====================== TYPHOON '99 ARCHIVES ====================== MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY FEBRUARY, 1999 (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.) TROPICAL CYCLONE REPORTS AVAILABLE I have discovered that JTWC now has available on its new website the complete Annual Tropical Cyclone Report for 1997 (1996-1997 season for the Southern Hemisphere). The URL is: Also, TPC/NHC has available on its webpage nice "technicolor" tracking charts for the 1998 Atlantic and Eastern North Pacific tropical cyclones; also, some of the preliminary storm reports are now available. The URL is: *********************************************************************** FEBRUARY HIGHLIGHTS --> New Caledonia and Queensland suffer cyclone strikes *********************************************************************** ACTIVITY BY BASINS ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico Activity for February: No tropical cyclones *********************************************************************** NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180 Activity for February: No tropical cyclones *********************************************************************** NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180 Activity for February: 1 tropical storm ** ** - This based upon JTWC's classification--JMA and PAGASA did not classify Iris/Bebeng as a tropical storm. NOTE: Most of the information on each cyclone's history presented in the narrative will be based upon JTWC's advisories, and references to winds should be understood as a 1-min avg MSW unless otherwise noted. However, in the accompanying tracking document I have made comparisons of coordinates with JMA (Japan) and the Philippines (PAGASA) when their positions differed from JTWC's by usually 40-50 nm or more. Also, as announced earlier in a separate posting, a column of 10-min avg MSW is included--the values being obtained from either PAGASA's or JMA's advisories. A special thanks to Michael V. Padua, owner of the Typhoon '99 webpage, for sending me the PAGASA tracks. In the title line for each storm I plan to reference all the cyclone names/numbers I have available: JTWC's depression number and name (if any), JMA's tropical storm numeric designator, and PAGASA's name for systems forming in or passing through their area of responsibility. Tropical Storm Iris/Bebeng (TC-02W) 15 - 19 February ------------------------------------ The second weak tropical storm to form in the Northwest Pacific in 1999 can be traced to an area of convection which developed between Pohnpei and Chuuk on 10 Feb. The disturbance appeared to be a tropical wave propagating toward the west as it very slowly became better organized. JTWC issued the first of three Formation Alerts at 2330 UTC on 13 Feb when the disturbance was approaching the Palau area. The system had the characteristics of a large monsoon depression when PAGASA initiated advisories at 15/0000 UTC, naming it Bebeng. Tropical Depression Bebeng was then located about 225 nm north- northeast of Palau and had been quasi-stationary for a couple of days. The depression began drifting westward, slowly increasing in convective organization. JTWC initiated depression advisories at 16/0000 UTC when the broad center was estimated to be about 275 nm north-northwest of Palau. There was evidence of multiple circulation centers and the depression was undergoing light to moderate vertical shear. At 0300 UTC on 17 Feb the center was re-located to the south based on visible imagery. This placed the low-level center under the deeper convection and JTWC upgraded the depression to Tropical Storm Iris with 35-kt MSW at this time. Iris' center was estimated to be about 325 nm northwest of Palau. The 17/0900 UTC warning from JTWC noted that Iris had developed an anticyclone and outflow appeared to be good. However, six hours later vertical shear had increased and Iris appeared to be weakening with multiple circulation centers apparent. As it began to weaken Iris/Bebeng slowly turned to the northwest east of the central Philippines. During its dissipation stages intense convection would occasionally fire up but the low-level center became increasingly disorganized. By 19/0000 UTC the low-level circulation center had been absorbed into a pre-existing cyclonic environmental shear zone and Iris/Bebeng was declared dissipated about 300 nm east of Manila. *********************************************************************** NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea Activity for February: 1 tropical cyclone of gale intensity NOTE: The tracking and intensity information for North Indian Ocean Basin tropical cyclones is based primarily upon