[Index]
Monthly Global Tropical Cyclone Summary April 2004
[Summaries and Track Data] [Prepared by Gary Padgett]
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Monthly Global Tropical Cyclone Summary April 2004 [Summaries and Track Data] [Prepared by Gary Padgett] |
MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY
APRIL, 2004
(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: The April summary is being sent before the second part
of the March summary. Part 1 of the March summary was disseminated
in late May. I have yet to tackle writing a report on the Brazilian
cyclone Catarina. Hopefully, Part 2 of the March summary will be
sent out within two weeks at the latest.
*************************************************************************
APRIL HIGHLIGHTS
--> Yap Island devastated by first typhoon of year
--> Tropics elsewhere quiet--only one named cyclone during month
*************************************************************************
***** Feature of the Month for April *****
TABLES OF NORTHEASTERN PACIFIC NET TROPICAL ACTIVITY
For the past few years I have featured tables of Atlantic and
Northeastern Pacific monthly net tropical activity (NTC). For this
month's feature I have included tables for the Northeast Pacific
basin (the Atlantic was featured in the March monthly summary). When
breaking up a tropical cyclone season temporally (into months), some
decisions have to be made regarding intermonthly cyclones. I have
previously explained in detail my reasoning here, and interested
persons can find this in the March, 2002, summary, which can be
obtained from any of the websites listed at the end of this summary.
Tropical cyclone activity in the Northeast Pacific (NEP) during
2003 began on schedule with the formation of Tropical Storm Andres
in late May, but the season was very unusual in that the first
hurricane did not form until 24 August. This is the latest date
for the appearance of the first hurricane since the beginning of the
modern satellite era in 1966. The only other year during this period
in which the first hurricane did not develop until August was 1968.
However, most of the latter cyclones did reach hurricane intensity
and the totals of 16 named storms and 7 hurricanes are near the annual
averages of 16.3 and 9.2, respectively. Another very unusual aspect
of the 2003 NEP season was that no intense hurricanes (Saffir/Simpson
category 3 or higher) formed. The only other year since 1971 to see
no intense hurricanes was 1977. Overall the 2003 Eastern Pacific
season was the third quietest on record with a NTC of 46. The only
other seasons with a lower NTC since 1971 were 1996 (NTC of 45) and
1977 (NTC of 22).
NOTE: The parameters NS, H, IH, NSD, HD, IHD and NTC are those which
are used by the Colorado State University forecast team headed by
Dr. Bill Gray. Documentation for these can found on the CSU website:
http://hurricane.atmos.colostate.edu/Forecasts/>
Northeast Pacific Tropical Cyclone Season of 2003
-------------------------------------------------
Month NS H IH NSD HD IHD NTC
MAY 1 0 0 5.00 0.00 0.00 2.15
JUN 2 0 0 4.00 0.00 0.00 2.94
JUL 3 0 0 4.75 0.00 0.00 4.13
AUG 4 2 0 12.50 4.50 0.00 12.90
SEP 3 2 0 9.50 2.75 0.00 10.27
OCT 3 3 0 14.00 3.75 0.00 13.62
TOTAL 16 7 0 49.75 11.00 0.00 46.0
The next table gives NEP statistics for the period 1971-2003,
arranged by months. The year 1971 was chosen as a starting point
since, even though the Dvorak method of satellite analysis had not
yet been introduced, there was extensive aerial reconnaissance of
NEP storms that season and during the following two. Reconnaissance
flights into NEP cyclones were curtailed after 1973, but by 1974 the
initial Dvorak method was being used and tropical cyclone intensities
in the Best Track file can be considered somewhat reliable.
Northeast Pacific Basin Monthly NTC Table
Based on Period 1971-2003
-----------------------------------------
Month NS H IH NSD HD IHD NTC
JAN 1 1 0 3.25 2.00 0.00 0.14
FEB 0 0 1 3.00 2.25 0.50 0.20
MAR 1 0 0 1.00 0.00 0.00 0.04
APR 0 0 0 0.00 0.00 0.00 0.00
MAY 17 9 2 60.25 16.75 2.75 2.09
JUN 70 36 14 255.25 93.25 26.00 10.51
JUL 123 65 36 531.00 234.75 74.25 23.26
AUG 131 79 37 671.75 270.00 60.50 25.11
SEP 116 71 35 558.00 266.00 79.00 24.23
OCT 67 40 20 315.25 140.75 40.75 13.37
NOV 11 3 0 33.50 8.25 0.00 0.87
DEC 2 1 0 7.50 1.00 0.00 0.18
TOTAL 539 305 145 2439.75 1035.00 283.75
AVG 16.3 9.2 4.4 73.9 31.4 8.6
The following chart tabulates the same set of NEP statistics but
arranged by year. The active period which abruptly began in 1982 and
continued through 1994, except for a short "coffee break" in the late
1980s, is most striking. Prior to 1982, the only really active year
was 1978, and following 1994, the only year with an above-normal NTC
was the strong El Nino year of 1997.
