MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY
SEPTEMBER, 2007
Third Installment
(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.)
NOTE!!! The September summary is being issued in three installments.
The first covered the Atlantic basin, while the second covered the
Northeast Pacific and North Indian Ocean basins and contained an extra
feature. The third installment covers the Northwest Pacific basin.
*************************************************************************
SEPTEMBER HIGHLIGHTS
--> Destructive Category 5 hurricane strikes Nicaragua
--> Typhoons strike Korea and China
--> Eight Atlantic tropical storms in September ties record for month
*************************************************************************
ACTIVITY BY BASINS
ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico
Activity for September: 1 tropical depression
4 tropical storms
3 hurricanes **
1 intense hurricane
** - one of these was treated operationally as a strong tropical storm
but was upgraded to hurricane status during post-storm analysis
NOTE!!! The Atlantic basin was covered in the first installment of the
September summary.
*************************************************************************
NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180
Activity for September: 1 tropical depression
1 tropical storm
2 hurricanes **
** - one of these formed in August and was covered in the August summary
NOTE!!! The Northeast Pacific basin was covered in the second
installment of the September summary.
*************************************************************************
NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180
Activity for September: 3 tropical depressions **
2 tropical storms
3 typhoons ++
1 super typhoon
** - two of these classified as tropical depressions by JMA only
++ - one of these formed in August and was covered in the August summary;
another was classified as a typhoon by JTWC only and reached typhoon
intensity in early October
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). A very special thanks to Michael for the
assistance he so reliably provides.
Also, in recent months Derrick Herndon of CIMSS has been sending me
increasingly detailed reports of surface observations, along with some
additional analysis. A special thanks to Derrick for his inputs.
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 September
-------------------------------------------------
September was an active month in the Northwest Pacific basin. As the
month opened Typhoon Fitow was drifting slowly westwards well to the
southeast of Japan. The storm later turned toward the northwest,
recurved, and made landfall on the Izu Peninsula as a minimal typhoon
late on the 6th, subsequently moving over the northernmost Japanese
island of Hokkaido. The report on Typhoon Fitow may be found in the
August summary.
Five named storms formed during September. Tropical Storm Danas
formed northwest of Wake Island on the 7th and became a strong tropical
storm as it recurved well to the east of Honshu. The extratropical
remnants of Danas moved all the way across the North Pacific and affected
the southeastern Alaskan coastline. Typhoon Nari formed on the 13th
between Taiwan and the northern Marianas and eventually made a
destructive strike on South Korea. Super Typhoon Wipha formed near
mid-month, passed just north of Taiwan, and made a destructive strike
in mainland China near the border between Fujian and Zhejiang Provinces.
Tropical Storm Francisco formed on 23 September in the northern South
China Sea and made landfall in northern Hainan Dao. The final cyclone
of September was somewhat unusual. A broad monsoon depression formed
in the Philippine Sea and was named Hanna by PAGASA. Hanna was upgraded
to a tropical storm by that agency prior to its striking Luzon. The
system weakened and its remnant circulation moved out into the South
China Sea where it began to redevelop. It was named Lekima by JMA early
on 30 September and continued westward, eventually making landfall in
Vietnam. JMA never upgraded Lekima to typhoon status, but JTWC did so,
estimating the peak MSW (1-min avg) at 70 kts on 2 October. Reports on
all these cyclones, written primarily by Kevin Boyle, follow.
In addition to the named tropical cyclones, three additional systems
were monitored as tropical depressions by one agency or another. The
first of these operated from 9-14 September as reported in High Seas
bulletins issued by JMA. The system was first reported as a weak
tropical depression at 09/0600 UTC when located about 265 nm west-
southwest of Okinawa. The LOW moved in the general direction of Okinawa
and the winds were upped to 30 kts at 10/1800 UTC when it was centered
only about 55 nm south-southwest of the island. The depression passed
only about 20 nm to the south around 11/0600 UTC and continued toward
the east-northeast, reaching a point about 100 nm east-northeast of
Okinawa by 11/1800 UTC. The system then came to a halt and turned back
to the west, passing around 75 nm north of Okinawa on the 12th. A
slow drift toward the west-northwest continued, and the depression began
to weaken on the 13th, being downgraded to weak depression (25 kts)
status at 13/1800 UTC when located about 260 nm northwest of Okinawa.
The final reference to the system was at 14/0600 UTC.
Although no warnings were issued on this depression by JTWC, the
system was carefully monitored by the agency and rather extensive remarks
included in the STWOs. Normally I don't include so much material for
non-developing systems, but this disturbance was rather interesting
and unusual. JTWC first referenced the system at 10/0600 UTC, assigning
a development potential of 'poor'. An elongated and poorly-organized
LLCC was near the southern end of an approaching mid-latitude baroclinic
trough. The potential for development was upped to 'fair' at 10/2200 UTC
when the LLCC had become better defined and a small area of deep
convection had formed east of the center. There was some interaction
with the trough and vertical shear was moderate to strong. By 11/0600
UTC the LLCC had become more elongated and the deep convection had taken
on a more frontal appearance, so the development potential was reduced
to 'poor'. By 11/2000 UTC drier subsident air in the mid-levels and
cold-air advection were noted to the west of the center. The LOW was
assessed as a shallow warm-core system in the process of transforming
into an extratropical LOW. By 12/0600 UTC the convection had dissipated
and the system was dropped as a suspect area from the STWOs.