operational warnings from the Joint Typhoon Warning Center of the U.S. Air Force and Navy (JTWC) at Pearl Harbor, Hawaii. For weaker systems not in warning status by JTWC, information gleaned from the twice-daily issuances of the Indian Meteorological Department (IMD) was used to complete the tracks. These bulletins usually give analyzed center positions at either 0300 or 0600 UTC and 1200 or 1500 UTC. The MSW are based on a 1-min averaging period, which is used by all U.S. civilian and military weather services for tropical cyclone warnings. For synoptic observations in the North Indian region, both 10-min and 3-min average winds are employed, but IMD makes no attempt to modify the Dvorak scale for estimating tropical cyclone intensity; hence, a 1-min avg MSW is implied. In the North Indian basin JTWC usually does not initiate warnings until a system is well-organized and likely to attain tropical storm status within 48 hours. Tropical Cyclone (TC-01B) 1 - 5 February -------------------------- The 1999 tropical cyclone season in the North Indian Ocean got off to a very early start with a rare February cyclone. The system can be traced back to a disturbed area in the south-central Bay of Bengal first mentioned by JTWC on 27 Jan. The weak LOW drifted west- northwestward over the succeeding days and gradually became better organized. JTWC issued a Formation Alert at 0400 UTC on 31 Jan with a second Alert issued 24 hours later. The first warning from JTWC, issued at 0900 UTC on 2 Feb, located a 35-kt tropical cyclone about 325 nm east-northeast of Colombo, Sri Lanka, at 0600 UTC. Strongest winds were in the western half of the storm due to asymmetric convection and the storm's forward translational effects. The cyclone, which had been moving west-northwestward due to the steering effects of a subtropical ridge located to its northeast, began to turn to the north-northwest as a trough moved through India. The MSW reached a peak of 40 kts at 03/0600 UTC when the system was centered about 275 nm east-southeast of Madras, India. Winds ahead of the trough began to induce shearing over the tropical cyclone, causing it to begin weakening. JTWC issued the final warning at 2100 UTC on 4 Feb, locating the low-level center, now devoid of any deep convection, about 225 nm east-southeast of Madras. *********************************************************************** SOUTH INDIAN OCEAN (SIO) - South Indian Ocean West of Longitude 90E Activity for February: 1 tropical disturbance 1 tropical depression 1 moderate tropical storm The primary sources of information upon which the narrative is based are the warnings issued by the TCWC on La Reunion Island, associated with Meteo France, and which is the RSMC for the South Indian Ocean basin. However, cyclones in this region are named by the sub-regional centres on Mauritius and Madagascar with longitude 55E as the dividing line between their respective areas. La Reunion only advises these centres regarding the intensity of tropical systems. References to sustained winds should be understood as meaning a 10-min averaging period unless otherwise stated. In the accompanying track file some position comparisons have been made with JTWC's positions, and warnings from JTWC were used as a source of 1-min avg MSW estimates. (A special thanks to Philippe Caroff of the La Reunion TCWC for sending me an analyzed Best Track File for Chikita and Tropical Depression D19899. This data forms the basis for the tracking information given for these systems in the accompanying track file.) Tropical Storm Chikita (TC-17S) 29 January - 5 February -------------------------------- JTWC began mentioning a disturbed area north of Cocos Island (in the Australian Region) in their Tropical Weather Outlooks as early as 24 Jan. During the following days the disturbance drifted generally southwestward. By 1200 UTC on 29 Jan the poorly-defined center was estimated to be about 175 nm southwest of Cocos. On 30 Jan the LOW began to move at an accelerated pace westward and intensified. JTWC issued the first warning at 31/0000 UTC with MSW (1-min) estimated to be 30 kts. The depression continued to organize rapidly and was named Chikita by the Mauritius TCWC at 1200 UTC. Chikita's center was then located about 850 nm west-southwest of Cocos and MSW were estimated at 37 kts, which was the highest during the storm's lifetime. (JTWC's peak 1-min MSW of 40 kts is in close agreement with the Best Track value from La Reunion.) The JTWC warning issued at 31/0900 UTC reported some ship observations of winds to 35 kts. Tropical Storm Chikita sailed rapidly westward to west-southwestward at speeds of nearly 20 kts at times, following in the tracks of Damien/Birenda. After the initial