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Monthly Global Tropical Cyclone Summary April 1999
[Summaries and Track Data] [Prepared by Gary Padgett]
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Monthly Global Tropical Cyclone Summary April 1999 [Summaries and Track Data] [Prepared by Gary Padgett] |
MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY
APRIL, 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.)
ATLANTIC and NORTHEASTERN PACIFIC
TROPICAL CYCLONE NAMES FOR 1999
---------------------------------
ATLANTIC, CARIBBEAN SEA, GULF OF MEXICO:
----------------------------------------
Arlene, Bret, Cindy, Dennis, Emily, Floyd, Gert, Harvey, Irene, Jose,
Katrina, Lenny, Maria, Nate, Ophelia, Philippe, Rita, Stan, Tammy,
Vince, Wilma
EASTERN NORTH PACIFIC (east of 140W):
-------------------------------------
Adrian, Beatriz, Calvin, Dora, Eugene, Fernanda, Greg, Hilary, Irwin,
Jova, Kenneth, Lidia, Max, Norma, Otis, Pilar, Ramon, Selma, Todd,
Veronica, Wiley, Xina, York, Zelda
CENTRAL NORTH PACIFIC (140W to 180):
------------------------------------
Upana, Wene, Alika, Ele, Huko, Ioke, Kika, Lana
***********************************************************************
EXTRA FEATURE - QUARTERLY TROPICAL DISTURBANCE TALLY
Mr. Matthew Saxby, of Queanbeyan, New South Wales, who assists me
with collecting information and preparing cyclone tracks for the
Australian Region, attempts to keep a tally of all the weak tropical
disturbances which are mentioned in tropical weather discussions and
outlooks from the various TCWCs. Matthew recently sent me his totals
of tropical disturbances and tropical cyclones in the various basins
for the first three months of 1999.
I present them below essentially as Matthew sent them. Using the
Perth AOR as an example, the pairs of figures should be read as "20
tropical disturbances and 6 tropical cyclones formed in the area", NOT
as "20 tropical disturbances of which 6 became tropical cyclones".
In the Southern Hemisphere tropical disturbances regularly form in
one AOR and wander into another centre's AOR where they develop into
tropical cyclones. Also, it should be pointed out that Matthew
apparently has used JTWC's 1-min MSW estimate as his criterion for
the count of tropical cyclones (equivalent to a tropical storm in
the Northern Hemisphere and the Southwest Indian Ocean).
REGION TROPICAL DISTURBANCES TROPICAL CYCLONES
----------------------------------------------------------------------
Arabian Sea 5 0
Bay of Bengal 8 1
Brisbane AOR 25 4
Central North Pacific 0 0
Darwin AOR 12 2
Eastern North Pacific 4 0
Fiji AOR (South Pacific) 22 6
North Atlantic 1 0
Papua New Guinea AOR 2 0
Perth AOR 20 6
Southwest Indian Ocean 28 7
Western North Pacific 49 2
***********************************************************************
APRIL HIGHLIGHTS
--> Western Australia struck by another cyclone
--> First two Northwestern Pacific typhoons of the year develop
***********************************************************************
ACTIVITY BY BASINS
ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico
Activity for April: No tropical cyclones
***********************************************************************
NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180
Activity for April: No tropical cyclones
***********************************************************************
NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180
Activity for April: 1 tropical storm **
2 typhoons **
** - This based upon JTWC's classification. PAGASA and JMA did not
classify Jacob as a tropical storm nor Kate as a typhoon.
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.
Northwest Pacific Activity for April
------------------------------------
In stark contrast to 1998 when the first Northwest Pacific typhoon
did not occur until August, the month of April saw the first two
typhoons of 1999 develop during the final days of the month. Prior
to the development of Typhoon Kate/Diding, JTWC had named three short-
lived, minimal tropical storms, but none of these was regarded as a
tropical storm by either JMA or PAGASA. Brief Tropical Storm
Jacob/Karing and Typhoon Kate/Diding remained in the Pacific east of
the Philippines, but Typhoon Leo formed in the South China Sea and
for a time posed a significant threat to Hong Kong and southern China,
but fortunately the storm weakened dramatically as it approached those
areas.
