Tropical
Cyclones
[Index] |
Monthly Global Tropical Cyclone Summary March 2006 [Summaries and Track Data] [Prepared by Gary Padgett] |
MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY MARCH, 2006 (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: TPC/NHC now has all the storm reports and the track charts for the 2005 Atlantic and Eastern North Pacific seasons available online. Links to the reports and track charts may be accessed at the following URLs: http://www.nhc.noaa.gov/2005atlan.shtml> http://www.nhc.noaa.gov/2005epac.shtml> Also, the Central Pacific Hurricane Center has available online their annual summary for the 2005 tropical cyclone season in that region. The link is: http://www.prh.noaa.gov/cphc/summaries/2005.php> And finally, the Canadian Hurricane Centre has a summary available of the 2005 tropical cyclones which entered their Response Zone. This summary may be accessed at: http://www.atl.ec.gc.ca/weather/hurricane/storm05.html> ************************************************************************* MARCH HIGHLIGHTS --> Two severe tropical cyclones form off Western Australia--one makes landfall --> Very destructive tropical cyclone strikes Queensland --> Another severe tropical cyclone in Coral Sea recurves away from Australia ************************************************************************* ********** EXTRA FEATURE ********** WESTERN HEMISPHERE TROPICAL CYCLONE NAMES for 2006 Tropical cyclones in the Atlantic Ocean, Gulf of Mexico, and Caribbean Sea are assigned names by the Tropical Prediction Center/ National Hurricane Center in Miami, Florida. A separate alphabetical set of alternating male/female names is used each year with the name of the first tropical storm beginning with the letter "A". Names are repeated every six years. The names of hurricanes which cause a lot of damage and/or fatalities are usually retired from the list with another name of the same alphabetical rank and gender replacing it. Following the 2005 season, the names Dennis, Katrina, Rita, Stan and Wilma were retired and have been replaced in the list for 2011 with Don, Katia, Rina, Sean and Whitney, respectively. It seemed likely that Emily also would have been retired, but Mexico did not request it, so Emily remains in the list for 2011. The highest number of tropical storms named in one season in the Atlantic was 27 during the incredibly active 2005 season, which has become the most active Atlantic tropical cyclone season on record. Other very active seasons include 1887 (19 storms), 1933 (21 storms), 1969 (18 storms) and 1995 (19 storms). The list of names for 2006 is the same one used during the active hurricane season of 2000 when fourteen tropical cyclones were named, down through Nadine. The only name retired after the 2000 season was Keith, and that name has been replaced with Kirk in the 2006 list. TPC/NHC also has warning responsibility for the Eastern North Pacific Ocean from the west coast of Mexico out to longitude 140W. Six separate alphabetical sets of names are used for this basin in the same manner as in the Atlantic. Initially, the Eastern Pacific name sets contained only 21 names, omitting "Q" and "U" and ending with the letter "W", as in the Atlantic. When the active 1985 season threatened to exhaust the list, the names Xina, York and Zelda were drafted to accommodate any additional storms which might develop. (Hurricane Xina was named in late October, 1985.) The decision was made sometime in the latter 1980s to extend the list with these three names in odd-numbered years, and to add the names Xavier, Yolanda and Zeke in even-numbered years (to preserve the alternating gender scheme). During the Northeast Pacific's year of record activity in 1992, all 24 names were allotted to tropical cyclones forming east of 140W, ending with Tropical Storm Zeke in late October. Had more storms developed, they would have been named with the letters of the Greek alphabet (Alpha, Beta, etc), which is also the backup plan for the Atlantic basin in case more than 21 tropical storms develop in a single season. The list for this year was last used in 2000 when seventeen tropical cyclones were named, the last one being Rosa. The most active season to utilize this set of names was in 1982, when 19 cyclones were named, down through Tara. The Central Pacific Hurricane Center, located in Honolulu, has tropical cyclone warning responsibility for that portion of the North Pacific Ocean lying between longitudes 140W and 180. The majority of the tropical storms and hurricanes seen in that region are visitors from east of 140W, but on the average about one tropical storm forms in the Central Pacific each year, and when this happens, the storm is given a Hawaiian name. The list consists of four sets of twelve names each, using only the letters of the Hawaiian alphabet. All the names are used--the first storm to form in a given year is assigned the next available name on the list. No tropical cyclones were named by CPHC in 2003 or in 2004. The last storm to form in Central Pacific waters was Hurricane Huko in late October, 2002, so the next name to be assigned will be Ioke. Names for 2006 are (** indicates name has already been assigned): ATLANTIC EASTERN PACIFIC CENTRAL PACIFIC Alberto ** Leslie Aletta ** Miriam Ioke Beryl Michael Bud Norman Kika Chris Nadine Carlotta Olivia Lana Debby Oscar Daniel Paul Maka Ernesto Patty Emilia Rosa Neki Florence Rafael Fabio Sergio Oleka Gordon Sandy Gilma Tara Peni Helene Tony Hector Vicente Ulia Isaac Valerie Ileana Willa Wali Joyce William John Xavier Ana Kirk Kristy Yolanda Ela Lane Zeke Halola ************************************************************************* 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 storm ** ** - treated as a tropical storm by JTWC only Sources of Information ---------------------- Most of the information presented below is based upon tropical cyclone warnings and significant tropical weather outlooks issued by the Joint Typhoon Warning Center of the U. S. Air Force and Navy (JTWC), located at Pearl Harbor, Hawaii. In the companion tropical cyclone tracks file, I normally annotate track coordinates from some of the various Asian warning centers when their center positions differ from JTWC's by usually 40-50 nm or more. All references to sustained winds imply a 1-minute averaging period unless otherwise noted. Michael V. Padua of Naga City in the Philippines, owner of the Typhoon 2000 website, normally sends me cyclone tracks based upon warnings issued by the Japanese Meteorological Agency (JMA) and the Philippines' Atmospheric, Geophysical & Astronomical Services Administration (PAGASA). A very special thanks to Michael for the assistance he so reliably provides. In the title line for each storm I have referenced all the cyclone names/numbers I have available: JTWC's depression number, the JMA-assigned name (if any), JMA's tropical storm numeric designator, and PAGASA's name for systems forming in or passing through their area of warning responsibility. TROPICAL STORM (TC-01W / BASYANG) 3 - 13 March -------------------------------------- A. Storm Origins ---------------- Tropical Storm 01W originated from a disturbance associated with a near-equatorial trough located approximately 410 nm south-southeast of Yap. At 2030 UTC 3 March JTWC issued a TCFA on this system, remarking: "Animated enhanced infrared imagery reveals that deep convection over a tightening low-level circulation center has increased. An upper-level analysis shows that the area is under low to moderate vertical wind shear, has an increasingly symmetric 850-mb vorticity signature, and has excellent poleward outflow." The