MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY
MARCH, 2007
(For general comments about the nature of these summaries, as well as
information on how to download the tabular cyclone track files, see
the Author's Note at the end of this summary.)
SPECIAL NOTE #1: Very happily, John Diebolt of Tucson, Arizona, now has
his tropical cyclone website up and running again and has begun once more
to produce graphic images depicting the tracks of all tropical systems
for which I prepare a tabular track in the companion cyclone tracks file.
These can be accessed at the following URL:
http://www.tropicalcyclone2005.com/
Scroll down the chart to the month of interest and click on the green
bar under "Operational Track Image" for the desired system.
The tabular track of positions and intensities may also be obtained
from the above website, or from the other archival sites listed in
the Author's Note in the closing section of this summary.
SPECIAL NOTE #2: 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/2007_Atlantic_hurricane_season
http://en.wikipedia.org/wiki/2007_Pacific_hurricane_season
http://en.wikipedia.org/wiki/2007_Pacific_typhoon_season
http://en.wikipedia.org/wiki/2007_North_Indian_cyclone_season
http://en.wikipedia.org/wiki/2006-07_Southern_Hemisphere_tropical_cyclone_se
ason
*************************************************************************
MARCH HIGHLIGHTS
--> Destructive tropical cyclone strikes Madagascar--another cyclone
makes landfall in early April
--> Intense tropical cyclone strikes Western Australia, followed by
two weaker cyclones in same area
--> South Pacific cyclone brushes by Vanuatu
*************************************************************************
ACTIVITY BY BASINS
ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico
Activity for March: No tropical cyclones
*************************************************************************
NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180
Activity for March: No tropical cyclones
*************************************************************************
NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180
Activity for March: 1 tropical depression **
1 tropical storm ++
** - classified as a tropical depression by JMA only
++ - system reached typhoon intensity in April and will be covered in
that month's summary
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 March
---------------------------------------------
During the opening days of March a tropical disturbance hung around
just south of the Mariana Islands. According to Mark Lander, Guam
received nearly 51 mm of rainfall within a 48-hour period around the
4th and 5th of March. JMA classified the system as a weak tropical
depression near 9.0N/143.0W at 0600 UTC on 6 March but downgraded it
to a low pressure area twelve hours later. The LOW remained quasi-
stationary and was referenced in JMA's High Seas Bulletins through
08/0000 UTC. JTWC mentioned this system in their STWOs for a couple
days but never assigned more than a 'poor' potential for development.
The LLCC apparently formed near the tail end of a baroclinic zone and
most of the associated deep convection remained displaced to the north-
east of the center along a convergent boundary. No track was included
for this depression in the companion cyclone tracks file.
At the end of the month, Tropical Depression 01W formed in the
eastern Carolines, and on the final day of the month was christened
Tropical Storm Kong-rey--the first tropical storm of 2007 in the NWP
basin. Kong-rey intensified into a typhoon of moderate intensity during
the early days of April and will be covered in the April summary.
*************************************************************************
NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea
Activity for March: No tropical cyclones
*************************************************************************
SOUTHWEST INDIAN OCEAN (SWI) - South Indian Ocean West of Longitude 90E
Activity for March: 1 tropical disturbance
1 possible subtropical storm **
2 intense tropical cyclones
** - no warnings issued on this system
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 March
--------------------------------------------------
Activity in the Southwest Indian Ocean slacked off somewhat from the
fast pace of February, but nonetheless two intense tropical cyclones
formed during the month. Tropical Cyclone Indlala formed on the 10th
well to the north of Rodrigues Island and moved generally westward,
making landfall as an intense tropical cyclone in northeastern Madagascar
early on the 15th. Late in the month, Tropical Cyclone Jaya formed
a few hundred miles northeast of Rodrigues and followed a track similar
to Indlala's, making landfall in Madagascar on 3 April a short distance
north of the area struck by Indlala. At its peak Jaya was a slightly
more intense storm than Indlala, but fortunately had weakened to minimal
hurricane intensity by the time of landfall. Reports on these two
cyclones follow.
In between the two cyclones another tropical disturbance formed,
numbered '13' by MFR. This system formed several hundred miles south-
southeast of Diego Garcia on the 13th (near 14.5S/77.0E) and meandered
slowly southward for the next three days, reaching 19.2S/76.3E by
16/0000 UTC. After this Tropical Disturbance 13 turned abruptly to
the northwest, eventually curving back to the north. The final bulletin
from MFR at 17/0600 UTC placed the center near 16.7S/74.0E. The highest
10-min avg wind estimated for this system was 25 kts, and no warnings
were issued by JTWC. A track for this system may be found in the
companion cyclone tracks file, and a track graphic is available on
John Diebolt's website.
One other system deserves mention. SAB issued satellite bulletins
on 20 and 21 March for a cyclonic system several hundred miles south-
east of Durban, South Africa. The LOW initially moved southward, then
curved to the east. This system was not tropical in nature, but rather
exhibited some characteristics of subtropical cyclones. NRL did not
open an invest number for the system, so SAB referred to it as '99S'.
The initial SAB bulletin at 20/0900 UTC, which located the center near
34.5S/36.7E, noted that a QuikScat pass at 20/0336 UTC had detected
winds of 35-40 kts. FSU cyclone phase space diagrams based on the
20/0000 UTC GFS run indicated a nominal shallow warm-core thermal
structure consistent with subtropical storms. Most of the associated
convection was located east and poleward of the center in a manner
typical of subtropical systems. The final SAB bulletin placed the
weakening center near 36.6S/41.2E at 1900 UTC. No TCWC issued warnings
on this system. A track for this system may be found in the companion
cyclone tracks file, and a track graphic is available on John Diebolt's
website.
INTENSE TROPICAL CYCLONE INDLALA
(MFR-12 / TC-19S)
10 - 17 March
----------------------------------------------------
A. General Information
----------------------
1. Identification
a. RSMC - Meteo France La Reunion (MFR)
b. MFR - Tropical Disturbance 12
c. JTWC - Tropical Cyclone 19S
d. NAME - Indlala (named by Mauritius at Mar 12/0000 UTC; name
contributed to the regional list by Swaziland)
2. Overview
a. Basins Affected: Southwest Indian Ocean (SWI)
b. Dates: 10 - 17 March
c. Max Sust Winds: 95 kts (10-min avg per MFR)
125 kts (1-min avg per JTWC)
d. Min Cent Press: 935 hPa (estimate per MFR)
3. Beginning of Track: Mar 10/1200 UTC, near 14.9S/61.8E, or about
400 nm northeast of Mauritius, as referenced in initial bulletin
issued by MFR.
4. Peak Intensity: Mar 14/1800 UTC, near 14.8S/51.0E, or about 315 nm
northeast of Antananarivo, Madagascar. (It should be noted that MFR's
MSW was at 95 kts from 14/1800 through 15/0600 UTC.)
5. Size: Based on MFR's warnings, at its peak Intense Tropical Cyclone
Indlala was perhaps slightly smaller than average with a gale radius
of 90 nm. However, JTWC's warnings described a significantly larger
system with gales extending outward 140 nm from the center in the
northwest quadrant and up to 195 nm in the southeast quadrant.
6. End of Track: Mar 17/0600 UTC, near 18.0S/47.5E, or inland about
90 km north of Antananarivo, Madagascar.
