[Index]
Monthly Global Tropical Cyclone Summary October 2008
[Summaries and Track Data] [Prepared by Gary Padgett]
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Cyclones
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Monthly Global Tropical Cyclone Summary October 2008 [Summaries and Track Data] [Prepared by Gary Padgett] |
MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY
OCTOBER, 2008
(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.)
*************************************************************************
OCTOBER HIGHLIGHTS
--> Smallest Atlantic tropical cyclone on record visits Mexican Gulf
Coast
--> Intense eastern Caribbean hurricane brushes Virgin and Leeward
Islands
--> Western coast of Baja California Peninsula struck by strong
Category 2 hurricane
--> First typhoon-free October in Western North Pacific since 1976
--> Remnants of Arabian Sea depression cause devastating floods in
Yemen
*************************************************************************
WIKIPEDIA TROPICAL CYCLONE REPORTS
Short reports with satellite pictures and small-scale maps for all
tropical cyclones may be found at the following links:
http://en.wikipedia.org/wiki/2008_Atlantic_hurricane_season>
http://en.wikipedia.org/wiki/2008_Pacific_hurricane_season>
http://en.wikipedia.org/wiki/2008_Pacific_typhoon_season>
http://en.wikipedia.org/wiki/2008_North_Indian_cyclone_season>
http://en.wikipedia.org/wiki/2008-09_Southern_Hemisphere_tropical_cyclone_season>
For some storms more detailed reports have been prepared. In those cases
I will include the specific links in the reports for the applicable
tropical cyclones.
*************************************************************************
ACTIVITY BY BASINS
ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico
Activity for October: 1 tropical depression
2 tropical storms
1 intense hurricane
Sources of Information
----------------------
Most of the information presented below was obtained from the
various tropical cyclone products issued by the Tropical Prediction
Center/National Hurricane Center (TPC/NHC) in Miami, Florida:
discussions, public advisories, forecast/advisories, tropical weather
outlooks, special tropical disturbance statements, etc. Some
additional information may have been gleaned from the monthly
summaries prepared by the hurricane specialists and available on
TPC/NHC's website. All references to sustained winds imply a
1-minute averaging period unless otherwise noted.
Atlantic Tropical Activity for October
--------------------------------------
Three named storms formed during October in the Atlantic basin, plus
a non-developing tropical depression. One of the tropical storms became
an intense hurricane. The 1950-2007 averages for October are about two
tropical storms, one hurricane, and an intense hurricane about every
three years. Omar was the first intense October hurricane since Wilma
and Beta in 2005.
In addition to the three named cyclones, Tropical Depression 16 formed
just off the coasts of Nicaragua and Honduras but failed to reach
tropical storm status. It was the only tropical depression not to do so.
TD-16 was a large and initially well-organized system, and was forecast
to move westward north of the Honduran coastline and reach Belize as a
55-kt tropical storm. However, due likely to its proximity to land,
convection associated with the depression diminished and the system did
not strengthen. The initial advisory was issued by NHC at 14/1500 UTC
with the MSW set at 25 kts. Initially drifting westward, TD-16 took a
jog to the southwest on the 15th which carried the center inland into
Honduras by 1800 UTC. The MSW was upped briefly to 30 kts after the
center had moved inland based on QuikScat data and a ship and buoy
report. However, in the Best Track prepared during post-season analysis,
the peak MSW has been lowered to 25 kts. The depression had degenerated
into a remnant LOW by early on 16 October.
According to Wikipedia, heavy rains from TD-16 left 16 people dead and
six missing and forced a further 100,000 persons from their homes across
Central America. Total damage is estimated at US$9.7 million. The full
Wikipedia report on Tropical Depression 16 may be accessed at the
following URL:
http://en.wikipedia.org/wiki/Tropical_Depression_Sixteen_(2008)>
The TPC/NHC report on the depression, authored by Dan Brown, is
available at the following link:
http://www.nhc.noaa.gov)2008atlan.shtml>
(Note: Reports on all the October cyclones, except for Omar, are
currently available at the above link.)
TROPICAL STORM MARCO
(TC-13)
6 - 8 October
----------------------------------------
Tiny Tropical Storm Marco formed from an area of low pressure which
had developed over the northwestern Caribbean Sea during the early days
of October. The disturbance moved inland across the southern Yucatan
Peninsula, temporarily stalling development. As it approached the Bay
of Campeche, convection began to increase early on 6 October. High-
resolution visible satellite imagery during the morning revealed that the
system had become sufficiently organized that it could be classified as
a tropical depression, so advisories were initiated on Tropical
Depression 13 at 1500 UTC. The center was estimated to be located about
120 nm east of Veracruz, Mexico, moving west-northwestward at 8 kts.