However, at 12/2100 UTC the disturbance was added back as a suspect
area with a 'poor' development potential. Convective banding was
wrapping into a well-defined LLCC located just north of the subtropical
ridge axis in the presence of good poleward outflow. By 13/0000 UTC
deep convection had developed over the LLCC, which had separated from a
shear line to the northeast, and an upper-level analysis indicated that
the system was warm-core to 700 mb, although weak cold-air advection was
still present to the west. Therefore, a TCFA was issued and the
development potential raised to 'good'. By 13/1700 UTC, shear had
increased and the deep convection had become sheared to the northeast of
the LLCC, but there was still a potential for rapid development should
the shear relax, given the well-defined LLCC and abundant warm water.
However, by 2100 UTC deep convection had dissipated near the center,
which was rapidly weakening and elongating, so the TCFA was cancelled and
the disturbance deleted as a suspect area. The system at this time was
located only about 175 nm southeast of Shanghai, China.
The second depression was treated as a tropical depression by both
JMA and JTWC, the latter agency designating it as TD-14W. An area of
convection developed on 19 September about 60 nm south-southwest of Yap.
A fairly well-defined LLCC was present under an area of good upper-level
divergence, and 24-hour pressure falls of 2 to 3 mb were noted at Yap.
JMA first referenced the system as a weak tropical depression at 19/1200
UTC. The system continued to show increased organization, and JTWC
issued a TCFA at 19/2000 UTC with the center then located about 40 nm
west of Yap. The first warning on Tropical Depression 14W was issued
at 20/1200 UTC, placing the 30-kt center about 460 nm west of Guam,
or about 265 nm north-northwest of Yap, and moving north-northwestward
at 11 kts. Low-level cyclonic shear was favorable, but vertical shear
was moderate and was displacing the majority of the deep convection to
the south of the center. Dvorak estimates from both SAB and JTWC reached
T2.5/2.5 on the 20th, but shortly afterward began to decline. A narrow
upper-level trough to the north of the depression appeared to be
inhibiting further intensification. Vertical shear subsequently
increased and TD-14W began to weaken, and JTWC issued their final
warning at 21/1200 UTC, locating the center 655 nm southeast of Naha,
Okinawa. JMA's final reference to the system was six hours later. The
latter agency's 10-min avg MSW estimates for this depression never
exceeded 25 kts. Tracks for TD-14W and the 9-14 September depression
were included in the companion cyclone tracks file.
The third depression of September was referenced only as a weak
tropical depression by JMA. The system was first noted at 24/1200 UTC
in the Philippine Sea near 25N/130E, moving south-southwestward slowly.
Over the next 36 hours the system drifted generally in a southwestward
direction, being last mentioned at 26/0000 UTC near 22N/127E. JTWC did
not list this disturbance as a suspect area in their STWOs, and I did
not prepare a tabular track for the system.
TROPICAL STORM DANAS
(TC-11W / STS 0710)
6 - 17 September
----------------------------------------
Danas: contributed by the Philippines, is a Tagalog word meaning "to
feel" or "to experience"
A. Synoptic History
-------------------
Prior to the development of Tropical Storm Danas on 4 September, the
monsoon trough was quiet and convection rather sparse in the Northwest
Pacific while an isolated Typhoon Fitow was travelling steadily westwards
southeast of Japan. Scattered amounts of convection were being generated
by troughing over the eastern part of Micronesia. This extended north
into the Marshall Islands to a weak circulation, located approximately
180 nm north-northwest of Wake Island. This was first alluded to in
JTWC's STWO issued at 0600 UTC 4 September when convective banding was
seen developing along the southern and eastern peripheries of the LLCC.
Even though low-level westerlies to the south and easterlies to the
north were providing favourable cyclonic wind shear, upper-level
analysis revealed unfavourable northerly shear caused by an upper-level
LOW to the north. The system slowly developed over the next two days
and a TCFA was issued at 06/2200 UTC. Animated infrared imagery
indicated a partially-exposed LLCC with the strongest convection to the
northeast. QuikScat imagery showed winds of 20-25 kts near the centre
as the disturbance drifted towards the west-northwest at 10 kts. The
first warning was issued at 07/1800 UTC, placing Tropical Depression 11W
approximately 850 nm east of Iwo Jima. JMA had first classified the
system as a tropical depression at 06/0600 UTC.
