[Index]
Monthly Global Tropical Cyclone Summary July 2001
[Summaries and Track Data] [Prepared by Gary Padgett]
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Cyclones
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Monthly Global Tropical Cyclone Summary July 2001 [Summaries and Track Data] [Prepared by Gary Padgett] |
MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY
JULY, 2001
(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.)
SPECIAL NOTE: Tony Cristaldi of the NWS office in Melbourne, Florida,
rather inadvertently "discovered" a hitherto unreported tropical (or
possibly subtropical) cyclone which occurred in the Southwest Indian
Ocean in April. According to Philippe Caroff of the La Reunion TCWC,
this system formed to the south of Reunion's AOR; therefore, no
warnings were issued on the cyclone. This system is being researched
and hopefully more information and a track will be forthcoming in a
couple of months.
***********************************************************************
JULY HIGHLIGHTS
--> Western North Pacific quite active--three typhoons make landfall
--> One hurricane and two minor tropical storms in Northeast Pacific
***********************************************************************
***** Feature of the Month for July *****
RESULTS OF TROPICAL CYCLONE SURVEY - PART 3
WARNING STRATEGIES FOR SUBTROPICAL/HYBRID CYCLONES
As noted last month, the responses to my tropical cyclone survey on
the subject of subtropical/hybrid cyclones tended to address two
different issues. In the June Feature of the Month I related some
of the respondees' comments on meteorological aspects of cyclone
classification and how subtropical systems should be treated with
regard to inclusion in the Best Tracks databases. Most of those
comments were from persons whose primary basin of interest is the
Atlantic. Several forecasters from the Southern Hemisphere addressed
the problem of providing adequate warnings for these systems.
Philippe Caroff, Chief Forecaster of the Meteo France La Reunion
TCWC, pointed out that in the Southwest Indian Ocean warnings are
issued for subtropical cyclones--the main problem being when to
estimate the point at which a given system is no longer mainly hybrid
but primarily tropical in nature. Philippe would personally favor
naming subtropical cyclones when the gale criteria is satisfied. David
Roth of HPC also indicated that he had no problem with subtropical
cyclones being named as tropical cyclones in real-time.
Steve Ready of the New Zealand Meteorological Service related that
currently Australia and New Zealand are looking into ways to handle
and possibly name disturbances which originate in the heart of the
tropics before transferring to the subtropics and cranking up into
severe cyclonic circulations with hurricane or near-hurricane force
winds. Jeff Callaghan of the Brisbane TCWC points out that sub-
tropical systems constitute a serious threat to Australia, especially
Queensland and New South Wales. Tropical cyclone warnings may not
be adequate for these types of storms since tropical cyclone warnings
normally refer to a point location. The radius of maximum winds tends
to be larger in hybrid systems, and winds can reach hurricane force
in a zone well-removed from the center. Milton Speer feels that
hybrid systems need to be flagged or named in some way that would
indicate their subtropical nature but would distinguish them from
purely tropical systems. Jeff Callaghan mentioned that the suggestion
has been made to give hybrid storms code names based on the Greek
alphabet.
Just as the issue of deciding whether or not to classify a given
storm as tropical or subtropical can be problematic, so also can the
boundary between subtropical and extratropical present a problem when
trying to design warnings specifically for subtropical/hybrid cyclones.
As a case in point, Jeff Callaghan writes, "Two (storms) which we
compared were one interacting with a mid-latitude trough though with
tropical characteristics (May, 1999 -- TD-26F) and one interacting
with an extremely vigorous mid-latitude trough. So if you think
tropical you would name the 1999 event and ignore the 1994 event which
devastated a yachting fleet between Tonga and New Zealand. On the
surface mariners would depict little difference between the two
systems." Jeff also contrasted the March (2001) subtropical storm
which caused significant damage in Queensland and New South Wales with
an earlier system in February which also produced storm-force winds
and serious flooding. The March system moved over 26 C water and
developed pronounced tropical characteristics as it moved away from
the subtropical jet and neared the coast, while the February system,
which developed in a quite similar fashion, remained close to the jet
and never developed tropical characteristics. But, again, as Jeff
points out, there would be little difference to a mariner.
With regard to the Atlantic basin, Rich Henning, a meteorologist
at Eglin AFB and a member of the Hurricane Hunters squadron, feels that
tropical-style warnings should not be issued to the public until a
system has acquired enough tropical characteristics to warrant naming
as a tropical cyclone, but that warnings classifying a system as a
subtropical storm could be issued to the marine/military community as
a means of highlighting the fact that the storm had some features of
tropical cyclones and that the potential existed for perhaps rapid
evolution into a more classic tropical storm or hurricane. However,
as stated in last month's Feature, Rich is definitely in favor of
including subtropical storms in the Best Tracks database so that it
will contain a complete tropical cyclone climatology for research
purposes.
More could certainly be said on this subject, but the purpose of
this month's Feature was to summarize responses to my survey of a
few months ago. Perhaps in the near future a sort of conference
with representatives from the various tropical cyclone warning centers
could be convened to discuss subtropical/hybrid cyclones (just as in
the 1980s there were a couple of conferences held for the purpose of
discussing polar LOWs). Next month I'll summarize the responses to
my survey on the subject of monsoon depressions.
***********************************************************************
ACTIVITY BY BASINS
ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico
Activity for July: 1 tropical depression
NOTE: Some of the information presented below was obtained from the
TPC/NHC discussion bulletins issued with every regular advisory. All
references to sustained winds imply a 1-min averaging period unless
otherwise noted.
Atlantic Tropical Activity for July
-----------------------------------
Only one tropical cyclone developed in the Atlantic basin in July.
This was a short-lived tropical depression which formed early on the
12th about 950 nm east of the island of Barbados. Tropical Depression
#2 formed over SSTs which were a little too cool to allow for
significant strengthening, and the depression had lost its LLCC by
2100 UTC on the 12th about 650 nm east of Barbados. Maximum sustained
winds were estimated at only 25 kts. Some of the numerical models had
forecast some modest intensification, but the GFDL model from the
outset forecast dissipation within 24 hours, and that is exactly what
happened. The final discussion on the system (at 12/2100 UTC) noted
that the wave still retained a vigorous mid-level circulation. The
wave continued westward through the Caribbean Sea and eventually moved
into the Eastern Pacific where it developed into Hurricane Dalila.
***********************************************************************
NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180
Activity for July: 2 tropical storms
1 hurricane
NOTE: Much of the information presented below was obtained from the
TPC/NHC discussion bulletins issued with every regular advisory (CPHC
for locations west of 140W.) All references to sustained winds imply
a 1-min averaging period unless otherwise noted.
Northeast Pacific Tropical Activity for July
--------------------------------------------
July, 2001, was a little less active than usual in the Northeast
Pacific basin. Averages for the month include about 4 named storms,
2 hurricanes with one hurricane on the average reaching Category 3
on the Saffir/Simpson scale. This year there were 3 named storms
with one reaching minimal hurricane intensity--there were no intense
hurricanes. In addition to the named storms, there was a well-
organized tropical disturbance early in the month which almost became
a tropical depression. This system was located on the 7th and 8th
roughly about 950-1000 nm southwest of the tip of Baja California.
Satellite data indicated winds of up to around 20 kts in the broad
circulation, but the system began to move over marginal SSTs which
thwarted any further development.
The reports below on Cosme, Dalila, and Erick were written by
John Wallace of San Antonio, Texas. A very special thanks to John
for writing the summaries.
Tropical Storm Cosme (TC-03E)
13 - 15 July
-----------------------------
A. Origins
----------
The tropical wave that spawned Cosme was first noted in the Eastern
Pacific on 7 July, just west of Central America. A tropical LOW
formed along the wave axis on the 10th as the wave tracked slowly
westward. The LOW soon replaced the tropical wave and organization
steadily improved. By 0900 UTC on 13 July, the LOW's organization had
increased enough to justify its upgrade to Tropical Depression Three-E
while located about 325 nm southwest of Manzanillo, Mexico. The
depression tracked west-northwestward around the periphery of a
mid-level ridge to its north.