rapid intensification, however, the storm did not strengthen any further, and slowly began to weaken. Chikita passed about 40 nm north of Rodrigues Island early on 3 Feb as either a strong depression or a minimal tropical storm. Rodrigues (which belongs to Mauritius) reported maximum wind gusts to 50 kts when the center was nearest. Rodrigues, which had been experiencing drought conditions, had some very welcome rainfall from Chikita. Coastal stations recorded around 75-80 mm while one location in the hills measured 113 mm. The low-level center had become exposed by this time, but Chikita's windfield remained strong, especially on the south side, due to the rapid forward motion even after most of the convection had decreased. Winds to gale force extended out only 30 nm to the north but out to 200 nm to the south. The weakening system passed around 100 nm north of Mauritius and La Reunion on 4 Feb and was dissipating off the east coast of Madagascar by 0600 UTC on 5 Feb. Mauritius reported peak wind gusts around 38-40 kts, while on La Reunion, gusts to 44 kts were experienced on the northern and southern coasts. A gust to 57 kts was recorded on the volcano La Fournaise at an elevation of 2250 m. On Mauritius an average rainfall of 86 mm in 24 hours was recorded on the 4th with a maximum of 160 mm measured at Mare-Aux-Vacoas, a reservoir in the southwestern portion of the island. Like Rodrigues, Mauritius had been experiencing a drought so the rainfall was very welcome. (Thanks to Arvind Mungur of London for passing along this information he'd gleaned from _L'Express_, a local daily newspaper.) On La Reunion Chikita brought the first episode of heavy rainfall since mid-December with the heaviest amounts falling in a 6-hour period early on 4 Feb before the remnant of Chikita made its closest approach. However, the rain continued for more than 48 hours so that significant amounts were recorded: . maximum of 119 mm in 48 hrs at Saint-Benoit (eastern coast) with 73 mm during the first 6 hrs . 100 mm at Saint-Denis (main city on the north coast) . more than 200 mm in 48 hrs over the central and eastern heights . maximum of 436 mm at Bellecombe's lodging (elevation 2250 m) with 132 mm during the first 6 hrs (Thanks to Philippe Caroff of the La Reunion TCWC for sending me the wind observations and rainfall amounts for Rodrigues and La Reunion.) Tropical Depression "D1" (TC-21S) 11 - 17 February ---------------------------------- This system, classified as a tropical depression by Madagascar but carried as a tropical storm by JTWC, formed and remained in the Mozambique Channel throughout its existence. The Mozambique Channel has indeed been a "hot spot" of development for the South Indian Ocean since early January with two systems forming in January and two in February. A weak LOW was mentioned by La Reunion just off the coast of Mozambique near Quelimane on 11 Feb. The system drifted slowly southward in the Channel for a couple of days, slowly becoming better organized. JTWC began issuing warnings at 1500 UTC on 13 Feb when the depression was located in the southern portion of the Channel east of the southern Mozambique coast. JTWC's estimated peak MSW (1-min) was 45 kts on 14 Feb, based in part on ship synoptic observations of 35 kts. The maximum sustained 10-min avg winds reported by the La Reunion TCWC were 33 kts at 14/1800 UTC--just under tropical storm strength. The system drifted slowly to the east-northeast on 14-15 Feb as it reached its peak intensity, then turned back to the north as it weakened. By the 15th about all the convection had been sheared away, although the low-level center was still well-organized. The weakening system continued north-northwestward and had dissipated near its point of origin by 17 Feb. Tropical Disturbance "D2" (TC-23S) 23 February - 4 March ----------------------------------- The second disturbance of the month to form in the Mozambique Channel was first mentioned by JTWC in a Tropical Weather Outlook on 21 Feb. The system had moved offshore into the Channel and was associated with the tail end of a passing shear line. La Reunion began issuing bulletins on 23 Feb, locating a weak LOW just off the Mozambique coast south of Beira. Over the succeeding days the disturbance remained quasi-stationary with MSW estimated at 25 kts. The LOW was classified as a subtropical cyclone on 25 Feb but designated as a tropical disturbance on 26 Feb as central convection increased. The system began to move at a slightly increased pace to the east- southeast on 27 Feb. JTWC initiated warnings at 1500 UTC on the 27th but never upgraded the LOW to tropical storm intensity. The warning indicated that the system appeared to be embedded in a frontal zone