Tracking northwestward along the southern periphery of a subtropical
ridge, TD-11W slowly consolidated and was upgraded to a 35-kt tropical
storm at 1200 UTC 7 September by both JTWC and JMA. Tropical Storm Danas
continued to slowly intensify as it moved northwestward, the system's
development being hampered by dry air intrusion and the limitation of
poleward and equatorial outflow. In addition, the storm passed over
SSTs cooled by Typhoon Fitow's passage a few days earlier and also into
a region of increasing westerly wind shear. Nevertheless, Tropical Storm
Danas kept itself together and intensified a little more late on
9 September as it turned northward over the warm waters (25-26 deg C) of
the Kuroshio Current, reaching a peak intensity of 60 kts at 10/0600 UTC
at quite a high latitude (38N). (JMA's peak 10-min avg MSW for Danas
was 50 kts.) At this time, the cyclone was centred 435 nm southeast of
Misawa, Japan. The system then recurved and accelerated northeastwards
on 10 September into the mid-latitude westerlies and began extratropical
transition. JTWC issued the final warning at 11/0000 UTC, and JMA
followed suit 18 hours later.
The extratropical stage of ex-Danas lasted almost another week as it
crossed the North Pacific. The system had weakened to 35 kts as it
crossed the Dateline late on the 12th, but then began to re-intensify,
reaching 50 kts by 15/0000 UTC (based on OPC warnings). The system moved
into the Gulf of Alaska and was centered just off the southeastern coast
of Alaska later on the 15th. The LOW began slowly weakening as it
drifted eastward along the Alaskan coastline. Winds had fallen below
gale-force by 16/1200 UTC, and the system was last referenced near
Juneau, Alaska, as a 30-kt LOW at 17/0000 UTC.
B. Meteorological Observations
------------------------------
A ship located about 60 nm southeast of Danas' center at 11/1200 UTC
reported a pressure of 993.5 mb and winds 260@28 kts (10-min avg). This
was after JTWC had declared Danas extratropical, but JMA was still
carrying the system as a tropical storm. (This information sent by
Derrick Herndon.)
C. Damage and Casualties
------------------------
There were no reports of damage or casualties associated with Tropical
Storm Danas.
(Report written by Kevin Boyle)
TYPHOON NARI
(TC-12W / TY 0711 / FALCON)
11 - 18 September
-----------------------------------------------
Nari: contributed by South Korea, is the lily, a kind of plant which
grows from a bulb, with large white or coloured flowers, commonly
found in Korea in summer
A. Synoptic History
-------------------
The origins of Typhoon Nari lay within an area of convection over a
developing LLCC, noted on 10 September approximately 390 nm northwest of
Guam. It was initially mentioned in JTWC's STWO at 2230 UTC and assessed
to have a 'poor' potential for development. A 10/1214 UTC ASCAT image
indicated 10-15 kt unflagged winds associated with the weak LLCC. Upper-
level analysis indicated a low wind shear environment and good outflow,
although a weak TUTT to the north was inhibiting outflow over the north-
west quadrant. The potential was raised to 'fair' at 11/2000 UTC. JMA
first classified this system as a tropical depression at 11/1200 UTC.
Moving west-northwestwards, the system continued to develop and a TCFA
was issued at 12/1630 UTC. The first JTWC warning on Tropical
Depression 12W was issued at 12/1800 UTC, locating the centre
approximately 475 nm southeast of Naha, Okinawa. Situated southwest
of a subtropical ridge, TD-12W tracked towards the northwest at 11 kts,
and was upgraded to a 45-kt tropical storm at 13/0600 UTC.
Simultaneously, JMA raised their 10-min avg MSW to 35 kts and assigned
the name Nari. Crossing into PAGASA's AOR early on 13 September, the
storm became known in the Philippines as Tropical Storm Falcon. Only
five warnings were issued by this agency before the storm exited PAGASA's
AOR.
After reaching tropical storm intensity, Nari continued to strengthen
and became a 65-kt typhoon at 13/1800 UTC while drifting on a west-
northwesterly heading. Turning northwestward, the system intensified
rapidly on 14 September, acquiring a 14-nm diameter eye by 14/1200 UTC
while passing just west of Okinawa. Aided by a strong polar outflow
induced by an approaching mid-latitude trough, Nari reached a peak
intensity of 120 kts at 14/1800 UTC while located 80 nm west-northwest
of Naha, Okinawa. On 15 September the typhoon veered northward and began
to slowly weaken. Travelling north to north-northeast, Nari continued to
gradually wind down. The tropical cyclone passed near Cheju Do at
16/0600 UTC before coming ashore over South Korea six hours later. The
MSW was estimated at 70-75 kts at landfall. JTWC issued the final
warning at 16/1200 UTC, downgrading the system to a tropical storm. At
the same JMA lowered their MSW to 55 kts (10-min avg). Nari turned
towards the northeast late 16 September as it weakened to 35 kts
and was declared a developing LOW in JMA's final tropical cyclone
warning at 17/0000 UTC. The system became quasi-stationary in the Sea
of Japan and had weakened to a 20-kt LOW near 40N/137E by 18/1800 UTC.