B. Synoptic History
-------------------
1. Origin: An area of convection formed and persisted on 9 March about
550 nm southwest of Diego Garcia, as referenced in a STWO issued by
JTWC at 09/1800 UTC. Microwave imagery depicted a developing LLCC
embedded in a monsoon trough. An upper-level analysis indicated that
the disturbance was lying beneath the center of a 200-mb anticyclone
with low vertical shear and favorable diffluence aloft. The primary
center of interest apparently reformed to the west--at 1200 UTC on
10 March MFR issued the first bulletin on Tropical Disturbance 12,
located approximately 400 nm northeast of Mauritius, or about 770 nm
southwest of Diego Garcia. Convection was continuing to build near
and over the center, and JTWC upped the potential for development to
'fair'. JTWC issued a TCFA for the system at 10/2300 UTC, and at
11/0600 UTC MFR upgraded the system to a 30-kt tropical depression
and relocated the center to a point over 100 nm to the north of the
previous position.
Convective banding began developing to the west of a partially-
exposed, though well-defined, LLCC, and even though vertical shear had
increased slightly, outflow was good and the depression continued to
slowly strengthen. At 0000 UTC on 12 March the Meteorological
Service of Mauritius upgraded the system to Tropical Storm Indlala,
located about 400 nm north of Mauritius, and moving westward around
6 kts. At the same time, JTWC issued their first warning on TC-19S,
estimating the MSW at 40 kts (1-min avg). (Due to a spelling error on
a roster of names originally posted on the WMO's website, the initial
MFR warning after the upgrade gave the storm's name as 'Indlada'. A
check was made with the Meteorological Service of Swaziland and it
was confirmed that 'Indlala' was the correct spelling, so an amended
warning was then issued.)
2. General Description of Track: At the time of its upgrade Tropical
Storm Indlala was moving on a westerly track, steered by a subtropical
ridge anchored south of Reunion Island. The ridge was forecast to
re-orient itself in response to a trough then located over South
Africa, resulting in a more west-southwesterly track for Indlala.
By the 13th the storm had turned to the west-southwest as forecast,
and this motion continued through landfall in Madagascar around
15/0000 UTC. Indlala was upgraded to tropical cyclone (hurricane)
status at 0600 UTC on 13 March, and reached its peak intensity of
95 kts (10-min avg) at 14/1800 UTC. Intense Tropical Cyclone
Indlala made landfall around 15/0000 UTC over the Masoala Peninsula,
in the vicinity of Antalaha at peak intensity. (JTWC estimated that
the storm peaked at a 1-min avg MSW of 125 kts at 14/1800 UTC, but
had weakened to 105 kts by the time of landfall.)
Following landfall Indlala predictably began to weaken rapidly.
MFR downgraded the system to a 60-kt severe tropical storm at 1200
UTC, and to a 30-kt tropical depression twelve hours later, although
the warning noted that winds of up to 40 kts were still being felt
along the coast. Also, at 16/0000 UTC JTWC issued their final warning
on Indlala. The general west-southwesterly motion continued until
around 16/0600 UTC, followed by a turn toward the south. The final
warning on Indlala issued by MFR at 17/0600 UTC placed a very weak
20-kt center approximately 90 km north of Antananarivo, Madagascar.
C. Meteorological Data
----------------------
I have only one observation for Indlala, sent by Derrick Herndon.
Ship ELVG8 was located about 150 nm west of the center on 12 March.
At 12/0000 UTC the ship reported 1004.4 hPa and 210/35 kts, and at
0600 UTC it reported 1007.8 hPa and 210/35 kts. (Thanks to Derrick
for sending this along.)
D. Damage and Casualties
------------------------
According to press reports, Indlala left 80 persons dead in Madagascar
with over 105,000 homeless. The online Wikipedia report contains some
links with a detailed region-by-region breakdown of the storm's impact.
E. Additional Discussion
------------------------
The peak intensity estimates for Indlala from MFR and JTWC were
further apart than normal with MFR's 10-min avg peaking at 95 kts,
whereas JTWC's peak 1-min avg MSW was 115 kts but with a statement in
the 15/0000 UTC warning to the effect that Indlala had peaked at 125 kts
at 14/1800 UTC. Dvorak intensity estimates from JTWC and AFWA reached
T6.5/6.5 (127 kts) at 14/1730 UTC, while SAB's peak rating was T6.0/6.0
(115 kts). Also, Chris Velden noted in an e-mail that they were getting
AODT readings of T6.2-6.4 with a 14/1100 UTC AMSU intensity of 115 kts.
In a reply to Chris' e-mail, Philippe Caroff explained that their
more conservative intensity was primarily predicated on the eyewall
replacement cycle which had begun around the time the cyclone appeared
to reach its peak intensity in satellite imagery. Philippe was of the
opinion that a pure Dvorak analysis could be somewhat misleading since
the eyewall cycle would likely be a limiting factor to some degree in
the intensification trend. This is just another example of the many
complicating issues to be dealt with in estimating tropical cyclone
intensities from satellite imagery.
(Report written by Gary Padgett)
INTENSE TROPICAL CYCLONE JAYA
(MFR-14 / TC-22S)
29 March - 8 April
-------------------------------------------------
A. General Information
----------------------
1. Identification
a. RSMC - Meteo France La Reunion (MFR)
b. MFR - Tropical Disturbance 14
c. JTWC - Tropical Cyclone 22S
d. NAME - Jaya (named by Mauritius at Mar 30/1200 UTC; name
contributed to the regional list by Zimbabwe)
2. Overview
a. Basins Affected: Southwest Indian Ocean (SWI)
b. Dates: 29 March - 8 April, 2007
c. Max Sust Winds: 105 kts (10-min avg per MFR)
110 kts (1-min avg per JTWC)
d. Min Cent Press: 930 hPa (estimate per MFR)
3. Beginning of Track: Mar 29/1200 UTC, near 12.9S/69.0E, or about
400 nm southwest of Diego Garcia, as referenced in initial bulletin
issued by MFR.
4. Peak Intensity: Mar 31/1800 UTC, near 14.7S/61.5E, or about 400 nm
northeast of Mauritius. (It should be noted that MFR's MSW was at
105 kts from 31/1800 through 01/0600 UTC.)
5. Size: Based on MFR's warnings, at its peak Tropical Cyclone Jaya was
a small tropical cyclone with a gale radius of 60 nm. However, JTWC's
warnings described a somewhat larger cyclone with gale radii ranging
from 95-110 nm.
6. End of Track: Apr 08/0600 UTC, near 17.4S/40.3E, or about 350 nm
east-northeast of Beira, Mozambique.
B. Synoptic History
-------------------
1. Origin: An interim STWO issued by JTWC at 0300 UTC on 28 March
noted that an area of convection had persisted approximately 455 nm
southeast of Diego Garcia. A partially-exposed LLCC was present with
deep convection and weak banding developing over the western quadrant.
An upper-level anticyclone was located east of the center with
diffluent, easterly flow over the area with weak vertical shear.