Tropical Storm Jacob/Karing (TC-03W)
6 - 10 April
-------------------------------------
A tropical disturbance was first mentioned in a JTWC Tropical
Weather Outlook on 3 Apr and was located about 500-600 nm south-
southwest of Guam. The disturbance continued moving generally
in a northwesterly direction, and by 0600 UTC on 6 Apr, when the first
depression warning was issued, was located about 200 nm west-northwest
of Palau. The center was relocated farther to the north at 0000 UTC
on 7 Apr based on visible satellite imagery. After some slow and
erratic movement, the depression took off on a steady west-
northwesterly course toward the central Philippines. This was a
shallow, weak system with satellite imagery indicating multiple low-
level circulation centers.
PAGASA initiated warnings on the system at 08/0000 UTC, naming the
depression Karing. JTWC upgraded the depression to Tropical Storm
Jacob at 2100 UTC. Satellite intensity estimates were only 30 kts,
but there was a ship observation of 35-kt winds. The low-level
center was partially exposed west of the deepest convection at this
time. However, six hours later the center had become fully
exposed about 40 nm west of the convection and the minimal tropical
storm was downgraded to a depression. An SSM/I pass over the system
at 09/1200 UTC showed the low-level circulation center to be virtually
non-existent. Tropical Depression Karing, or what was left of it,
limped into the central Philippines around 10/0000 UTC with only
20-kt winds. Convection briefly increased as the system moved over
land but the effects were very slight.
Typhoon Kate/Diding (TC-04W / STS 9901)
22 - 28 April
----------------------------------------
A tropical disturbance was located several hundred miles east of
southern Mindanao in the Philippines as early as 12 Apr. The system
moved westward and by the 15th had more or less taken up residence
over the island. The weak LOW center remained quasi-stationary in
the vicinity of Mindanao for about one week prior to the issuance of
the first warnings. JTWC wrote the first depression warning at
0000 UTC on 22 Apr, placing the center near Surigao on the northern
tip of Mindanao. PAGASA commenced bulletins at the same time, naming
the depression Diding. PAGASA's initial center position was about
90 nm east-northeast of JTWC's position, indicating that the system
was still quite disorganized.
Tropical Depression Diding slowly began to move northward into a
weakness between two subtropical ridges. PAGASA classified the
system as a tropical storm by 22/1200 UTC, but JTWC did not upgrade
it to Tropical Storm Kate until 23/0000 UTC when the center was
approximately 150 nm east of Catanduanes Island. Tropical Storm
Kate/Diding slowly intensified as it moved northward and later north-
eastward, steered by a ridge to its southeast. Although upper-level
winds were out of the southwest, the storm was moving with the flow,
thus lessening the relative shear. MSW estimates from JTWC reached
60 kts on 25 Apr but were down to 50 kts by 26/1800 UTC. The original
warning at 27/0300 UTC gave 50 kts as the MSW, but an amended warning
was issued later which raised the winds back to 60 kts based upon
recent satellite imagery.
The next JTWC warning, issued at 27/0900 UTC, upgraded Kate to a
typhoon with 75-kt MSW. The 0600 UTC position placed the typhoon about
100 nm west-southwest of Iwo Jima, moving northeastward at 18 kts.
The Dvorak rating of Kate at this time was T4.5. Interestingly, the
MSW (10-min) estimates from JMA, which reflected the aforementioned
slight weakening on 26 Apr, did not increase during this phase of
Kate's life. The maximum 10-min MSW from either JMA or PAGASA was
55 kts, so Kate/Diding was not a typhoon by their reckoning.