At its peak Typhoon Nari was a tidy, compact system of small size
with the radius of 64-kt winds extending 20 nm around the eye. The
peak 10-min avg MSW assigned by JMA was 95 kts with an estimated
minimum CP of 940 hPa.
B. Meteorological Observations
------------------------------
The following information was sent by Derrick Herndon of CIMSS. (All
winds are 10-min avg unless otherwise stated, and the date in the
description of Nari's passage over Kumejima and Okinawa is 14 September.)
Nari passed directly over Kumejima Island. At 1500 UTC the station
reported sustained winds ENE@58 kts and a pressure of 949.6 mb, then at
1600 UTC winds SSE@48 kts and a pressure of 948.4 mb. It appears from
the radar imagery that both of these observations occurred just inside
the eyewall. Based on the observations, I would put the MSLP at about
934 mb. The core of Nari was quite small and Naha, Okinawa, only
recorded winds 150@35G68 kts at 1348 UTC with a pressure of 994 mb. The
MSLP would support 1-min avg winds of about 118 kts. The pressure
gradient between Kumejima and Okinawa would also support that value.
There is also a news report which indicated winds to about 140 mph. I
would assume this was a gust but can not confirm. Here is the quote:
"Packing the strongest winds ever recorded, Typhoon Nari pounded
Kumejima late Friday night and early Saturday before moving across
Okinawa's main island, wreaking even more havoc. Kumejima Town
registered wind speeds of 52.4 meters per second (118 mph), beginning
at 11:00 pm, then the storm buffeted the island with record-breaking
speeds of 62.8 m/s (140 mph) about 1:30 am. Landslide and flood warnings
were issued for the Kerama Archipelago after 45.5 mm (1.8") of rain fell
in an hour. Forecasters predicted 250 mm (9.8") of rain for Okinawa by
the time Typhoon Nari had passed by."
Nari then made a direct hit on Jeju Island, passing over the eastern
part of the island. Jeju airport (24 meters elevation) on the north part
of the island and NW of the center reported winds of 010@52G71 kts and a
pressure of 985 mb at 0400 UTC on the 16th. The Jeju radar site located
a little higher at 73 meters recorded winds of 340@81 kts at 0300 UTC on
the 16th. Seogwipo, located on the southern part of the island and
closer to where the center made landfall, reported winds 140@29 kts and a
pressure of 973.1 mb at 0300 UTC on the 16th. The obs put the MSLP at
0300 UTC around 968 mb. The wind at the Jeju radar site would suggest
max 1-min avg winds of about 85 kts. The MSLP would suggest something
closer to 80 kts; however, the storm's forward motion of 17 kts along
with the well-defined eyewall structure in radar could support a slight
upward bump to 85 kts.
C. Links and Comments
---------------------
Images of the Typhoon Nari, as well as a radar animation of its
passage across Okinawa, may be found at the following link:
http://cimss.ssec.wisc.edu/tropic/archive/2007/storms/12W_Nari/12W_Nari.html
D. Damage and Casualties
------------------------
According to the online Wikipedia report, twenty people were killed or
missing in South Korea due to massive flooding. Rainfall totals reached
a record 590 mm in Jeju, South Korea.
(Report written by Kevin Boyle, with Section B contributed by Derrick
Herndon)
SUPER TYPHOON WIPHA
(TC-13W / TY 0712 / GORING)
15 - 21 September
-----------------------------------------------
Wipha: contributed by Thailand, is a woman's name
A. Synoptic History
---------------
Super Typhoon Wipha formed in the Philippine Sea in an active
monsoon trough which extended to around 145E. It was first mentioned
in JTWC's STWO at 1730 UTC 13 September when convective banding was
forming around a consolidating LLCC located approximately 775 nm west
of Guam. Both a 13/0943 UTC QuikScat image and synoptic data indicated
strong convergent 20-25 kt westerlies south of this LLCC with 10-15 kt
easterlies to the north. Upper-level analysis revealed weak to
moderate vertical wind shear, a developing anticyclone northeast of the
centre, and favourable outflow aloft. The potential for development
was assessed as 'fair'. This was increased to 'good' at 14/2200 UTC
and a TCFA issued. The first warning on Tropical Depression 13W was
issued at 15/0600 UTC with the system tracking towards the northwest at
around 6 kts. (JMA had identified the developing LLCC as a tropical
depression six hours earlier.)
Moving more to the west, Tropical Depression 13W intensified slowly
on 15 September as a small TUTT cell to the north inhibited convection
over the LLCC and suppressed poleward outflow. The hindering effects
of this TUTT subsequently decreased, allowing more rapid
intensification. TD-13W was upgraded to a 35-kt tropical storm at 0000
UTC 16 September, and then to a 65-kt typhoon at 16/1200 UTC, at which
time it was located 320 nm south-southeast of Naha, Okinawa. JMA also
raised their 10-min avg MSW to 35 kts at 16/0000 UTC and dubbed the
tropical cyclone Wipha. (The cyclone was known locally as Goring in
the Philippines.)