Northeast Pacific Basin Annual NTC Table
Based on Period 1971-2003
----------------------------------------
Year NS H IH NSD HD IHD NTC
1971 18 12 6 84.00 38.50 6.00 112
1972 14 8 4 83.25 33.75 4.50 88
1973 12 7 3 62.25 28.50 7.25 78
1974 18 11 3 63.75 22.25 2.50 79
1975 17 9 4 71.75 26.75 5.50 88
1976 15 9 5 66.50 27.25 9.75 97
1977 8 4 0 20.50 5.25 .00 22
1978 19 14 7 102.75 51.50 16.00 150
1979 10 6 4 33.75 13.75 3.25 56
1980 14 7 3 48.25 22.75 2.75 65
1981 15 8 1 58.00 18.25 1.00 57
1982 23 12 5 106.50 39.25 7.50 121
1983 21 12 8 110.00 47.75 16.25 152
1984 21 13 7 103.50 46.25 14.75 145
1985 23 13 8 108.50 49.75 8.50 142
1986 17 9 3 62.50 28.75 6.75 86
1987 20 10 4 78.50 29.00 7.75 100
1988 15 7 3 65.25 29.50 6.50 81
1989 17 9 4 67.25 27.25 5.75 88
1990 21 16 6 126.00 58.25 20.25 168
1991 14 10 5 86.25 44.00 14.00 119
1992 27 16 10 148.75 65.50 20.75 199
1993 15 11 9 86.75 50.75 16.75 145
1994 20 10 5 85.50 33.00 17.00 125
1995 10 7 3 51.75 22.25 9.00 73
1996 9 5 2 32.00 13.00 3.25 45
1997 19 9 7 78.50 33.50 15.00 124
1998 13 9 6 62.75 33.00 10.75 102
1999 9 6 2 44.50 23.50 6.00 60
2000 19 6 2 67.50 16.75 4.75 70
2001 15 8 2 58.25 18.50 5.00 69
2002 15 8 6 64.75 26.00 9.00 97
2003 16 7 0 49.75 11.00 0.00 46
AVG 16.3 9.3 4.5 74.0 31.4 8.6
The next table is identical to the preceding one except that it
covers the Eastern North Pacific proper only--from longitude 140W
eastward to the Mexican and Central American coasts. The "days"
parameters--NSD, HD and IHD--do not include portions of cyclones spent
west of 140W.
Eastern North Pacific (East of 140W)
Annual NTC Table
Based on Period 1971-2003
-----------------------------------------
Year NS H IH NSD HD IHD NTC
1971 18 12 6 80.75 36.75 6.00 124
1972 12 8 3 62.50 24.75 2.75 78
1973 12 7 3 51.75 24.00 7.00 82
1974 17 11 2 59.25 18.75 2.25 79
1975 16 8 4 68.50 26.00 5.50 96
1976 14 8 5 57.75 22.50 9.75 101
1977 8 4 0 20.50 5.25 0.00 25
1978 18 12 6 73.00 35.25 13.25 137
1979 10 6 4 33.75 13.75 3.25 63
1980 14 7 3 43.75 20.00 2.75 71
1981 15 8 1 55.25 18.25 1.00 63
1982 19 11 4 77.25 33.00 6.00 112
1983 21 12 8 98.00 46.25 15.00 166
1984 18 12 6 93.25 43.50 14.50 150
1985 22 11 7 90.25 37.00 5.75 133
1986 17 9 3 56.25 24.75 5.25 89
1987 18 9 4 66.00 24.75 7.75 103
1988 13 6 1 51.25 18.75 2.25 59
1989 17 9 4 62.75 24.75 5.75 96
1990 20 16 6 115.25 55.50 18.00 181
1991 14 10 5 82.00 42.75 14.00 133
1992 24 14 8 132.75 57.00 18.25 196
1993 14 10 8 73.50 42.25 15.25 146
1994 17 8 4 51.50 14.50 4.25 82
1995 10 7 3 51.75 22.25 9.00 84
1996 9 5 2 32.00 13.00 3.25 51
1997 17 9 7 67.25 33.50 15.00 136
1998 13 9 6 60.75 32.75 10.75 116
1999 9 6 2 35.50 16.25 5.75 61
2000 17 6 2 56.50 15.75 4.75 73
2001 15 8 2 58.25 18.50 5.00 77
2002 12 6 5 48.00 19.25 8.50 88
2003 16 7 0 46.25 9.25 0.00 48
AVG 15.3 8.8 4.1 64.0 27.0 7.50
Following is a similar table but for the Central North Pacific
between longitudes 140W and 180. All storms which either formed in
the Central North Pacific or else moved into the region from east of
140W are counted. The "days" parameters only include portions of the
storms spent in the Central North Pacific. The listing does not
include any storms which entered the region from the Western North
Pacific, nor does it include several storms which, according to the
JTWC Best Track file, reached tropical storm intensity east of
longitude 180 but were unnamed by the Central Pacific Hurricane
Center. Some information on these storms follows the table.