By early on the 29th the LLCC was consolidating and JTWC upped the
development potential to 'fair'. MFR initiated bulletins on the
disturbance at 29/1200 UTC with the system located farther to the
west, or about 400 nm southwest of Diego Garcia. MFR did not issue
another bulletin until 0600 UTC on 30 March, at which time the system
was upgraded to Tropical Depression 14 with 30-kt winds. At the same
time JTWC issued their first warning on TC-22S, estimating the MSW at
45 kts (1-min avg). Six hours later MFR upgraded the depression to
tropical storm status with the Meteorological Service of Mauritius
assigning the name Jaya. Tropical Storm Jaya, at 30/1200 UTC, was
located approximately 650 nm northeast of Mauritius, moving westward
at 5 kts. (Note: The online Wikipedia report on Jaya suggests that
Mauritius upgraded and named the storm at 30/0600 UTC.)
2. General Description of Track: In a manner similar to its predecessor,
Tropical Cyclone Indlala, Jaya followed a rather smooth westerly
track as it was steered by a subtropical ridge located to its south.
Environmental conditions were favorable for continued strengthening,
and after its upgrade to tropical storm status, Jaya intensified
fairly quickly, reaching tropical cyclone (hurricane) intensity at
0000 UTC on 31 March (per both MFR and JTWC). The cyclone continued
to intensify and reached its estimated peak intensity of 105 kts with
a CP of 930 hPa at 31/1800 UTC while located about 400 nm northeast of
Mauritius. However, very early on 1 April SSMI water vapor imagery
revealed that some drier air had become entrained into the storm's
northwestern quadrant, leading to a significant reduction in the
amount of deep convection near the center. MFR reduced the MSW to
85 kts at 01/1200 UTC where it remained pegged for another 30 hours.
On 2 April Jaya underwent a short-lived spurt of re-intensification
with fairly symmetric deep convection surrounding a 6-nm round eye.
MFR upped the intensity to 90 kts (10-min avg) with JTWC assigning
their peak intensity of 110 kts (1-min avg) for the storm's history.
(At the time of MFR's peak intensity of 105 kts, JTWC's 1-min avg MSW
had also been 105 kts.) As Jaya neared the coastline of Madagascar it
began to weaken rather quickly and moved inland around 03/0800 UTC
about 25 km south of Sambava with 10-min avg winds of around 75 kts.
Jaya jogged northwestward between 03/0000 and 0600 UTC, but the
westerly motion resumed as the cyclone neared Madagascar and moved
inland. Once inland the small system weakened very rapidly. The
weak remnant LOW moved out into the northern Mozambique Channel
around 0000 UTC on 4 April. The system spent the next four days
meandering erratically in the Channel between Madagascar and
Mozambique. After 04/0600 UTC, MFR issued only two bulletins for
ex-Jaya: at 05/1200 and 07/1200 UTC with the MSW estimated at only
20 kts. JTWC did not issue any further warnings (although a couple
of TCFAs were issued), but satellite bulletins from that agency and
AFWA supported 35-kt winds (1-min avg) at 05/1800 and 06/0000 UTC
when the LOW was fairly close to the Mozambique coast. By 0600 UTC
on the 8th the LLCC had become very weak with no associated deep
convection. According to Philippe Caroff of RSMC La Reunion, the
remnant of Jaya was absorbed into a developing LOW to the southwest
which was later identified as Subtropical Depression 15. A report
on this system will be included in the April summary.
C. Meteorological Data
----------------------
I have received no observations in association with Intense Tropical
Cyclone Jaya.
D. Damage and Casualties
------------------------
The only information I have regarding damage and casualties resulting
from Tropical Cyclone Jaya was sent in an e-mail from Philippe Caroff,
Chief Forecaster at RSMC La Reunion. (A thanks to Philippe for replying
to my request for information.) Philippe reports that shortly after Jaya
made landfall, the press reported 2 or 3 deaths in the Sambava area, but
that a later report mentioned only one fatality with more than 3600
persons affected and more than 900 houses or buildings destroyed.
(Report written by Gary Padgett)
*************************************************************************
NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (AUW) - From 90E to 135E
Activity for March: 3 severe tropical cyclones
Sources of Information
----------------------
The primary sources of tracking and intensity information for
Northwest Australia/Southeast Indian Ocean tropical cyclones are
the warnings and advices issued by the Tropical Cyclone Warning
Centres at Perth, Western Australia, and Darwin, Northern Territory.
References to sustained winds imply a 10-minute averaging period
unless otherwise stated.
In the companion tropical cyclone tracks file, I occasionally
annotate positions from warnings issued by the Joint Typhoon Warning
Center (JTWC) of the U. S. Air Force and Navy, located at Pearl
Harbor, Hawaii, when they differ from the Australian centres' coor-
dinates 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.
Northwest Australia/Southeast Indian Ocean
Tropical Activity for March
------------------------------------------
For the first time in three years, the Darwin TCWC got to bestow a
name upon a developing tropical system. Tropical Cyclone George was the
first cyclone to form in waters between 138E and 125E since Tropical
Cyclone Fay in March, 2004. That isn't to say that the forecasters at
Darwin have been idle since 2004--two visitors from the Coral Sea,
Ingrid of March, 2005, and Monica of April, 2006, both attained great
intensity as they traversed waters off the Northern Territory. Like
its predecessor, Fay, George moved westward and eventually made landfall
in Western Australia as a severe tropical cyclone. George was the most
intense cyclone to affect the Port Hedland area since Tropical Cyclone
Joan of 1975.
Tropical Cyclone Jacob was co-existent with George for part of its
life, and after initially moving westward and flirting with Christmas
Island, Jacob reversed its course toward the southeast, aiming at the
very spot where the destructive George had landed about three days
earlier. Very fortunately, however, Jacob began to weaken and reached
the coast as a minimal tropical cyclone. Late in the month, Tropical
Cyclone Kara formed from a LOW which moved off the Kimberley coast, and
in a manner similar to Jacob, after moving westward, reversed course and
headed for the Western Australian coastline. Kara became quite intense,
but as happened with Jacob, the storm began to weaken as it approached
the coast and had dropped to just below cyclone intensity before moving
onshore.
Reports on Severe Tropical Cyclones George, Jacob and Kara follow.
The reports on Jacob and Kara were authored by Matthew Saxby of
Queanbeyan, New South Wales (very near Canberra). A special thanks to
Matthew for writing the reports.
SEVERE TROPICAL CYCLONE GEORGE
(TC-17S)
26 February - 10 March
--------------------------------------------------
A. General Information
----------------------
1. Identification
a. RSMC - BoM Darwin/Bom Perth
b. JTWC - Tropical Cyclone 17S
c. NAME - George (named by BoM Darwin at Mar 03/1800 UTC)
2. Overview
a. Basins Affected: Northeast Australia/Coral Sea (AUE)
Northwest Australia/Southeast Indian Ocean (AUW)
b. Dates: 26 February - 10 March, 2007
c. Max Sust Winds: 105 kts (10-min avg per BoM Perth)
110 kts (1-min avg per JTWC)
d. Min Cent Press: 910 hPa (estimate per BoM Perth)
3. Beginning of Track: Feb 26/0130 UTC, near 10.5S/135.5E, or about
210 nm north-northwest of Alyangula, Northern Territory, as referenced
in a Tropical Cyclone Outlook issued by BoM Darwin.
4. Peak Intensity: Mar 08/1200 UTC, near 19.9S/119.1E, or about 35 nm
northeast of Port Hedland, Western Australia.