With a mid-latitude trough approaching from the northwest and still
being steered by the ridge to its southeast, Kate accelerated to the
northeast, moving at about 21 kts by 1500 UTC on 27 Apr. As Kate
continued to the northeast, cooler and drier air was entrained into
the system and the storm began to weaken. By 28/0300 UTC the low-
level center was fully exposed and there was limited convection found
in the eastern quadrant only. By 1200 UTC on the 28th Kate had become
extratropical about 500 nm northeast of Iwo Jima.
Typhoon Leo (TC-05W / TY 9902)
27 April - 2 May
-------------------------------
The first Northwest Pacific cyclone of 1999 to be recognized as a
typhoon by all relevant warning centers began as a monsoon depression
in the South China Sea. First mentioned in a JTWC Tropical Weather
Outlook on 25 Apr, the system had become sufficiently organized by
27 Apr that depression warnings were initiated by JTWC, placing the
weak center about 385 nm west of Manila. Most of the convection at
this stage was located along the periphery of the circulation. The
center, which had been quasi-stationary for a day or so, was relocated
at 27/1800 UTC to a point about 140 nm northwest of its prior location.
Deep convection was beginning to consolidate around the new center, and
the system slowly began to take on the appearance of a more typical
tropical depression.
Tropical Storm Leo was christened at 0600 UTC on 28 Apr about 65 nm
east of Da Nang, Vietnam. However, the system was still somewhat
disorganized with several circulation centers apparent. Visible
satellite imagery showed a broad circulation extending northeastward
from the warning position. There were numerous ship reports of winds
to tropical storm intensity. Leo appeared to describe a tight loop
off the central Vietnamese coast, and then commenced a northeastward
heading as it steadily intensified.
The storm was upgraded to Typhoon Leo at 1800 UTC on 29 Apr when it
was centered about 250 nm south of Hong Kong. Satellite intensity
estimates were 65 kts but some scatterometer data indicated winds to
70 kts. The typhoon at this time was located under a 200-mb ridge,
and intensification proceeded at a fairly quick pace. By 30/0000 UTC
winds were up to 80 kts with Leo sporting a 45-nm diameter eye. Steered
by a mid-level ridge to its east, Leo continued on its northeastward
track toward southern China. Peak intensity of 110 kts was reached
at 30/1800 UTC when the by now 15-nm diameter eye was centered roughly
150 nm south-southeast of Hong Kong. This intensity was based on
Dvorak ratings of T5.5 and T6.0. The 10-min MSW from JMA was
predictably much lower, reaching 75 kts from 0600 through 1800 UTC.
As the month of May opened, Typhoon Leo was presenting a severe
threat to Hong Kong and the southern Chinese mainland. This threat,
however, was never realized. As the storm continued northeastward,
it encountered significant vertical shear associated with the mid-
latitude westerlies over China. After reaching its peak intensity
on 30 Apr, Leo began to weaken quite rapidly, dropping below typhoon
intensity by 0000 UTC on 2 May. Only 12 hours later the storm was
downgraded to a tropical depression centered about 25 nm east of Hong
Kong. The very weak center limped ashore into southern China where
it quickly dissipated. This very rapid weakening of Leo was
somewhat reminiscent of the rapid collapse of Hurricane Madeline off
the west coast of Mexico last October in which the storm weakened
from a 75-kt hurricane to a dissipating depression with only 20-kt
winds in 24 hours after being blasted with strong vertical shear.
***********************************************************************
NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea
Activity for April: No tropical cyclones
***********************************************************************
SOUTH INDIAN OCEAN (SIO) - South Indian Ocean West of Longitude 90E
Activity for April: 1 weakening tropical storm
1 tropical cyclone
The primary source 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 implying 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 Evrina and Hamish.
This forms the basis for the tracking information given for these
systems in the accompanying track file.)
South Indian Ocean Activity for April
-------------------------------------
Both of the tropical systems in the South Indian Ocean west of
90E during April were visitors from the Australian Region. Intense
Tropical Cyclone Frederic entered the basin early on 1 Apr and was
renamed Evrina by Mauritius, but was beginning to weaken rather
quickly at that point. Later, weakening Tropical Cyclone
Hamish crossed the boundary as a sheared and weakening cyclone.