Central North Pacific (140W to 180)
Annual NTC Table
Based on Period 1971-2003
-----------------------------------------
Year NS H IH NSD HD IHD NTC
1971 2 1 0 3.25 1.75 0.00 35
1972 5 1 1 20.75 9.00 1.75 161
1973 2 1 1 10.50 4.50 0.25 87
1974 2 1 1 4.50 3.50 0.25 73
1975 1 1 0 3.00 0.75 0.00 25
1976 1 1 0 8.75 4.75 0.00 50
1977 0 0 0 0.00 0.00 0.00 0
1978 6 4 2 30.00 16.25 2.75 285
1979 0 0 0 0.00 0.00 0.00 0
1980 1 1 0 4.50 2.75 0.00 35
1981 2 0 0 3.00 0.00 0.00 16
1982 10 5 1 30.00 6.25 1.50 237
1983 4 1 1 12.00 1.50 1.25 104
1984 4 1 1 10.25 2.75 0.25 91
1985 5 4 2 18.25 12.75 2.75 246
1986 2 2 1 6.50 4.25 1.50 110
1987 4 1 0 12.50 4.25 0.00 72
1988 4 2 2 14.25 10.75 4.25 225
1989 1 1 0 4.50 2.50 0.00 34
1990 3 1 1 10.75 2.75 2.25 116
1991 2 2 0 4.50 1.50 0.00 48
1992 7 2 2 16.25 8.50 2.50 211
1993 3 2 1 13.25 8.50 1.50 143
1994 8 5 3 34.00 18.50 12.75 500
1995 0 0 0 0.00 0.00 0.00 0
1996 0 0 0 0.00 0.00 0.00 0
1997 4 0 0 11.25 0.00 0.00 42
1998 1 1 0 2.00 0.25 0.00 22
1999 2 2 1 9.00 7.25 0.25 106
2000 4 1 0 11.00 1.00 0.00 57
2001 0 0 0 0.00 0.00 0.00 0
2002 5 2 1 16.75 6.75 0.50 138
2003 1 1 0 3.50 1.75 0.00 30
AVG 2.9 1.4 0.7 10.0 4.4 1.1
NTC generated by the following storms is not included in the
preceding table:
(1) Tropical Storm Carmen of April, 1980
----------------------------------------
Carmen developed from a tropical depression which originated east
of longitude 180, but moved westward across the Dateline before
attaining tropical storm intensity. Both the CPHC and JTWC Best Track
files indicate that Carmen drifted back eastward into the Central
Pacific as a tropical storm, but differ as to the peak intensity and
the duration of tropical storm-force winds.
(2) Typhoon Skip of September, 1985
-----------------------------------
Like Carmen, Skip developed from a tropical depression of Central
Pacific origin which moved westward across the Dateline before becoming
a tropical storm. After attaining typhoon intensity, Skip recurved
northeastward and was rapidly weakening and undergoing extratropical
transition as it crossed longitude 180 eastward bound. CPHC declared
the system extratropical on the first and final advisory issued by
that agency.
(3) Tropical Storm Winona of January, 1989
------------------------------------------
This is the most puzzling discrepancy between JTWC's and CPHC's
records. No tropical cyclone advisories were apparently issued on
this system (which originated east of longitude 180) by CPHC; yet,
JTWC's Best Track file indicates that it was a tropical storm with
a MSW of 40 kts for almost two days while east of the Dateline.
The system was christened Winona by JTWC after it had entered the
Western North Pacific.
(4) Typhoon Ward of September, 1992
-----------------------------------
This cyclone began as a depression east of longitude 180 and
according to JTWC's files, reached tropical storm intensity just
about the time it crossed the Dateline, at which time it was named
by JTWC.
(5) Typhoon Dan of October, 1992
--------------------------------
An almost identical situation to Tropical Storm Ward.
(6) Other Storms in the Mid-1990s
---------------------------------
According to the JTWC Best Track file, there were several cyclones
between 1993 and 1997 which recurved and maintained tropical cyclone
status until after crossing the Dateline. However, the fact that
there were none before and since this period strongly suggests that
this is at least in part a function of the particular person(s)
performing the analysis.
*************************************************************************
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 super typhoon
Sources of Information
----------------------
Most of the information presented below is based upon tropical
cyclone warnings and significant tropical weather outlooks issued
by the Joint Typhoon Warning Center of the U. S. Air Force and
Navy (JTWC), located at Pearl Harbor, Hawaii. In the companion
tropical cyclone tracks file, I normally annotate track coordinates
from some of the various Asian warning centers when their center
positions differ from JTWC's by usually 40-50 nm or more. All
references to sustained winds imply a 1-minute averaging period
unless otherwise noted.
Michael V. Padua of Naga City in the Philippines, owner of the
Typhoon 2000 website, normally sends me cyclone tracks based upon
warnings issued by the Japanese Meteorological Agency (JMA) and the
Philippines' Atmospheric, Geophysical & Astronomical Services
Administration (PAGASA). Also, Huang Chunliang of Fuzhou City, China,
sends data taken from synoptic observations around the Northwest
Pacific basin. A very special thanks to Michael and Chunliang for
the assistance they so reliably provide.
In the title line for each storm I have referenced 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 warning responsibility.