The initial intensity was estimated at 30 kts.
A fortuitous flight by the U. S. Air Force Reserve Hurricane Hunters
around mid-day revealed that the small depression had intensified into
a tropical storm with a MSW of about 55 kts. Hence, TD-13 was upgraded
to Tropical Storm Marco at 2100 UTC. Marco, did not intensify further
as it continued westward across the southern extremities of the Gulf of
Mexico. The storm made landfall between Veracruz and Tuxpan around
1200 UTC 7 October and quickly weakened once inland. The final advisory
by TPC/NHC was issued at 08/0300 UTC with the dissipating depression
center located about 165 km west-northwest of Veracruz.
One of the most amazing things about Marco was its small size. The
reconnaissance flight around 2000 UTC on 6 October found that the radius
of 34-kt winds was no more than 15 nm, and high-resolution QuikScat data
from very early on the 7th suggested that tropical storm-force winds
extended outward from the center no more than 10 nm. Marco's gale radii
makes it the smallest tropical cyclone in the Atlantic over a period of
record dating back to 1988.
In the final Best Track for Marco, the MSW for 06/1200 and 08/1800
UTC has been upped to 40 kts and 50 kts, respectively. Also, the track
begins at 06/0000 UTC with a MSW of 25 kts at that hour and 30 kts at
06/0600 UTC.
The Wikipedia report on Marco may be found at the following URL:
http://en.wikipedia.org/wiki/Tropical_Storm_Marco_(2008)>
The official TPC/NHC report on Marco, written by James Franklin, may
be accessed at the link given in the introductory paragraph above.
(Report written by Gary Padgett)
TROPICAL STORM NANA
(TC-14)
12 - 14 October
---------------------------------------
Tropical Storm Nana was a minor, minimal tropical storm which formed
and remained well out in the central tropical North Atlantic. The system
was named on the first advisory at 2100 UTC 12 October when a QuikScat
pass indicated winds of 35 kts. Nana battled strong shear as it moved
west-northwestward and was forecast to soon weaken and dissipate even on
the initial advisory. It is almost a certainty that this system would
never have been classified as a tropical cyclone prior to the days of
QuikScat, since it was not being operationally carried as a tropical
depression at the time it was named.
The Wikipedia report on Nana may be found at the following URL:
http://en.wikipedia.org/wiki/Tropical_Storm_Nana_(2008)>
The official TPC/NHC report on Nana, written by Stacy Stewart, may
be accessed at the link given in the introductory paragraph above.
(Report written by Gary Padgett)
HURRICANE OMAR
(TC-15)
13 - 21 October
-----------------------------------
Omar's progenitor was a tropical wave which departed the west coast of
Africa on 30 September. The wave moved slowly across the tropical
Atlantic and reached the eastern Caribbean Sea on 10 October. The
associated convection showed signs of organization on the 11th, and a
tropical depression formed on 13 October about 150 nm north-northwest of
Curacao in the Netherlands Antilles. The initial advisory on TD-15 was
issued at 13/1500 UTC, and the MSW was estimated at 30 kts. The cyclone
moved slowly and erratically on 13-14 October, and was upgraded to
Tropical Storm Omar at 1500 UTC on 14 October while centered about
310 nm south-southwest of San Juan, Puerto Rico, or approximately 110 nm
north of Curacao. Omar subsequently turned northeastward and
accelerated on the 15th, reaching hurricane intensity around 0600 UTC.
The hurricane intensified very rapidly late on 15 October and into
the early hours of the 16th. Operationally, the peak intensity assigned
was 110 kts, but the working Best Track indicates that Omar very briefly
reached 115 kts at 16/0600 UTC, and the 16/0900 UTC discussion bulletin
suggested that this was the case. A reconnaissance plane found two
spot winds of 132 and 124 kts at flight level, but could not sample the
entire eyewall due to extremely high turbulence. Objective T-numbers
oscillated between T6.5 and T7.0 around the same time.
The hurricane's center moved through the Anegada Passage which
separates the Virgin Island group from the remainder of the Leewards.
The closest approach to any land seems to have been around 16/0500 UTC
when the eye lay about 22 nm east-northeast of St. Croix. Given that
hurricane-force winds extended out about 30 nm to the southwest, it seems
likely that at least the eastern end of St. Croix would have experienced
hurricane winds. The intense inner core remained over the Anegada
Passage, fortunately sparing any island a direct hit by the dangerous
eastern eyewall.