first warning on Tropical Depression 01W was written at 04/0000 UTC, locating the centre approximately 240 nm east-southeast of Palau. At this time, the system was drifting slowly towards the northwest at 3 kts, heading towards a weakness in the subtropical ridge. B. Synoptic History ------------------- Tropical Depression 01W was upgraded to a 35-kt tropical storm at 0600 UTC 4 March while located approximately 260 nm east-southeast of Palau. Tropical Storm 01W did not intensify further. The system maintained its peak strength of 35 kts for a little over 24 hours while drifting north-northwestward. Plagued by moderate wind shear, TS-01W became disorganized on 5 March and was downgraded to a tropical depression at 05/1800 UTC. At this time, the centre was relocated to a position approximately 210 nm east of Palau after enhanced satellite imagery and a 05/1028 UTC QuikScat pass revealed the formation of a weak LLCC to the south of the previous location. A further relocation was required at 06/0000 UTC, placing the centre a little further to the south. Turning onto a westerly heading, TC-01W passed 195 nm south of Palau late 6 March/early 7 March. After multi-spectral satellite imagery failed to reveal the poorly-defined LLCC, JTWC issued the final warning at 07/0000 UTC. JTWC continued to monitor the remnants of Tropical Storm 01W through their STWOs and considered the development potential to be fair at 0600 UTC 8 March after multi-spectral satellite imagery indicated a consolidating LLCC with convection wrapping around the western periphery. At this time, the system was located approximately 305 nm east-southeast of Zamboanga, Philippines, and tracking towards the west-northwest. Continuing on this heading, the system made landfall over Mindanao late on 8 March. Did TC-01W reach the southern Philippines as a re-vitalised tropical storm? Some analysts felt that the system did. However, it was never officially re-upgraded and JTWC downgraded the disturbance back to poor status at 09/0600 UTC and dropped it from their STWOs altogether at 10/1730 UTC. Re-emerging back over the waters of the Sulu sea, the LOW crossed Palawan Island early on 11 March before dissipating halfway across the South China Sea early on 13 March. The peak intensity estimated by JMA was 30 kts with the lowest CP estimated at 1004 mb. PAGASA issued only three warnings on Tropical Depression Basyang after it entered their AOR before it was downgraded. The first was released at 06/1200 UTC and the final at 07/0200 UTC. The peak 10-min avg MSW assessed by that agency was also 30 kts. Graphics depicting the track of Tropical Storm 01W/Basyang may be found at the following link: http://www.tropicalcyclone2005.com/database/2006/WPAC/BT-IMAGES/2006-01W-NONAME.gif> http://www.tropicalcyclone2005.com/database/2006/WPAC/BT-IMAGES/2006-01W-NONAME-A.gif> C. Damage and Casualties ------------------------ There were no reports of damages and casualties associated with Tropical Storm 01W/Basyang. (Report written by Kevin Boyle) ************************************************************************* 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 tropical storm Sources of Information ---------------------- The primary sources of tracking and intensity information for Southwest Indian Ocean tropical cyclones are the warnings issued by the Tropical Cyclone Warning Centre on La Reunion Island, part of Meteo France (MFR), and the Regional Specialised Meteorological Centre for the basin. However, tropical cyclones in this region are named by the Sub-regional Tropical Cyclone Advisory Centres in Mauritius and Madagascar with longitude 55E being the demarcation line between their respective areas of naming responsibility. The La Reunion centre only advises these agencies regarding the intensity of tropical systems. References to sustained winds imply a 10-minute averaging period unless otherwise stated. In the companion tropical cyclone tracks file, I occasionally annotate positions from warnings issued by the Joint Typhoon Warning Center (JTWC) of the U. S. Air Force and Navy, located at Pearl Harbor, Hawaii, when they differ from MFR's coordinates by usually 40-50 nm or more. The JTWC warnings are also the source of the 1-minute average maximum sustained wind values included in the tracks file. Additionally, information describing details of satellite imagery and atmospheric circulation features included in the narratives is often gleaned from the JTWC warnings. Southwest Indian Ocean Tropical Activity for March -------------------------------------------------- Three tropical systems were in warning status during the month of March in the Southwest Indian Ocean basin, all during the first part of the month. Intense Tropical Cyclone Carina was near its peak intensity over the east-central portion of the basin on 1 March, but encountered a hostile environment which led to its very rapid weakening and dissipation by 3 March. The report on Carina may be found in the February summary. Severe Tropical Storm Diwa operated from the 2nd until the 10th over the western portion of the basin, passing southward between the Mascarene Islands (Reunion and Mauritius) and Madagascar. Diwa originated as a large, sloppily-organized monsoon depression which gradually acquired tropical storm characteristics. A report on Diwa follows. Meteo France on La Reunion (MFR) issued two warnings on another system, numbered as Tropical Disturbance 12. At 0600 UTC on 4 March this disturbance was centered approximately 200 north-northeast of Tromelin Island, or about 335 nm due north of the center of Tropical Storm Diwa. Peak 10-min avg winds were estimated at 25 kts, locally reaching 30 kts in squalls. The system moved rapidly southeastward around the north- eastern periphery of Diwa, and the second and final MFR warning at 1200 UTC placed the center of the disturbance about 190 nm east of Tromelin and about 240 nm northeast of Diwa's center. No more warnings were issued, and due to the large size of the circulation around Diwa, it is assumed that the weak Tropical Disturbance 12 was absorbed into the circulation of the tropical storm. A graphic depicting the track of Tropical Disturbance 12 and Tropical Storm Diwa may be found at the following link: http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-12R-DIWA.gif> TROPICAL STORM DIWA (MFR-11 / TC-16S) 2 - 10 March --------------------------------------- Diwa: contributed by Malawi A. Introduction and Storm Origins --------------------------------- Tropical Storm Diwa was a large, odd tropical storm which occupied the first week of March moving slowly southward through the Southwest Indian Ocean between Madagascar and the Mascarene Islands. Diwa was in its early stages actually a monsoon depression which developed gales along its periphery. In the author's opinion, the Meteorological Service of Mauritius is to be commended for assigning a name and treating the system as a tropical storm when it was apparent it was intensifying and becoming an increasing threat. Another unusual feature of Tropical Storm Diwa was that it achieved its peak intensity and most tropical-like structure after moving into subtropical latitudes--something rarely seen in the Southwest Indian basin. MFR issued their first warning on the pre-Diwa system at 0600 UTC on 2 March, calling it simply a "zone of disturbed weather" located about 175 nm southeast of the island of Agalega. Around the same time JTWC included the disturbance in a STWO, noting that it was a elongated LLCC embedded within the monsoon trough east of Madagascar. Convection had been increasing near the low-level disturbance, and an upper-level