Northwest Pacific Tropical Activity for April
---------------------------------------------
In three of the past four years, the first super typhoon of the year
developed prior to 1 June, and 2004 has continued that trend. In 2000
Super Typhoon Damrey developed deep in the Philippine Sea in mid-May;
in 2002 Super Typhoon Mitag formed in late February and passed around
40-50 nm south of Yap in early March with 100-kt winds; and in 2003
Super Typhoon Kujira formed in mid-April southeast of Guam and
followed a long trajectory which took it south of the Marianas and
eventually recurved it east of the Philippines. Whereas Mitag of 2002
was somewhat destructive to Yap, the damage pales in comparison with
the destruction sustained by Yap due to this year's Super Typhoon Sudal.
Long-time residents of the island stated that Sudal was the worst typhoon
to visit Yap since the 1950s. A report on Sudal follows, written by
Kevin Boyle, and contains a report by Mark Landers of his post-typhoon
visit to Yap.
SUPER TYPHOON SUDAL
(TC-03W / TY 0401 / COSME)
3 - 18 April
----------------------------------------------
Sudal: contributed by South Korea, is the name for the otter--a small
river animal with thick brown fur, four webbed feet and a flat
tail
A. Storm Origins
----------------
At 0600 UTC on 28 March JTWC began issuing STWOs on a persistent
area of convection approximately 290 nm southeast of Pohnpei. The
potential for development was considered poor, and initial prospects
for strengthening were not good in the high shear environment. However,
the next day shearing conditions eased and multi-spectral satellite
imagery depicted cycling deep convection associated with a broad LLCC.
The development potential remained poor for several days. Following a
relocation of the system's centre to a position 100 nm east-southeast
of Chuuk at 0000 UTC on 2 April, the disturbance was finally upgraded
to a fair potential for development. Multi-spectral satellite
animations revealed deep convection and low-level inflow associated
with the LLCC while surface pressures on the island of Chuuk were
falling steadily (3 mb per 24 hours). A TCFA was issued at 02/0300 UTC
with the environment now much more conducive for development. Despite
this, the disturbance was slow to develop and did not achieve tropical
depression status until 04/0000 UTC, when the first warning was issued.
B. Storm History
----------------
At 0000 UTC on 4 April Tropical Depression 03W was located 100 nm
west-southwest of Chuuk and moving slowly west at 4 kts. Although the
centre was partially-exposed, increased deep convection soon filled
the LLCC, and after further intensification TD-03W was upgraded to a
tropical storm with 35-kt winds. Continued strengthening brought the
MSW up to 55 kts at 05/0600 UTC, and following JMA's upgrade to tropical
storm intensity, the system was named Sudal--the first named tropical
cyclone of 2004 in the Northwest Pacific basin. At this point Tropical
Storm Sudal was moving toward the north, but this heading proved to be
a temporary phase as a building mid-latitude ridge soon shifted the
track back toward the west by 06/0000 UTC.
At 06/0000 UTC Sudal was nearing typhoon intensity approximately
260 nm south-southeast of Guam. Six hours later, the MSW was raised to
70 kts, resulting in an upgrade to typhoon status. At this time,
enhanced infrared satellite imagery suggested that a cloud-filled eye
could be forming. The 06/0600 UTC and 06/1200 UTC positions were each
shifted about 30 nm to the north in order to reflect data from a
06/0818 UTC QuikScat pass and Guam radar. Typhoon Sudal continued
westward and passed approximately 180 nm south of Guam at 06/1800 UTC
with the island community remaining outside the radius of gale-force
winds.
Typhoon Sudal had intensified to 80 kts by 0000 UTC on 7 April as it
tracked west-northwestward roughly 200 nm south of Guam. A 07/1014 UTC
microwave pass revealed a distinct eye, although it was still cloud-
covered in infrared pictures. The storm turned to a west-southwesterly
track as a mid-level ridge built to the northwest of the system.
Continuing west-southwestward at 9 kts, Sudal became a major typhoon
(>=100 kts) at 0000 UTC on 8 April when it was centred approximately
125 nm east of Yap. The island at this time lay inside the radius of
gale-force winds and conditions steadily worsened as the typhoon
approached. By 1800 UTC Sudal was bearing down on Yap with the MSW
nudging up to 110 kts. To make matters worse, the forward motion
of Sudal was slowing as it threatened to make a transition to a more
poleward track. Also, the upper-level environment was still favourable
for further intensification.
The island of Yap was located a mere 25 nm north of the eye at 09/0000
UTC and was being given a real walloping within Sudal's inner eyewall.
The lowest SLP recorded on the island was 958.5 mb at 0050 UTC on
9 April. Sudal subsequently began to move slowly away from Yap on a
west-northwesterly to northwesterly heading, accelerating to around
8 or 9 kts. Strengthening had resumed and by the end of the 9 April the
MSW had risen to 125 kts.
A 09/2224 UTC AMSU image depicted concentric eyewalls, indicating
that Sudal had reached super typhoon intensity (>=130 kts) at 10/0000
UTC while centred approximately 190 nm west-northwest of Yap. This was
to be the peak intensity, and subsequent satellite imagery revealed that
weakening had begun--the eye had become partially cloud-filled as seen
in enhanced infrared and multi-spectral imagery. Despite this, the
maximum intensity of 130 kts was maintained throughout the 10th and
into the 11th.