Just as Omar had intensified very rapidly, so it also weakened very
rapidly as it encountered strong southwesterly vertical shear. Even as
Omar was passing between the Virgin Islands and Leewards, the cloud
pattern was beginning to deteriorate. At 17/0600 UTC, only 24 hours
after its peak intensity of 115 kts, Omar's MSW had fallen to 50 kts.
The storm by this time was racing northeastward into the open Atlantic.
A temporary decrease in shear allowed Omar to briefly regain hurricane
intensity later on the 17th, but it weakened back to a tropical storm
early on the 18th. Tracking over colder SSTs, Omar had decayed to a
remnant LOW by the afternoon of 18 October while located about 715 nm
east of Bermuda. This LOW moved slowly northeastward and dissipated
early on 21 October about 565 nm west of the western Azores Islands.
The Wikipedia report on Omar may be found at the following URL:
http://en.wikipedia.org/wiki/Hurricane_Omar_(2008)>
Damage from Omar was rather light in the Virgin and Leeward Island
groups due to the fact that the intense inner core remained over water.
There was some significant damage to beaches on the leeward side of several
islands. Strong westerly winds caused some severe damage in the form
of power outages and fallen trees on Dominica, Antigua, Barbuda, and
in the U. S. Virgin Islands. Hurricane Omar was responsible for an
estimated $96 million in damages and 2 fatalities--one direct and one
indirect--in Puerto Rico.
(Report written by Gary Padgett)
*************************************************************************
NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180
Activity for October: 1 tropical depression
1 tropical storm
1 hurricane
1 intense hurricane
Sources of Information
----------------------
Most of the information presented below was obtained from the
various tropical cyclone products issued by the Tropical Prediction
Center/National Hurricane Center (TPC/NHC) in Miami, Florida (or the
Central Pacific Hurricane Center (CPHC) in Honolulu, Hawaii, for
locations west of longitude 140W): discussions, public advisories,
forecast/advisories, tropical weather outlooks, special tropical
disturbance statements, etc. Some additional information may have
been gleaned from the monthly summaries prepared by the hurricane
specialists and available on TPC/NHC's website. All references to
sustained winds imply a 1-minute averaging period unless otherwise
noted.
Northeast Pacific Tropical Activity for October
-----------------------------------------------
Three named storms, plus a non-developing tropical depression, formed
in the Eastern North Pacific during the month of October. Two of the
storms reached hurricane intensity, and one became an intense hurricane.
The October averages over the 1971-2007 period are about two tropical
storms, one hurricane, and a major hurricane about every other year.
Therefore, in October, 2008, tropical cyclone activity was slightly above
the long-term average for the basin.
Tropical Depression 17E formed from a broad area of low pressure
on 23 October about 355 nm south of Manzanillo, Mexico. The depression
initially moved northward, but turned toward the northwest on 24 October
and remained well offshore during its short lifespan. Strong vertical
shear hindered any further development of the system. However, the
strong upper-level winds brought rainfall from the depression to the
southwestern coast of Mexico. The continued strong shear led to the
degeneration of the depression into a remnant LOW on 24 October about
255 nm southwest of Manzanillo. This remnant LOW moved toward the
west-northwest and west until it dissipated on 28 October about 650 nm
southwest of the southern tip of the Baja California Peninsula. The
official report on Tropical Depression 17E, written by Michael Brennan,
is available at the link below.
The official TPC/NHC storm reports for all the October tropical
cyclones are available at the following URL:
http://www.nhc.noaa.gov/2008epac.shtml>
HURRICANE MARIE
(TC-14E)
1 - 6 October
-----------------------------------
Marie developed from a tropical wave that had left the African coast
on 6 September, taking two weeks to reach Central America. The wave
emerged into the Eastern Pacific on 24 September but was very slow to
develop, showing no signs of a closed circulation until around the 28th.
Tropical Depression 14E formed on 1 October about 510 nm southwest of
the southern tip of Baja California. While moving in a westerly
direction, TD-17E strengthened into Tropical Storm Marie later that day.
After turning west-southwestward, Marie became a hurricane on 3 October
while located about 755 nm west-southwest of the Baja. Marie reached
its peak intensity of 70 kts on 4 October with steady weakening
thereafter. The cyclone degenerated into a remnant low-pressure area
on 7 October about 860 nm west-southwest of Baja California. Marie
lasted longer as a remnant LOW that it did as a tropical cyclone. After
moving southwestward for the next 12 days, the system was finally
absorbed into the ITCZ on the 19th about 1050 nm east-southeast of the
Hawaiian Islands.