5. Size: At its peak Severe Tropical Cyclone George was roughly an
average-sized cyclone with gale radii of around 90-110 nm.
6. End of Track: Mar 10/0000 UTC, near 23.6S/121.7E, or inland about
500 km southeast of Port Hedland, Western Australia.
B. Synoptic History
-------------------
1. Origin: Early on 26 February a developing tropical LOW was located
in the southern Arafura Sea near the coast of the Northern Territory
about 230 km northwest of Nhulunbuy. Later that same day JTWC began
to include the disturbance in their daily STWOs. QuikScat data and
animated radar imagery from Gove indicated tight cyclonic turning
with the center just north of an upper-level ridge axis. Diffluence
aloft was good but vertical wind shear was moderate. Over the next
2 or 3 days the LOW remained quasi-stationary, meandering around the
northeastern portion of the Top End. At one point it appeared that
it would move eastward into the Gulf of Carpentaria and develop
further there, but on 1 March the LOW embarked on a westerly course
across the Top End approximately 100 km inland from and roughly
parallel to the coastline.
The LOW remained well-organized as it transited the Northern
Territory (something not unusual at all for inland systems over
northern Australia), and as it began to approach the Joseph Bonaparte
Gulf region, convection began to increase. BoM Darwin initiated
Tropical Cyclone Advices for the system at 0600 UTC on 2 March
with the center located about 75 km south-southeast of Oenpelli
and moving west at 12 km/hr. Gale warnings had been issued as of
28 February for monsoon gales occurring along the northern coast of
the Top End. JTWC issued a TCFA for the LOW at 2230 UTC on 2 March
as the center passed southeast of Darwin. Deep convection was
increasing along the western periphery of the consolidating LLCC.
BoM Darwin upgraded the LOW to Tropical Cyclone George at 1800 UTC
on 3 March with the center moving offshore into the Joseph Bonaparte
Gulf about 20 nm south-southwest of Port Keats, or about 150 nm
southwest of Darwin. George was moving southwestward at 6 kts with
the MSW estimated at 35 kts. (Earlier, at 03/1200 UTC, JTWC had
issued the first warning on TC-17S with the 1-min avg MSW estimated
at 45 kts.)
2. General Description of Track: A subtropical ridge firmly anchored
over Western Australia provided a steering mechanism for George for
several days, sending the cyclone on an almost straight westerly
track. George intensified to 50 kts while crossing the Joseph
Bonaparte Gulf, but briefly weakened to below cyclone intensity while
crossing the extreme northeastern portion of the state of Western
Australia. By 1800 UTC on the 4th George's center was about to emerge
into the open Timor Sea and the winds had rebounded to 40 kts. After
that, however, the cyclone was slow to re-intensify due to the loss of
its polar outflow channel and also to the presence of moderate
vertical shear. George continued tracking westward through 0600 UTC
on 7 March. A weakness had developed in the subtropical ridge and
the cyclone responded by making an abrupt turn to the south.
An upper-level LOW to the west was situated such that it helped to
improve outflow, and in conjunction with decreasing vertical shear,
the stage was set for George to intensify significantly as it
approached the coastline of Western Australia. BoM Perth upgraded
George to severe tropical cyclone (i.e., hurricane) status at 07/0600
UTC, and the cyclone intensified rapidly early on the 8th (UTC). The
eye passed directly over Bedout Island (apparently between 0900 and
1000 UTC) with peak 10-min avg winds of 105 kts being recorded. This
observation was the basis for Perth and JTWC upping the winds to the
respective peak values for the storm's history of 105 kts (10-min avg)
and 110 kts (1-min avg).
The center of Severe Tropical Cyclone George crossed the Western
Australian coastline near Port Hedland around 1400 UTC on 8 March at
its peak intensity--a strong Category 4 cyclone on the Australian
scale with the CP estimated at 910 hPa. Around the time of landfall
the system made a slight jog to the south-southwest, but by 09/0600
UTC the still potent cyclone was moving southeastward across north-
central Western Australia. By 1200 UTC winds had dropped below
hurricane intensity, and by 10/0000 UTC George had weakened to below
tropical cyclone status about 95 km east-southeast of Jigalong as
it tracked east-southeastward at 15 km/hr.
C. Meteorological Data
----------------------
(1) Northern Territory Rainfall
-------------------------------
During the early days of March, the pre-cyclone stage of George moved
across the northern portion of the Northern Territory, dropping copious
amounts of moisture. Some stations across the Top End recorded their
highest rainfalls on record during the month of March. Not all of this
rainfall was due to pre-George, but following are some March daily
rainfall records which were likely broken due to this system:
Station Highest Daily Date Previous Highest Date
Rainfall (mm) (mm)
-------------------------------------------------------------------------
Oenpelli 311.2 01 Mar 209.6 06 Mar 1919
Black Point 162.2 03 Mar 129.9 04 Mar 2000
Howard Springs 212.0 04 Mar 184.9 04 Mar 1969
Adelaide River PO 244.0 03 Mar 123.2 04 Mar 1969
Channel Island 225.0 03 Mar 194.6 26 Mar 1941
Mango Farm 295.0 03 Mar 143.6 15 Mar 1983
Elizabeth Valley 190.4 03 Mar 150.6 10 Mar 1989
Jabiru Airport AWS 393.4 02 Mar 129.0 10 Mar 1973
Karama 206.5 04 Mar 177.8 22 Mar 2006
Wagait Beach 279.2 03 Mar 192.8 02 Mar 1997
Territory Wildlife
Farm 142.5 03 Mar 113.4 03 Mar 1998
Thorak Cemetery 240.0 03 Mar 200.0 02 Mar 1998
Walker Creek 255.5 03 Mar 164.0 08 Mar 1995
While not all the heavy rainfall for March could be attributed to
George, the amounts dropped by this system contributed to several
stations setting new monthly rainfall totals for March:
Station Total Rainfall Previous Highest Year
(mm) (mm)
-------------------------------------------------------------------------
Oenpelli 1106.6 601.8 1981
Darwin River Dam 657.3 614.5 1977
Adelaide River Post Office 653.0 580.0 1976
Humpty Doo Collard Road 686.0 622.2 1995
Mango Farm 710.6 533.4 1983
Jabiru Airpost AWS 1141.6 590.4 1976
Leanyer 708.6 662.0 2006
Elizabeth Valley 642.2 589.0 1989
Mary River Rangers 562.0 540.1 2000
Wagait Beach 685.2 624.6 1995
Territory Wildlife Park 571.5 554.7 1995
Thorak Cemetery 810.8 759.8 1995
Walker Creek 741.6 663.2 2000
Batchelor Aero AWS 702.2 495.8 2001
Jabiru Council 455.6 443.8 1999
(A special thanks to Mark Kersemakers for pointing me to the above data.)
During the evening of 1 March a line of strong thunderstorms
associated with the pre-George LOW passed over the Kakadu National Park,
spawning a tornado which carved a trail of destruction along a 3-km long
path which passed within a few hundred metres of the Mary River Ranger
Station. Hardwood trees such as eucalyptus and ironwoods were uprooted
or torn apart with mature trees being reduced to de-barked and
de-foliated stumps within the 300-metre wide path of the tornado. Based
on a damage survey, winds within the tornado were estimated at between
125 and 145 kts.
