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: 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: ************************************************************************* 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: (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: A brief summary of the storm can be found on BoM's website at the following URL: (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: Information regarding how to interpret the coded reconnaissance messages may be found at the following URL: 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: Links to tropical products archives for earlier years are available at the following URL: JTWC warnings for past storms are archived on the NRL Monterrey website: 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: 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: (2) For the Atlantic, Gulf of Mexico and Caribbean Sea: 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): 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: 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: 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: 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 ************************************************************************* ************************************************************************* Posted: 06.11.07 / Typhoon2000.ph, Typhoon2000.com