Typhoon Wipha continued to strengthen on 17 September as it tracked
west-northwestward along the periphery of a subtropical ridge which was
extending across the subtropical Northwest Pacific. It became a super
typhoon at 17/1800 UTC before reaching its peak intensity of 135 kts at
18/0000 UTC. Gradual weakening began on 18 September, the storm
passing 70 nm north of Taipei, Taiwan, at 18/1200 UTC. Typhoon Wipha
made landfall over China with a MSW of 100 kts at 18/1800 UTC
approximately 50 nm south of Wenzhou. Once inland, it continued to
weaken and was downgraded to a 50-kt tropical storm on JTWC's final
warning at 19/0600 UTC. JMA also lowered Wipha to tropical storm
status at this time. The extratropical Wipha changed to a more
northerly heading on 19 September and tracked across eastern China
before emerging into the Yellow Sea the next day. The system continued
to weaken and was only a 25-kt LOW near 39N/128E by 21/0000 UTC.
B. Meteorological Observations
------------------------------
The following information was sent by Derrick Herndon of CIMSS. (All
winds are 10-min avg unless otherwise stated.)
A number of ships were located in the northern portion of the
circulation of Wipha on the 15th and 16th. At 1800 UTC on the 15th a
ship located 130 nm NE of the center reported winds 140@36 kts and a
pressure of 999.9 mb. Another ship 105 nm NW of the center at the same
time reported winds 340@31 kts and a pressure of 996.2 mb. Neither
ship was located in the deeper convection which at the time was located
in the eastern and southern portions of the tropical cyclone. During
this time both the CIRA and CIMSS AMSU methods indicated a 1-min avg
MSW of 50-55 kts while the AODT indicated 39 kts. The Satellite
Consensus (SATCON) suggested a MSLP of 991 mb and a 1-min avg MSW of
47 kts. Given the ship observations the MSLP was at least 995 mb, which
would support a MSW of more than 35 kts. A 2100 UTC QuikScat pass
indicated several unflagged 35-kt wind vectors; however, the center of
the cyclone was near the eastern edge of the swath.
Wipha passed directly over Iriomote Island on the 18th at 0000 UTC.
The pressure at the station fell from 987 mb at 17/1600 UTC to 928 mb
at 18/0000 UTC when the winds dropped to 19 kts. The strongest sustained
winds I saw from the station were NE@72 kts at 17/2300 UTC while the
pressure was 929 mb, only 1 mb higher than the minimum one hour later.
I think the MSLP at 18/0000 UTC can pretty confidently be put at 926 mb.
Karl Hoarau provided some additional information indicating the gusts at
this station reached 128 kts. Eleven miles NE of the center and just on
the outer edge of the eyewall Ishigaki Island recorded a pressure of
953 mb with winds 070@64G88 kts. Karl indicated that this station
recorded a peak gust of 115 kts. Another station, Ohara, located south
of Iriomote and on the southern edge of the eyewall, reported winds of
SSW@76 kts at 18/0000 UTC.
Wipha passed 18 nm north of Pengjia Yu (north of Taiwan) at 0800 UTC
on the 18th when the station reported winds of 240@74 kts and a pressure
of 958.6 mb. The station was south of the eyewall at that time.
C. Links and Comments
---------------------
Radar animations of Wipha may be found at the following link:
http://cimss.ssec.wisc.edu/tropic/archive/2007/storms/13W_Wipha/13W_Wipha.ht
ml
D. Damage and Casualties
------------------------
According to the online Wikipedia report, the total damage
attributable to Super Typhoon Wipha was estimated at over $880 million
and the overall death toll was nine. Nearly 2 million people were
evacuated from the Shanghai and Fujian-Zhejiang areas in what is
considered to be the most extensive evacuation in over a half a
century. Typhoon Wipha caused widespread severe flooding in Shanghai
where at least 80 streets were flooded. At least twenty flights were
cancelled and fifty postponed at both Shanghai airports. The storm
forced FIFA to reschedule four matches in the Women's Soccer World Cup
hosted by China.
There was a report of a casualty in the Ryukyu Islands. The storm
left more than 7,500 travellers stranded as the two airports between
Ishigaki and Miyakojima closed down and ferries remained at port. On
Iriomote Island, some 10,600 homes were left without power, and
telephone communications cut to 1,200 homes. Half the homes were left
without electricity on Ishigaki.