Hamish was of tropical storm intensity west of 90E for a few hours
on 21 Apr, but was not renamed Francine by Mauritius, probably
because it was rapidly weakening and not forecast to re-intensify.
Tropical Cyclone Frederic/Evrina (TC-31S)
26 March - 8 April
------------------------------------------
Tropical Cyclone Frederic crossed 90E into the South Indian Ocean
basin around 0400 UTC on 1 Apr at a point about 525 nm west-southwest
of Cocos Island and was renamed Evrina by the Mauritius TCWC.
Frederic had reached its peak intensity of 110 kts (140 kts 1-min avg)
MSW late on 31 Mar, but even then the convection was beginning to
elongate due to increased shear. This shear appears to have
been due to the cyclone moving into a weakness in the subtropical
ridge between two HIGH cells. (As was pointed out in the March Global
Summary, a similar situation occurred with Atlantic Hurricane Georges
east of the Lesser Antilles last September.) As Frederic/Evrina
continued on a course slightly south of due west, it began to weaken
fairly quickly, due to the aforementioned shear and some low-level
cold air entrainment from the south.
The Best Track data from La Reunion indicates Evrina's intensity
had dropped below hurricane force by 02/0600 UTC, but JTWC carried the
storm as a hurricane for about 24 hours longer. Strong northwesterly
flow in the upper levels continued to weaken the system with the
low-level center completely exposed by 1200 UTC. As Evrina continued
westward it maintained a well-defined low-level circulation center
with occasional bursts of intense convection developing, so it was
rather slow to weaken. Satellite intensity estimates were only
about 25 kts after 06/0000 UTC, but the MSW estimates from JTWC and
La Reunion were slightly higher to account for the tightly-wrapped
low-level circulation center. Evrina was downgraded to a tropical
depression by La Reunion at 05/0600 UTC when located about 450 nm
east of Rodrigues Island, while JTWC maintained gale-force winds in
their warnings through 1200 UTC on 6 Apr. The weakening system
slowed in its forward motion on the 7th due to a weakness in the
subtropical ridge which had been steering it westward. From the
8th through the 10th the remnant LOW drifted back eastward roughly
parallel to and south of its earlier westward track.
Evrina was only the second tropical cyclone (hurricane) to occur
in the South Indian Ocean west of 90E this season, and there was only
one tropical cyclone--Anacelle--in this region during the 1997-98
season. Tropical depression/storm/cyclone developments across the
entire South Indian Ocean have been clustered into three areas this
season: the Mozambique Channel, the area around longitude 90E along
the border with the Australian Region, and off the northwestern and
northern coasts of Australia, with the latter area producing the most
intense cyclones by far in the entire Southern Hemisphere this season.
Tropical Storm Hamish (TC-33S)
19 - 24 April
-------------------------------
A weak disturbance in the monsoon trough southwest of Sumatra was
mentioned in the daily JTWC Tropical Weather Outlooks as early as
8 Apr in the general vicinity of 8 S, 85 E. The area remained quasi-
stationary for several days, becoming a little better organized on
the 9th and 10th, then weakening again. By 17 Apr a weak low-level
circulation was evident and convection was becoming better organized
once more. The LOW had also drifted eastward and had moved east of 90E
into the Australian Region by 18 Apr.
The system intensified and was named Tropical Cyclone Hamish by the
Perth TCWC at 1000 UTC on 20 Apr. The cyclone remained in the western
extremity of the Perth AOR and moved back westward across 90E around
1600 UTC on 21 Apr at a point about 475 nm west-southwest of Cocos
Island. The cyclone was rapidly weakening at this time, and
although of tropical storm intensity for a few hours (as per La
Reunion's intensity assessments), was not renamed by the Mauritius
TCWC (the name would have been Francine). Likely, the system was not
renamed due to the fact that it was rapidly weakening and not likely
to re-intensify. However, JTWC maintained the system at tropical
storm intensity through 1200 UTC on 23 Apr due to some scatterometer
winds of 40 kts and very tightly-wound low-level cloud lines, even
though satellite intensity assessments were only 30 kts. The remnant
LOW continued westward, losing its identity by 24/0600 UTC about
900 nm south-southeast of Diego Garcia.