and tracking off to the southeast. By 28/1500 UTC most of the convection had been sheared away to 90 nm east of the low-level center. For some reason of which I am not totally sure of the cause, I was unable to access any bulletins from La Reunion between 28/0600 UTC and 0000 UTC on 4 Mar. JTWC's last warning at 0600 UTC on 1 Mar placed the center about 100 nm south of Tulear on the southeast coast of Madagascar and accelerating to the southeast. However, I began receiving La Reunion's releases once more at 0000 UTC on 4 March and discovered that they were still issuing bulletins on Tropical Disturbance "D2", and that it was back in the Mozambique Channel, just off the African coast and near its point of origin. The disturbance continued drifting northward and was last located near the Mozambique coast north of Beira at 04/1800 UTC. (After Tropical Storm Davina was named in the central Indian Ocean on the 4th, bulletins on this system were re-designated as "E1"--indicating that the next storm name would begin with the letter "E" and that this was the first disturbance to be in existence after the "D" name had been allotted.) *********************************************************************** AUSTRALIAN REGION (AUG) - From Longitude 90E Eastward to Longitude 160E Activity for February: 1 tropical LOW (depression) 1 tropical cyclone of storm intensity The primary sources of information for Australian Region tropical cyclones are the warnings and bulletins issued by the three TCWC's at Perth, Darwin, and Brisbane. Information gleaned from JTWC's warnings is used as a supplement for times when it was impossible to obtain Australian bulletins and for comparison purposes. Additionally, some information came from the Monthly Report of the RSMC at Darwin, Northern Territory. References to sustained winds should be understood as being based on a 10-min averaging period unless otherwise noted. Mr. Matthew Saxby, a tropical cyclone enthusiast from Queanbeyan, New South Wales, Australia, is going to assist me with collecting information and preparing tracks for tropical cyclones in the Australian Region. Some of the information contained in the narratives is based upon information forwarded to me by Matthew. A special thanks to Matthew for his assistance. Tropical LOW (TC-18S) 31 January - 14 February ------------------------ A weak tropical disturbance south of Java was mentioned by both JTWC and Perth in their daily Tropical Weather Outlooks beginning around the end of January. Perth began issuing bulletins on the system at 2200 UTC on 3 Feb when it was centered about 250 nm north of Port Hedland, Western Australia. JTWC initiated warnings on the LOW at 2100 UTC on 4 Feb. The depression moved west-southwestward through around 1000 UTC on 5 Feb, then turned to more of a west- northwesterly course at a slower pace. Perth issued the final warning at 06/2200 UTC when the LOW was centered about 500 nm south- southeast of Christmas Island. JTWC continued issuing warnings through 09/0000 UTC as the system slowly weakened. A residual LOW remained quasi-stationary in the general area for several more days. This tropical LOW experienced vertical shear throughout most of its life. An upper-level anticyclone over Western Australia supplied easterly shear which kept the convection sheared to the western side of the circulation. Gales on the western side of the circulation did accompany this depression, but in accordance with the definition of a tropical cyclone utilized by WMO Region 5, the system was not classified as a tropical cyclone and named. On the 6th scatterometer data indicated winds of 35-40 kts out to 120 nm southwest of the low- level center which was fully exposed about 90 nm northeast of the nearest convection. By the 7th most of the deep convection had dissipated due to increasing vertical shear and cold-air stratus entrainment. Tropical Cyclone Rona (TC-20P) 8 - 12 February ------------------------------- A tropical LOW persisted for several days in the Coral Sea, near the Cape York Peninsula, during the second week of February. Upper- level conditions became favorable for tropical development, and the system began to intensify quite rapidly on 10 Feb, becoming Tropical Cyclone Rona at 1800 UTC. Both JTWC and Brisbane initiated warnings at the same time, locating Rona about 175 nm east of Cooktown on the Queensland coast. Rona initially moved southward, but soon turned to the west-southwest under the steering influence of a subtropical ridge to the southeast of the cyclone. The storm also accelerated somewhat to a forward translational speed of about 10 kts by the time it reached the Queensland coast. By 11/0300 UTC synoptic data indicated that 35-kt winds were