More information on this rare, deep-tropics tornado along with damage
photos may be found at the following link:
http://www.bom.gov.au/announcements/media_releases/20070320.shtml
(2) Wind Observations
---------------------
The maximum wind recorded in Tropical Cyclone George was a 10-min avg
wind of 105 kts at Bedout Island at 1000 UTC 8 March. At the Port
Hedland Airport, the peak 10-min avg wind recorded was 61 kts at
1351 UTC 8 March, and the peak gust of 82 kts was measured at 1340 UTC
on 8 March. The minimum SLP recorded was 962.7 hPa at 08/1512 UTC.
However, wind speed data is missing during the time that the strongest
winds were affecting Port Hedland, so likely the actual peak winds
experienced were stronger than the values reported above.
(A special thanks to Joe Courtney for sending me the above data.)
D. Damage and Casualties
------------------------
According to the online Wikipedia report, George was the most
powerful cyclone to hit the Port Hedland area since Cyclone Joan in
1975. (For an eyewitness account of Joan's strike on Port Hedland,
see the monthly feature in the February, 2001, summary, available
on the archive sites listed near the end of this summary.) In the
Port Hedland area George's winds downed power and telephone lines and
fences, caused roof damage and uprooted trees. BoM's Port Hedland
radar dome was damaged by the cyclone.
Three deaths and 28 injuries were attributed to the storm. One
fatality, and another injury which ultimately proved to be fatal,
occurred at a Fortescue Metals Group camp about 100 km south of Port
Hedland when strong winds blew down temporary accommodation shelters.
Another death occurred at Indee station, located between Port Hedland
and the mining camp.
The Wikipedia report may be accessed at the following link:
http://en.wikipedia.org/wiki/Cyclone_George
A brief summary of the storm can be found on BoM's website at the
following URL:
http://www.bom.gov.au/announcements/sevwx/wa/watc20070303.shtml
(Report written by Gary Padgett)
SEVERE TROPICAL CYCLONE JACOB
(TC-18S)
5 - 12 March
-------------------------------------------------
A. General Information
----------------------
1. Identification
a. RSMC - BoM Perth
b. JTWC - Tropical Cyclone 18S
c. NAME - Jacob (named by BoM Perth at Mar 07/0000 UTC)
2. Overview
a. Basins Affected: Northwest Australia/Southeast Indian Ocean (AUW)
b. Dates: 5 - 12 March, 2007
c. Max Sust Winds: 75 kts (10-min avg per BoM Perth)
75 kts (1-min avg per JTWC)
d. Min Cent Press: 954 hPa (estimate per BoM Perth)
3. Beginning of Track: Mar 05/0000 UTC, near 14.3S/114.8E, or about
440 nm north of Onslow, Western Australia, as referenced in initial
gale warning issued by BoM Perth.
4. Peak Intensity: Mar 09/1800 UTC, near 15.6S/109.8E, or about 400 nm
southeast of Christmas Island. (It should be noted that BoM Perth's
MSW was at 75 kts from 09/1800 through 10/0600 UTC.)
5. Size: Based on BoM Perth's warnings, at its peak Severe Tropical
Cyclone Jacob was an average-sized cyclone with gales extending
outward 90 nm from the center in the southern quadrants and 140 nm
to the north. However, JTWC's warnings described a slightly smaller
system with a gale radius of 80 nm.
6. End of Track: Mar 12/0600 UTC, near 20.3S/119.5E, or inland about
90 km east of Port Hedland, Western Australia.
B. Synoptic History
-------------------
1. Origin: BoM Perth's Tropical Cyclone Outlook (TCO) of 03 March makes
first mention of the pre-Jacob system. At this time it was not
expected to develop. However, a JTWC STWO issued either later the
same day or early 04 March (UTC) gave it a FAIR chance of developing
(NB: The actual STWO is unavailable to the author, but the 04/1800 UTC
STWO is clearly not JTWC's first mention of pre-Jacob; this STWO
notes an elongated LLCC with favourable poleward outflow but
decreasing convection and unfavourable vertical wind-shear, and
downgrades pre-Jacob to POOR). Nonetheless, BoM Perth began issuing
gale warnings at 05/0242 UTC as winds to 40 kts were forecast
in the system's western quadrants. Slow development took place in a
marginal environment (good upper-level divergence but strong vertical
wind shear) during the next two days, and Jacob was named in a public
TC Advisory affecting Christmas Island issued at 07/0050 UTC
(9:50 am WDT). Maximum wind gusts were assessed at 100 km/h,
equivalent to 10-minute winds of 40 kts or 1-minute winds of 45 kts.
JTWC's first warning followed at 07/0300 UTC, giving 1-minute winds
of 35 kts.
2. General Description of Track: Until about 08/0400 UTC, Jacob tracked
generally west to west-northwestwards around the northern periphery of
a subtropical ridge. Thereafter it became quasi-stationary as the
influence of a near-equatorial ridge increased and the subtropical
ridge weakened. The near-equatorial ridge became the dominant
steering influence from about 08/1300 UTC, and Jacob thereafter moved
generally south-eastwards until after making landfall on the Western
Australian coastline near Port Hedland at about 12/0300 UTC.
Vertical wind shear hindered Jacob throughout its lifetime. Despite
that, it twice peaked at 75 kts (10-minute wind), first at 07/2200
UTC, and again at 09/1800 UTC. However, after 10/0600 UTC, dry air
entrainment, increasing vertical wind shear and decreasing poleward
outflow all combined to cause steady weakening; Jacob was only a
marginal TC at landfall and dissipated rapidly thereafter.
C. Meteorological Data
----------------------
Christmas Island recorded 80.8 mm of rain on 07 March as Jacob
approached from the east. Curiously, however, rainfall was much less
on 08 March (21.6 mm) when Jacob was closest to the island. Although
records are unavailable from 08/1227 - 09/0223 UTC, it appears that
at no time were gales recorded, and the lowest SLP was 999 hPa at
07/2200 UTC.
Jacob's chief effect on the mainland was rainfall, though this was
confined to the Pilbara District. Top 24-hour readings were 114 mm at
Port Hedland (12 March) and 123 mm at Yarrie (13 March). Yarrie also
recorded a 72-hr total of 212 mm on 12 March. These falls, plus
widespread readings of 50 mm and above, were enough to cause some
flooding in the De Grey River catchment, and BoM Perth issued flood
warnings for this river and its tributaries on 12 - 13 March.
Only Bedout Island recorded gales (34 kts at 12/0300 UTC), and the
lowest SLP recorded was 998.3 hPa at Legendre Island at 11/1900 UTC.
D. Damage and Casualties
------------------------
This author knows of no casualties or significant damage directly
attributable to TC Jacob. However, according to reports on "The West
Australian" website, winds from Jacob may have torn away some of the
tarpaulins being used to re-roof buildings damaged by TC George, and
Jacob's approach led to the old Port Hedland Detention Centre (closed
2004) being re-opened to hold evacuees from Port Hedland and nearby
areas. Jacob also forced Fortescue Metals Group, some of whose
employees were among TC George's victims, to evacuate its other rail
camps in order to prevent any further injury or loss of life.