There is no detailed Wikipedia report on Marie, but a general report,
along with a track graphic, is available at the link given above near the
beginning of this summary.
The official TPC/NHC report on Marie, authored by Stacy Stewart, is
available at the URL given in the introductory paragraph.
(Report written by Gary Padgett)
HURRICANE NORBERT
(TC-15E)
4 - 12 October
-------------------------------------
Hurricane Norbert formed from a broad area of low pressure which had
developed in association with a vigorous tropical wave that had moved
off the west coast of Mexico in late September. Organization increased
and the system was designated Tropical Depression 15E on 4 October
about 200 nm south of Acapulco. The depression moved little initially,
but building high pressure to the north induced a westerly track by
late that day. The system was upgraded to Tropical Storm Norbert on
the 5th and slowly intensified, reaching hurricane strength on 7 October
about 275 nm south-southwest of Manzanillo, Mexico. Norbert continued
to strengthen as it moved west-northwestward, reaching a peak intensity
of 115 kts--Category 4 on the Saffir/Simpson Scale--on 8 October about
385 nm south of Cabo San Lucas.
The hurricane then turned northwestward and by the time a
reconnaissance plane reached the cyclone around 09/1800 UTC, Norbert
had weakened into a 70-kt Category 1 hurricane. Norbert was still over
warm SSTs and within an environment of light shear, so it appears that
structural changes, including an eyewall replacement cycle, were
responsible for the weakening. Recurving ahead of a deep-layer trough,
Norbert turned north-northeastward toward the Baja California Peninsula.
The hurricane re-intensified, briefly regaining intense hurricane status
of 100 kts at 11/0600 UTC. Norbert made landfall near Puerto Chale on
the west coast of the Peninsula around 11/1630 UTC with the MSW estimated
at 90 kts--a Category 2 hurricane. Continuing northeastward, Norbert
crossed the Baja Peninsula and made a second landfall in mainland Mexico
about 40 km southeast of Huatabampo around 0400 UTC on 12 October with
peak winds of 75 kts. Norbert weakened rapidly after landfall and
dissipated over the mountains of Mexico later that day.
Some storm surge flooding was reported in the fishing town of Puerto
San Carlos. Media reports indicate that nearly half the homes were
totally or partially damaged, mostly from roof damage, on the islands of
Margarita and Magdalena near the first landfall site. Information from
meteorological and civil defense officials in Mexico indicated that
there were five deaths directly associated with Norbert in Alamos,
Sonora, with all these being due to flooding.
The Wikipedia report on Hurricane Norbert may be accessed at the
following URL:
http://en.wikipedia.org/wiki/Hurricane_Norbert_(2008)>
The official TPC/NHC report on Norbert, written by James Franklin,
is available at the link given in the introductory paragraph.
Hurricane Norbert is the strongest known hurricane on record to strike
the western coast of the Baja California Peninsula, and is the first
hurricane in the month of October to strike the Peninsula's western side
since Hurricane Pauline in 1968.
(Report written by Gary Padgett)
TROPICAL STORM ODILE
(TC-16E)
8 - 12 October
----------------------------------------
The official TPC/NHC report on Tropical Storm Odile, authored by
Jack Beven, is available at the link given in the introductory
paragraph. The following two paragraphs on Odile's rather unusual and
interesting origin are taken from Jack's report:
"Odile had a complex origin. A tropical wave moved westward from the
coast of Africa on 23 September. This wave merged with another area of
vorticity over the tropical Atlantic on 26 September, with the combined
system continuing westward. The wave reached the western Caribbean on
4 October, where it merged with the southern end of an old frontal
system. The northern end of this combination moved west-northwestward
across the Yucatan Peninsula into the Bay of Campeche, where it
contributed to the formation of Atlantic Tropical Storm Marco.
"The southern end of the system moved westward into the eastern
Pacific and almost immediately showed signs of organization. However,
the development was stopped by easterly vertical wind shear as the
system stalled south of El Salvador on 5 October. There was little
motion or change in organization during the next couple of days. Early
on 8 October, another tropical wave moved into the eastern Pacific and
approached the disturbance. Development resumed at that time, and it is
estimated that a tropical depression formed at 1200 UTC that day about
105 nm south-southwest of San Salvador, El Salvador."
Advisories were initiated on Tropical Depression 16E at 08/2100 UTC,
and the depression was upgraded to Tropical Storm Odile at 09/0600 UTC.