B. Track and Intensity History
------------------------------
A large and impressive CDO developed over Three-E upon its first
warning, even in the face of easterly shear. Satellite data supported
the system's upgrade to Tropical Storm Cosme at 1500 UTC on 13 July
roughly 400 nm west-southwest of Manzanillo. Cosme's deep convection
held on despite the shear, and the storm managed to strengthen to its
peak MSW of 45 kts, with an estimated central pressure of 1000 mb, at
0300 UTC on 14 July about 500 nm west-southwest of Manzanillo.
Increased easterly shear, coupled with cooler SSTs along the storm
track, quickly weakened Cosme. The system was downgraded to a
depression at 1500 UTC on the 14th--the LLCC was exposed and nearly
devoid of convection, while Quickscat data showed no tropical storm-
force winds. The depression lingered as it tracked west-northwestward;
the possible benefits of slackening shear were offset by cool seas.
As is often the case, Cosme's track slowed on the 15th and turned
more westward under shallow flow. The final advisory on Tropical
Depression Cosme was issued at 2100 UTC on 15 July and placed the
center some 800 nm west of Manzanillo; the remnant vortex dissipated
while tracking slowly westward.
C. Damage and Casualties
------------------------
No casualties or damage are known to have resulted from Cosme.
Hurricane Dalila (TC-05E)
21 - 28 July
--------------------------
A. Origins
----------
Dalila was spawned by the remnant tropical wave of Atlantic
Tropical Depression Two, which itself was spawned by a tropical wave
that was first noted in the eastern Atlantic on 9 July. After TD-02's
dissipation, the remnant tropical wave tracked uneventfully across the
Caribbean, though it was admittedly more robust than most. Deep
convection erupted along the southern half of the wave axis beginning
late on 18 July while it was crossing Central America; by 0600 UTC on
the 19th a LOW had developed west of the isthmus. The LOW's convection
waxed and waned as it tracked roughly west-northwestward, paralleling
the coast; T-numbers hovered around 1.0 through the 20th (a special
thanks to Michael Pitt for sending me the pre-depression fix file for
Dalila). The LOW's organization finally increased enough to warrant
its upgrade to Tropical Depression Five-E at 0300 UTC on 21 July while
located roughly 270 nm south-southeast of Puerto Angel, Mexico. The
depression tracked to the west-northwest, south of a strong low- to
mid-level ridge; this track persisted throughout its duration.
B. Track and Intensity History
------------------------------
Five-E developed in an environment of low shear and very warm SSTs;
significant intensification was almost a given, and no one could rule
out rapid strengthening. At 1500 UTC on 21 July, the tropical cyclone
was upgraded to Tropical Storm Dalila approximately 190 nm south of
Puerto Angel, Mexico. Its proximity to the coast, along with its
forecast track, warranted the issuance of a tropical storm watch for
the Mexican coast, extending from Acapulco to Puerto Angel. At
0300 UTC on the 22nd the Mexican government issued a tropical storm
warning and hurricane watch for the coast, extending from Punta
Maldonado to Lazaro Cardenas; the hurricane watch extended west of
Lazaro Cardenas to Manzanillo, while the tropical storm watch east of
Punta Maldonado was discontinued. At 0900 UTC on the 22nd, all watches
and warnings east of Acapulco were dropped, while the tropical storm
warning was extended west of Acapulco to Punta San Telmo; a hurricane
watch remained in effect from Acapulco to Manzanillo. As the 22nd
wore on, it became apparent that Dalila posed little threat to the
coast; all watches and warnings were dropped at 0300 UTC on the 23rd
as the storm passed south of Manzanillo on its way out to sea.
While Dalila tracked offshore, the storm experienced a minor case
of arrested development; the marked intensification that was initially
forecast did not materialize. Easterly shear interfered with Dalila on
the 22nd, eroding outflow in its eastern semicircle and displacing the
center northeast of the deepest convection. The shear worsened on the
23rd; the storm became ragged and distorted and weakened slightly.
There was a turnaround on the 24th when the shear relaxed and allowed
the storm to intensify. At 0900 UTC on 24 July the system was upgraded
to Hurricane Dalila about 240 nm west of Manzanillo. It reached peak
intensity on the next advisory, at 1500 UTC on 24 July, about 300 nm
west of Manzanillo; the estimated CP was 984 mb with an associated MSW
of 70 kts. Dalila was a compact hurricane; the radii of tropical
storm-force winds extended no farther than 60 nm from the center at
its peak. The hurricane soon began weakening as easterly shear again
disrupted the circulation; indeed, a satellite pass on the 24th
elicited some uncertainty on the estimate of Dalila's peak intensity.
Dalila weakened to a tropical storm at 0300 UTC on the 25th while
passing over Socorro Island. Its forward motion decreased slightly
beginning on the 25th, due to a trough's weakening the ridge to its
north. The ridge held fast, though, and the storm's west-northwesterly
track continued; the dissipation of Erick's remnants helped strengthen
the ridge. The shear also lessened on the 25th, allowing Dalila to
strengthen back to near-hurricane intensity on the 26th. Even so,
Dalila's track into cooler water offset most of the benefit of the
reduced shear, and the storm weakened slowly once more; its slow
track gave its intensity a reprieve. The minor fluctuations in
Dalila's intensity were almost mirrored by the storm's dramatic
convective "pulses", as easterly shear alternately increased and
decreased in a diurnal pattern.
The storm's west-northwestward trek hastened on the 27th, and its
deterioration began in earnest as it crossed unfavorably cool SSTs.
Dalila's convection soon dispersed, and by the 28th the system was
nearly devoid of deep convection. The storm was downgraded to a
depression at 0900 UTC on 28 July, and the final advisory was issued
at 1500 UTC the same day, placing the dissipating center some 860 nm
west of Mazatlan, Mexico.
C. Damage and Casualties
------------------------
The AP reported that heavy rains from Dalila damaged 20 homes in
Acapulco on the 22nd. The storm caused flash flooding that damaged
dozens of homes on the Chiapas coast, along with minor flooding in the
state of Guerrero. No casualties are known as of this writing.
Tropical Storm Erick (TC-04E)
20 - 24 July
------------------------------
A. Origins
----------
Erick developed from a tropical wave, one that was first noted
east of the Lesser Antilles on 9 July. The wave tracked uneventfully
across the Caribbean and Central America and showed no sign of possible
tropical cyclone formation until the 20th, when a tropical LOW formed.
The LOW's organization increased sufficiently to warrant its upgrade to
Tropical Depression Four-E at 2100 UTC on 20 July when located roughly
800 nm west-southwest of Manzanillo, Mexico. The depression tracked
northwestward, following a weakness in the subtropical ridge.
B. Track and Intensity History
------------------------------
Though poorly-organized at first--due in part to some northerly
shear--the depression strengthened to Tropical Storm Erick at 2100 UTC
on 21 July about 950 nm west of Manzanillo. Minimal storm-strength
was to be Erick's peak intensity, as the system was fast approaching
cooler waters. Erick maintained a 35-kt MSW for 42 hours; however, it
didn't reach its minimum estimated CP of 1002 mb until 1500 UTC on
22 July when located some 1100 nm west of Manzanillo. Interestingly,
the time of Erick's lowest CP coincided with a marked decrease in
the storm's convection; Erick's large, well-organized circulation
apparently took precedence in Dvorak analyses. The storm's track
turned more to the west-northwest late on the 22nd as low-level
steering currents became dominant.