(For more details on the history of this system while it was east
of 90E, see the section of this summary covering the Australian
Region.)
***********************************************************************
AUSTRALIAN REGION (AUG) - From Longitude 90E Eastward to Longitude 160E
Activity for April: 1 tropical LOW (depression)
1 tropical cyclone of gale intensity
1 severe tropical cyclone (hurricane 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, assists 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.
Australian Region Activity for April
------------------------------------
Less than two weeks after intense Tropical Cyclone Vance had cut a
destructive swath across Australia, another intense cyclone threat
appeared off Western Australia in the form of Tropical Cyclone Gwenda,
which briefly became a very intense storm, but fortunately weakened
considerably before making landfall. Short-lived Tropical Cyclone
Hamish formed in the western extremity of the Perth AOR during the
third week of the month but soon moved into the Mauritius AOR and
weakened.
A weak but persistent Tropical LOW developed and hung around the
northern Gulf of Carpentaria for several days around mid-month. The
Darwin TCWC tracked the system for several days and a couple of gale
warnings were issued on 17 Apr with winds to 35 kts forecast for the
southern and eastern quadrants only, but the LOW did not develop
further and was not upgraded to a tropical cyclone. Some stations
along the Northern Territory and Queensland coasts did receive some
significant rainfall from this system. Some 24-hr totals from the
18th include Coconut Island - 28 mm, Horn Island - 88 mm, Lockhart
River - 36 mm (these stations in Queensland); and from the Northern
Territory: Gove - 51 mm and Northeast Island - 65 mm. From the
period 16-18 Apr (presumably) some 72-hr rainfall accumulations
were Gove - 191 mm, Nhulunbuy - 167 mm, Northeast Island - 71 mm,
and Nabalco - 147 mm. All of these stations are located in the
Northern Territory. (Thanks to Matthew Saxby for sending me this
rainfall information.)
Severe Tropical Cyclone Gwenda (TC-32S)
3 - 7 April
----------------------------------------
A weak tropical disturbance appeared as early as 1 Apr in the
Arafura Sea off the Northern Territory coast. It drifted westward,
slowly becoming better organized, and by late on 3 Apr was located
about 300 nm west of Darwin. The TCWC at Darwin issued the first
warning at 2300 UTC indicating that the LOW possibly might develop
into a tropical cyclone. The system continued steadily westward
and passed into the Perth AOR by 1000 UTC on 4 Apr. The LOW moved
directly beneath a 200-mb ridge axis and quickly intensified to
Tropical Cyclone Gwenda by 05/0400 UTC. Gwenda's center at this time
was approximately 350 nm north-northwest of Broome. The cyclone
intensified explosively, reaching a peak MSW of 110 kts and an
estimated central pressure of 915 mb only 30 hrs later when it was
centered about 300 nm north-northwest of Port Hedland. (JTWC's peak
1-min MSW of 125-130 kts agrees well with Perth's 10-min MSW values.)
Gwenda became the fourth tropical cyclone this season in the
southeast Indian Ocean to reach Category 5 on the Australian cyclone
scale, the others being Thelma, Vance, and Frederic. At its peak
intensity Tropical Cyclone Gwenda displayed an eye 16 nm in diameter.
Gwenda's track beginning with the point at which it became a
tropical cyclone constituted an almost perfect parabola. The cyclone
reached its westernmost point about the time it reached maximum
intensity, moved slowly southward for about 12 hrs, and then curved
back to the southeast toward the Western Australian coast. By 0700 UTC
on the 4th Gwenda had passed the 200-mb ridge axis and was beginning
to encounter significant shear which caused the convection to stream
off to the southeast. The cyclone continued to rapidly weaken as it
approached the coast just east of Port Hedland.