Odile turned northwestward on 10 October, then moved west-northwestward
near the southwestern coast of Mexico on the 11th. Odile reached an
estimated peak intensity of 55 kts early on 11 October. Southeasterly
vertical wind shear caused the storm to weaken later that day, and Odile
weakened to a tropical depression early on 12 October. The cyclone
further degenerated to a remnant LOW later that day about 15 nm southwest
of Manzanillo, Mexico, and subsequently moved slowly southwestward before
dissipating on 13 October. (NOTE: The operational peak intensity of
55 kts has been lowered to 50 kts in the final Best Track.)
Odile was responsible for causing rainfall in Mexico, and the pre-
cursor disturbance dumped heavy rainfall in Nicaragua; however, any
impact is unknown.
There is no detailed Wikipedia report on Odile, but a general report
along with a track graphic is available at the link given above near the
beginning of this summary.
(Report written by Gary Padgett)
*************************************************************************
NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180
Activity for October: 2 tropical storms **
** - one of these treated as a tropical storm by JTWC only
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.
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 October
-----------------------------------------------
October, 2008, was one of the quietest months of October on record
in the Northwest Pacific basin. Tropical Storm Higos/Pablo was active
over northern Luzon as the month began. This system remained a minimal
tropical storm and had moved inland in southern China and dissipated
by the 6th. Two more tropical depressions formed during the month,
and both reached tropical storm status per JTWC's warnings, but only
one was named by JMA. Neither reached typhoon intensity--making this
the first typhoon-free October since 1976. That month was most unusual.
Following a fairly active September, not a single tropical cyclone formed
during October (based on JTWC's records). Short reports on Tropical
Storm 22W and Tropical Storm Bavi (23W) follow.
TROPICAL STORM
(TC-22W)
13 - 15 October
-----------------------------------
Tropical Storm 22W was classified as a tropical storm by JTWC only.
The system was slow-moving and formed in the northwestern South China
Sea to the southwest of Hainan Dao. At 13/0000 UTC JMA identified a
low-pressure area as a minor tropical depression near 18N/108E. Twenty-
four hours later the system had shown some improved organization and
JMA increased the winds to 30 kts with the system located approximately
160 nm southeast of Hanoi, Vietnam. JTWC issued their first warning on
Tropical Depression 22W at 14/0600 UTC, and six hours later upgraded the
system to a minimal tropical storm. This was based on Dvorak intensity
estimates of 35 kts from both JTWC and SAB.
Tropical storm intensity was maintained for only 18 hours with the
system being downgraded to a tropical depression at 15/0600 UTC. TS-22W
drifted slowly westward while a tropical storm, but moved to the west-
southwest and inland while weakening. The final bulletin from both JMA
and JTWC, issued at 15/1200 UTC, placed the dissipating center inland
about 315 km east of Vientiane, Laos.
No reports of damage or casualties resulting from this system have
been received.
(Report written by Gary Padgett)
TROPICAL STORM BAVI
(TC-23W / TS 0818)
18 - 25 October
---------------------------------------
Bavi: contributed by Vietnam, is a mountain chain in Hatay Province
(about 40 km west of Hanoi) with its peak of 1281 metres, and
where there is a national forest
JTWC issued a STWO at 0200 UTC 18 October noting that an area of
convection had developed about 565 nm northeast of Guam. At about the
same time JMA identified this system as a weak tropical depression.
A large area of deep convection had previously been associated with some
mid-level turning, but animated multi-spectral satellite imagery revealed
that a LLCC had finally formed. The circulation was slow to close off
in the southern semicircle due to a lack of equatorward westerlies, a
factor which has likely been one reason for a quieter-than-normal
tropical cyclone season in the WESTPAC. The LOW's organization increased
and JMA upped the MSW to 30 kts at 18/1200 UTC. At 1800 UTC JTWC issued
their first warning, upgrading the LOW directly to Tropical Storm 23W,
located about 395 nm east-southeast of Chichijima. TS-23W at the time
was moving northwestward at 14 kts.
At 19/0600 UTC JMA upgraded the system to tropical storm status,
assigning the name Bavi. Bavi by this time was located about 325 nm
east of Chichijima and moving northward at 11 kts. As the 19th wore on,
Bavi recurved and accelerated to the northeast. The storm's intensity
increased to 45 kts (per both warning agencies) at 19/1800 UTC, but Bavi
was already beginning to exhibit signs of extratropical transition.