Weakening commenced on the 23rd; Erick dropped below storm-strength
at 1500 UTC while its forward speed decreased. The final advisory on
Tropical Depression Erick was issued at 0300 UTC on 24 July with the
weakening center located about 1110 nm west of Manzanillo; by this time
it was a convection-free whorl of low clouds. Its impressive remnant
circulation continued to generate 20-25 kt winds on the 24th, however,
and lingered for some time thereafter.
C. Damage and Casualties
------------------------
No casualties or damage are known to have resulted from Erick.
***********************************************************************
NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180
Activity for July: 2 tropical depressions **
1 tropical storm
4 typhoons ++
** - One of these systems was treated as a tropical depression only
by JTWC; the other only by JMA
++ - One of these was not treated as a typhoon by JMA, but was by
JTWC, the National Meteorological Center of China, and the Hong
Kong Observatory
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. A special
thanks to Michael V. Padua, owner of the Typhoon 2000 website, for
sending me the PAGASA and JMA tracks.
Also, some information based upon warnings issued by the National
Meteorological Center of China (NMCC) and the Hong Kong Observatory
(HKO) is included. The tracks from these agencies were sent to me
by Huang Chunliang of Fuzhou City, China. A special thanks to
Chunliang for sending me these additional tracks.
In the title line for each storm I plan to reference all the cyclone
names/numbers I have available: JTWC's depression number, the
JMA-assigned name (if any), JMA's tropical storm numeric designator,
and PAGASA's name for systems forming in or passing through their area
of responsibility.
Northwest Pacific Tropical Activity for July
--------------------------------------------
The month of July was quite active in the Northwest Pacific basin
with a total of 7 tropical cyclones being tracked by the various
warning centers. Additionally, as the month opened, Tropical Storm
Durian was located in the northern South China Sea. The storm was
upgraded to a typhoon on 1 July and subsequently crossed the northern
Luichow Peninsula before traversing the Gulf of Tonkin and making a
final landfall in southern China near the Laotian border. (See the
June summary for a complete report on Typhoon Durian.)
Typhoons Utor and Yutu both formed east of the Philippines and
followed similar tracks through the Luzon Strait, both eventually
making landfall in southern China. Typhoon Toraji and Tropical Storm
Trami also formed east of the northern Philippines but followed north-
westerly tracks which took them into eastern Taiwan. Of the named
cyclones, only Typhoon Kong-rey did not make landfall but instead
recurved into the westerlies well southeast of Japan. With the
apparent exception of Typhoon Yutu, all the landfalling tropical
cyclones resulted in fatalities.
One weak, short-lived system was warned on briefly by JTWC only, and
another system was carried as a tropical depression only by JMA. (It
should be noted that HKO and PAGASA have somewhat limited AORs and
these two systems were well-outside their respective regions. NMCC
now issues warnings for the entire NWP basin, but normally only
does so for systems that are at tropical storm intensity and higher.
Warnings are sometimes issued for tropical depressions that are near
the coast of China.) Tropical Depression 08W was a short-lived,
hybrid system that formed on 10 July about 525 nm southwest of Midway
Island. The depression moved eastward in an environment of strong
vertical shear with the deep convection sheared well to the east of
the exposed center. The first JTWC warning at 10/1800 UTC indicated
that the depression was already becoming extratropical, and the final
warning was issued only 12 hours later. Maximum winds were estimated
at 25 kts. A Tropical Weather Outlook issued by the Central Pacific
Hurricane Center in Honolulu at 0200 UTC on 12 July remarked that the
remnant LOW was located about 1000 miles west of Kauai and moving
northeastward at 25 kts.
Another system was classified as a tropical depression by JMA from
16 to 19 July in their High Seas bulletins. The system was centered
approximately 450 nm east-northeast of Iwo Jima at 1200 UTC on the
16th. JTWC had given this disturbance a fair potential for development
on the 15th, but downgraded the potential to poor on the 17th. The
LOW moved slowly and erratically through the 17th, then began to
move off toward the east-northeast. JMA elevated it to warning status
(30-kt winds) at 18/0000 UTC when it was located about 675 nm northeast
of Iwo Jima, but demoted it back to the summary portion of the bulletin
at 1800 UTC. The STWO issued by JTWC at 18/0600 UTC indicated that
the disturbance was merging with an approaching shortwave trough and
was no longer considered a suspect area for tropical cyclone formation.
The final reference to the system by JMA was made at 1800 UTC on the
19th, placing it far to the east of Japan.
Typhoon Utor (TC-06W / TY 0104 / Feria)
1 - 7 July
----------------------------------------
Utor: contributed by the United States, is a Marshallese word
meaning "squall line"
A. Origins
----------
JTWC issued a STWO at 2100 UTC on 26 June which noted that an area
of convection was developing about 490 nm south-southeast of Guam.
Animated infrared imagery indicated that the area of unorganized
convection had increased in areal coverage during the previous eight
hours, and QuikScat data and a synoptic analysis indicated the
existence of a broad LLCC situated in the monsoon trough. CIMSS shear
products indicated weak to moderate shear over the region with good
diffluence enhancing the convection. The disturbance remained quasi-
stationary through 28 June with little change in organization. At
0000 UTC on the 29th JTWC upgraded the development potential to fair;
areal coverage of the convection had increased over the past few hours,
vertical shear was weakening and divergence aloft was improving.
At 29/1200 UTC JTWC issued a TCFA for the disturbance; a synoptic
analysis indicated falling pressures within the broad LLCC and water
vapor imagery revealed good outflow in both semicircles of the system.
However, the alert was cancelled at 1200 UTC on 30 June. The
disturbance had failed to organize further, and QuikScat and synoptic
data suggested the likely existence of multiple LLCCs. The disturbance
was by this time tracking rapidly westward and the development
potential was downgraded to fair. By 30/2200 UTC the system was
located roughly 85 nm south of Yap, and animated satellite imagery
indicated that deep convection was beginning to organize around the
broad LLCC. The minimum SLP was estimated at 998 mb, and JTWC issued
a second TCFA at this time.
JTWC issued the first warning on TD-06W at 0600 UTC on 1 July. The
depression was centered about 170 nm east of Palau, drifting slowly
northward. The system continued to drift slowly toward the north and
at 0000 UTC on 2 July, both JTWC and JMA upgraded the depression to
tropical storm status with JMA assigning the name Utor. Tropical Storm
Utor was then centered approximately 85 nm northwest of Yap and its
northward motion had accelerated to 19 kts. At 0600 UTC the storm
entered PAGASA's AOR and was named Feria (a Spanish word meaning "fair"
or "market").
B. Track and Intensity History
------------------------------
Initially Utor was steered northward by a peripheral ridge to the
east of the system. About the time that it was upgraded to a tropical
storm, the cyclone began to move on a fairly straight northwesterly
track. Tropical Storm Utor/Feria steadily intensified and was upgraded
to a typhoon by both JTWC and JMA at 0600 UTC on 3 July while located
about 480 nm southeast of Port San Vicente on Luzon. A TRMM pass
(37 GHz) at 03/0609 UTC depicted a deep convective banding feature
extending over the southern semicircle. A SSM/I pass at 1138 UTC
indicated that the intense convection was still confined to the
southern half of the typhoon. Upper-level easterlies associated with
a HIGH east of Taiwan were hampering the development of banding over
the northern semicircle.
The shear lessened and by 04/0600 UTC convective bands were
developing over the northern half of the storm. It was at this time
that Typhoon Utor/Feria reached its peak estimated intensity of 80 kts
(per JTWC's warnings). As it approached Luzon a mid-level HIGH south
of Japan ridged westward and caused the typhoon to turn to a course
just north of due west. This brought Utor/Feria's center very close
to northern Luzon. At 0600 UTC on the 4th, when the storm reached its
peak intensity, it was centered only about 30 nm north of Port San
Vicente.