E. Additional Discussion
------------------------
TC Jacob could have caused a major disaster, given that its
landfall was very near to that of TC George only a few days before,
and given that at one time it was expected to reach Category Four
status -- the same as George -- and be a good deal more intense at
landfall than it finally was. Thanks to vertical wind shear, a
potential catastrophe became a non-event.
(Report written by Matthew Saxby)
SEVERE TROPICAL CYCLONE KARA
(TC-20S)
24 - 28 March
------------------------------------------------
A. General Information
----------------------
1. Identification
a. RSMC - BoM Perth
c. JTWC - Tropical Cyclone 20S
d. NAME - Kara (named by BoM by Perth at Mar 25/0600 UTC)
2. Overview
a. Basins Affected: Northwest Australia/Southeast Indian Ocean (AUW)
b. Dates: 24 - 28 March, 2007
c. Max Sust Winds: 85 kts (10-min avg per BoM Perth)
105 kts (1-min avg per JTWC)
d. Min Cent Press: 942 hPa (estimate per BoM Perth)
3. Beginning of Track: Mar 24/0600 UTC, near 16.0S/120.8E, or about
145 nm northwest of Broome, Western Australia, as referenced in
initial advice issued by BoM Perth.
4. Peak Intensity: Mar 26/1200 UTC, near 18.3S/115.3E, or about 170 nm
north-northwest of Karratha, Western Australia. (It should be noted
that BoM Perth's MSW was at 85 kts from 26/0800 through 27/0600 UTC.)
5. Size: At its peak Tropical Cyclone Kara was a fairly small tropical
cyclone with a gale radius of around 70 nm.
6. End of Track: Mar 28/0000 UTC, near 19.4S/121.3E, or inland about
85 km southwest of Bidyadanga, Western Australia.
B. Synoptic History
-------------------
1. Origin: According to BoM Perth's first daily Tropical Cyclone Outlook
mentioning the pre-Kara system (24 March), it originated over the
Kimberley region of northern Western Australia before moving out to
sea. It began to develop in a favorable environment almost
immediately, and BoM Perth initiated both marine and public advisories
at 24/0700 UTC. 10-minute sustained winds were then stated as 25 kts,
but gales were expected to develop in the western quadrants and
extend throughout the system within 24 hours. JTWC issued a TCFA at
25/0221 UTC (as per the first warning; the TCFA did not reach the
author), but development was rapid, as forecast, and Kara was named
in a BoM Perth public advisory issued at 25/0545 UTC. The then
maximum wind gusts of 95 km/h equate to 10-min winds of 35 kts and
1-minute winds of 40 kts. JTWC issued their first warning at
25/0900 UTC, giving 1-minute winds of 35 kts.
2. General Description of Track: Kara tracked generally west to west-
southwestwards along the northern periphery of a subtropical ridge
until about 25/1700 UTC, then turned southwards as a mid-latitude
trough to the south-west created a weakness in the ridge. While
tracking southwards it intensified rapidly, reaching its peak
intensity of 85 kts (10-min) at 26/0800 UTC (as per the BoM public
advisory issued 26/0850). JTWC's 26/0900 UTC warning forecast a very
sharp turn eastward as the subtropical ridge broke down under the
influence of the approaching trough. This happened almost immediately,
and by 26/1700 UTC Kara was moving to the east-southeast, and
continued moving erratically east-southeast to southeastward until
landfall.
Shortly after turning eastwards, Kara encountered increasing
vertical wind shear and began to weaken rapidly. At landfall just
east of Wallal (27/2000 UTC) Kara was only a marginal TC, and like
its predecessor Jacob, it dissipated soon after it struck. (Editor's
Note: The remnant LOW of Kara drifted back northward over the Timor
Sea and meandered for a few days in the area southwest and west of
Broome without showing any signs of re-generation. The track listing
and track graphic do not contain this remnant LOW stage.)
C. Meteorological Data
----------------------
There were no reports of gale-force winds or significant low SLP's
from Kara, partly because it was small and made landfall in a
sparsely-populated area, but also because the offshore sites nearest
Kara's path were out of action during its passage.
As with Jacob, Kara's chief effect was rainfall. However, unlike
Jacob, the remnants persisted for several days and affected a larger
area (Kimberley and Pilbara). 24-hour rainfalls for each of 27 - 30
March were typically in the 25-75 mm range, with isolated heavier
recordings. Pardoo's 285 mm (Pilbara - 27 March) was the highest
overall, but Mandora (Pilbara - 28 March) with 197 mm and Warmun
(Kimberley - 30 March) with 155 mm were also notable. Though no other
site recorded over 100 mm, rainfall was enough to cause significant
flooding in the Fitzroy and Margaret Rivers during the next several
days.
D. Damage and Casualties
------------------------
This author has not received any reports of damage or casualties
attributable to TC Kara. However, Kara did force the closure of Port
Hedland's seaport at noon (WDT) 27 March, and Fortescue Metals Group
had to evacuate its mining camps for the second time in three weeks.
The threat from Kara also helped to highlight safety issues at
another of FMG's rail-camps, and the company was officially ordered
to make the camp safe by May.
E. Additional Discussion
------------------------
Post-analysis carried-out by BoM resulted in Kara's peak intensity
(27 March/0300 UTC) being raised from 85 kts to 105 kts, which equates
to a 1-minute wind speed of 120 kts and a Dvorak T6.0, possibly even
6.5. Kara's rapid intensification on 26 - 27 March (T3.0 - T6.0
in 24 hours) also broke normal Dvorak constraints. As the analyst
said, "Kara was an interesting midget...that [stretched] the Dvorak
technique to its limits".
(Report written by Matthew Saxby)
*************************************************************************
NORTHEAST AUSTRALIA/CORAL SEA (AUE) - From 135E to 160E
Activity for March: 1 tropical LOW **
1 tropical cyclone ++
** - system moved east of 160E where it later became a tropical cyclone
++ - system not classified as tropical cyclone by JTWC
Sources of Information
----------------------
The primary sources of tracking and intensity information for
Northeast Australia/Coral Sea tropical cyclones are the warnings
and advices issued by the Tropical Cyclone Warning Centres at
Brisbane, Queensland, and Darwin, Northern Territory, and on very
infrequent occasions, by the centre at Port Moresby, Papua New
Guinea. References to sustained winds imply a 10-minute averaging
period unless otherwise stated.
In the companion tropical cyclone tracks file, I occasionally
annotate positions from warnings issued by the Joint Typhoon Warning
Center (JTWC) of the U. S. Air Force and Navy, located at Pearl
Harbor, Hawaii, when they differ from the Australian centres' coor-
dinates 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.
Northeast Australia/Coral Sea
Tropical Activity for March
-----------------------------
A tropical LOW which formed late in February strengthened in early
March into Tropical Cyclone Odette, which was a tropical cyclone of
minimal intensity for only about 30 hours. The system meandered about
on a highly erratic track for several days well east of the Queensland
coast. Odette exhibited more characteristics of a monsoon depression
than a classic tropical cyclone, and likely for this reason no warnings
were issued for this system by JTWC. There were several reports of
gale-force winds from ships--one even up to 56 kts--and most of these
ranged from 100 to almost 300 nm from Odette's center. A report on
Tropical Cyclone Odette, written by Simon Clarke, follows.