Based on some information from a JTWC warning, landfall occurred
around 07/1600 UTC about 45 km east of Port Hedland with MSW (1-min)
estimated near 60 kts, which corresponds to a 10-min MSW of around
50-55 kts. A Tropical Cyclone Advice from Perth indicated that
gusts to 100 km/hr (54 kts) were experienced in Port Hedland. The
final Perth warning placed the weakening system inland about 50 km
west-southwest of Pardoo (or 65 km east of Port Hedland) and almost
stationary.
Apparently the strong northwesterly shear stripped away the
deep convection from the low-level center and propelled it rapidly
away to the southeast while the center remained near the coast; thus
there were no large accumulations of rainfall at any one locale.
Both Matthew Saxby and Mark Kersemakers reported that they'd learned
of no significant damage resulting from Tropical Cyclone Gwenda.
Tropical Cyclone Hamish (TC-33S)
19 - 24 April
---------------------------------
A tropical disturbance which had formed around 8 Apr in the monsoon
trough southwest of Sumatra west of 90E moved into the Australian
Region late on 17 Apr as it was beginning to show signs of increased
organization. Perth initiated warnings on the LOW at 19/1000 UTC when
it was centered roughly 350 nm west-northwest of Cocos Island. The
first JTWC warning at 20/0000 UTC noted that the system was under a
200-mb ridge axis but that there was a high vertical shear zone to
the south. The LOW continued to intensify and was named Tropical
Cyclone Hamish at 1000 UTC on 20 Apr when the center was located about
300 nm west of Cocos. The system had been moving south-southeastward
during its development stage, but after reaching cyclone intensity
began to move to the southwest.
As Hamish continued moving poleward it soon began to encounter
increasing vertical shear. Peak MSW (as estimated by Perth) of 55 kts
was reached at 0400 UTC on 21 Apr. Interestingly, JTWC's highest
1-min MSW was only 45 kts. A ship reported winds to 45 kts around
21/0000 UTC and scatterometer data also indicated winds of 45 kts were
occurring in the system. As the convection began to be sheared off
to the southeast, the subtropical ridge to the storm's south became
the predominant steering influence and the weakening Hamish turned to
a westward track which carried it across 90E and back into the South
Indian Ocean basin.
(For more details on the early and latter history of this system
west of 90E, see the section of this summary covering the South Indian
Ocean basin.)
ADDENDA to FEBRUARY TROPICAL CYCLONE SUMMARY
--------------------------------------------
In early February a couple of strong LOWS formed in the Coral
Sea off Queensland which perhaps had some hybrid (subtropical)
characteristics. The second of these contributed to significant
rainfall amounts over southeastern Queensland which led to widespread
flooding and several deaths. Since this flooding immediately
preceded Tropical Cyclone Rona, there was some confusion in the media
between the two storms, and the fatalities caused by the flooding
from the LOW near Brisbane were erroneously attributed to Rona.
Matthew Saxby and Jeff Callaghan from the Brisbane TCWC have sent me
some information on these storms, and I shall synopsize some of the
information in the following paragraphs. (A special thanks to Jeff
and Matthew for forwarding the information to me.)
LOW #1 - The first of the two LOWs tracked southward at a distance
off the Queensland coast, roughly straddling the 158th meridian. It
was centered about 425 nm east of Rockhampton at 1800 UTC on 3 Feb,
passed about 300 nm east of Brisbane around 0600 UTC on the 4th,
and was weakening about 375 nm northeast of Sydney by 04/1800 UTC.
Marine Gale Warnings from Brisbane warned of winds up to 40 kts near
the center. Highest observed winds were 28 kts at Cape Byron and
Casino at 04/0400 UTC and 27 kts from Lord Howe Island at the same
time. (I do not know if these were peak gusts or sustained winds.)
Highest 24-hr rainfall totals were Norfolk Island - 70 mm (3 Feb)
and 129 mm (4 Feb), Lismore - 43 mm (4 Feb), Alstonville - 35 mm
(3 Feb), Mt. Seaview - 30 mm (4 Feb), and Lord Howe Island - 44 mm
(4 Feb).