After passing Luzon, Typhoon Utor turned back to a more west-
northwesterly track and began to slowly weaken. The storm made land-
fall in southeastern China around 0000 UTC on 6 July about 40 nm
(75 km) east of Hong Kong as a minimal typhoon. Utor continued to
track west-northwestward into China and quickly weakened. JTWC issued
their final warning at 06/1800 UTC with the center well inland. The
central convection had dissipated, although a strong convective band
still lingered along the Chinese coast.
C. Meteorological Aspects
-------------------------
At its peak Utor was a large typhoon. Winds of 50 kts extended
outward 130 nm to the northeast of the center and 50 nm to the south-
west. Gales covered an area almost 500 nm in diameter. By the time
of landfall the storm had weakened to minimal typhoon intensity and
was a bit smaller in areal extent: 50-kt winds reached out 50 nm from
the center with the diameter of the gale area about 400 nm. The
estimated peak intensity (per JTWC) of 80 kts occurred from 0600
through 1800 UTC on 4 July. The minimum estimated central pressure
(from JMA's bulletins) was 960 mb.
Patrick Hoareau sent me some observations from several locations
in the Philippines he'd gleaned from various websites. Aparri, on
the north coast of Luzon (18.4N, 121.6E), reported a pressure of 967 mb
and northerly winds of 38 kts at 0500 UTC on 4 July. Laoag (18.2N,
120.5E) in northwestern Luzon reported 978 mb and winds of 33 kts from
the north-northwest at the same time. At 0300 UTC Dagupan (16.0N,
120.3E) reported 988 mb and westerly winds of 35 kts.
Calayan Island (19.3N, 121.5E) was in the eye of Typhoon Utor/Feria
at 04/0900 UTC and reported a minimum pressure of 967 mb with east-
southeasterly winds of 19 kts. At 1000 UTC Laoag reported a pressure
of 966 mb with 31-kt northwesterly winds. Michael V. Padua in Naga
City reports that the lowest pressure he observed at that location was
993.9 mb at 04/0600 UTC. Peak wind gusts were 41 kts; the rainfall
was light during the strongest winds but became heavy after the winds
had calmed down. (A special thanks to Patrick and Michael for passing
these observations along.)
Baguio City, a popular mountain resort on Luzon, set a new 24-hour
rainfall record during Typhoon Utor/Feria. On 4 July, 1085.8 mm of
rain was measured, exceeding the 994.6 mm recording during Typhoon
Zeb/Iliang in 1998. The July monthly average for the station is
1074 mm.
Huang Chunliang sent me the link to a very nice and informative
report on Typhoon Utor prepared by the Hong Kong Observatory. The URL
for the report is: http://www.weather.gov.hk/informtc/utor/utor.htm>.
(A special thanks to Chunliang for sending me the link to the report.)
The following information is taken from this report.
The lowest pressures observed in the Hong Kong area during Utor's
passage were 980.6 mb at HKO at 05/2121 UTC and 978.6 mb at Waglan
Island at 05/2116 UTC. Most areas around Hong Kong received in excess
of 150 mm of rainfall from Typhoon Utor. Tung Chung measured 308 mm
for a storm total with 276 mm falling on 6 July. The highest sea
levels observed during Utor's passage were 3.6 m at Tsim Bei Tsui and
3.4 m at Quarry Bay. The reading at Quarry Bay was the highest
recorded in Victoria Bay since Typhoon Wanda in 1962.
Following are some of the stronger wind observations gleaned from
the HKO report:
Location Date/Time Hourly Sustained Peak Gusts Last Hour
(UTC) (10-min avg kts) (kts)
-----------------------------------------------------------------------
Central Plaza 06/1200 S 45 71
Chek Lap Kok 06/1600 S 41 66
Cheung Chau 06/1600 S 46 64
Green Island 06/1600 WSW 45 70
Lau Fau Shan 06/0100 WNW 35 63
Tai Mo Shan 06/1200 SSW 42 67
Tsing Yi 06/1600 SSE 39 64
D. Comparisons Between JTWC and Other Centers
---------------------------------------------
Center position coordinates in general were in fairly good agree-
ment throughout the life of Utor. JMA's intensity estimates also
agreed rather well with those reported by JTWC. JMA's peak 10-min
mean MSW was 75 kts, which correlates very well with JTWC's peak MSW
estimate of 80 kts. PAGASA's peak 10-min mean MSW was also 75 kts,
while NMCC and HKO were slightly lower at 70 kts. JTWC, JMA, and
PAGASA all upgraded Utor to typhoon status at 03/0600 UTC, and NMCC
did so six hours later. The storm was already a typhoon when it
entered HKO's AOR.
E. Damage and Casualties
------------------------
Typhoon Utor left a vast trail of death and destruction from the
Philippines to China. Even though the center of Utor/Feria remained
offshore of northern Luzon, the large circulation channeled in huge
amounts of moist tropical air which led to extremely heavy rainfall.
The typhoon was responsible for at least 168 deaths in the Philippines
with 180 injured and 60 missing. The hardest hit provinces were
Apayao, Cagayan and Benguet. Over 28,000 houses were destroyed and
more than 12,000 partially damaged. Many major highways were closed
due to landslides, floods and fallen trees--at least 17 landslides were
reported. Over 1 million persons were displaced by the storm, and the
total damage in the country to property and agriculture was estimated
at 1.8 billion pesos (US $37 million).
In Taiwan two persons were reported killed with six injured. The
storm's outer rainbands brought torrential rains and strong winds to
the island--agricultural losses were estimated at NT $68 million. A
Taiwanese fishing boat, the Shan-Yu-Shing, with two Taiwanese and
five Chinese crewmen on board was reported missing. In the Hong Kong
area gales and strong winds toppled trees and blew down scaffolding in
many places. One person was injured, and a barge sank in high seas off
Tuen Mun but the crew was rescued.
Although the death toll was much lower than in the Philippines, the
greatest devastation was wrought in southern China. Typhoon Utor
followed so closely on the heels of Typhoon Durian that it is nigh
impossible to separate the effects of the flooding spawned by the
two storms' heavy rains. Between 2 and 8 July the two typhoons
brought incredibly heavy rainfall to Guangdong Province and the Guangxi
Autonomous Region with as much as 4.2 metres recorded in some locales.
Heavy rains in eastern Guangdong Province brought rivers to their
highest levels in years, inundating buildings and power installations
in Meizhou and Huizhou Cities. Near Chaozhou City power and water
supplies were cut off, 15 fishing vessels were sunk, and 30,000
hectares of crops were destroyed. In the Guangxi Autonomous Region
torrential rain brought severe flooding to the capital city of Nanning
where the Yongjiang River rose to 5.4 metres above the danger level--
the highest in 50 years.
In Guangdong Province 23 persons were reported killed with 1448
injured. Over 22,150 homes were destroyed with 102,810 more damaged.
Around 558,000 hectares of farmland were adversely affected by the
flooding, and the direct economic losses to this province are estimated
at 6.7 billion yuan (US $813 million). In the Guangxi area, the death
toll stands at 10 with 6850 persons injured. More than 82,000 houses
were destroyed and approximately 423,000 damaged. The amount of crop-
lands affected was placed at 669,500 hectares with crops lost
completely on 210,200 hectares. The total economic losses in Guangxi
are estimated at 16 billion yuan (US $1.93 billion).
(The information on damage and casualties came from many sources.
Patrick Hoareau, Huang Chunliang, and Michael V. Padua all sent tidbits
of information, plus a significant amount was found on the website for
disaster relief: http://www.reliefweb.int/>.)
Tropical Storm Trami (TC-07W / TS 0105 / Gorio)
8 - 12 July
------------------------------------------------
Trami: contributed by Vietnam, is a kind of tree belonging to the
rose family. Its flowers are pink or red without a fragrance
and is used as a decorative tree.