A tropical LOW which formed on 25 March near 12.0S/157.5E moved
eastward across 160E into Nadi's AOR where it strengthened and became
Tropical Cyclone Becky on the 26th. A report on Becky may be found
in the section covering the South Pacific basin.
TROPICAL CYCLONE ODETTE
(NRL Invest 93P)
26 February - 7 March
-------------------------------------------
A. General Information
----------------------
1. Identification
a. RSMC - BoM Brisbane
b. NAME - Odette (named by BoM Brisbane at Mar 03/0000 UTC)
2. Overview
a. Basins Affected: Northeast Australia/Coral Sea (AUE)
b. Dates: 26 February - 7 March, 2007
c. Max Sust Winds: 35 kts (10-min avg per BoM Brisbane)
d. Min Cent Press: 990 hPa (estimate per BoM Brisbane)
3. Beginning of Track: Feb 26/1700 UTC, near 12.7S/153.8E, or about
550 nm east-northeast of Cape Melville, Queensland, as referenced
in initial gale warning issued by BoM Brisbane.
4. Peak Intensity: Mar 03/0000 UTC, near 16.6S/154.8E, or about 515 nm
east of Cairns, Queensland. (It should be noted that BoM Brisbane's
MSW was at 35 kts from 03/0000 through 04/0600 UTC.)
5. Size: Based on BoM Brisbane's warnings, at its peak Tropical Cyclone
Odette was a large, albeit weak, cyclone with gales extending outward
up to 240 nm from the center.
6. End of Track: Mar 07/0000 UTC, near 16.6S/159.4E, or about 65 nm
northeast of the Chesterfield Islands.
B. Synoptic History
-------------------
1. Origin: Odette originated within a developing monsoon trough that had
become established across the northern Coral Sea by 24 February with
two low-pressure circulations forming: one to the northeast of
Cooktown and the other and more dominant LOW to the south of the
Solomon Islands. This easternmost LOW moved to the west at 5 kts and
developed a band of gale-force winds primarily on its eastern flank.
At one stage it was suggested that the two circulations would merge
into one new cyclone. However, with time, the easternmost LOW
continued to dominate, eventually absorbing the LOW to the northeast
of Cooktown into its outermost circulation. All the while this LOW
was subject to very strong upper-level northwesterly wind shear
(40 kts plus) which completely exposed the LLCC (which could be
clearly seen in visible satellite imagery from time to time. By
2 March the LOW had become stranded in the central Coral Sea in a
region of weak steering influence. The LLCC gradually turned to the
east before looping back to the southwest, eventually looping back
through the northwest and then west. At 03/0000 UTC the Low was
named Odette based on a ship's observation. Odette was located near
16.6S/154.8E (approximately 430 nm ENE of Bowen) at this time and
almost stationary.
2. General Description of Track: There were no strong steering
influences affecting Odette and it drifted only a short distance to
the west-northwest during its fleeting life as a named cyclone.
Odette was a sheared system throughout its entire life with its LLCC
exposed most of the time. No lasting CDO ever developed close to
Odette's LLCC with the most significant rains and gales displaced to
the eastern side of the system. The cyclone was downgraded at 04/0600
UTC near 16.2S/155.5E (approximately 565 nm ENE of Cairns) with the
remnant LOW continuing to drift slowly in an easterly direction. On
6 March, the ex-cyclone showed some signs of regeneration as the
system moved to the south-southeast and into more favourable
environmental conditions. However, this regeneration proved to be
short-lived as the system continued on to the east, eventually
dissipating just west of 160E.
C. Meteorological Data
----------------------
Jeff Callaghan of BoM Brisbane has sent a list of all ship
observations which reported gales in association with Tropical Cyclone
Odette or the pre-Odette LOW. The more significant ones are listed
below (all assumed to be 10-min avg winds):
(1) At 01 March/1500 UTC ship VJNV reported 080/56 kts from a
position 125 nm at an azimuth of 120 deg from the LOW's center.
(2) At 01 March/2000 UTC the same ship reported 080/42 kts from a
position 125 nm at an azimuth of 111 deg from the LOW's center.
(3) At 02 March/0000 UTC ship PCKU reported 290/41 kts from a
position 295 nm almost due north of the LOW's center.
(4) At 03 March/0000 UTC ship A8HJ4 reported 350/41 kts from a
position 120 nm at an azimuth of 73 deg from Odette's center.
(It was at this hour the system was upgraded to TC Odette.)
(5) At 04 March/0000 UTC ship MARU reported 020/40 kts from a
position 75 nm at an azimuth of 212 deg from Odette's center.
(The ship actually reported 80 kts, but it was felt that 40 kts
was the intended reading.)
(6) At 01 March/1200 UTC the Marion Reef AWS reported 090/38 kts with
the station at this time being located 110 nm at an azimuth of
148 deg from the pre-Odette LOW's center.
A special thanks to Jeff for sending the reports.
D. Damage and Casualties
------------------------
There were no significant impacts associated with Odette.
However, there was much local media interest in the system over
several days due to the large size of the system's developing
circulation. At one stage it was thought that Odette might even track
toward the southern coast of Queensland, thereby having the potential to
break the extremely severe drought affecting that part of the State.
However, the strong shear affecting the system ensured that the
strongest winds and any rains were kept on the eastern side of the
system well out to sea. As the system lost cyclone status and drifted
farther out to sea, hopes of a major rain event were dashed.
Nonetheless, the cyclone brought large ocean swells to beaches in
central and southern Queensland with the big seas keeping lifesavers
busy. Dozens of people from Coolangatta to Southport were rescued,
while large swells challenged competitors at the Queensland Surf Life
Saving Championships at Kawana on the Sunshine Coast.
(Report written by Simon Clarke, except that Section C was added by
Gary Padgett)
*************************************************************************
SOUTH PACIFIC (SPA) - South Pacific Ocean East of Longitude 160E
Activity for March: 1 tropical LOW with associated gales **
1 tropical depression
1 tropical cyclone of storm intensity
** - gale warnings were issued for this LOW, but it was not classified
as a tropical depression by Fiji
Sources of Information
----------------------
The primary sources of tracking and intensity information for
South Pacific tropical cyclones are the warnings and advisories
issued by the Tropical Cyclone Warning Centres at Nadi, Fiji (for
waters north of latitude 25S), and Wellington, New Zealand (for
waters south of latitude 25S). References to sustained winds imply
a 10-minute averaging period unless otherwise stated.
In the companion tropical cyclone tracks file, I occasionally
annotate positions from warnings issued by the Joint Typhoon Warning
Center (JTWC) of the U. S. Air Force and Navy, located at Pearl
Harbor, Hawaii, when they differ from the Southern Hemisphere
centres' coordinates by usually 40-50 nm or more. The JTWC warnings
are also the source of the 1-minute average maximum sustained wind
values included in the tracks file. Additionally, information
describing details of satellite imagery and atmospheric circulation
features included in the narratives is often gleaned from the JTWC
warnings.