ridge axis to the north was helping to provide an environment of low vertical shear and favorable diffluence aloft. On their second bulletin, issued at 02/1200 UTC, MFR upgraded the area to Tropical Disturbance 11 with winds estimated at 25 kts. St. Brandon, well to the southeast, reported 10-min avg winds of 35 kts with a SLP of 1002 hPa at 02/2100 UTC. JTWC upgraded the development potential to 'fair' at 1800 UTC since convection was persisting near the LLCC. B. Synoptic History ------------------- MFR upgraded the disturbance to a 30-kt tropical depression at 0600 UTC on 3 March, and at 1200 UTC the system was upgraded to Tropical Storm Diwa, centered at the time about 125 nm west of St. Brandon. The MFR warning noted that the system had a monsoon depression structure with weak winds near the center but with gales, locally reaching 40 kts, over 100 nm from the center in the eastern semicircle under the convective bands. JTWC issued a TCFA at 03/2100 UTC and the first warning on TC-16S followed at 04/0000 UTC. In its formative stages Diwa had moved basically to the south, but by now was moving on a slow southwesterly track under the influence of ridging to the southeast. After having reached tropical storm intensity, however, the storm did not strengthen significantly during the next three days. By the 5th Diwa had turned to the south, although it made a jog to the southwest on the 6th. Tropical Storm Diwa passed about 200 nm west of Mauritius around 0900 UTC on 5 March and about 100 nm west of Reunion Island around 1500 UTC the same day. Earlier on 3 March, while Diwa's center was a little less than 200 nm northwest of Mauritius, a wind gust to 59 kts was recorded at 2130 UTC at Savannah, a location in the southeastern part of Mauritius near L'Escalier. (This observation, as well as the earlier one taken from St. Brandon, was sent by Patrick Hoareau.) After the aforementioned jog to the southwest, Diwa's motion became primarily south-southeastward ahead of an approaching baroclinic zone. The storm gradually began to strengthen--the MSW was upped to 40 kts at 06/0600 UTC and to 50 kts at 07/0000 UTC. Diwa was experiencing favorable poleward and equatorward outflow with the deepest convection located in the southeastern quadrant. Both JTWC and MFR upped their respective MSW estimates to 55 kts at 0600 UTC 8 March. Diwa by this time was tracking southeastward at 15 kts along the southwestern periphery of a mid-level ridge to the east. The tropical storm was beginning to interact with a baroclinic zone to the south, but enhanced poleward outflow was leading to an increase in convection. Based upon MFR's analysis, Severe Tropical Storm Diwa reached its peak intensity of 60 kts (10-min avg) at 08/1200 UTC while centered approximately 475 nm south-southeast of Reunion Island. MFR maintained Diwa at 60 kts for the next warning at 1800 UTC, but JTWC issued their final warning at that time, deeming extratropical transition to be well under way and estimating the intensity at only 35 kts. Six hours later MFR classified Diwa as a 55-kt extratropical storm but continued to issue warnings for the next 36 hours as ex-Diwa continued to track off into the subtropical South Indian Ocean. The final MFR warning, issued at 10/1200 UTC, placed a weakening 40-kt center a little more than 1300 nm southeast of Reunion Island. A graphic depicting the track of Severe Tropical Storm Diwa may be found at the following link: http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-16S-DIWA.gif> C. Damage and Casualties ------------------------ No reports of damage or casualties resulting from Tropical Storm Diwa have been received. (Report written by Gary Padgett) ************************************************************************* NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (AUW) - From 90E to 135E Activity for March: 2 tropical LOWs 2 severe tropical cyclones (hurricanes) 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 ------------------------------------------ After a rather quiet February in which only one minor tropical cyclone (Emma) formed, the tropical seas off northern and northwestern Australia became quite active during March. Four tropical LOWs were tracked by the Darwin and Perth TCWCs with two of these becoming the very intense cyclones Floyd and Glenda. Reports on these two severe tropical cyclones follow. A weak tropical LOW formed late on 28 February just west of the Indonesian island of Jamdena, where the Arafura and Banda Seas meet. During the first week of March this system drifted southwestward, then erratically westward, crossing the island of Timor and passing south of Sumba. By 5 March the westward motion ceased and the LOW turned toward the southeast toward the Kimberley region of Western Australia. The highest MSW estimated for this LOW was 30 kts briefly on 2 March; the remainder of the time peak winds were estimated at only 25 kts. Gale warnings were issued by Darwin and Perth in the anticipation that the LOW would strengthen into a tropical cyclone. This failed to materialize, however, and the final gale warning by BoM Perth was issued at 0400 UTC on 7 March. By 0400 UTC on 8 March the weakening LOW was inland in the Kimberley region. A graphic depicting the operational track of this tropical LOW may be found at the following link: http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-01D-NONAME.gif> The Perth TCWC also issued several gale warnings in late March for a tropical LOW which formed over waters southwest of Christmas Island and east of the Cocos Islands. The first warning was issued at 0300 UTC on 26 March and the system subsequently drifted pretty much due southward. The final gale warning was issued by Perth at 27/0600 UTC, but the remnant LOW continued to generate some Dvorak ratings of T2.5/2.5 by various agencies until early on the 29th. A very broad cyclonic circulation existed in the area with possible multiple LLCCs, and there were considerable differences in the center fixes from the satellite analysis agencies. Disturbed weather continued in the region for several days, and during the first week of April another LOW developed which ultimately became Tropical Storm Elia in the Southwest Indian Ocean basin. There does not appear to be, however, any direct continuity between the late March tropical LOW and the LLCC which became Elia. A graphic depicting the operational track of the late March tropical LOW may be found at the following link: http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-01U.gif> SEVERE TROPICAL CYCLONE FLOYD (TC-19S) 19 - 27 March ------------------------------------------------- (Editor's Note: The following report on Severe Tropical Cyclone Floyd is based largely on a preliminary report on this storm written and sent to the author by Joe Courtney, a forecaster at the Perth TCWC. A very big thanks to Joe for sending the report.) A. Introduction --------------- Floyd was a midget tropical cyclone that reached top-end Category 4 (Australian cyclone scale) intensity before rapidly weakening under northwesterly shear. Tropical cyclone advices were issued for the western Pilbara region and for upper western coastal areas of Western Australia as Floyd approached, but the system weakened and remained offshore and did not impact coastal parts. Floyd did have an economic impact as some resource companies evacuated offshore oil and gas installations. B. Origins and Synoptic History ------------------------------- A tropical LOW developed on 18 March south of the Indonesian island of Sumba and moved to the west to southwest, gradually strengthening. The LOW is estimated to have reached cyclone