plymouth (central North Island) and
drowned. After passing New Zealand the remains of Yali eventually
became absorbed into the circumpolar trough between 65S and 75S.
Some of the southernmost islands of Vanuatu: Aniwa, the northern
and western portions of Tanna, and the southern and western sides
of Erromango, suffered rather severe damage from Yali. About 60-70%
of the crops and 30% of the houses were badly damaged by winds with
some damage to roads on Tanna. Both Tanna and Aniwa had suffered
from a drought before the cyclone came along so stocks of food were
quite low. Only minor damage was reported elsewhere in Vanuatu.
Tropical Cyclone Zuman (TC-31P) 29 Mar-->
-------------------------------------------
The tropical depression that was to develop into Tropical Cyclone
Zuman was first noted about 300 nm northeast of Port Vila in Vanuatu
at 2100 UTC on 29 Mar. The system had become a tropical cyclone and
was named at 1200 UTC the next day when centered about 250 nm north-
northeast of Vila. Zuman moved westward until around 0600 UTC on
31 March as it steadily strengthened, then took a turn to the south-
west and intensified quite rapidly. The cyclone had struck the island
of Espiritu Santo by 0000 UTC on 1 Apr with sustained 10-min winds
estimated at 80 kts. Early reports indicate that the island incurred
rather heavy damage from the cyclone. Next month's summary will
contain a full report on Tropical Cyclone Zuman.
***********************************************************************
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) The files will be named with an obvious nomenclature--using
March as an example: mar98.tracks
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 March summary is the sixth cyclone summary in this series;
the first one covering the month of October, 1997. If anyone did
not receive any of the previous summaries, they may be downloaded
from the aforementioned FTP site at HRD. The summary files are
catalogued with the nomenclature: oct97.sum, for example.
Back issues can also be obtained from the following website
(courtesy of Michael Bath):
http://australiansevereweather.com/cyclones/>
The preliminary storm reports for all the 1997 Atlantic and Eastern
North Pacific tropical cyclones are available on the Tropical
Prediction Center's website: http://www.nhc.noaa.gov> . These
reports include the analyzed best-track for each cyclone. The staff
of JTWC is also working on an on-line version of their Annual Tropical
Cyclone Report for 1997. It is still under construction, but the
best-track files are already available for 1997 Northwestern Pacific
and North Indian Ocean cyclones. The URL is:
http://www.npmocw.navy.mil/npmocw/prods/jtwc.html>
Prepared by: Gary Padgett
E-mail: [email protected]
Phone: 334-222-5327
***********************************************************************
***********************************************************************
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Document: summ9803.htm
Updated: 18th March 2008 |
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