(Report written by Kevin Boyle, with Section B contributed by Derrick
Herndon)
TROPICAL STORM FRANCISCO
(TC-15W / TS 0713)
23 - 26 September
--------------------------------------------
Francisco: contributed by the United States, is a Chamorro man's name
(Spanish form of Francis)
A. Track History
----------------
Tropical Storm Francisco originated as part of a large monsoon
depression and was first mentioned in JTWC's STWO at 1800 UTC
21 September, located approximately 280 nm north-northeast of Manila,
Philippines. Both multi-spectral and infrared imagery showed a
consolidating LLCC on the periphery of the monsoon depression while a
21/1553 UTC TRMM microwave pass revealed convective banding wrapping
into the LLCC from the south. The disturbance tracked slowly westwards,
crossing northern Luzon into the South China Sea on 22 September.
Strong southwesterly flow, low vertical wind shear, and good divergence
aloft all aided in development, and a TCFA was issued at 22/1500 UTC.
The first warning on Tropical Depression 15W was released at 23/0000 UTC,
the system being then located approximately 190 nm south-southeast
of Hong Kong, China. (JMA had first referenced the system as a tropical
depression at 21/1800 UTC.)
Tracking west-southwestwards, Tropical Depression 15W was upgraded to
a 35-kt tropical storm at 23/1200 UTC by both JTWC and JMA, the latter
agency assigning the name Francisco. After passing south of Hong Kong,
Francisco continued to strengthen and reached its peak intensity of
45 kts at 24/0000 UTC near the northeastern corner of Hainan. Francisco
began to weaken as it tracked across northern Hainan into a region of
unfavourable wind shear. It was downgraded to a tropical depression at
24/1800 UTC before JTWC issued its final warning at 25/0000 UTC. JMA
issued their final bulletin six hours later. The poorly-defined centre
of Francisco continued westwards across the Gulf of Tonkin on
25 September before dissipating over northern Vietnam on the 26th.
B. Meteorological Observations
------------------------------
The following information was sent by Derrick Herndon of CIMSS. (All
winds are 10-min avg unless otherwise stated.)
Dongsha Dao (WMO 59791, 20.67N/116.72E) was located 40 nm north of
the center at 1800 UTC on the 22nd when the station recorded a pressure
of 994.5 mb and winds 020@23 kts. This would put the MSLP at about
992 mb. For the landfall on Hainan, Meilan (ZKHK), located on the
northern part of the island, recorded winds of 350@31G45 kts and a
pressure of 994 mb at 0400 UTC on the 24th. The pressure continued to
fall at the station, reaching a low of 988 mb two hours later at 0600
UTC with winds of 040@23 kts. Winds continued to veer to the east over
the next few hours, suggesting the center passed south of the station.
C. Damage and Casualties
------------------------
There were no reports of damage or casualties in association with
Tropical Storm Francisco.
(Report written by Kevin Boyle, with Section B contributed by Derrick
Herndon)
TROPICAL STORM HANNA - TYPHOON LEKIMA
(TC-16W / STS 0714 / HANNA)
27 September - 4 October
---------------------------------------------------------
Lekima: contributed by Vietnam, is the name of a tree whose fruit has
only one seed surrounded by a yellow pulp which resembles an egg
yolk
A. Synoptic History
-------------------
Typhoon Lekima originated from a broad, monsoon depression in the
Philippine Sea. It was first classified as a tropical depression by JMA
at 0000 UTC 27 September. Six hours later, PAGASA initiated warnings,
assigning the name Hanna. Hanna drifted westwards and was upgraded to a
tropical storm by PAGASA at 0600 UTC 28 September. Hanna moved inland
in Luzon on the 29th and was downgraded to a tropical depression. A
QuikScat pass about six hours prior to landfall depicted some good
30-35 kt wind vectors, so it appears that PAGASA did the right thing
in upgrading Hanna to tropical storm status. By late 29 September the
centre of Hanna was located well out over the South China Sea and
drifting towards the west-southwest. (Prior to landfall in Luzon, JMA
had carried the system as a 30-kt depression on 27 and 28 September, but
downgraded it to below 30 kts at 28/0600 UTC--the same time that PAGASA
upgraded it to Tropical Storm Hanna. Prior to the system's crossing of
Luzon, JTWC issued no warnings. A TCFA was issued on the 27th, but
cancelled on the 28th. It seems that the primary reason for JTWC's
dropping the system was that it was assessed to be more of a monsoon
depression than a formative tropical cyclone.)
JTWC first mentioned Hanna as a disturbance in a TCFA at 0900 UTC
29 September. Remarks in this statement: "Recent animated multi-
spectral satellite imagery indicates a well-defined mid-level
circulation has moved over Luzon and into the South China Sea.
A 29/0117 UTC Ascat pass and recent ship observations indicate a LLCC
may be developing beneath the mid-level circulation, although this
cannot be confirmed in satellite imagery due to contamination. The
ship observations and Ascat indicate winds between 20 and 25 kts. A
200-mb anticyclone over Luzon is contributing to excellent diffluence
aloft along with dual outflow channels. Deep convection has decreased
slightly near the center of the circulation, most likely due to
interaction with land over the past six hours. Deep convective banding
is developing in the northeastern and southwestern quadrants of the
disturbance."