intensity around 2100 UTC on 20 March while located roughly 450 nm west-northwest of Cape Leveque. The moderate easterly shear on the 21st gradually eased and Floyd developed rapidly later on the 22nd, reaching Category 3 (65 kts) intensity around 23/0000 UTC while located about 560 nm north-northwest of Exmouth. Infrared satellite imagery on the 22nd had revealed very cold cloud tops. Severe Tropical Cyclone Floyd reached its maximum intensity of 105 kts at 24/0000 UTC, centred approximately 530 nm northwest of Exmouth. The cyclone at the time was making a turn to the south due to the approach of a mid-latitude trough. The eye of the system was very small with a diameter of about 10-15 nm, and the minimum CP was estimated at 915 hPa. JTWC's peak 1-min avg MSW was a comparable 115 kts, and hurricane-force winds extended outward from the center only about 20 nm. Arguably Floyd may have reached Category 5 intensity on the basis of an infrared image at 23/2330 UTC showing a Data T-number of 6.5. However, images at 23/2130 and 24/0130 UTC showed Data T-numbers of only 5.5 and 5.0, respectively. Floyd slowly weakened as it moved on a southeasterly track towards the northwestern coastline of Western Australia. Microwave imagery showed that Floyd underwent an eyewall replacement cycle on the 24th, culminating around 25/0000 UTC. The cyclone's intensity at that time was still estimated at 90 kts, but Floyd continued to weaken more rapidly thereafter as it encountered increasing upper-level northwesterlies. The storm reached a point about 155 nm northwest of Exmouth at 26/1200 UTC, but had encountered cooler SSTs and strong upper-level winds. A post- cyclone analysis revealed that likely winds were below gale force by 26/1800 UTC, but operationally Floyd was maintained as a tropical cyclone until 0200 UTC on the 27th when it was downgraded to a tropical LOW. A QuikScat image at 26/0925 UTC had indicated that peak winds were barely of gale force. The final advice, issued at 27/0200 UTC, placed the center of the former tropical cyclone to the west-northwest of Exmouth, near 20.9N/111.6E. The remnant LOW continued to drift southwards off the Western Australian coast for a few more days. A graphic depicting the track of Severe Tropical Cyclone Floyd may be found at the following link: http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-19S-FLOYD.gif> C. Damage and Casualties ------------------------ There are no impacts from Tropical Cyclone Floyd, although some economic losses were incurred with the evacuation of some offshore oil and gas installations. (Report based largely on a report received from Joe Courtney of the BoM Perth TCWC) SEVERE TROPICAL CYCLONE GLENDA (TC-20S) 23 - 31 March -------------------------------------------------- A. Introduction and Storm Origins --------------------------------- Glenda was a severe tropical cyclone which followed closely on the heels of Floyd in waters off Western Australia. Whereas Floyd dissipated offshore, Glenda made landfall near Onslow as a Category 3 cyclone (Australian scale) with peak 10-min avg winds estimated near 95 kts. The storm had peaked a couple of days earlier as a Category 5 cyclone but fortunately weakened some as it approached the coast. Glenda had its origins over the Northern Territory. On 20 March a 1004-hPa tropical LOW was located over the Top End near Katherine. This LOW subsequently moved westward and by early on the 22nd had moved out over the Joseph Bonaparte Gulf about 55 nm west of Port Keats. BoM Darwin initiated tropical cyclone advices on the developing system at 2130 UTC on 23 March with the LOW centered on the coast about 45 nm east-northeast of Wyndham. The LOW moved very slowly for a couple of days, remaining in the extreme southern portion of the Joseph Bonaparte Gulf before commencing a westerly heading which took it inland across the extreme northeastern portion of Western Australia. Environmental conditions were very favorable for intensification with a developing anticyclone over the disturbance, providing low vertical shear and good radial outflow. Emerging into the Timor Sea on 26 March, the LOW began to slowly strengthen and BoM Perth began issuing shipping warnings at 26/1500 UTC. The system was then centered approximately 200 nm northeast of Broome and moving west-southwestward at about 4 kts. Associated convection continued to consolidate and JTWC issued their first warning on TC-20S at 27/0000 UTC. Three hours later, Perth upgraded the system to Tropical Cyclone Glenda, centered about 140 nm north of Derby and moving westward at 5 kts. B. Synoptic History ------------------- Once named as a cyclone, Glenda intensified very rapidly. At 27/1200 UTC, only nine hours after being upgraded, Glenda had reached severe tropical cyclone (i.e., hurricane) status with 65-kt winds. The storm embarked on a west-southwesterly track which gradually became more southwesterly. Environmental conditions were very favorable for intensification and Glenda continued to strengthen, reaching its peak intensity of 115 kts at 28/1200 UTC while centered about 245 nm north- northeast of Port Hedland, moving southwestward at 10 kts. (JTWC's peak 1-min avg MSW was 140 kts at 28/1200 UTC.) Glenda's estimated lowest CP was 910 hPa. The storm was being steered by a 500-mb ridge to the southwest over Australia, and as a mid-latitude trough over the west coast of Australia began to create a weakness in the ridge, the cyclone turned to a more southwesterly track toward the northwestern coastline of Western Australia. Fortunately Glenda's strength began to ebb as the dangerous storm neared the coast. By 0800 UTC on 30 March the center of Severe Tropical Cyclone Glenda was beginning to cross the coastline between Onslow and Dampier. The CP was then estimated at 930 hPa and peak gusts near the center were estimated at 135 kts, which translates into a 10-min mean wind of 95 kts. At 30/1200 UTC Glenda's center was located only 20 km east of Onslow and moving south-southwestward at 11 kts. Once inland Glenda's track became more southerly with hints of a recurvature to the south-southeast by the time the final advice was issued at 31/0300 UTC. As is typical with landfalling tropical cyclones, Glenda began to quickly weaken after the center had moved inland. The final BoM advice placed the center of the former tropical cyclone about 250 km south-southeast of Exmouth with a MSW of 30 kts. (Interestingly, JTWC issued their final warning on Glenda with the center barely inland and with the MSW (1-min avg) estimated at 90 kts.) A report on Severe Tropical Cyclone Glenda may be found on BoM's website at the following URL: http://www.bom.gov.au/announcements/sevwx/wa/watc20060315.shtml> A graphic depicting the track of Tropical Cyclone Glenda may be found at the following link: http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-20S-GLENDA.gif> C. Damage and Casualties ------------------------ The weakening of the cyclone, coupled with the preparedness of the city of Onslow, helped to avert major damage. The BoM report referenced above seems to be a work in progress, and it is likely that further information will be added after a post-storm analysis is completed. (Report written by Gary Padgett) ************************************************************************* NORTHEAST AUSTRALIA/CORAL SEA (AUE) - From 135E to 160E Activity for March: 1 hybrid storm 2 severe tropical cyclones (hurricanes) ** ** - one of these originated in Fiji's AOR east of 160E 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. For the portion of Tropical Cyclone Wati's track lying east of longitude 160E, the following applies: 