already occurring just offshore near Cape Bowling Green. Tropical Cyclone Rona continued to intensify until the eye made landfall just north of the resort town of Port Douglas around midnight on 11-12 Feb. Just how intense did Rona become? The peak 10-min MSW reported by Brisbane was 60 kts at 11/1200 UTC. However, the Tropical Cyclone Advices had Rona classified as a Severe Tropical Cyclone (i.e., a hurricane), and the peak estimated gusts of 180 km/hr, when reduced to 10-min MSW by the standard reduction factor of 1.4, yields a MSW of 70 kts. With an attendant estimated central pressure of 970 mb, it seems likely that Rona perhaps did reach hurricane intensity shortly before making landfall. The JTWC warning at 11/2100 UTC estimated that peak winds (1-min MSW) reached 65 kts just prior to landfall. After making landfall, Rona weakened but the remnants hung around in the coastal area for a few days, then drifted southward and eastward back out into the Pacific. The renmant LOW subsequently moved eastward and re-intensified, becoming Tropical Cyclone Frank in the Fiji AOR. For a description of Tropical Cyclone Frank, see the portion of this summary covering the Southwest Pacific Basin. (NOTE: This Rona/Frank connection is based upon information taken from the Monthly Tropical Diagnostic Statement from the Darwin TCWC. JTWC continued tracking Rona's remnants westward south of the Gulf of Carpentaria. However, it seems likely JTWC may have been tracking the upper-level circulation while the low-level center remained near the coast. The JTWC warning from 11/2100 UTC makes the observation: "TC-20P (Rona) has slowed rapidly as it moved into the Great Dividing Range Mountains. Satellite animation shows the convection weakening and continuing across the mountains, but synoptic data indicates the low-level circulation remains caught up in the mountain range.") Although the eye moved inland just north of Port Douglas, newspaper accounts stated that Cow Bay, an idyllic resort about 125 km north of Port Douglas, took the brunt of the storm. Two houses were flattened, 12 others damaged, and a car crushed by a falling tree. Flooding was a major concern, extending as far south as Ingham. About 2000 people were evacuated from their homes near Cairns and Innisfail due to rain-swollen streams. Highest 24-hour rainfall totals ending at 2200 UTC on 11 Feb were: Topaz - 531 mm; Greenhaven - 474 mm; Kuranda - 420 mm; Cardwell - 369 mm; Ravenshoe - 354 mm; and Tully - 340 mm. Roads were cut in many districts, and powerlines were down across a wide area. Two potential marine disasters were narrowly averted. A 40-m tourist vessel, Atlantic Clipper, was caught at sea and rode out the cyclone with a crew of 13 and 26 passengers. Two elderly sailors were rescued by helicopter from an isolated beach on South Molle Island in the Whitsundays after their yacht hit rocks in the huge seas. The Darwin Monthly Report mentions six fatalities due to the flooding caused by Rona. Matthew Saxby, however, reports that he monitored news accounts of the cyclone and heard of no fatalities mentioned in connection with the cyclone. He did hear of six deaths due to flooding on the evening (Australian time) of 10 Feb, but Rona was only a fairly weak depression at that time. Perhaps this discrepancy can be clarified later, and if so, will be reported on in a future summary. There was a lot of flooding occuring in portions of Queensland due to a couple of LOWS (possibly subtropical or hybrid storms) which had struck the coast farther south in the days preceeding Rona. As far as agricultural losses go, the principal crop affected was sugarcane. Cyclone Rona flattened cane crops between Mossman and Townsville--a region which grows one-third of the state's sugarcane. Winds gusting to 55 kts played havoc with the cane stalks (up to 3 m in height), leaving them a tangled and matted heap. Other crops hit hard by the high winds and torrential rains were bananas and papaws. Banana farms around Innisfail, Tully, and Mission Beach sustained major damage. Much of the information presented above was taken from newspaper accounts mailed to me by Matthew Saxby. A very special thanks to Matthew for sending me the clippings. *********************************************************************** SOUTHWEST PACIFIC (SWP) - South Pacific Ocean East of Longitude 160E Activity for February: 1 tropical depression 2 tropical cyclones of gale intensity 1 tropical cyclone of hurricane intensity NOTE: Most of the information presented below was taken from the operational warnings and advisories issued by the Fiji TCWC at Nadi and from the Monthly Summary for February prepared by Alipate Waqaicelua, Principal Scientific Officer and Chief