JTWC issued their final warning at 20/0000 UTC with the storm located
approximately 595 nm northeast of Chichijima and racing northeastward
at 26 kts. JMA carried Bavi as a tropical cyclone for two more warning
cycles, then declared the system extratropical at 20/1200 UTC.
The extratropical remnants of Bavi raced very rapidly to the east-
northeast across the North Pacific, crossing the Dateline shortly after
22/0600 UTC. The system became a deep 946-mb LOW with hurricane-force
winds estimated up to 75 kts by 22/1200 UTC. Gradual weakening ensued
thereafter as the former Bavi turned northeastward. By 24/1200 UTC
the gale center had moved inland into southeastern Alaska.
No damage or casualties are known to have resulted from Tropical
Storm Bavi.
(Report written by Gary Padgett)
*************************************************************************
NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea
Activity for October: 1 tropical cyclone **
1 cyclonic storm
** - treated as a deep depression by IMD
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. Occasionally some
information may be gleaned from the daily tropical weather outlooks
and other bulletins issued by the Indian Meteorological Department
(IMD), which is the World Meteorological Organization's Regional
Specialised Meteorological Centre (RSMC) for the basin.
The reported maximum sustained winds (MSW) are based on a 1-minute
averaging period, which is used by all U. S. civilian and military
weather services for tropical cyclone warnings. For synoptic
observations in the North Indian Ocean region, both 10-minute and
3-minute average winds are employed, but IMD makes no attempt to
modify the Dvorak scale for estimating tropical cyclone intensity;
hence, a 1-minute average MSW is implied. In the North Indian Ocean
basin JTWC usually does not initiate warnings until a system has
become well-organized and likely to attain tropical storm status
within 48 hours.
North Indian Ocean Tropical Activity for October
------------------------------------------------
Over the period 1981-2002, an average of one tropical cyclone of
tropical storm intensity formed in the North Indian Ocean basin (based
on JTWC's records) during the month of October. Three storms during
this period reached hurricane intensity--two of those were both intense
cyclones in October, 1999. In 2008, JTWC issued warnings on two systems,
treating both as tropical storms. One of these, however, was classified
as only a deep depression by IMD. Both cyclones occurred during the
latter part of the month. Tropical Cyclone 03B (a deep depression per
IMD) formed in the central Arabian Sea and moved westward toward the Horn
of Somalia. It weakened in the Gulf of Aden on 23 October, but the
remnants moved into southeastern Yemen where heavy rainfall resulted in
devastating floods. Shortly afterward, Cyclonic Storm Rashmi formed in
the western Bay of Bengal and moved quickly northeastward, making land-
fall in Bangladesh on 27 October. Reports on both these systems follow.
TROPICAL CYCLONE
(TC-03B)
19 - 23 October
------------------------------------
A tropical disturbance which had initially developed in the Bay of
Bengal around mid-October (NRL Invest 98B) continued tracking westward
into the Arabian Sea. JTWC issued an interim SWTO at 0230 UTC on
17 October, noting that an area of convection was persisting about
740 nm west-southwest of Cochin, India. The potential for development
at the time was assessed as 'poor'. Over the next few days the
disturbance moved slowly westward across the Arabian Sea. The potential
for development was upgraded to 'fair' at 20/0630 UTC as the system had
shown increasing organization and was forecast to move closer to a ridge
axis with decreasing shear. IMD had earlier identified the system as a
depression on the 19th, and at 20/1430 UTC, JTWC issued a TCFA for the
system. The LOW was then centered about 255 nm east-southeast of Cape
Guardafui, Somalia, and deep convection was persisting on the western
periphery of an elongated LLCC.
JTWC issued their first warning on Tropical Cyclone 03B at 20/1800
UTC with the center located approximately 205 nm east-southeast of Cape
Guardafui. The initial MSW was 35 kts and TC-03B was moving west-
northwestward at 9 kts. (NOTE: Even though this was an Arabian Sea
system, the 'B' suffix was used since its precursor was identified as
Invest 98B--having originated in the Bay of Bengal.) IMD upgraded the
system to deep depression status at 0300 UTC on 21 October. TC-03B was
not forecast to intensify beyond minimal tropical storm status, and this
verified perfectly. JTWC maintained the MSW at 35 kts for 24 hours, then
downgraded the system to a tropical depression at 21/1800 UTC. The
main inhibiting factor was strong vertical shear.