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. Northeast Australia/Coral Sea Tropical Activity for March ----------------------------- Three significant cyclonic storm systems traversed waters between the coast of Queensland and 160E during the month of March. The first, during the opening days of the month, was a subtropical, hybrid-type storm which brought high winds, heavy seas and moderate rainfall to southeastern Queensland. The second system, Severe Tropical Cyclone Larry, formed well out in the Coral Sea around mid-month, intensifying into a Category 5 cyclone as it marched westward toward the Queensland coastline. Larry made landfall near Innisfail on the 19th with peak 10-min avg winds estimated at around 110-115 kts. The storm was reported to have been the most destructive to strike Queensland in almost 20 years. Finally, a visitor from Fiji's AOR, Tropical Cyclone Wati, moved into the eastern Coral Sea and became a fairly strong hurricane, but very fortunately for residents of Queensland, recurved southeastward and did not affect the Australian coastline. Reports on all three of these storm systems, authored by Simon Clarke, follow. SUBTROPICAL HYBRID STORM 1 - 6 March -------------------------------------------- A. Introduction and Origins --------------------------- Exactly two years ago to the date, a subtropical hybrid storm swept down the Coral Sea and lashed the southeastern Queensland and the northern New South Wales regions of Australia with heavy rains and gale- force winds (see separate report in the March, 2004, global summary). A similar and perhaps more intense event unfolded in the first week of March, 2006. On 1 March 2006, a strong pressure gradient became established along the south coast of Queensland, generated by a strong (1032 hPa) HIGH in the southern Tasman Sea and a low pressure area well to the east of Townsville. This forced a large area of strong to gale force onshore winds onto the coastline south of the Whitsunday Islands. By 02/0000 UTC warm air advection extended from inland Queensland over to southeastern Queensland and adjacent waters as a new 1008-hPa LOW developed near 23.0S/154.5E (approximately 210 nm east of Yeppoon). Over the ensuring 18-hour period this LOW moved southward to near 24.0/154.5E (approximately 70 nm northeast of Sandy Cape, Fraser Island) while steadily deepening to 1000 hPA. At this time, a ship reported storm-force winds to 50 kts near the centre. B. Synoptic History ------------------- Over the ensuing three-day period, the complex low pressure system drifted quite slowly in a general southerly direction between 50 and 60 nm off the south Queensland coast with new centres periodically forming and being re-absorbed into the overall complex system. This LOW was not a traditional tropical cyclone, but rather a sheared-type hybrid with storm-force winds concentrated around the LOW's southern quadrant. Satellite imagery throughout the life of the subtropical hybrid clearly showed an upper-level cloud structure concentrated to the east and south of the LLCC. At times a large, clear "eye-like" feature could be seen in visible satellite images as the LOW hovered off the south Queensland coast. Occasionally, the deep convection attempted (unsuccessfully) to wrap around the western side of the centre. Two distinct peaks in intensity were observed. The first peak occurred at approximately 04/0600 UTC with the main centre of the LOW (998 hPA) near 27.0S/154.8E. Low-level clouds in satellite imagery depicted a vigorous surface cyclonic circulation with convection along the southern eye wall. There were no observations near the convective areas near the eye, but storm-force winds were reported farther out. BoM estimated that winds of at least 60 kts may have been experienced near the centre at this time. The second peak occurred approximately at 04/2300 UTC with the main centre of the LOW (995hPa) near 27.2S/154.2E. This occurred on Sunday morning local time as the LOW edged slightly towards Brisbane with strong winds induced by cold air northwest of Brisbane producing a strong area of low-level warm air advection south and west of the centre. Most of the wind damage occurred around Brisbane's eastern suburbs and through Moreton Bay at this time. BoM reported high inbound wind speeds in the southern quadrant of up to 55kts. Subsequently the LOW accelerated to the east-southeast at 20 kts away from the coast and started to fill. The final gale warning was issued by BoM at 06/0600 UTC with the LOW (1000 hPA) located near 29.5S/160.0E (approximately 380 nm east of Yamba). The LOW was subsequently captured by the mid-latitude westerlies and accelerated across the Tasman Sea, eventually washing out to the north of New Zealand on 8 March 2006. A graphic depicting the track of this hybrid storm system may be found at the following link: http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-01Q.gif> The operational track in tabular format may be accessed at the following link: http://www.tropicalcyclone2005.com/database/2006/SOHEM/B-TRACKS/2006-01Q-BT.txt> C. Synoptic Observations and Damage Reports ------------------------------------------- The following notes and observations (slightly edited) were provided by BoM: (1) Wind and Wind Damage ------------------------ Maximum 10-min avg reported below: Cape Moreton 53 kts (03/1430 UTC) Double Island Point 49 kts (03/0430 UTC) Spitfire Channel 38 kts (04/2256 UTC) Inner Beacon 37 kts (03/1435 UTC) and (04/2200 UTC) Banana Bank 36 kts (03/1530 UTC) Gold Coast Seaway 36 kts (04/0800 UTC) Point Lookout 53 kts (04/0500 UTC) Ship near 25.1S/154.0E 180/52 kts (03/1200 UTC) Ship near 26.7S/153.7E 180/52 kts (04/0900 UTC) Ship near 26.4S/153.9E 230/55 kts (05/0000 UTC) Wind damage affected many areas in southeastern Queensland. A Counter Disaster and Rescue Service spokeswoman said volunteers had been "flat out" as trees crushed houses and cars. A nursing home at Kirra was evacuated when a tree fell on a unit. No residents were injured. In Brisbane, residents of a unit block in Wooloowin and a house in Chermside were lucky to escape when trees fell on their properties. Traffic accidents kept police busy and one vehicle crashed into a house at St Lucia. Energex staff reported blackouts from 100,000 homes and businesses from Friday morning to Sunday afternoon. At Mt. Tamborine and Bonogin boggy grounds hampered restoration efforts, and in Beaudesert trees and branches continued to damage wires. In Moreton Bay on Sunday, 5 March, boats were damaged and ripped from their moorings. One of these yachts was found later in the week at Noosa Heads. (2) Landslide on Gold Coast --------------------------- A landslide occurred at Burleigh Heads, where about 30 metres of land shifted in a vacant Council allotment, eventually moving towards four nearby villas. (3) Waves and Storm Surge ------------------------- The second highest significant wave height since 1976 was recorded at the EPA's Brisbane wave recording station on Saturday (4 March). Significant wave heights up to 7.2 m were recorded by an EPA wave monitoring buoy located 0.5 nm southeast of Point Lookout, North Stradbroke Island, while individual waves up to 15.0 m (and possibly 16.7 m) were also recorded. Significant wave heights of 5.4 m, 5.3 m and 5.5 m were also recorded respectively at the Sunshine Coast, Gold Coast and Tweed Heads wave recorders. These waves were the second, fifth and third highest wave events at these sites. Severe Beach erosion occurred on the Sunshine and Gold Coasts. On the Gold Coast erosion scarps up to 2 metres formed along the beaches. Waves surged up into walkways and an amount of beach fencing was