of the forecasting group. A special thanks to Alipate for sending the summary to me. Also, a special thanks is due Steve Ready of the New Zealand Meteorological Service for forwarding to me some damage reports on Tropical Cyclones Ella and Frank which he had received from Claude Gaillard, the Director of Meteo France in New Caledonia. References to sustained winds imply a 10-minute averaging period unless otherwise noted. Also, the basic definition of a cyclone in WMO Region 5 (Australia and the South Pacific) has the unique requirement that a depression must have gale-force winds more or less completely surrounding the center before the system is named as a tropical cyclone. Hence, often gales of 35-40 kts may be present in one or two quadrants but the system is not considered a tropical cyclone. Fiji this season has initiated their own numbering scheme for tropical disturbances (01F, 02F, etc) that form in the Nadi AOR. Some of the numbered disturbances never warrant depression status. Numbers 11F, 12F, 13F, and 15F were all weak, short-lived tropical disturbances occurring over the first half of February which did not reach tropical depression status. Tropical Cyclone Ella (TC-14F / TC-19P) 9 - 14 February ---------------------------------------- JTWC mentioned a LOW in their Tropical Weather Outlook at 0600 UTC on 9 Feb located near 13S, 160E, or about 75 nm south-southwest of Rennell Island, the southernmost island in the Solomon group. The LOW was located in a monsoon trough, and a better-defined center had consolidated farther to the north by 10/0000 UTC. JTWC and Nadi both initiated bulletins on the system at this time, placing the center about 35 nm north of Rennell Island. The depression drifted slowly eastward for a day or so, passing just south of San Cristobal Island, then turned to the southeast and began to intensify. Nadi named the system Tropical Cyclone Ella at 0400 UTC on the 11th when it was well southeast of San Cristobal. After reaching cyclone intensity Ella turned to more of a southerly to south-southeasterly course and accelerated. Tropical Cyclone Ella passed about 100 nm west of the northern tip of the Vanuatuan island of Espiritu Santo around 1500 UTC on 11 Feb. The cyclone reached its peak intensity of 45 kts also about this time. An area of strong subsidence to the south of Ella and a southerly flow entrained drier air into the system which hindered its development. Also, as a subtropical ridge to the east steered Ella quickly southward, the cyclone moved into an area of increasing vertical wind shear. By early on 12 Feb the low-level center had become exposed, but later in the day moved back under some deep convection and re-intensified slightly. This was reflected in the MSW estimates by both JTWC and Nadi. Ella passed about 175 nm west of Port Vila, Vanuatu, at 12/0000 UTC and continued on rather quickly to the south-southeast. The cyclone passed through the Loyalty Islands lying to the east of New Caledonia; passing over Ouvea around 1200 UTC and brushing the west coast of Lifou a few hours later. Ella passed about 60 nm east-northeast of Noumea around 1800 UTC and continued on southeastward, slowly weakening. The storm was declared extratropical by Wellington at 0000 UTC on 14 Feb when it was located about 200 nm northeast of Norfolk Island. Tropical Cyclone Ella was moving at about 20 kts when it passed through the Loyalty Islands. The estimated MSW at the time was 40 kts, but the rapid translational motion augmented the winds on the lefthand side of the storm. Lifou recorded a maximum 10-min wind of 46 kts at 12/1314 UTC with a peak gust of 65 kts. Some significant damage was sustained by buildings and vegetation on the northern side of the island of Lifou, but no casualties or fatalities have been reported. Tropical Cyclone Frank (TC-16F / TC-22P) 16 - 23 February ----------------------------------------- Tropical Cyclone Frank had its origin in the Australian Region, being a re-development of Tropical Cyclone Rona which had wreaked havoc along the Queensland coast on 11 and 12 February. (See the section of this summary covering the Australian Region for a description of Rona.) After Rona weakened over the Queensland coast, its remnant low- to mid-level circulation tracked southward, re-emerging over water and then tracking to the east. By 0600 UTC on 17 Feb the LOW was located about 300 nm east-northeast of Rockhampton and moving eastward. By 18/1800 UTC the system had just crossed into Fiji's AOR and had been named Frank. The cyclone was centered at that time about 350 nm west-northwest of Noumea. Steered by a mid-level ridge to its north, Frank continued on a more or less due easterly course towards the northern tip of