The system continued to drift west-northwestward into the Gulf of Aden
region. JTWC's Dvorak estimates continued to slowly decrease, but SAB's
came back up to T2.0/2.0 at 23/0230 UTC from a low of T1.0/1.5 at
22/1430 UTC. JTWC's final warning on TC-03B was issued at 23/0600 UTC,
placing the center about 165 nm west-northwest of Cape Guardafui. A
satellite picture of TC-03B on the Wikipedia website depicts TC-03B just
off the coast of Yemen, and the system appears to still be quite well-
organized. The remnant LOW made landfall in southeastern Yemen on
24 October, bringing torrential rainfall and flooding. Media reports
indicate that as many as 180 persons may have died with 100 more
missing, mainly from the region of Hadhramawt. 733 houses were destroyed
in the governorates of Hadhramawt and Al-Mahrah, while 22,000 people
were displaced. Damage was estimate at about US$1billion.
A Wikipedia report on the Yemen floods may be found at the following
link:
http://en.wikipedia.org/wiki/2008_Yemen_floods>
(Report written by Gary Padgett)
CYCLONIC STORM RASHMI
(TC-04B)
25 - 27 October
-----------------------------------------
Rashmi: contributed by Sri Lanka
In their regular SWTO issued at 24/1800 UTC, JTWC noted that an area
of convection had developed and persisted approximately 165 nm east-
southeast of Visakhapatnam, India. Banding convection was developing
around an elongated LLCC and the system was located within a area of
low vertical shear. Winds were estimated at 20-25 kts and the potential
for development was assessed as 'fair'. IMD classified the system as a
depression at 0900 UTC on 25 October. JTWC issued a TCFA at 1500 UTC,
placing the center about 315 nm south of Kolkata. Organization
continued to improve and JTWC initiated warnings on Tropical Cyclone 04B
with 35-kt winds at 26/0000 UTC. TC-04B was located about 325 nm south-
southwest of Kolkata and moving northeastward at 5 kts. JTWC upped the
MSW to 40 kts at 26/1200 UTC--the same time that IMD named the system
Cyclonic Storm Rashmi.
Rashmi continued north-northeastward toward the Bangladesh coastline.
The cyclone reached a peak intensity of 45 kts at 26/1800 UTC while
located about 110 nm south-southeast of Kolkata. Rashmi's large cloud
shield was beginning to break down as it approached land, but a
26/1553 UTC AMSU pass depicted increased convective banding and a
tightly wrapped LLCC. The cyclone made landfall between 26/1800 and
27/0000 UTC near Patharghata, Bangladesh, as it accelerated north-
northeastward. Rashmi began to quickly weaken after making landfall,
and JTWC issued their final warning at 27/0000 UTC, placing the center
about 200 km east-northeast of Kolkata. IMD's final reference to Rashmi
downgraded it to a deep depression near 23.0N/91.0E at 27/0300 UTC.
The Wikipedia report indicates that 15 people were killed and thousands
of homes damaged. Rashmi's winds downed utility poles and uprooted
trees, and also large areas of crops were destroyed. In India,
13 persons were killed--five in Meghalaya and eight in Arunachal Pradesh.
At least 50 fishermen were reported missing when 15 fishing trawlers
capsized offshore.
(Report written by Gary Padgett)
*************************************************************************
SOUTHWEST INDIAN OCEAN (SWI) - South Indian Ocean West of Longitude 90E
Activity for October: 1 moderate tropical storm
Sources of Information
----------------------
The primary sources of tracking and intensity information for
Southwest Indian Ocean tropical cyclones are the warnings issued by
the Tropical Cyclone Warning Centre on La Reunion Island, part of
Meteo France (MFR), and the Regional Specialised Meteorological Centre
for the basin. However, tropical cyclones in this region are named
by the Sub-regional Tropical Cyclone Advisory Centres in Mauritius and
Madagascar with longitude 55E being the demarcation line between their
respective areas of naming responsibility. The La Reunion centre only
advises these agencies regarding the intensity of tropical systems.
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 MFR's 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.
Southwest Indian Ocean Tropical Activity for October
----------------------------------------------------
One tropical storm of moderate intensity formed in the Southwest
Indian Ocean basin during October. Tropical Storm Asma formed around
mid-month deep in the tropics in the central portion of the basin and
moved generally west-southwestward, dissipating near the northern tip
of Madagascar on the 23rd. A short report on Asma follows.