A. Origins
----------
A STWO, issued by JTWC at 0323 UTC on 7 July, mentioned that an area
of convection was developing about 120 nm northwest of Chuuk--animated
infrared imagery indicated cycling deep convection north of a possible
LLCC. Water vapor imagery indicated diffluent upper-level north-
easterly winds across the region and a TUTT cell to the northwest that
was enhancing outflow. A SSM/I (85 GHz) pass at 03/2342 UTC depicted
poorly-defined low-level cloud lines attempting to close off a LLCC,
while animated satellite imagery revealed a significant decrease in
cloud coverage during the past 10 hours. JTWC upgraded the development
potential to fair at 05/0000 UTC, and at 0600 UTC the disturbance was
centered about 380 nm south-southeast of Guam. SSM/I data indicated a
broad LLCC with little associated deep convection.
Twenty-four hours later the system was located approximately 290 nm
east of Yap. A QuikScat pass depicted a broad, unorganized region
of turning in the clouds about a weak LLCC. By 0600 UTC on the 7th,
the disturbance was located just northwest of Yap. Recent bursts of
deep convection near the center had been observed, but the system was
still rather disorganized; however, a 200-mb analysis indicated that
the LLCC was in a more favorable environment for strengthening. JTWC
issued a TCFA at 08/0100 UTC with the area located about 250 nm east
of the Philippines. Animated visible and infrared imagery indicated
deep convection developing over the LLCC, and a 07/2134 UTC SSM/I pass
revealed curved bands of convection along the western semicircle.
A second TCFA was issued at 08/2200 UTC with the disturbance placed
northwest of the previous TCFA position. Organization was improving,
and a TRMM pass at 08/1302 UTC had indicated a nearly closed convective
ring around the system's center. Also, a 200-mb analysis indicated
that the LLCC was moving beneath an extension of an upper-level ridge
with improved outflow. PAGASA issued the first warning on the
incipient system at 1800 UTC, naming it Tropical Depression Gorio (a
Filipino nickname). JTWC initiated warnings on TD-07W at 09/0000 UTC
with the depression centered approximately 300 nm east-southeast of the
northeastern tip of Luzon. JMA upgraded the system to Tropical Storm
Trami at 10/0000 UTC--by this time the cyclone's center was located
about 230 nm east-southeast of the southern tip of Taiwan. JTWC and
PAGASA also upgraded the depression to a tropical storm at 0000 UTC,
while NMCC did so at 0600 UTC on the 10th.
B. Track and Intensity History
------------------------------
When Trami/Gorio was upgraded to a tropical storm at 10/0000 UTC,
its center was well-defined but partly-exposed about 40 nm east of
the deep convection. Outflow was fair south of the center.
Initially the storm was guided north-northwestward by a peripheral
ridge to its southeast; later it moved into a weakness in the sub-
tropical ridge. Persistent northeasterly shear throughout its life
prevented Trami from strengthening significantly by forcing the deep
convection to the southwest of the center.
Based upon JTWC's tracking information, the weak tropical storm
moved north-northwestward into the eastern coast of Taiwan. At
1200 UTC on 11 July the minimal tropical storm was centered about
140 nm south-southeast of Taipei. The storm crossed Taiwan and moved
into the Taiwan Strait, weakening as it crossed the mountainous island.
JTWC and NMCC issued the final warnings on Trami at 12/0600 UTC. No
LLCC was discernible in visible and enhanced infrared imagery. The
peak MSW estimated by JTWC was only 35 kts, although some of the other
warning centers estimated the winds to be a little higher. The lowest
central pressure estimated by JMA was 992 mb.
C. Comparisons Between JTWC and Other Centers
---------------------------------------------
As would be expected with a weak, rather nebulous system, there was
quite a bit of divergence in the center position estimates between the
various warning agencies. As Trami approached Taiwan JMA's coordinates
consistently seemed to lie west of those from JTWC. Regarding
intensity, JTWC and NMCC kept Trami at minimal tropical storm intensity
(although NMCC's 35-kt MSW represents a 10-min avg). JMA and PAGASA,
however, reported the maximum 10-min avg wind at 45 kts at 10/1800 and
11/0000 UTC, and HKO's estimated 10-min avg MSW was 40 kts during this
time. These values correlate to a 1-min avg MSW of around 45-50 kts
and represent a somewhat stronger tropical cyclone than indicated by
JTWC and NMCC.
D. Damage and Casualties
------------------------
While Trami's winds were not severe, the storm brought some of the
heaviest rainfall in 40 years to Kaohsiung and Pingtung Counties. The
resulting floods were responsible for five deaths in southern Kaohsiung
County. Kaohsiung City was flooded; streets were clogged with
abandoned cars, and more than 100,000 homes were without electrical
power.
Typhoon Kong-rey (TC-09W / TY 0106)
21 July - 1 August
------------------------------------
Kong-rey: contributed by Cambodia, is the name of a pretty girl in
a Khmer legend; also the name of a mountain
A. Origins
----------
JTWC issued a STWO at 0000 UTC on 21 July which noted that an area
of convection had developed about 560 nm northeast of Saipan. Animated
visible imagery indicated persistent convection associated with a LLCC.
A SSM/I image taken at 20/2020 UTC had revealed a weak LLCC with a
small band of convection located to the south. A TCFA was issued
three hours later with deep convection developing rapidly around the
LLCC. A 200-mb analysis indicated that the disturbance was located
within a favorable environment below a small, upper-level anticyclone.
The first warning on TD-09W was issued by JTWC at 21/0600 UTC as
convection continued to consolidate around the center, and the system
was upgraded to a tropical storm at 1800 UTC when located about 540 nm
east of Iwo Jima, moving slowly north-northwestward. JMA upgraded
the system to Tropical Storm Kong-rey at 22/0000 UTC, and NMCC followed
suit six hours later.
B. Track and Intensity History
------------------------------
Kong-rey was initially steered westward by a mid-level ridge east
of Japan. JTWC upgraded the storm to typhoon status at 1200 UTC on
the 23rd when the center was located about 260 nm east of Iwo Jima.
(NMCC and JTWC were the only other agencies issuing warnings for
Kong-rey, and they didn't upgrade the storm until the 25th.) By the
24th the steering ridge had gradually shifted eastward in response to
a mid-latitude trough digging southward over the Sea of Japan and
extending southwestward to Taiwan. Typhoon Kong-rey began to move
more to the west-northwest, passing about 130 nm north of Iwo Jima
with 75-kt winds around 24/1800 UTC, and as the ridge strengthened on
the 25th, the storm recurved sharply to the north-northeast. The
point of recurvature was about 200 nm north-northwest of Iwo Jima,
and the typhoon reached an initial peak intensity of 85 kts about this
time.
After recurvature, the above-mentioned mid-latitude trough over
Japan helped to create a steering pattern in conjunction with the
ridge, and Kong-rey moved rather smoothly off to the northeast. The
intensity had dropped down to 75 kts (per JTWC) by 26/0000 UTC, and
the JTWC warning noted that extratropical transition was beginning to
occur. The warnings at 0600 and 1200 UTC also made the remark that
Kong-rey was becoming extratropical--it was noted that convection was
weakening. However, at 26/1800 UTC the MSW was bumped back up to
85 kts and the warning noted that a small eye had redeveloped. This
second peak in intensity was reached when Kong-rey was located about
360 nm north-northeast of Iwo Jima. This second lease on life was
short-lived, however, and by 1200 UTC on 27 July the winds were back
down to 75 kts. Animated satellite imagery depicted weakening
convection and increasing shear. (It should be noted that the 10-min
avg MSW estimates from NMCC and JMA do not show a double peak in
intensity.)
JTWC downgraded Kong-rey to a 55-kt tropical storm at 0000 UTC on
28 July, and issued their final warning six hours later when the storm
was centered about 700 nm northeast of Iwo Jima. Winds were estimated
at 50 kts, but JTWC assessed the system to be more or less extra-
tropical. JMA and NMCC, however, continued to classify Kong-rey as a
tropical storm through 0600 UTC on the 29th. JMA deemed the storm to
be extratropical by 1200 UTC. The extratropical remains of Kong-rey
tracked northeastward through the 31st, then began to turn northward
just west of the Dateline. By 0000 UTC on 1 August the system was a
weakening gale near the southwestern Aleutian Islands.