South Pacific Tropical Activity for March
-----------------------------------------
Three systems were tracked by RSMC Nadi during March. The first was
a tropical LOW well east of the Dateline early in the month. The system
was first referenced in Nadi's Tropical Disturbance Summary issued at
0907 UTC on 8 March when it was located near 20.0S/173.0W, or well south
of Samoa, in a moderate to strongly sheared environment. Gale warnings
were initiated at 09/0000 UTC for a region of associated peripheral
gales. The LOW continued to move slowly east-southeastward, and by the
time of issuance of the final gale warning at 10/1800 UTC, it was located
near 26.0S/153.5W, or far to the south-southwest of Tahiti. This system
was never classified as a tropical depression by Nadi. Given its
latitude of formation, it possibly was not fully tropical. No track was
included for this system in the companion cyclone tracks file.
Tropical Depression 12F formed on 21 March to the north-northwest of
Fiji, being located near 14.2S/174.2E at 21/2030 UTC. Over the next
several days TD-12F moved on a slow, generally southerly track which kept
it to the west of the Fijian islands. The depression was forecast to
reach tropical cyclone intensity, and in anticipation of that, gale
warnings were issued from 22/0000 through 22/1800 UTC, but were
discontinued after that point due to the system becoming less organized.
TD-12F continued southward, finally losing its identity on the 26th
a few hundred miles south-southwest of Nadi.
TD-12F was very possibly a tropical storm based on a 1-min avg MSW.
Dvorak ratings on the 22nd and 23rd reached T2.5/2.5 from AFWA, CPHC,
Nadi and Brisbane. However, JTWC never ranked the system stronger than
T2.0/2.0; hence, no warnings were issued by that agency. The depression
apparently became better organized for a time on the 24th, as CPHC's
Dvorak ratings reached T3.0/3.0 on that date; also, SAB gave the system
its highest ranking of T2.5/2.5 on the 24th. A track file was included
for this system in the companion cyclone tracks file, and a track
graphic is available on John Diebolt's website.
The third system of the month in the South Pacific basin was Tropical
Depression 13F, which moved eastward from Brisbane's AOR and intensified
into Tropical Storm Becky. Becky intensified to near hurricane force
as it tracked south-southeastward just west of the islands of Vanuatu.
A report on Becky follows.
One final item--the previous numbered system in the South Pacific
basin (based on Fiji's 'F' numbering scheme) prior to Tropical Depression
12F was Tropical Depression 09F very early in February (also tracked as
TC-11P by JTWC). I have been asked by more than one person what
happened to '10F' and '11F'. I receive all of Nadi's bulletins,
warnings, advisories, etc and scan them closely. I never saw any
reference to systems with those missing numbers. Two possibilities come
to mind:
(1) The numbers were allotted for internal office use to two systems (the
likely candidates being the tropical LOW of 8-10 March discussed
above, and the ex-TC Odette tropical LOW which almost moved across
160E on 7 March and which Nadi referenced in some Tropical
Disturbance Summaries) but were never included in any public or
marine warning products.
(2) An inadvertent numbering error was made when TD-12F developed which
was not corrected.
If I should ever learn the answer to this question, I shall relate it
in a future summary.
TROPICAL CYCLONE BECKY
(TD-13F / TC-21P)
25 - 31 March
------------------------------------------
A. General Information
----------------------
1. Identification
a. RSMC - BoM Brisbane/Nadi, Fiji, Tropical Cyclone Warning Centre
b. Fiji - Tropical Disturbance 13F (East of 160E)
c. JTWC - Tropical Cyclone 21P
d. NAME - Becky (named by Fiji at Mar 26/1800 UTC)
2. Overview
a. Basins Affected: Northeast Australia/Coral Sea (AUE)
South Pacific Ocean (SPA)
b. Dates: 25 - 31 March, 2007
c. Max Sust Winds: 60 kts (10-min avg per Fiji)
70 kts (1-min avg per JTWC)
d. Min Cent Press: 975 hPa (estimate per Fiji)
3. Beginning of Track: Mar 25/0000 UTC, near 12.0S/157.5E, or about
200 nm southwest of Honiara, Solomon Islands, as referenced in initial
gale warning issued by BoM Brisbane.
4. Peak Intensity: Mar 27/1200 UTC, near 15.9S/166.3E, or about 150 nm
northwest of Port Vila, Vanuatu. (It should be noted that Fiji's MSW
was at 60 kts from 27/1200 through 29/1800 UTC.)
5. Size: Based on Fiji's warnings, at its peak Tropical Cyclone Becky
was an average-sized cyclone with gales extending outward from the
center 80 nm to the northwest and 120 nm to the southeast. However,
JTWC's warnings described a smaller system with gale radii ranging
from 65-70 nm.
6. End of Track: Mar 31/1800 UTC, near 22.0S/163.0E, or about 200 nm
west of Noumea, New Caledonia.
B. Synoptic History
-------------------
1. Origin: BoM Brisbane issued a gale warning at 0000 UTC on 25 March
for a tropical LOW centered approximately 200 nm southwest of Honiara
on Guadalcanal in the Solomon Islands. Peak winds were estimated
at 30 kts but gales were forecast to gradually develop. A STWO issued
by JTWC at 0600 UTC noted that the LLCC was consolidating with weak
convective banding present. The disturbance lay under an upper-level
ridge axis with low vertical shear and favorable poleward and
equatorward diffluence. The system began to drift eastward and by
1800 UTC the same day had moved east of 160E into Fiji's AOR where it
received the designation Tropical Depression 13F. About the same
time JTWC upgraded the potential for development to 'fair'. The final
warning issued by Brisbane at 25/1800 UTC noted that gales had
developed in the northern quadrants.
By early on the 26th TD-13F was beginning to track slightly east-
southeastward due to the influence of a near-equatorial ridge located
to the northeast. A 26/0740 UTC QuikScat pass showed a well-defined
LLCC with winds of at least 35 kts with deep convective banding
wrapping into the LLCC. JTWC issued the first warning on TC-21P
at 26/1200 UTC, and at 1800 UTC Nadi upgraded the depression to
Tropical Cyclone Becky, centered about 300 nm southeast of Honiara
and moving to the east-southeast at about 7 kts. The intensity
was estimated at 40 kts.
2. General Description of Track: The newly-christened cyclone's track
became increasingly southeasterly and eventually south-southeasterly
as it was steered by an extension of the near-equatorial ridge to its
east and a high-amplitude trough to its west. Becky approached the
islands of Vanuatu but the south-southeasterly track kept the center
to the west of the main islands. The cyclone reached its peak MSW
of 60 kts at 1200 UTC on 27 March, maintaining that intensity for
30 hours. The minimum estimated CP was 975 hPa. JTWC's estimated
1-min avg MSW reached a peak of 70 kts at 28/1200 UTC, shortly before
rapid weakening set in due to a significant increase in vertical shear
and the entrainment of some drier air. Between 28/1200 and 29/0000
UTC Becky's MSW dropped from 60 kts to 35 kts, and six hours later
Nadi downgraded the system to a tropical depression with the exposed
center located east of New Caledonia. By 29/1200 UTC all the deep
convection had disappeared and JTWC issued their final warning. Fiji
continued to track the weak remnants southwestward across the island
of New Caledonia. The final reference to the system at 31/1800 UTC
placed the very weak center approximately 200 nm west of Noumea.
C. Meteorological Data
----------------------
No meteorological observations taken in association with Tropical
Cyclone Becky have been received.
D. Damage and Casualties
------------------------
No reports of damage or casualties resulting from Tropical Cyclone
Becky have been received.
(Report written by Gary Padgett)
*************************************************************************
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
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: https://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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