Earlier, on 6 October, RSMC La Reunion had designated an area of
low pressure south-southeast of Diego Garcia as a "zone of disturbed
weather"--the weakest classification assigned by MFR and usually equating
to a Dvorak rating of T1.5. The first bulletin on Zone of Disturbed
Weather 01, issued at 06/1200 UTC, reported a Dvorak classification of
T2.0/2.0, and winds were estimated at 20-25 kts near the center, locally
reaching 30 kts in the southern semicircle. Normally, such a system is
usually treated as a "tropical disturbance", but in this case the system
soon began to weaken and the category was not raised. Only three
warnings at irregular intervals were issued on this disturbance, the
final one at 08/0600 UTC. SAB's Dvorak ratings reached T2.0/2.0 late
on 7 October and early on the 8th, but had dropped by 08/0830 UTC. This
system perhaps could have been classified as a weak tropical depression
(per 1-min avg MSW criterion), but I did not include a track for it in
the companion cyclone tracks file.
TROPICAL STORM ASMA
(MFR-02 / TC-01S)
16 - 23 October
---------------------------------------
Asma: contributed by Mauritius
JTWC issued an interim STWO at 1230 UTC 15 October, noting that an
area of convection had persisted approximately 165 nm north-northwest
of Diego Garcia--very deep in the tropics. Deep convection was
developing along the peripheries of an elongated LLCC, and strong
low-level westerly winds to the north and strong easterlies to the
south were aiding spin-up of the cyclone. The development potential was
initially assessed as 'poor', but this was upgraded to 'fair' at 16/0200
UTC as the system was tracking southwestward into a more favorable
environment with decreasing vertical shear. MFR initiated warnings on
Tropical Disturbance 02 at 16/1200 UTC, and at 1630 UTC JTWC issued a
TCFA. The LLCC had become well-defined with more intense convective
banding, and a 16/0421 UTC ASCAT pass had indicated unflagged 25-30 kt
winds near the center. The first JTWC warning on TC-01S was issued at
16/1800 UTC, placing the center about 225 nm west-northwest of Diego
Garcia. The initial MSW (1-min avg) was 35 kts. MFR upgraded the
system to 30-kt tropical depression status six hours later.
The depression initially was moving westward, but the track shifted
to the southwest the next day. TC-01S was located in a weak steering
environment between a subtropical ridge to the south and strong, low-
level equatorial westerlies to the north. Vertical shear was fairly
high, so only slow intensification was forecast. The system's intensity
remained static for the next several days, with JTWC's 1-min avg MSW
remaining pegged at 35 kts and MFR's 10-min avg winds fluctuating
between 25 and 30 kts. By the 19th vertical shear had decreased and the
system began to intensify. MFR upgraded Tropical Disturbance 02 to
moderate tropical storm status at 19/1800 UTC, and the Meteorological
Service of Mauritius assigned the name Asma. At its christening Tropical
Storm Asma was located about 745 nm northeast of Reunion Island and
moving west-southwestward at 8 kts.
Continued light shear and enhanced polar outflow as Asma neared the
axis of an upper-level ridge resulted in further intensification, and
the storm reached its peak intensity of 45 kts (per MFR) at 20/0600 UTC
while centered about 630 nm northeast of Reunion Island. (JTWC's peak
1-min avg MSW of 55 kts compares well with the peak 10-min avg wind
estimated by MFR.) However, shortly after peaking, Tropical Storm Asma
began to track into a region of marginal SSTs and increasing vertical
shear, so weakening began later on the 20th. MFR downgraded Asma to
a 30-kt depression at 21/0600 UTC, and JTWC issued their final warning
at the same time, placing the center about 575 nm north-northeast of
Reunion Island. Ex-Asma continued to track generally westward while
slowly filling. MFR's final bulletin on the system placed a weak 20-kt
center about 50 nm north of the northern tip of the island of Madagascar
at 23/1200 UTC.
No damage or casualties are known to have resulted from Tropical
Storm Asma.
(Report written by Gary Padgett
*************************************************************************
NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (AUW) - From 90E to 135E
Activity for October: No tropical cyclones
*************************************************************************
NORTHEAST AUSTRALIA/CORAL SEA (AUE) - From 135E to 160E
Activity for October: No tropical cyclones
*************************************************************************
SOUTH PACIFIC (SPA) - South Pacific Ocean East of Longitude 160E
Activity for October: 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, 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.metoffice.gov.uk/weather/tropicalcyclone>
TROPICAL CYCLONE REPORTS AVAILABLE
JTWC now has available on its website the Annual Tropical Cyclone
Report (ATCR) for 2007 (2006-2007 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 2007 Atlantic and Eastern North Pacific
tropical cyclones; also, storm reports for all the 2007 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 (Northwest Pacific)
E-mail: [email protected]
*************************************************************************
*************************************************************************
|
Document: summ0810.htm
Updated: 19 January 2009 |
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