New Caledonia and intensified. The cyclone reached hurricane force just about the time it struck the extreme northern tip of the island around 1800 UTC on 19 Feb. As a ridge to the east began to build and with a trough approaching from the west, Frank turned to a south- easterly course which took the center skimming along the eastern coast of New Caledonia. Frank reached its estimated peak intensity of 80 kts (100 kts 1-min MSW from JTWC) around 20/0000 UTC. Even though very near the coast, the eye became much better defined. After moving about halfway down the island, the cyclone turned to the south and crossed right over the middle of the island, passing a short distance to the west of Noumea around 20/1200 UTC. After crossing over New Caledonia, Tropical Cyclone Frank began to weaken due to the influence of increased northwesterly shear and cooler SSTs. Fiji had downgraded Frank from hurricane force to storm force by 20/2100 UTC, but JTWC kept the cyclone at hurricane strength through 21/1800 UTC. By 0600 UTC on the 21st the low-level center was fully exposed about 25 nm from the nearest deep convection. Ship synoptic reports indicated that a broad 35-kt wind field existed southeast to southwest of the cyclone. Frank turned to the southwest after crossing New Caledonia, and warning responsibility was passed to Wellington after 0600 UTC on 21 Feb. Wellington declared the storm extratropical at 1800 UTC that day, but JTWC continued to issue warnings through 23/0000 UTC, tracking the storm westward and then curving to the south-southeast. The final JTWC warning located the extratropical center about 275 nm west of Norfolk Island. Frank possessed a very small radius of damaging winds, which meant that Noumea experienced relatively light winds, even though the centre of the cyclone passed only about 15 nm to the west. Some townships in the north and west end of New Caledonia suffered power outages, disruption to water supply and telecommunications, and there were some landslides on coastal roads. Flooding caused some crop damage in the northeast portion of the island, but there were no casualties or serious damage to the infrastructure. After the cyclone, Meteo France in New Caledonia alleged that the actual maximum wind speeds were much lighter than the estimates provided by Fiji and JTWC--that the highest MSW was closer to 65 kts (Fiji's highest estimate was 80 kts--JTWC's was 100 kts 1-min avg). Presumably this was based upon actual measurements from La Grande Terre (New Caledonia's largest island) or else inferred from the observed damage. But it should be pointed out that the island was on the righthand (weaker) side of the storm with respect to its direction of motion. With the translational speed being about 10 kts, the MSW in the left semicircle could have easily been 15-20 kts higher than in the right semicircle, especially considering that a substantial portion of the right half of the cyclone's circulation lay over the mountainous landmass. Tropical Depression (TD-17F) 18 - 19 February ----------------------------- A weak tropical depression was first identified on surface charts at 17/1200 UTC, embedded along a monsoon trough over the southern parts of Fiji and moving slowly eastward. By 0000 UTC on 18 Feb the LOW was turning more to the southeast but had not become any better organized. After 18 hours had elapsed some organization was beginning to appear when the depression was just south of Tongatapu. Convection associated with the system increased slightly but under increasing shear. The first marine warning was issued at 2100 UTC, warning of gales in the southern semicircle since it was moving into a surface ridge to the south. The depression moved off to the southeast and the final warning was issued at 19/1200 UTC when it was approaching Wellington's AOR. Tropical Cyclone Gita (TC-18F / TC-24P) 27 February - 2 March ---------------------------------------- At 0000 UTC on 25 Feb a shallow depression was located just north of the Southern Cooks, drifting slowly southward and embedded in the SPCZ. Convection was quite disorganized though low-level cloud lines were visible under the thick cirrus outflow, curving into the estimated low-level center. The disturbance at this time was located in a fairly strong shearing environment, but after 1800 UTC the upper-level situation began to change to a slightly more favorable one, with diffluence increasing and a weak ridge developing over the system. By 26/1200 UTC curved convective bands were beginning to form with the overall organization greatly improved as the LOW moved out of the Southern Cooks towards the southeast. At 27/0000 UTC Dvorak classifications from Honolulu had reached a weak T3.0, so Nadi