(Editor's Note: The peak 10-min avg MSW and minimum CP assigned by
JMA were 85 kts and 940 mb, respectively. NMCC and PAGASA each
estimated the peak intensity at 100 kts, while the CWB of Taiwan's
maximum MSW was 85 kts--the same as Japan's. HKO estimated Sudal's
peak intensity at 95 kts, but did not issue any real-time warnings
as the cyclone remained outside that agency's AOR.)
By 0000 UTC on 11 April Super Typhoon Sudal had moved well away from
Yap, being located 410 nm to the west-northwest. Enhanced infrared
satellite pictures indicated that the eye temperature had warmed
considerably over the previous six hours by 30 degrees Celsius.
Movement was still toward the northwest, but the cyclone began to respond
to an opening in the subtropical ridge axis and turned toward the
north-northwest at 11/1200 UTC. By this time Sudal had failed to
defend its super typhoon title and was downgraded at 0600 UTC. By the
time the 1800 UTC warning was issued the MSW had fallen further to
110 kts.
(PAGASA had been issuing bulletins on Sudal since 10 April, assigning
the name Cosme. Super Typhoon Sudal never ventured very far into
PAGASA's AOR and reached its most westerly point (15.7N/130.9E) at 0600
UTC on 12 April. Warnings were issuing for a further two days until
14/0600 UTC, when Sudal exited the northeast quadrant of PAGASA's AOR.
The highest sustained wind estimated by that agency was 100 kts (10-min
avg) with an estimated minimum central pressure of 944 mb.)
Sudal underwent a brief rejuvenation period after the MSW had dropped
to 105 kts at 0000 UTC 12 April. This resulted in a secondary peak of
125 kts being reached at 12/1200 UTC. Winds began to drop off again
six hours later as the typhoon began to move to the right of its
northward track. At 13/0000 UTC the eye of Sudal was situated some
765 nm southwest of Iwo Jima, moving north-northeastward at 5 kts.
At 12/1800 UTC a large 45-nm symmetrical eye was observed in satellite
images and this remained a prominent feature through the 13th. Further
slow weakening occurred and the MSW was estimated at 115 kts at
13/1800 UTC.
In defiance of the increasingly hostile upper-level conditions,
Typhoon Sudal held itself together during the 14th--in fact, by 1800
UTC the intensity still had yet to fall below 100 kts. However, by
15/0600 UTC Sudal had quickly succumbed to the increasing vertical wind
shear and cooler SSTs with winds dropping to 65 kts. At this time the
exposed LLCC was passing only 15 nm south of Iwo Jima. At 15/1200 UTC
Typhoon Sudal was downgraded to tropical storm intensity as it sped
east-northeastward at a little over 20 kts. Six hours later, Sudal had
completed extratropical transition and the final warning was issued by
JTWC, placing the center about 270 nm east-northeast of Iwo Jima. JMA,
however, retained tropical classification for another 18 hours, declaring
Sudal extratropical at 16/1200 UTC. The gale center continued speeding
east-northeastward, crossing the International Dateline at 17/1800 UTC.
The final reference to the system by JMA was at 0000 UTC on the 18th,
the 40-kt gale center then being located well to the south of the
Aleutian Islands.
C. Meteorological Statistics
----------------------------
At 0000 UTC on 9 April Typhoon Sudal passed 25 nm south of the
island of Yap. The peak MSW recorded on the island was 79 kts with a
peak gust of 117 kts at 08/2256 UTC. The lowest minimum SLP was
958.5 mb at 0050 UTC on 9 April.
Sudal was undergoing extratropical transition as it passed over Iwo
Jima at 0600 UTC on 15 April. The MSW on the island reached 50 kts with
the highest gust of 76 kts recorded at 15/0819 UTC. The strongest winds
occurred in a region well away from the deep convection but were
associated with a strong cumulus line. The MSLP recorded on Iwo Jima
was 972 mb at 15/0612 UTC. (Thanks to Roger Edson for sending this
information.)
D. Mark Lander's Post-storm Visit to Yap
----------------------------------------
The following report was sent by Mark Lander. A special thanks
to Mark for sharing the report of his post-typhoon visit to Yap.
"A week ago Friday (April 09), Typhoon Sudal devastated Yap Island
(9.5N/138.1E). I went out there as part of a team to perform a
regional NWS Service Assessment and to gather meteorological data on
the typhoon. The U. S. military and other U. S. government agencies
have been busy with relief efforts to the island, and they are doing
a good job over there helping the local inhabitants with the recovery
process.
"Very nearly all wooden homes were damaged to some extent. Some of
the worst damage occurred where the sea drove inland and smashed down
the many houses that are built along the shoreline. Yap is famous for
its large stone money (large rock disks with central holes for carrying
on poles). Just south of Colonia--the main urban center on the
central eastern coastal region--there is a large collection of the
stone "coins" in a place known as the Yap Stone MoneyBank. The sea
flooded in there at a standing level of about 6 feet, over-washed the
many rows of stone money, and knocked them down. These can easily be
righted, but the downed homes will take a bit more effort to bring
back to habitable condition. Concrete structures fared well, and the
new office of the National Weather Service was hardly touched (this
served as a shelter for many people during the typhoon). Many people
are homeless, but for the most part they are coping well.