lost. The Elephant Rock car park was closed, full of sand. Large sections of beach fencing (up to 100 m) were also lost at Miami and Mermaid beaches. A significant storm surge occurred with storm water outlets blocked by surging waves and this caused localised flooding of low lying coastal areas such as Flat Rock Creek and Marine Parade at Kirra. The Mayor of Redcliffe said there was a significant storm surge in Moreton Bay. However, following the issue of the first Severe Weather Warnings, sand bagging was carried out and this prevented large-scale erosion. Significant coastal erosion also occurred on the coastal side of Fraser Island. (4) Rainfall ------------ As the system remained over water, there was not widespread heavy rainfall associated with this event. Some areas received useful rain: 24hrs to 01/2300 UTC ==================== Byfield (Capricornia) 123 mm Samuel Hill (Capricornia) 110 mm Tuan (near Noosa) 75 mm Rainbow Beach 64 mm 24hrs to 02/2300 UTC ==================== Strathmay 113 mm Kingfisher Resort 89 mm Oyster Creek 73 mm Carbrook 71 mm 24hrs to 03/2300 UTC =================== Springbrook 169 mm Tomewin 158 mm Coolangatta 124 mm Tallebudgera 91 mm Gold Coast Seaway 80 mm 24hrs to 04/2300 UTC ==================== Springbrook 92 mm Mt. Nebo 79 mm Tomewin 63 mm Coolangatta 60 mm (Report written by Simon Clarke with significant input by Jeff Callaghan of the Brisbane TCWC) SEVERE TROPICAL CYCLONE LARRY (TD-15F / TC-17P) 16 - 21 March ------------------------------------------------- A. Introduction --------------- Tropical Cyclone Larry was the first cyclone to make a major impact in coastal Queensland in almost twenty years. The last cyclone to cause significant damage was Tropical Cyclone Aivu (1989), and prior to that Tropical Cyclone Winifred (1986). Larry crossed the coastline close to Innisfail at almost the identical location as Winifred twenty years earlier and subsequently cut a swathe of destruction from the coast to the adjacent Atherton Tablelands, eventually producing flooding rains across the Northern Goldfields and Gulf Country of Queensland. A preliminary report on Tropical Cyclone Larry, authored by the Australian Bureau of Meteorology is available on-line at the following URL: http://www.bom.gov.au/weather/qld/cyclone/tc_larry/> B. Storm Origins ---------------- An area of organised convection established itself in the northeastern Coral Sea to the south of the Solomon Islands as early as 16 March. A tropical LOW developed with increasing low to mid- level organisation and flaring convection. Initially, the LOW drifted slowly in a general south-southwesterly direction before turning to the south-southeast and back again to the southwest under the influence of a building upper-level ridge to its southeast. Early stages of development depicted an elongated low-level central circulation with a trough extending west of the low centre out to 300 nm and two complex areas of consolidating convection. The system lay underneath an outflow region in the upper-level subtropical ridge which allowed very weak vertical shear and good outflow in all quadrants. Hence, conditions were favourable for development. The LOW consolidated, and by 17/1800 UTC had deepened to 995 hPa while centered near 16.6S/157.6E, or approximately 680 nm east of Cairns. The system was moving west-southwestward at 15 knots and was officially named Tropical Cyclone Larry. (Editor's Note: At 17/0000 UTC the pre-Larry LOW just reached 160E and was assigned a tropical disturbance number (15F) by RSMC Nadi, but as the system turned back to the west and remained in Brisbane's AOR, the Fiji number is essentially irrelevant.) C. Synoptic History ------------------- The Bureau of Meteorology, Brisbane, issued its first Tropical Cyclone Watch for coastal and island communities between Cape Tribulation and Proserpine at mid-morning on 18 March (local time) as it was clear that the cyclone would indeed move in an almost direct westerly path due to solid mid-level ridging to the cyclone�s south. The cyclone continued to intensify as it approached the coast, benefiting from improved radial outflow and a low shear environment. Hurricane intensity was attained at 19/0000 UTC with 65-kt winds (10-min avg) about 480 nm east of Cairns (approximately 17.7S/151.1E). A ship with the ELZI5 call sign reported ESE 41.7-kt avg winds at both 0900 UTC and 1200 UTC near 18.24S/154.42E and 19S/154.48E, respectively. Larry continued to move westwards at 15 kts to the south of Willis Island where radar and satellite imagery commenced picking up Larry�s well defined eye (see Link 6 below). The eye passed to the north of Flinders Reef where winds of 79 kts from the east were reported at 19/2100 UTC. The cyclone eventually crossed the coastline at Innisfail (17.6S/146.2E) at 19/2030 UTC (at 6:30 AM local time). Two hours previously, the Bureau of Meteorology estimated that it had reached a peak strength of 915 hPa with maximum 10-min avg winds of 115 kts. [Note: This is where Category 5 starts on the Australian Cyclone Severity Scale, which uses peak gusts as its measure rather than sustained winds. This certainly caused confusion in the world-wide media at the time with comparisons to Hurricane Katrina from the previous Atlantic season. However, based on the Saffir-Simpson Scale (which uses 1-minute average sustained winds), Larry would have probably been a low-moderate Category 4 storm by US standards. A complete comparison between the two systems can be found as a special feature within the February, 2006 Summary.] As Larry approached the coast, satellite and radar imagery depicted a significant increase in very strong convection in the northern eyewall as the cyclone made landfall. This convection subsequently wrapped rapidly into the southeast quadrant and came ashore to the south of Innisfail, where some of the most severe damage was observed. The eyewall subsequently malformed as it squeezed its way onto the Atherton Tablelands between Atherton and Ravenshoe. Larry progressively weakened as it tracked overland toward the west- southwest at 30 km/hr (16 kts) for several hundred kilometers, finally losing cyclone status at 20/1530 UTC near Iffley Station (19.0S/141.2E), inland south of the Gulf of Carpentaria. The Bureau of Meteorology continued to issue Severe Weather Warnings as the remnant system moved westward into the Northern Territory. A graphic depicting the track of Severe Tropical Cyclone Larry may be found at the following link: http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-17P-LARRY.gif> The operational track of Larry in tabular format may be accessed at the following link: http://www.tropicalcyclone2005.com/database/2006/SOHEM/B-TRACKS/2006-17P-BT.txt> (C) Observations ----------------- The preliminary BoM Report at the following URL provides the most salient observations recorded with the cyclone and also provides further links to wind and pressure charts: http://www.bom.gov.au/weather/qld/cyclone/tc_larry/> Further observations can be found at the Australian Weather News Website (see Links 6 & 7 below). For the purposes of this report, it is not intended to reproduce any further data here. (D) Preliminary Damage Reports ------------------------------ Similar to Cyclone Ingrid in the previous year, Larry was not only a significant weather event, but also a major media story, not only locally, but globally following on from media focus on the prolonged and damaging Atlantic hurricane season of 2005. However, there was some criticism at the time that many people were not aware that Larry was approaching until a very late stage. Nonetheless, the fact that only 30 people were