C. Meteorological Aspects
-------------------------
Early in its life Kong-rey was a rather small tropical cyclone. A
QuikScat pass shortly before 1200 UTC on 22 July failed to resolve a
radius of maximum winds but did indicate a small field of 35-kt winds.
The concurrent JTWC warning estimated the MSW at 50 kts with the
maximum radius of gales 50 nm to the northeast and northwest of the
center and 35 nm elsewhere. At the time JTWC upgraded Kong-rey to a
typhoon (1200 UTC on 23 July), CI numbers were 55 and 65 kts. The
storm displayed intense convection with an embedded LLCC. A 23/0302
UTC TRMM pass revealed a 30-nm diameter eye feature with deep
convection in the eastern semicircle.
By 24/1800 UTC the CDO was expanding in areal extent, and a 25/0211
UTC TRMM pass depicted tightly-curved banding with a banding eye. Good
outflow was observed in all quadrants, enhanced by mid-latitude
westerlies to the north of the cyclone and an upper-level LOW to the
southeast. NMCC and JMA upgraded Kong-rey to typhoon status at 0600
and 1200 UTC, respectively. At the time of its peak intensity (26/1800
UTC) of 85 kts, Kong-rey was a somewhat smaller than average typhoon.
Winds of 50 kts extended outward 110 nm to the southeast and 35 nm to
the northwest while gales reached out 140 nm southeast of the center
and 90 nm to the northwest. The minimum estimated central pressure
(per JMA's bulletins) was 955 mb.
D. Comparisons Between JTWC and Other Centers
---------------------------------------------
Center position coordinates were in excellent agreement between JMA,
JTWC, and NMCC for Typhoon Kong-rey. Early in the storm's history,
the intensity estimates reported by JTWC and JMA were in good agreement
while NMCC's values were a little lower on 22 and 23 July. The most
glaring disagreement was from the 23rd to the 25th when JTWC upgraded
Kong-rey to a typhoon while the other centers' 10-min avg MSW values
were 45 and 40 kts. For about a 30-hour period, JTWC's 1-min avg MSW
was 75 kts while JMA's 10-min mean MSW was 55 kts and NMCC's was 50
kts, increasing to 60 kts. However, once the other TCWCs had upgraded
Kong-rey to typhoon status, their peak 10-min avg MSW value of 70 kts
agrees rather closely with JTWC's peak MSW estimate of 85 kts. As
noted above, the intensities from JMA and NMCC do not show a double
peak as does JTWC's. JMA and NMCC continued to classify Kong-rey as
a tropical storm for another 24 hours after JTWC had classified the
storm as extratropical and issued their final warning.
E. Damage and Casualties
------------------------
The author has learned of no damage or casualties resulting from
Typhoon Kong-rey.
Typhoon Yutu (TC-10W / STS 0107 / Huaning)
22 - 26 July
-------------------------------------------
Yutu: contributed by China, is the name of the Jade Hare, who, in an
ancient Chinese legend, fled to the moon with the wife of a
tribal chief in ancient China after she had stolen her husband's
elixir of immortality. The two are said to still be living on
the moon in a palace.
A. Origins
----------
A STWO issued at 0000 UTC on 21 July remarked that an area of
convection had developed about 480 nm northwest of Guam. Animated
visible imagery indicated persistent but unorganized convection, and
a QuikScat pass depicted a broad, weak LLCC. The system continued to
move westward--by 22/0600 UTC it was located approximately 400 nm east
of Luzon. A 200-mb analysis indicated moderate northeasterlies over
the region. JTWC upgraded the development potential to fair at
1200 UTC; animated visible imagery indicated persistent convection and
the possibility of multiple LLCCs within a large monsoon gyre. A
TCFA was issued at 22/1730 UTC, locating the LLCC approximately 275 nm
east of Port San Vicente on Luzon. Deep convection continued to
organize around the center and the first warning was issued on TD-10W
at 1800 UTC. The depression was centered about 210 nm east of Port
San Vicente and was moving west-northwestward at 9 kts.
NMCC was the first to upgrade the incipient cyclone to tropical
storm status--that occurred at 0600 UTC on the 23rd. PAGASA began
issuing warnings on the system also at 0600 UTC, naming the disturbance
Tropical Depression Huaning (a Filipino nickname). JTWC (along with
PAGASA and HKO) upgraded the depression to a tropical storm at 1200 UTC
with the center located roughly 110 nm south-southeast of the southern
tip of Taiwan. Six hours later, at 1200 UTC, JMA classified the
system as Tropical Storm Yutu.
B. Track and Intensity History
------------------------------
A mid-level ridge to the northeast of the storm steered Yutu on a
fairly straight westerly track throughout its life. Tropical Storm
Yutu/Huaning remained fairly weak as it trekked westward through the
Luzon Strait, passing roughly halfway between Luzon and Taiwan. At
24/0000 UTC JTWC estimated the MSW at 45 kts--the center was partly-
exposed with convection sheared to the west of the LLCC. However,
by 0600 UTC Yutu had undergone a rapid intensification. A 24/0456
UTC TRMM pass depicted tightly-wrapped convective banding around a
33-nm round eye. Water vapor imagery revealed that the storm had
excellent outflow over the southern semicircle and improving outflow
to the north. JTWC abruptly upgraded Yutu to a 70-kt typhoon; NMCC
also upgraded the storm to a typhoon at 0600 UTC and HKO followed suit
six hours later. JMA, however, never upgraded Yutu to typhoon status.
(The storm was already west of PAGASA's AOR by the time it reached
typhoon intensity.) Yutu was centered about 180 nm east-southeast of
Hong Kong when JTWC classified it as a typhoon.
A 24/1018 UTC SSM/I pass revealed that the eyewall convection had
consolidated. JTWC upped the MSW to the peak value of 85 kts at 1200
UTC. Typhoon Yutu passed about 100 nm due south of Hong Kong shortly
before 1800 UTC on 24 June. The storm continued on its westerly track
and made landfall around 1900 UTC on 25 July about 55 km east of
Zhanjiang in the county of Dianbai in China's Guangdong Province. This
location is about 170 nm (310 km) southwest of Hong Kong. Yutu had
weakened slightly before making landfall; JTWC estimated the MSW at
75 kts at 1800 UTC--shortly before landfall. Once inland the storm
quickly weakened and had essentially dissipated by 1800 UTC on 26 July.
C. Meteorological Aspects
-------------------------
Typhoon Yutu's peak intensity (per JTWC) was 85 kts from 1200 UTC
on the 24th through 0600 UTC on the 25th. The minimum estimated
central pressure (per JMA's bulletins) was 970 mb. At the time of
Yutu's peak intensity, the radius of 50-kt winds was 40 nm while gales
covered an area a little over 200 nm in diameter.
Patrick Hoareau sent me some observations he'd obtained from
various websites. The eye of Yutu passed near Dongsha Dao (20.7N,
116.7E) just before 24/0600 UTC. At 0900 UTC the station reported
an easterly wind of 38 kts with a pressure of 984 mb. Shangchuan
Dao (21.7N, 112.8E) at 24/0400 UTC reported a pressure of 999 mb
and north-northeasterly winds of 27 kts. The pressure was slowly
falling and Yutu's center passed about 75 nm to the south-southeast
at 0600 UTC. Xuwen County in Guangdong Province recorded 260 mm of
rain in the 24 hours ending at 26/1800 UTC. According to information
sent to me by Huang Chunliang, the sustained winds (10-min avg) at
landfall were 64 kts, gusting to 82 kts. (I'm not sure if these were
measured winds or based upon estimates given in warnings.) Fuzhou
City, far from Yutu's track, recorded 67.2 mm of rain indirectly
associated with the storm.