"Flying over the island on approach to landing one is struck by the
brownness of the terrain--a typical post-typhoon appearance due in
part to the wind stripping the leaves off of the trees, and also due
to a coating of sea salt that shrivels and kills any remaining green
leaves. Mashed tangles of crushed and broken trees are seen at
locations exposed to higher winds along the upslope regions of
hills and along the shore line.
"One of the first efforts was to try to determine if the eye passed
over any portion of the island. Very reliable eyewitness reports
(pun inescapable) indicate that the eye was experienced briefly on
the very southern-most tip of the island. Families sitting in the
shade under surviving roofed structures were eager to comment on the
experience. One young woman very convincingly described eye passage:
for a brief period the wind stopped and the sun came out. The wind at
first had been blowing from the northeast, then after the eye, it
roared in directly from the sea (a southeast wind) towards her house.
The sea inundated her property and over-washed the whole southern end
of the island 50 yards or more inland to a run-up level of 12 feet
above mean sea level. Dozens and maybe hundreds of reef fish (parrot
fish, trigger fish, small groupers and others) lay dead along the
base of a sea wall...not really sure how these died, but it must
have been a miserable time for the sea critters as the white water
thrashed inland.
"Yap is quite small: about 10 miles north-south and 3 or 4 miles
east-west. It is completely surrounded by a fringing reef, and has a
number of world-class dive sites. One of the mysteries of the
typhoon brought to my attention (as soon as people knew that I was a
weather guy) was that local divers noted that since the typhoon, the
water had become as cold as they have ever experienced. A report
(perhaps grown to the status of an urban legend) was that one group
of divers noted that the water at dive depth (40-80 feet) was 12
degrees (F) colder than normal (72 F instead of the usual 84). I told
them that typhoons cool the ocean surface as they pass, but that such
a large magnitude cooling was truly remarkable. Another mystery
presented to me was an observation of an unusual fog that had settled
on the island and coastal regions in the mornings after the winds had
died post-typhoon. Rising early one morning, I perhaps saw this
"fog", and it was a whole lot of smoke from burning debris piles
trapped under a shallow inversion perhaps 75 feet above the surface.
It lay low in the bays and valleys with the hills poking above it
into clean air. Can't say for sure whether by the time I arrived,
I missed the formation of a true fog caused by the cold sea, or
radiational night cooling. During the days it was hot and dry, and
the roads had actually become dusty. There was some concern of
wildfire if rains did not return and the typhoon debris became a dry
tinder to fuel raging fires.
"Emergency crews quickly cleared the roads of fallen trees, and by
the time that we arrived, we could drive to just about any location on
the island. Getting clean drinking water out to the people was one of
the first priorities. On my way over, there was little room in the
C-130 among the pallets of bottled water.
"Although Yap is influenced by a few typhoons every year (mostly in
the southern fringes of TC's that are passing by to the north), the
island is rarely hit directly by an intense typhoon. Sudal is the
worst typhoon to hit Yap in roughly 50 years. Only the older
residents remember a typhoon that hit some time in the 1950's that
was perhaps worse than Sudal.
"Despite the heavy damage, there are no known deaths directly
attributable to the typhoon. This is quite remarkable, given the
tales of many who were caught in their homes as the sea invaded, and
then found themselves suddenly in water up to their waists or higher.
"On the way out from Yap, we dropped back down to about 100 feet
above the water and made a fly-over of Ulithi Atoll (10.0N/139.8E).
Ulithi was hit hard by Typhoon Lupit just this past December. Sudal
passed far enough south to spare them another hard hit. The larger
inhabited islets looked fine, and it was fun to see the kids running
along the sand spits waving at the plane.
"Then it was back to Guam for a late night arrival, and business
as usual."
E. Damage and Casualties
------------------------
Sudal had a devastating effect on Yap. The typhoon damaged or
destroyed 90% of property, private houses, and public utilities, and
forced 900 people into shelters. Dehydration became a serious problem
with fresh drinking water having to be brought in by air. Ninety
percent of crops were completely destroyed. Coastal areas were
devastated by the tidal surge, severely damaging seawalls. About
1000 persons were left homeless by the typhoon.
Although there has been no confirmed deaths attributable to the
storm, some news articles have reported at least one.
Additional articles on Sudal's aftermath on Yap can be accessed at
the following link:
http://www.reliefweb.int/w/rwb.nsf/vLND>
(Report written by Kevin Boyle)
*************************************************************************
NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea
Activity for April: No tropical cyclones
*************************************************************************
SOUTHWEST INDIAN OCEAN (SWI) - South Indian Ocean West of Longitude 90E
Activity for April: No tropical cyclones
Southwest Indian Ocean Tropical Activity for April
--------------------------------------------------
No tropical storms or depressions formed in the South Indian Ocean
west of 90E during April. MFR issued one bulletin on 26 April for an
area of disturbed weather several hundred miles north-northeast of
Mauritius, identifying it as Tropical Disturbance 14. The system
subsequently weakened, and to the author's knowledge, no further
bulletins were issued.