The JTWC's first warning on Tropical Depression 16W was issued at
30/0000 UTC with the center located approximately 460 nm east-northeast
of Nha Trang, Vietnam. However, at the same hour JMA upgraded the
depression to Tropical Storm Lekima with 10-min avg winds estimated at
35 kts. Six hours later, JTWC also upgraded Lekima to tropical storm
status while JMA raised their 10-min avg MSW estimate to 40 kts.
Tracking west-southwestward, Lekima intensified slowly over the next
two days due to the hindering effects of an upper-level LOW. This
synoptic feature suppressed deep convection over the northern
semicircle. Late on 30 September the storm entered a weak steering
flow which caused it to slow and turn abruptly more northwards.
Accelerating onto a west-northwest to northwesterly heading, Lekima
maintained a MSW of 55 kts through 1 October. The tropical cyclone
intensified early the following day and was upgraded to a 70-kt typhoon
by JTWC at 02/0600 UTC. This was to be its peak intensity. Typhoon
Lekima passed just south of Hainan Dao late on 2 October while
maintaining 70-kt winds. Tracking more westwards, Lekima then crossed
the Gulf of Tonkin on 3 October before making landfall over Vietnam at
around 03/1200 UTC with a MSW of 65 kts. The cyclone was downgraded to
a tropical storm on JTWC's last warning at 03/1800 UTC. After coming
ashore over Vietnam, JMA carried the weakening Lekima via their
bulletins for a further twelve hours. JTWC's last satellite fix on
Lekima's remnants was at 04/1800 UTC, placing the center near
16.9N/100.6E, or over north-central Thailand, headed for the northern
end of the Bay of Bengal.
Around the same time NRL opened an invest (95B) for a feature at the
head of the Bay of Bengal. This system was referenced briefly as a
depression by IMD. According to Julian Heming, the remnants of Lekima
were at least partly responsible for this depression over Bangladesh.
Julian traced back through satellite images and model analyses, and
concluded that the separate feature at the head of the Bay (Invest 95B)
was likely energized by the ex-Lekima system as it crossed Myanmar and
reached Bangladesh.
B. Meteorological Observations
------------------------------
The following information was sent by Derrick Herndon.
On October 01 at 0000 UTC a ship located 115 nm SE of the center
reported 60 kts with a pressure of 992 mb. The same ship reported
52 kts and a pressure 997 mb six hours later; however, another ship
nearby only indicated 35 kts, and that latter value is supported by
QuikScat. Therefore, the winds of 50-60 kts east and south of the
center seem too high. However, winds of this strength do seem to have
occurred south and west of the center. A ship 160 nm SW of the center
at 0600 UCT on October 01 reported winds from the west at 60 kts and a
pressure of 995 mb while another ship 180 nm west of the center
indicated winds W at 50 kts and 1003 mb. Based on these observations
and obs from Sanhu Dao (WMO 59985), the MSLP of Lekima was likely below
985 mb. Both of the ships indicating winds > 50 kts to the SW of the
center were located within the strongest gradient and near the active
convective band. At 2100 UTC on October 1 the center passed close to
Xisha Dao (WMO 59981) when the station recorded a pressure of 981.5 mb
with winds dropping to 160@8 kts. At the same time Sanhu Dao 40 nm to
the east had 982 mb, suggesting a broad center. Several hours later
at 0300 UTC on October 02 the strongest winds impacted Xisha Dao with
sustained 1-minute winds of 60 kts (station elevation is 5 meters). It
was about three hours after this that an eye feature became evident in
the microwave imagery. The eye feature was about 30 nm in diameter,
suggesting a possible tightening of the wind field during this time.
At 1400 UTC the center passed about 45 nm south of Phoenix (ZJSY) on
Hainan. The station reported a pressure of 988 mb and winds
070@33G50 kts. It appears the station was outside of the apparent
eyewall. For the landfall in Vietnam Dong Hoi (WMO 48848) was about
45 nm south of the center at 0900 UTC and reported 989 mb; however,
that was the last observation I saw from the station and CPA occurred a
few hours later.
C. Damage and Casualties
------------------------
According to the online Wikipedia report, Typhoon Lekima brought
torrential rains to Luzon which caused a landslide that killed eight
people, including three children. In addition, one person was found
dead in Quezon City. There were no further reports of casualties in the
Philippines.
Over 100,000 people were evacuated in southern China as the storm
approached, and more than 20,000 fishing boats were recalled back to
the harbors. There are no reports of casualties.
At least 42 people were reported dead or missing in Vietnam where
Lekima caused extensive damage, destroying about 100,000 houses.
(Report written by Kevin Boyle and Gary Padgett, with Section B
contributed by Derrick Herndon)
*************************************************************************
NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea
Activity for September: 1 depression **
** - no warnings issued on this system by JTWC
NOTE!!! The North Indian Ocean basin was covered in the second
installment of the September summary.