Chunliang also sent me the link to a report on Typhoon Yutu prepared
by the Hong Kong Observatory. The URL for the report is:
http://www.weather.gov.hk/informtc/yutu/yutu.htm>. The following
information was taken from the report.
The lowest pressure measured was 999.8 mb at Waglan Island at
2013 UTC on 24 July. All the four-day storm rainfall totals were
under 100 mm except for Tai Mo Shan, which recorded 130 mm. Some
of the stronger wind observations given in the report follow:
Location Date/Time Hourly Sustained Peak Gusts Last Hour
(UTC) (10-min avg kts) (kts)
-----------------------------------------------------------------------
Central Plaza 25/0300 E 35 57
Cheung Chau 25/0900 ESE 37 63
Tai Mo Shan 25/0400 SE 43 61
Tate's Cairn 24/2000 E 34 61
Waglan Island 24/2200 E 37 49
D. Comparisons Between JTWC and Other Agencies
----------------------------------------------
Center position coordinates were in excellent agreement between the
various warning agencies for Typhoon Yutu. While JMA upgraded the
system to a tropical storm only six hours after JTWC and the intensity
estimates agreed well at that point, JMA never upgraded Yutu to typhoon
status--the peak 10-min avg MSW never got higher than 60 kts (which
correlates roughly to a 70-kt 1-min avg MSW). JTWC's intensity
estimates were already decreasing when JMA's values reached their
peak. JMA's 10-min mean MSW was 50 kts at the time of JTWC's estimated
peak intensity of 85 kts--a considerable difference. NMCC and HKO
both upgraded Yutu to typhoon status, however. NMCC's peak 10-min avg
MSW was 65 kts, but HKO's peak was 80 kts, in close agreement with
JTWC.
E. Damage and Casualties
------------------------
While Typhoon Yutu affected some of the same areas in China
devastated by Typhoons Durian and Utor, the storm was not nearly as
destructive as the earlier storms. In Guangdong Province 4650 houses
were wrecked by Yutu. The total loss sustained by the cities of
Maoming, Yangjiang and Zhanjiang is estimated at 700 million yuan.
In the Hong Kong area ten persons sustained injuries due to the storm.
The author has not learned of any fatalities attributed to Typhoon
Yutu.
Typhoon Toraji (TC-11W / TY 0108 / Isang)
25 - 31 July
------------------------------------------
Toraji: contributed by the Democratic People's Republic of Korea
(North Korea), is the name of a flower (broad bell flower)
A. Origins
----------
JTWC issued a STWO at 24/0600 UTC which noted that an area of
convection had developed approximately 310 nm west of Guam. A
23/2355 UTC SSM/I pass had depicted persistent but isolated deep
convection near a broad LLCC embedded in the monsoon trough. A
CIMSS analysis indicated light to moderate vertical shear over the
region. By 25/0600 UTC the disturbance was located about 390 nm
north of Koror; animated visible and infrared imagery depicted
improving organization and a 24/2111 UTC SSM/I pass revealed a
possible LLCC on the eastern periphery of a mid-level circulation.
A TCFA was issued at 1700 UTC on the 25th. Organization had
improved significantly during the previous few hours with a possible
banding feature developing over the northwest quadrant. A SSM/I
pass indicated that a LLCC was tucked beneath the extreme eastern
edge of the deep convection, and a 25/0851 UTC QuikScat pass showed
the strongest winds to be located southwest of the LLCC. JTWC issued
the first warning on TD-11W at 25/1800 UTC with the center located
approximately 650 nm east-southeast of the northeastern tip of Luzon.
PAGASA initiated warnings on the depression at 26/0000 UTC, naming
it Isang (a Filipino nickname). By 0600 UTC Tropical Depression
Isang/11W was tracking north-northwestward at 9 kts with a partially-
exposed center located beneath the eastern edge of the deep convection.
The depression was slow to intensify due to some easterly shear.
Shortly after issuing the fifth warning at 26/1800 UTC, JTWC released
an amended warning, relocating the center 90 nm to the southwest of the
previous warning position and upgrading the system to a tropical storm.
PAGASA also upgraded Isang to tropical storm status. Tropical Storm
Isang/11W was centered about 350 nm east-southeast of northeastern
Luzon at this time. NMCC and JMA classified the system as a tropical
storm at 27/0000 UTC with JMA assigning the name Toraji.
B. Track and Intensity History
------------------------------
JTWC increased the MSW to 40 kts at 27/0000 UTC--a CDO 60 nm in
diameter was located over the center of the vortex. Toraji/Isang
steadily intensified, and at 1800 UTC on the 27th JTWC, JMA, and PAGASA
all upgraded the storm to typhoon intensity with the center located
approximately 375 nm southeast of the southern tip of Taiwan. The
storm had entered HKO's AOR by 28/0000 UTC and the first warning from
that agency classified Toraji as a typhoon. NMCC was the last TCWC to
upgrade the storm to typhoon status; that happened at 28/0600 UTC.
Toraji formed in a weakness in the subtropical ridge. Initially
the cyclone moved westward, then followed a general northwesterly to
north-northwesterly track along the periphery of a mid-level ridge
located to the east-northeast. The MSW had reached 90 kts (per JTWC)
by 28/0600 UTC and remained pegged there until Toraji was nearing
the east coast of Taiwan around 1200 UTC on the 29th. JTWC upped the
winds to 95 kts at that time, and at 1800 UTC, just as the center was
making landfall about 85 nm (155 km) south of Taipei, estimated the
MSW at 100 kts--the peak for the storm's history. The minimum central
pressure reported by JMA was 960 mb.
Typhoon Toraji tracked on across Taiwan and had moved out into the
Taiwan Strait by 0600 UTC on 30 July. JTWC was still maintaining the
storm at typhoon intensity but the other warning centers had downgraded
Toraji to a tropical storm. JTWC downgraded Toraji to a 55-kt tropical
storm at 1800 UTC when it was centered about 100 nm west-northwest of
Taipei. The cyclone made its final landfall near Lianjiang (near
Fuzhou City) around 30/1930 UTC--very near where Typhoon Chebi had
made landfall in late June. The intensity at landfall (per JTWC) was
55 kts with gusts to 70 kts. The weakening storm continued to move
northward through eastern China. By 31/0000 UTC the center was located
roughly 90 km north-northeast of Fuzhou City. The final warning from
JTWC, at 31/1200 UTC, downgraded Toraji to a depression and placed the
system inland about 370 km south-southwest of Shanghai.
C. Meteorological Aspects
-------------------------
As mentioned earlier, the peak MSW of 100 kts as estimated by JTWC
occurred at 1800 UTC on 29 July when the center had just made landfall
in eastern Taiwan. Winds to 50 kts extended to the east 85 nm over
water, and gales covered an area approximately 300 nm in diameter.
Roger Edson sent an e-mail with two attached TRMM pictures made at
0205 UTC on 29 July--one in the 85 GHz band and the other a visible
shot. The microwave image showed the eye wall becoming much more
circular and uniformly more vigorous. In Roger's opinion the
intensity of Toraji at that point was near 100 kts.
I received no surface wind and pressure observations from the areas
where Typhoon Toraji made landfall. Huang Chunliang sent me some press
reports on the effects of the typhoon in Taiwan and near Fuzhou City
which included a few rainfall amounts. In Taiwan, Fenglin measured
556 mm of rain within a 35-hour period ending at 0300 UTC on 30 July.
Also, Hsiaokuanshan reported 686 mm, presumably during the same period.
While Toraji made a final landfall in China near Lianjiang in the
county of Fuzhou, Chunliang reports that the winds never exceeded gale
force in Fuzhou City. Heavy rains fell, however, with 6 mm falling
within a 5-minute period in the urban area of Fuzhou.