*************************************************************************
NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (AUW) - From 90E to 135E
Activity for April: No tropical cyclones
*************************************************************************
NORTHEAST AUSTRALIA/CORAL SEA (AUE) - From 135E to 160E
Activity for April: 1 tropical LOW
Northeast Australia/Coral Sea
Tropical Activity for April
-----------------------------
Although no tropical cyclones formed over waters between 135E and
160E during April, there was one tropical LOW which warrants mentioning.
A tropical LOW formed on 10 April in the northeastern Coral Sea about
250 nm west-northwest of Honiara on Guadalcanal. Brisbane initiated
gale warnings on the LOW in anticipation that gales might develop. No
gales actually occurred, at least near the center, as the system was
not upgraded to tropical cyclone status. The LOW had drifted east of
160E by 1800 UTC on 11 April, where it was numbered as Tropical
Disturbance 13F by Fiji. Although briefly referred to as a tropical
depression on the 12th, Nadi dropped the system from their summaries
after that date. The LOW began to drift westward and organization
increased somewhat on the 14th and 15th. At 1200 UTC on 15 April
the system was located just off the southeastern tip of New Guinea
and had become fairly well-organized. The tropical LOW looked its
best 24 hours later at around 16/1200 UTC when it was located just
east of the central Cape York Peninsula. The system appeared to be
on the verge of becoming a tropical cyclone, but it suddenly weakened
and the remnant LOW drifted across the Peninsula into the Gulf of
Carpentaria. The final reference to this system was in Darwin's daily
Tropical Weather Outlook on 21 April when it was a weak 1009-mb LOW
in the Arafura Sea. (Thanks to Carl Smith for sending some satellite
imagery which was very helpful in writing up this system.)
*************************************************************************
SOUTH PACIFIC (SPA) - South Pacific Ocean East of Longitude 160E
Activity for April: 4 tropical depressions **
** - one of these classified as a weak tropical cyclone by JTWC
Sources of Information
----------------------
The primary sources of tracking and intensity information for
South Pacific tropical cyclones are the warnings and advisories
issued by the Tropical Cyclone Warning Centres at Nadi, Fiji (for
waters north of latitude 25S), and Wellington, New Zealand (for
waters south of latitude 25S). References to sustained winds imply
a 10-minute averaging period unless otherwise stated.
In the companion tropical cyclone tracks file, I occasionally
annotate positions from warnings issued by the Joint Typhoon Warning
Center (JTWC) of the U. S. Air Force and Navy, located at Pearl
Harbor, Hawaii, when they differ from the Southern Hemisphere
centres' coordinates by usually 40-50 nm or more. The JTWC warnings
are also the source of the 1-minute average maximum sustained wind
values included in the tracks file. Additionally, information
describing details of satellite imagery and atmospheric circulation
features included in the narratives is often gleaned from the JTWC
warnings.
South Pacific Tropical Activity for April
-----------------------------------------
The South Pacific basin literally crawled with weak tropical LOWs
during April; yet, none of these became named tropical cyclones. The
definition of a tropical cyclone in WMO Region V a few years back
required the existence of a ring of gales surrounding the center. This
criterion was abolished at the Rarotonga meeting in September, 2000, but
the tropical cyclone definition was further amended at a meeting in
Manila in May, 2002, to stipulate that gales at least be present near
the center of the system. Some of the April LOWs had peripheral gales
well-removed from the center, but none developed concentrated central
convection and gale-force winds near enough to the center to be named
as tropical cyclones. The most notable of these systems was Tropical
Depression 10F (designated as TC-22P by JTWC). A report on this system,
written by Simon Clarke, follows.
Tropical Depression 09F developed very early in the month far to the
east of the International Dateline. On 1 April the LOW was located
about 200 nm southeast of Tahiti. TD-09F remained quasi-stationary for
a day or so, then moved slowly to the west-southwest, being last
referenced on the 3rd when located about 250 nm south-southwest of
Tahiti. Peripheral gales were reported in association with this
depression--a ship reported winds to 45 kts northwest of the center at
1200 UTC on 2 April. Weak Tropical Depression 11F occurred on 7 April.
This system formed just east of the Dateline approximately 300 nm east-
southeast of Fiji. The LOW drifted southward during the day and was
last referenced at 2330 UTC on the 7th. No gale warnings were issued
for this system, and no track was included in the companion global
tropical cyclone tracks file.
Tropical Depression 12F also developed on 7 April in the Solomon
Islands about 125 nm east-southeast of Honiara on Guadalcanal. On
the 8th the center of action was relocated about 475 nm to the east-
southeast to a position about 300 nm north-northeast of Port Vila in
Vanuatu. The LOW drifted generally in an eastward direction and by
the 11th was located roughly 250 nm north of Fiji. This system was
right behind TD-10F and likely contributed to the overabundant rain-
fall in Fiji which caused severe flooding. Tropical Disturbance 13F
had its origins west of 160E, and later moved back into Brisbane's AOR
where it almost developed into a tropical cyclone. This system is
described above in the Northeast Australia/Coral Sea section of this
summary.