*************************************************************************
SOUTHWEST INDIAN OCEAN (SWI) - South Indian Ocean West of Longitude 90E
Activity for September: No tropical cyclones
*************************************************************************
NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (AUW) - From 90E to 135E
Activity for September: No tropical cyclones
*************************************************************************
NORTHEAST AUSTRALIA/CORAL SEA (AUE) - From 135E to 160E
Activity for September: No tropical cyclones
*************************************************************************
SOUTH PACIFIC (SPA) - South Pacific Ocean East of Longitude 160E
Activity for September: No tropical cyclones
*************************************************************************
SPECIAL FEATURE - SOURCES OF TROPICAL CYCLONE INFORMATION
The purpose of this section is to list some websites where many and
varied types of tropical cyclone information are archived. Many readers
will know about these already, but for the benefit of those who don't,
I wanted to include them.
(1) Aircraft Reconnaissance Information
---------------------------------------
Various types of messages from reconnaissance aircraft may be
retrieved from the following FTP site:
ftp://ftp.nhc.noaa.gov/pub/products/nhc/recon/
Information regarding how to interpret the coded reconnaissance
messages may be found at the following URL:
http://www.nhc.noaa.gov/reconlist.shtml
Links are also included to websites with further information about the
U. S. Air Force 53rd Weather Reconnaissance Squadron and the NOAA Air-
craft Operations Center.
(2) Archived Advisories
-----------------------
All the advisory products (public advisories, forecast/advisories,
strike probabilities, discussions, various graphics) issued by TPC/NHC
are archived on TPC's website. For the current year (using 2004 as an
example), the archived products can be found at:
http://www.nhc.noaa.gov/archive/2004/index.shtml
Links to tropical products archives for earlier years are available at
the following URL:
http://www.nhc.noaa.gov/pastall.shtml
JTWC warnings for past storms are archived on the NRL Monterrey website:
http://www.nrlmry.navy.mil/tc_pages/tc_home.html
On the NRL site, the link to past years can be found in the upper left
corner of the screen.
I am not aware at the moment of any other TCWC which archives all
its tropical cyclone warning/advisory products for public access, but
if I learn of any, I will add them to this list.
(3) Satellite Imagery
---------------------
Satellite images of tropical cyclones in various sensor bands are
available on the NRL Monterrey and University of Wisconsin websites,
courtesy of Jeff Hawkins and Chris Velden and their associates. The
links are:
http://www.nrlmry.navy.mil/tc_pages/tc_home.html
http://cimss.ssec.wisc.edu/tropic/tropic.html
On the NRL site, the link to past years can be found in the upper left
corner of the screen. For the CIMSS site, a link to data archives is
located in the lower left portion of the screen.
Additional tropical satellite imagery, along with looping ability for
composite microwave imagery for the Western Hemisphere north of the
equator, can be found at:
(1) For the Eastern North Pacific:
http://www.ssd.noaa.gov/PS/TROP/trop-epac.html
(2) For the Atlantic, Gulf of Mexico and Caribbean Sea:
http://www.ssd.noaa.gov/PS/TROP/trop-atl.html
(4) Cyclone Tracking Information
--------------------------------
There is a U. S. Navy site that tracks tropical cyclones at 6-hourly
intervals which often includes pre and post-advisory positions. The
link to the site is:
http://www.nrlmry.navy.mil/atcf_web/doc_archives/
Steve Young has compiled many of these tracks onto a single webpage
which is very user-friendly:
http://home.earthlink.net/~shy9/tc1.htm
I'm sure there are other sites with available imagery available, and
as I learn of them, I will add the links to this list.
*************************************************************************
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 August, 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, Chris
Landsea, and John Diebolt):
http://australiasevereweather.com/cyclones/
http://www.typhoon2000.ph <http://www.typhoon2000.ph/>
http://mpittweather.com <http://mpittweather.com/>
ftp://ftp.aoml.noaa.gov/hrd/pub/landsea/padgett/
http://www.tropicalcyclone2005.com/
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.metoffice.gov.uk/weather/tropicalcyclone
TROPICAL CYCLONE REPORTS AVAILABLE
JTWC now has available on its website the Annual Tropical Cyclone
Report (ATCR) for 2005 (2004-2005 season for the Southern Hemisphere).
ATCRs for earlier years are available also.
The URL is: http://metocph.nmci.navy.mil/jtwc.php
Also, TPC/NHC has available on its webpage nice "technicolor"
tracking charts for the 2006 Atlantic and Eastern North Pacific
tropical cyclones; also, storm reports for all the 2006 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 <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: garyp@alaweb.com
Phone: 334-222-5327
Kevin Boyle (Northwest Pacific)
E-mail: newchapelobservatory@btinternet.com
Simon Clarke (Northeast Australia/Coral Sea, South Pacific)
E-mail: scla4255@bigpond.net.au
*************************************************************************
*************************************************************************
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