LOW #2 - The second and by far more significant of the two storms
formed on 7 Feb and at 2300 UTC was centered off Double Island Point
about 200 nm northeast of Brisbane. The LOW moved westward toward the
coast and by 08/0600 UTC was on the coast about 120 nm north of
Brisbane. Rainbow Beach and Cape Moreton reported winds of 39 kts
at 08/2300 UTC, and Rainbow Beach reported 42 kts at 09/0500 UTC.
Again, I'm not sure if these were sustained winds or gusts, but given
that the Marine Warnings were indicating gales to 40 kts, they could
have been sustained winds. An AWS at Double Island Point recorded
a gust to 63 kts at 08/0047 UTC while the AWS at Cape Moreton
registered a gust of 56 kts at 08/0119 UTC. A peak wave height of
8 m was measured on the waverider buoy off Main Beach Southport at
08/1300 UTC.
Rainfall amounts were tremendous with many 24-hr totals exceeding
100 mm. Some of the most notable 24-hr totals ending at 08/2300 UTC
(9 am local time on the 9th) were Maleny - 404 mm, Mary Cairncross -
370 mm, Nambour - 332 mm, Tewantin - 252 mm, Rainbow Beach - 224 mm,
Strathpine (near Brisbane) - 182 mm, and Toowoomba (an island centre) -
166 mm. Heavy rainfall continued even after the system dissipated
with Nambour and Sandy Cape recording 6-hr totals of 67 mm and 56 mm,
respectively, from 08/2300 through 09/0500 UTC. The Mary River at
Gympie peaked at 21.95 m -- its highest level this century, inundating
130 businesses and 60 homes.
Floodwaters and landslips closed many dozens of roads. The strong
winds blew down power lines (causing blackouts) and damaged roofs on
many homes. Nearly 18,000 houses were without power in southeastern
Queensland. Seven deaths were reported, all by drowning in the
floodwaters.
ADDENDUM to MARCH TROPICAL CYCLONE SUMMARY
------------------------------------------
Matthew Saxby sent me a tidbit of information on Tropical Cyclone
Elaine back in March. The ex-cyclone made landfall near Geraldton,
Western Australia, on 20 Mar, and was responsible for setting a new
March 24-hr rainfall record for Geraldton of 100 mm. (Thanks to
Matthew for sending this information along.)
***********************************************************************
SOUTHWEST PACIFIC (SWP) - South Pacific Ocean East of Longitude 160E
Activity for April: No tropical cyclones
Southwest Pacific Activity for April
------------------------------------
There were no tropical cyclones nor significant tropical depressions
in the South Pacific east of 160E during the month of April. The
TCWC at Nadi, Fiji, mentioned a couple of weak disturbances in their
daily Tropical Disturbance Summary. TD-22F was a weak system which
formed around 9 Apr in the eastern portion of the Brisbane AOR. The
disturbance formed in a high-shear environment and did not
strengthen as it moved slowly southeast into the Fiji AOR. TD-23F
formed along the SPCZ on 21 Apr well to the southeast of Tonga and
on the boundary with the Wellington AOR. Development of this system
likewise was inhibited by strong northwesterly winds (60 kts) aloft.
It subsequently moved southeastward far to the east of New Zealand
and deepened (presumably as an extratropical system), generating
damaging southeast swells that affected most of the Southwest Pacific
islands for almost a week.
***********************************************************************
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,1998 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
March as an example: apr99.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: apr99.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>
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). Also, tracks only for the 1998 tropical
cyclones are currently available.
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, preliminary storm reports for all the 1998
Atlantic cyclones are now available.
The URL is: http://www.nhc.noaa.gov/1998.html>
Prepared by: Gary Padgett
E-mail: [email protected]
Phone: 334-222-5327 (nights & weekends) / 850-882-2594 (weekdays)
***********************************************************************
***********************************************************************
|
Document: summ9904.htm
Updated: 18th March 2008 |
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