D. Comparisons Between JTWC and Other Centers
---------------------------------------------
As was the case with the previous two typhoons, center position
coordinates were in excellent agreement between the several warning
centers. And during the early tropical storm stage, the intensity
estimates from the various agencies agreed fairly well. During the
time Toraji's intensity was plateaued at 90 kts for about a day and
a half while the storm was approaching Taiwan, JMA and PAGASA estimated
the 10-min avg MSW at 75 kts which correlates to a 1-min MSW of about
85 kts; NMCC and HKO were a little lower at 70 kts. The most
significant disagreement was at 29/1800 UTC when JTWC upped the MSW to
100 kts. PAGASA, HKO and NMCC did not increase their intensity
estimates, and JMA downgraded the typhoon to a 60-kt tropical storm at
that time. However, all the Asian TCWCs had downgraded Toraji to
tropical storm intensity by 30/0600 UTC whereas JTWC maintained the
system as a 75-kt typhoon through 1200 UTC. NMCC and HKO, along with
JTWC, maintained Toraji as a fairly strong tropical storm until
landfall in China while JMA had lowered the winds to minimal tropical
storm intensity by the time the center reached the coast.
E. Damage and Casualties
------------------------
An article from the Taipei Times which I located on the internet
seems to give the definitive figures for Typhoon Toraji's effects in
Taiwan. The death toll was at least 35 with 108 persons still missing
at the time of the report a couple of days after the storm had struck.
Most of the deaths appeared to be due to landslides triggered by the
heavy rainfall. Over 340,000 people were without electricity, and
the losses to agriculture and forestry were estimated at NT $700
million.
***********************************************************************
NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea
Activity for July: No tropical cyclones
***********************************************************************
SOUTHWEST INDIAN OCEAN (SWI) - South Indian Ocean West of Longitude 90E
Activity for July: No tropical cyclones
***********************************************************************
NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (AUW) - From 90E to 135E
Activity for July: No tropical cyclones
***********************************************************************
NORTHEAST AUSTRALIA/CORAL SEA (AUE) - From 135E to 160E
Activity for July: No tropical cyclones
Northeast Australia/Coral Sea
Tropical Activity for July
-----------------------------
In mid-July I received an e-mail from Jeff Callaghan detailing a
severe hybrid-type storm whose heavy seas wrought havoc along the
Queensland and New South Wales coastlines. The LOW originally formed
to the south of Noumea, New Caledonia, equatorward of a large blocking
HIGH over New Zealand as an upper-level trough crossed the Tasman Sea.
The UK analysis around the time of peak intensity (04/1200 UTC) showed
a circulation up to 500 mb and strongest in the 850 to 700 mb layer.
Above 400 mb the system was an open trough. Jeff sent along a QuikScat
diagram for 04/0615 UTC which revealed a LOW with gales almost
completely surrounding it and with a huge area of gale to storm-force
winds on the poleward side. The LOW tracked to the east of Norfolk
Island where the lowest MSLP of 990.3 mb occurred at 1500 UTC on the
4th. The maximum 10-min mean wind of 100/43 kts, gusting to 63 kts,
occurred at 04/0230 UTC. The MSLP at that time was 1001.3 mb. Jeff
also included three sets of rawinsonde observations from Norfolk Island
which indicated winds to hurricane force a short distance above the
surface.
Heavy swells affected the Australian coastline. The most exposed
wave rider buoy (just east of Brisbane) recorded a peak wave height of
7.9 metres. The peak wave period was 15.9 seconds--a long period swell
like those produced by Tropical Cyclone Sose in April. The long period
swells produce a larger breaking wave height than shorter period swells
do. The 11-metre cruiser "Just Cruising" was found wrecked on Spitfire
Bank near the entrance to Moreton Bay and just southwest of Cape
Moreton. The boat had been flipped over by the large breakers; the
crew of four were never found.
A yacht was wrecked by large waves on a sandbar near Fraser Island
and the lone yachtsman was never found. Also, a woman was reported
missing after being swept off her dinghy on the 7th near Jumpinpin Bar
(which separates North and South Stradbroke Islands) halfway between
Brisbane and the Gold Coast. Farther east, a French yachtsman was
found drowned near his stricken yacht in the Norfolk Island area.
I'd like to extend a special thanks to Jeff for sending me the
information on this storm.
***********************************************************************
SOUTH PACIFIC (SPA) - South Pacific Ocean East of Longitude 160E
Activity for July: No tropical cyclones
NOTE: The hybrid system described above affected the western portion
of the South Pacific basin also; in fact, its center seems to have
formed and remained east of 160E. I have reported on it as an
Australian Region system because of the effects the heavy seas had
in eastern Australia.
***********************************************************************
EXTRA FEATURE
In order to shorten the amount of typing in preparing the narrative
material, I have been in the habit of freely using abbreviations and
acronyms. I have tried to define most of these with the first usage
in a given summary, but I may have missed one now and then. Most of
these are probably understood by a majority of readers but perhaps a
few aren't clear to some. To remedy this I developed a Glossary of
Abbreviations and Acronyms which I first included in the July, 1998
summary. I don't normally include the Glossary in most months in
order to help keep them from being too long. If anyone would like to
receive a copy of the Glossary, please e-mail me and I'll be happy
to send them a copy.
***********************************************************************
AUTHOR'S NOTE: This summary should be considered a very preliminary
overview of the tropical cyclones that occur in each month. The cyclone
tracks (provided separately) will generally be based upon operational
warnings issued by the various tropical cyclone warning centers. The
information contained therein may differ somewhat from the tracking and
intensity information obtained from a "best-track" file which is based
on a detailed post-seasonal analysis of all available data. Information
on where to find official "best-track" files from the various warning
centers will be passed along from time to time.
The track files are not being sent via e-mail. They can be retrieved
in the following manner:
(a) FTP to: hrd-type42.nhc.noaa.gov [140.90.176.206]
(b) Login as: anonymous
(c) For a password use your e-mail address
(d) Go to "data" subdirectory (Type: cd data)
(e) Set file type to ASCII (Type: ascii)
(f) Transfer file (Type: get remote_file_name local_file_name )
(The files will be named with an obvious nomenclature--using
July as an example: jul01.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: jul01.sum, for
example.
Back issues can also be obtained from the following websites
(courtesy of Michael Bath, Michael V. Padua, Tom Berg, Michael
Pitt, and Rich Henning):
http://australiasevereweather.com/cyclones/>
http://www.typhoon2k.com> OR http://65.108.205.8>
http://www.hurricanealley.net/>
http://www.qisfl.net/home/hurricanemike>
http://www.met.fsu.edu/gsc/Docs/Grads/henning/cyclones/>
NOTE: The URL for Michael V. Padua's Typhoon 2000 website has
changed.
Another website where much information about tropical cyclones may
be found is the website for the UK Meteorological Office. Their site
contains a lot of statistical information about tropical cyclones
globally on a monthly basis. The URL is:
http://www.met-office.gov.uk/sec2/sec2cyclone/sec2cyclone.html>
TROPICAL CYCLONE REPORTS AVAILABLE
JTWC now has available on its website the complete Annual Tropical
Cyclone Report (ATCR) for 2000 and a report on the 2000-2001 season in
the Southern Hemisphere. ATCRs for earlier years are available also.
The URL is: http://199.10.200.33/jtwc.html>
Also, TPC/NHC has available on its webpage nice "technicolor"
tracking charts for the 2000 Atlantic and Eastern North Pacific
tropical cyclones; also, preliminary storm reports for all the 2000
Atlantic and Eastern North Pacific cyclones are now available, as
well as track charts and reports on storms from earlier years.
The URL is: http://www.nhc.noaa.gov>
Prepared by: Gary Padgett
E-mail: [email protected]
Phone: 334-222-5327 (nights & weekends) / 850-882-2594 (weekdays)
***********************************************************************
***********************************************************************
|
Document: summ0107.htm
Updated: 27th December 2006 |
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