reported as sustaining minor injuries is a testament to the quality of the warning system in place to deal with such a cyclone. Prior to landfall, evacuation centres were established in communities between Innisfail and Ingham. An official disaster declaration gave authorities the power to legally enforce evacuation if necessary. Hundreds of people were evacuated from the small coastal communities in the cyclone�s path, including tourists holidaying at resorts on Bedarra Island and Dunk Islands. Both Cairns and Townsville airports were closed and all flights in the area cancelled. Ports were closed, with large vessels shifted to sea to ride out the storm. Disaster response teams, thousands of sandbags, and Australian Defence Forces Black Hawk helicopters were positioned to provide assistance when needed. Larry was a relatively small cyclone in size with the most significant wind damage being confined to the stretch of coastline between Cairns and Cardwell, and extending 110 km inland to Mount Garnet to the west. The cyclone caused damage to houses, businesses, infrastructure, crops and forestry totaling at least AUD1.5 billion (USD1.1 billion). The eye of cyclone Larry crossed the coast between Innisfail and Mission Beach, causing widespread and extensive damage to housing, buildings and crops. More than 1000 buildings were damaged by the cyclone, many of which were damaged beyond repair. A breakdown of the structural damage caused by Larry can be found at Link 1. The towns of Babinda and Silkwood bore the brunt of the winds, as they were clipped by the northern and southern portions of Larry's eyewall. More than 120,000 homes lost power during the cyclone with many areas without electricity for several days. More remote areas were without power for several weeks. Road and rail transport was disrupted for several days. The initial cost estimate of damage to crops alone was estimated to be as high as 1 billion (AUS) dollars. Between 90 and 100% of the banana crop in the region, which accounts for 80% of the nation�s supply, was wiped out by Larry. Sugar cane was also flattened in areas in Larry's path, with much of the crop "snapped and ripped out by the roots". The stack on the chimney at Mourilyan Sugar Mill was toppled. Larry crossed the coast at a neap tide, so the significant storm surge and effects of the waves only caused the sea level to exceed highest astronomical tide in a few locations and resulted in only minor salt water inundation. Sea levels exceeded the predicted tide by 1.75 metres at Clump Point, 1.76 metres at Cardwell and 1.54 metres at Mourilyan. As Larry moved inland, heavy rains fell across northwestern Queensland with totals approaching 600 mm in 48 hours in the region to the north of Mount Isa. The rain caused rapid rises to major flood stages and the highest river levels on instrumental record in the Leichhardt River system. In the Flinders River basin to the east, moderate flooding occurred onwards from 25 March. At the time of writing, insurers have reported more than 18,000 claims as a result of the cyclone, and insured losses are expected to exceed AUD350 million (USD225 million). E. Displaced Cassowaries ------------------------ The following news item was obtained from a link to a press release sent to Gary Padgett by Matthew Saxby. A special thanks to Matthew for sending this interesting story. "They have borne Cyclone Larry and weeks of torrential rain, but now the luckless residents of Innisfail face a new dilemma, a posse of hungry marauding cassowaries. The critically endangered and famously testy flightless bird, known for its ability to disembowel humans with its razor-sharp claws, is running amok through the backyards and suburban streets of north Queensland in search of food. "The birds are believed to have left rainforest areas after much of the fruit-bearing plants they depend on were knocked down by Larry's 260 km/h winds. It is expected to be months before the birds' food sources begin to replenish. "Meanwhile, roaming cassowaries are reported to have chased several residents through town. One recently fell into a backyard swimming pool and had to be rescued. The people of Innisfail and surrounds have now been warned not to feed the birds. Queensland Parks and Wildlife rangers have set up food stations throughout the cyclone-affected region to entice cassowaries back into the forests and save them from being hit by cars or chased by dogs. At least six cassowaries have died in the Mission Beach region, south of Innisfail, since the cyclone, all struck by cars. "The birds are vital to the survival of the World Heritage-listed wet tropics rainforest because they are the only animals capable of distributing the seeds of more than 70 species of trees whose fruit is too large for any other forest-dwelling animal to eat and thus relocate. There are less than 1200 cassowaries left in Australia. "Rangers had to remove roadside feeding stations in the weeks after Larry because too many of the endangered birds were being drawn to traffic. Smaller birds found in suburban streets are being relocated into rainforest areas. During the evening, hundreds of flying foxes can also be seen hovering over Gordonvale, south of Cairns. The loss of their regular food sources has led them to raid backyard trees in search of fruit." � (E) Links --------- Link 1--Bureau of Meteorology Official Report: http://www.bom.gov.au/weather/qld/cyclone/tc_larry/> Link 2--Alternative Report, pictures and in depth links: http://en.wikipedia.org/wiki/Tropical_Cyclone_Larry> Link 3--Further satellite imagery: http://earthobservatory.nasa.gov/NaturalHazards/shownh.php3?img_id=13421> Link 4--Satellite Imagery of Larry after landfall: http://earthobservatory.nasa.gov/NaturalHazards/shownh.php3?img_id=13431> Link 5--Larry to the south of Willis Island: http://www.nrlmry.navy.mil/archdat/tropical_cyclones/tc06/SHEM/17P.LARRY/ir/geo/1km/20060319.0930.gms6.x.ir1km.17PLARRY.75kts-967mb-178S-1498E.100pc.jpg> Link 6--Larry - Synoptic and Satellite Details 19 March : http://www.australianweathernews.com/news/2006/060319.SHTML> Link 7--Larry - Synoptic and Satellite Details 20 March: http://www.australianweathernews.com/news/2006/060320.SHTML> Link 8--Complete Radar Loop of Larry: http://australiasevereweather.com/tropical_cyclones/2006/radar/tropical_cyclone_larry.gif> (Report written by Simon Clarke with additions by Gary Padgett) SEVERE TROPICAL CYCLONE WATI (TD-16F / TC-18P) 17 - 28 March ------------------------------------------------ A. Introduction --------------- Wati aroused much interest in Queensland as it emerged from the northeastern Coral Sea on an initial path that was almost identical to that of Cyclone Larry which had just cut a destructive path across Australia's northeastern coastline. As events were to unfold, Wati was eventually swept to the southeast parallel to the Queensland Coast, passing between Lord Howe and Norfolk Islands before crossing the North Island of New Zealand as a powerful extratropical cyclone almost a week later. B. Storm History ---------------- The cyclone was first identified as a westward-moving depression (TD-16F) approximately 325 nm east of the northern tip of Vanuatu as early as 17 March 2006. The depression moved westwards with improving organisation as a result of decreasing vertical wind shear, good equatorial outflow and high SSTs. By 18/1800 UTC, the developing depression rounded the northern tip of Vanuatu before entering the Coral Sea on a 15-kt west-southwesterly track. The depression was upgraded to cyclone status at 19/1200 UTC by the RSMC Nadi and named Wati as deep convection increased and became superimposed