issued the first gale warning but with gales forecast only in the southeastern semicircle. The depression at this time was centered about 175 nm southeast of Mangaia or about 275 nm southeast of Rarotonga. Another gale warning was issued 6 hours later as the system was nearing the border of the Wellington AOR. By 1200 UTC the system was clearly a tropical cyclone but had moved out of Fiji's AOR. For procedural/policy reasons, it was named Gita belatedly after it had entered Wellington's AOR. (The monthly summary from Alipate states that, in retrospect, the system should have been upgraded to a tropical cyclone at 27/0000 UTC.) Tropical Cyclone Gita continued south-southeastward into the "no man's land" of the South Pacific, reaching an estimated peak intensity of 45 kts by 0600 UTC on 28 Feb. Although Gita was downgraded to an extratropical gale by 28/1800 UTC, it continued to display significant central convection until after 0600 UTC on 1 Mar. Atypical of most tropical cyclones in this part of the South Pacific, Gita was not picked up by a westerly trough and accelerated into higher latitudes. In a relatively weak shearing environment with gradually cooling SSTs, the cyclone spun down slowly, continuing to generate some convection near the center until 2 Mar. This sort of slow "spin down" is often seen in Eastern North Pacific tropical cyclones which move out over cooler waters, protected from the westerlies by a ridge to the north. NPMOC issued only two warnings on Gita, with the highest estimated 1-min MSW being 35 kts; but Dr. Mark Lander of the University of Guam, unaware that any agency was issuing warnings on the cyclone, posted a couple of reports to an e-mail discussion list. Mark's estimated MSW (presumably 1-min avg) was 50 kts, in excellent agreement with Wellington's 45-kt MSW (10-min avg). A good bit of discussion ensued, especially concerning at what point should Gita have been called extratropical. TPC/NHC (and presumably JTWC also) usually does not classify a tropical cyclone as extratropical until it has merged with a distinctive baroclinic zone. Regarding the Eastern North Pacific cyclones which spin down slowly over cooler waters, TPC/NHC normally carries these as tropical depressions until they have been reduced to a swirl of low clouds with no convection and little hope of re-generation. Steve Ready of the New Zealand Meteorological Service, in an e-mail message, stated that likely the decision to downgraded Gita to an extratropical gale was premature, but that marine warnings were continued through 0500 UTC on 3 Mar for the benefit of any "not-so-ancient" mariners (Steve's expression) who might have been in the vicinity. According to Steve it is very rare in the South Pacific for a tropical cyclone to be carried as such after it has crossed 30S. In New Zealand, if and when any tropical cyclone (or one which has recently transformed into an extratropical cyclone) threatens, the word "tropical" is dropped and the system is referred to as Cyclone "So-and-so". This enables the weather service to highlight the origin of the storm and to raise the level of public response. *********************************************************************** 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 included in the July summary. I will include this glossary from time to time, primarily in "lean" months without a lot of tropical cyclone activity to cover. But if anyone missed receiving it and wishes to obtain a copy, send me an e-mail privately and I'll forward 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 in the following manner: (a) FTP to: hrd-type42.nhc.noaa.gov [140.90.176.206] (b) Login as: anonymous (c) For a password use your e-mail address (d) Go to "data" subdirectory (Type: cd data) (e) Set file type to ASCII (Type: ascii) (f) Transfer file (Type: get remote_file_name local_file_name ) (The files will be named with an obvious nomenclature--using February as an example: feb99.tracks) (g) To exit FTP, type: quit 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. If anyone wishes to retrieve any of the previous summaries, they may be downloaded from the aforementioned FTP site at HRD. The summary files are catalogued with the nomenclature: feb99.sum, for example. Back issues can also be obtained from the following websites (courtesy of Michael Bath, Michael V. Padua, Tom Berg, and Michael Pitt): 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: Prepared by: Gary Padgett E-mail: garyp@alaweb.com Phone: 334-222-5327 (nights & weekends) / 850-882-2594 (weekdays) *********************************************************************** *********************************************************************** Uploaded: 12:22 PM 4/21/99