Two other weak systems were numbered by the Nadi TCWC. Tropical
Disturbance 14F formed on the 18th just east of the Dateline and moved
through the Tonga area on the 19th. Tropical Disturbance 15F formed
a few days later in the Solomon Islands area and remained quasi-
stationary in that region through the 24th when it was last referenced.
Neither of these systems were referred to as tropical depressions in the
Tropical Disturbance Summaries issued by Nadi.
TROPICAL DEPRESSION
(TD-10F / TC-22P)
4 - 9 April
---------------------------------------
The current Southwest Pacific season has been notable for a string
of tropical disturbances strung along the inter-tropical convergence
zone, none of which developed with a central core of gale-force winds
close to the LLCC (i.e., tropical cyclone status). Nonetheless, this
string of depressions was responsible for a prolonged wet season to
many parts of the South Pacific and most notably, Fiji.
Tropical Depression 10F perhaps is the system that will be remembered
the best. However, it was not specifically TD-10F that caused the
problems, but rather the combined effect of a series of tropical LOWs
through the region that caused the year to be exceptionally wet in
this part of the world.
TD-10F was first identified near 11.4S/167.5E at 05/0023 UTC in a
broad monsoonal trough extending from the Solomon Islands to the north
of Fiji with major convection located to the north and northeast of
the system. Vertical shear was light with good upper-level outflow.
The average SST around the depression was 30 C. At the time, a QuikScat
pass indicated a series of eddies strung along the trough axis.
By 07/2300 UTC TD-10F (995 hPa) was located near 17.0S/177.5E and
moving southeastward at 15 knots. The TRMM pass at 07/1641 UTC and
SSM/I pass at 07/1936 UTC suggested that the LLCC was sheared. Very
cold and deep convection was displaced about 0.5 degree to the south,
over the Yasawa Group of islands, and was responsible for about four
hours of gale-force winds over Yasawa-I-Rara between 07/1800 UTC and
07/2100 UTC, inclusive.
TD-10F crossed over the Viti Levu landmass on a 15-knot southeasterly
heading, being steered by a mid-level ridge to the south. The depression
was subject to 40-knot northwesterlies at the 250-hPa level, and despite
some weakening in the upper-level winds, transitioned into an extra-
tropical system to the southeast of the island without attaining official
cyclone status. The peak MSW estimated near TD-10F's centre was
32 knots.
Of note, JTWC briefly recognised TD-10F as a tropical cyclone
(TC-22P) with a peak 1-min avg MSW of 35 knots.
Furthermore, TD-10F was responsible for the deaths of at least ten
people, with 11 still missing as of mid-April.
An estimated 20,000 people have been left homeless from the
persistent wet season this year in Fiji with millions of dollars
worth of damage incurred. Eighteen houses were washed away in Nalidi
Wainibuka, with the Town of Rakiraki and the Tailevu district
affected by mudslides.
Additional articles on the flooding in Fiji can be accessed at the
following link:
http://www.reliefweb.int/w/rwb.nsf/vLND>
(Report written by Simon Clarke)
*************************************************************************
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
from the archive sites listed below. (Note: I do have a limited e-mail
distribution list for the track files. If anyone wishes to receive
these via e-mail, please send me a message.)
Both the summaries and the track files are standard text files
created in DOS editor. Download to disk and use a viewer such as
Notepad or DOS editor to view the files.
The first summary in this series covered the month of October,
1997. Back issues can be obtained from the following websites
(courtesy of Michael Bath, Michael V. Padua, Michael Pitt, and
Chris Landsea):
http://australiasevereweather.com/cyclones/>
http://www.typhoon2000.ph>
http://mpittweather.com>
ftp:// ftp.aoml.noaa.gov/hrd/pub/landsea/padgett/>
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 2002 (2001-2002 season for the Southern
Hemisphere). ATCRs for earlier years are available also. The report
for the 2002-2003 Southern Hemisphere season has also recently been
added.
The URL is: http://199.10.200.33/jtwc.html>
Also, TPC/NHC has available on its webpage nice "technicolor"
tracking charts for the 2003 Atlantic and Eastern North Pacific
tropical cyclones; also, storm reports for all the 2003 Atlantic
and Eastern North Pacific cyclones are now available, as well as
track charts and reports on storms from earlier years.
The URL is: http://www.nhc.noaa.gov>
A special thanks to Michael Bath of McLeans Ridges, New South Wales,
Australia, for assisting me with proofreading the summaries.
PREPARED BY
Gary Padgett
E-mail: [email protected]
Phone: 334-222-5327
Kevin Boyle (Eastern Atlantic, Western Northwest Pacific, South
China Sea)
E-mail: [email protected]
Huang Chunliang (Assistance with Western Northwest Pacific, South
China Sea)
E-mail: [email protected]
Simon Clarke (Northeast Australia/Coral Sea, South Pacific)
E-mail: [email protected]
*************************************************************************
*************************************************************************
|
Document: summ0404.htm
Updated: 26th October 2006 |
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