over the LLCC. The developing cyclone was located near 15.9S/163.2E (about 300 nm north-northwest of Noumea, New Caledonia) at this time. Wati was initially steered to the west-southwest under the influence of a large subtropical ridge to the south. Early development was somewhat inhibited by the presence of Tropical Cyclone Larry to its east, which restricted outflow on the southern periphery of Wati, which in turn confined favourable outflow to the equatorward direction. As Tropical Cyclone Larry weakened overland, Wati's radial outflow improved and the system intensified under low vertical wind shear conditions. By 21/1800 UTC, the cyclone was located near 17.4S/ 153.7E (approximately 400 nm east of Innisfail) and had attained hurricane status (Severe Category 3 under the Australian Cyclone Severity Scale). At this time Wati entered a weak steering flow environment and become quasi-stationary before eventually being captured by a major shortwave trough digging northwards from near New Zealand. This trough induced a recurvature in Wati's track toward the southeast parallel to the Queensland coast. Peak intensity was achieved at 23/1800 UTC: 950 hPa and maximum 10-min avg winds of 85 kts near 20.3S/157.1E (approximately 460 nm east of Proserpine). Soon afterward, Wati commenced extratropical transition due to increasing vertical wind shear. The cyclone accelerated to the southeast from 6 kts to 16 kts as it slowly lost both its embedded centre and its convective organization due to the increasing northwesterly wind shear. Cold air was advected into the centre and the LLCC became detached to the northwest of the sheared convective cloud mass. By 25/0600 UTC Wati had undergone complete extratropical transition near 28.4S/ 163.3E (approximately 460 nm east of Cape Moreton, Australia). The storm remained a powerful 988-hPa extratropical system at this time with winds estimated to 50 kts. The extratropical Wati passed as close as 150 nm to the west- southwest of Norfolk Island before sliding southwards and then almost due east over the North Island of New Zealand. The system was finally absorbed in the mid-latitude westerlies to the east of New Zealand after 28/0600 UTC. A graphic depicting the operational track of Tropical Cyclone Wati may be found at the following link: http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-18P-WATI.gif> The operational track of Wati in tabular format may be accessed at the following link: http://www.tropicalcyclone2005.com/database/2006/SOHEM/B-TRACKS/2006-18P-BT.txt> (C) Observations and Preliminary Damage Reports ----------------------------------------------- Wati remained an ocean-based storm throughout its life. The main impacts of the cyclone were associated with the high seas and ocean swells generated across the Coral and Tasman Seas. Battering waves and large swells up to 5 metres in height affected the Capricorn and Southern Coast of Queensland from 23 through 25 March. Cyclone watch advisories were issued by BoM Brisbane for Lord Howe Island and cyclone warnings were issued by the BoM Sydney for Norfolk Island. However, Wati tracked almost midway between the islands without causing significant damage to either. Following extratropical transition, Wati maintained much of its energy which was unleashed on the North Island of New Zealand on 26 March, bringing heavy rain and strong winds. The New Zealand Herald reported high school students stranded near Whangaruru on Northland's east coast after being unable to cross the rising Punaruku Stream, 15 nm north of Hikurangi. The 25 students and two teachers were safely rescued without injury. Elsewhere, fallen tree branches caused minor property damage. In the 48 hours to 9 AM on 27 April, totals of 147 mm of rain were recorded in Kaikohe and 143 mm in Kerikeri, with close to 100 mm in many other parts of the region. Northeasterly gales affected exposed parts of Northland on the 26 April with a gust of 76.5 kts recorded at Cape Reinga. (D) Links --------- A satellite image of Wati in formative stages of development can be found at: http://earthobservatory.nasa.gov/NaturalHazards/shownh.php3?img_id=13427> Photographs of large swells on the Gold Coast whipped up by Wati can be found at: http://www.swellnet.com.au/sessions/Gold_Coast_Mar25_01.php> Interesting images of Wati undergoing extra tropical transition at: http://sharaku.eorc.jaxa.jp/cgi-bin/typ_db/data_disp.cgi?lang=e&A2AMS=OFF&P1AME=ON&TRMM=OFF&ym=200603&num=18P> (Report written by Simon Clarke) ************************************************************************* SOUTH PACIFIC (SPA) - South Pacific Ocean East of Longitude 160E Activity for March: 1 tropical depression 1 tropical cyclone of hurricane intensity ** ** - system spent most of its life west of 160E in Brisbane's AOR South Pacific Tropical Activity for March ----------------------------------------- Three tropical depressions were numbered by RSMC Nadi during March. The first of these, Tropical Depression 14F, formed on 13 March over waters between Fiji and New Caledonia. This system formed in a region of fairly high vertical shear and never became well-organized. Deep convection remained sheared well east of the center and winds were never estimated greater than 25 kts. The depression was slow-moving and drifted generally in a southerly direction for 2 or 3 days, the final reference in Nadi's Tropical Disturbance Summaries being at 2100 UTC on the 16th. No track was given for this system in the companion global cyclone tracks file. A system moving eastward from the Coral Sea reached 160E and was numbered Tropical Depression 15F before reversing direction. This depression developed into the intense Severe Tropical Cyclone Larry which dealt a very destructive blow to the Queensland coast. Tropical Depression 16F formed on 17 March northwest of Fiji and began marching westward where it strengthened into Tropical Cyclone Wati near Vanuatu on the 19th. Wati continued westward as it intensified, entering Brisbane's AOR as a 50-kt tropical cyclone at 20/0000 UTC. Since Wati spent most of its lifetime and reached its greatest intensity west of 160E, the report on this cyclone was included in the preceding section of this summary covering the Northeast Australia/Coral Sea basin. ************************************************************************* 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 Monterry 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://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 2004 (2003-2004 season for the Southern Hemisphere). ATCRs for earlier years are available also. The URL is: http://199.10.200.33/jtwc.html> Also, TPC/NHC has available on its webpage nice "technicolor" tracking charts for the 2004 Atlantic and Eastern North Pacific tropical cyclones; also, storm reports for all the 2004 Atlantic and Eastern North Pacific cyclones are now available, as well as track charts and reports on storms from earlier years. The URL is: http://www.nhc.noaa.gov> A special thanks to Michael Bath of McLeans Ridges, New South Wales, Australia, for assisting me with proofreading the summaries. PREPARED BY Gary Padgett E-mail: [email protected] Phone: 334-222-5327 Kevin Boyle (Eastern Atlantic, Western Northwest Pacific, South China Sea) E-mail: [email protected] Simon Clarke (Northeast Australia/Coral Sea, South Pacific) E-mail: [email protected] ************************************************************************* *************************************************************************
Document: summ0603.htm
Updated: 9th July 2006 |
[Australian Severe Weather index] [Copyright Notice] [Email Contacts] [Search This Site] |