MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY JANUARY, 2000 (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.) NOTE: The January summary is being issued in two installments. The first installment, covering the Australian Region and the South Pacific, was disseminated on 6 March. This second installment covers the Southwest Indian Ocean basin *********************************************************************** JANUARY HIGHLIGHTS --> Intense cyclone threatens Southwest Indian Ocean islands --> South Pacific sees first cyclones of season *********************************************************************** ACTIVITY BY BASINS ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico Activity for January: No tropical cyclones *********************************************************************** NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180 Activity for January: No tropical cyclones *********************************************************************** NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180 Activity for January: No tropical cyclones *********************************************************************** NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea Activity for January: No tropical cyclones *********************************************************************** SOUTH INDIAN OCEAN (SIO) - South Indian Ocean West of Longitude 90E Activity for January: 1 tropical disturbance 1 tropical depression (from December) 1 tropical cyclone 1 intense tropical cyclone 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. Also, the comments about satellite imagery and other sources of data such as SSM/I and TRMM were obtained for the most part from the JTWC warnings. A special thanks to Philippe Caroff of the La Reunion TCWC for sending me information on the tropical disturbance #03, and a special thanks to Patrick Hoareau and Jean Marc de Maroussem for passing along some observations from Mauritius and Reunion during the approach of Tropical Cyclone Connie. South Indian Ocean Activity for January --------------------------------------- After getting off to a rather late start (in late December), the tropical cyclone season in the South Indian Ocean became significantly more active during the month of January. Babiola became the first actual tropical cyclone (hurricane force) in the region, and Connie became an intense tropical cyclone and threatened the islands of Mauritius and La Reunion. As the month opened, Tropical Depression Astride (formerly a tropical storm) was still present in the Mozambique Channel. (See the December summary for a full report on Tropical Storm Astride.) In addition to Babiola and Connie, disturbed weather persisted in the Mozambique Channel for a couple of weeks starting just before mid-month. Meteo France on Reunion Island (MFR) issued a couple of bulletins on this system on 12 and 13 Jan, numbering it as disturbance #03. JTWC mentioned the area in its STWOs for a few days, but dropped it on 16 Jan. Beginning on 22 Jan JTWC once again began mentioning an area of convection in the Channel with an associated partially-exposed LLCC. MFR issued a single bulletin at 0600 UTC on 24 Jan, referring to the disturbance as #03 once more, so apparently there was possibly some connection between this flare-up and the earlier disturbance. JTWC continued to monitor the disturbance through 26 Jan when it had weakened significantly. I have attempted to piece together a track for this system in the companion tracks file. Finally, a new disturbance/depression formed at the end of the month and was christened Tropical Storm Damienne on 1 Feb. A report on the short-lived Damienne will be included in the February summary. Tropical Cyclone Babiola (TC-04S / SIO #02) 3 - 12 January -------------------------------------------- A STWO issued by JTWC on 1 Jan indicated that an area of convection with an associated very weak LLCC had formed approximately 130 nm south-southeast of Diego Garcia. Over the next couple of days the disturbed area drifted eastward and by 3 Jan was located about 650 nm east-southeast of Diego Garcia. MFR began issuing bulletins on the developing disturbance at 0600 UTC. Animated visible satellite imagery and scatterometer data indicated weak vertical shearing over the disturbance and animated water vapor imagery indicated fair outflow. JTWC issued the first of three Formation Alerts at 1630 UTC, noting that there had been a significant increase in the areal coverage of convection. SSM/I data revealed deep convection developing around the eastern and southern sides of the LLCC. JTWC issued a second Formation Alert at 04/1430 UTC and a third one on 5 Jan at 1430 UTC. The disturbance had continued to drift slowly eastward (or quite possibly a new center had formed) during this time. The first JTWC warning, issued at 05/1800 UTC, placed the center of the system almost 700 nm east-southeast of Diego Garcia and moving southwestward at 9 kts. The MSW (1-min) was estimated at 35 kts, and convection was consolidating around the LLCC. The system was forecast to track southwestward under the influence of a low- to mid-level subtropical ridge to the south-southeast. MFR upgraded the developing LOW to a tropical depression six hours later with 30-kt winds (10-min avg), and Moderate Tropical Storm Babiola was christened at 0600 UTC on 6 Jan, located about 625 nm east-southeast of Diego Garcia. At 1800 UTC Babiola's intensity was holding steady at 35 kts (45-kts 1-min avg from JTWC) with the LLCC displaced somewhat to the east-southeast of the primary convection. On 7 Jan Babiola continued to move slowly to the southwest and steadily increased in intensity. MSW estimates from both MFR and JTWC had reached 55 kts by 1800 UTC. A TRMM pass indicated a significant convective band extending southeast through north wrapping in toward the LLCC with animated infrared imagery depicting another band forming 180 nm to the west of the LLCC. Babiola began to accelerate toward the west-southwest on the 8th and continued to intensify, reaching cyclone (hurricane) strength at 1200 UTC when centered about 575 nm south of Diego Garcia. A banding eye became apparent, and Babiola presented a rather symmetrical appearance in satellite imagery with an upper-level HIGH over the storm enhancing outflow in all quadrants. The west-southwestward to southwestward motion continued through 9 Jan with Babiola reaching its peak intensity late on the 9th. 200-mb analysis showed that the cyclonic circulation extended into the upper levels with good outflow. At 1800 UTC Babiola displayed a ragged eye 20 nm in diameter with good outflow channels over the western half of the system. The cyclone was by this time beginning to move south- southwestward. JTWC's peak MSW (1-min) of 90 kts was reached at this time, and MFR had upgraded Babiola to its peak intensity of 80 kts at 1200 UTC. This represents a perfect agreement of Babiola's peak intensity between the two TCWCs, corresponding to a Dvorak scale rating of T5.0. The minimum CP estimated by MFR was 954 mb. On 10 Jan Babiola remained intense but began to show signs of weakening. The storm began to move due southward and reached the westernmost point of its trajectory around 1200 UTC when it was located about 250 nm east-southeast of Rodrigues Island (which lies about 315 nm east of Mauritius). Early in the day the eye disappeared and Babiola began to elongate and merge with a trough moving rapidly across the South Indian Ocean. By 1800 UTC the storm was tracking south-southeastward and the MSW was down to 70 kts (65 kts per JTWC). Babiola was becoming less organized due to northwesterly shear. The storm continued to weaken on 11 Jan as it continued toward the south-southeast and experienced strong vertical shear. By 0600 UTC Babiola was merging with the approaching trough and beginning extra- tropical transition (this based upon remarks in the 0600 UTC JTWC warning). Animated satellite imagery and data from a SSM/I pass showed an exposed LLCC with convection sheared 85 nm to the south and east. JTWC issued its last warning on Babiola at 0600 UTC on 12 Jan with winds estimated at only 25 kts, but MFR continued gale warnings for the weakening system through 12/1200 UTC, although the bulletins indicated that the gales were forecast to be occurring well away from the center (up to 120 nm) in the southeast quadrant. Early on the 12th the previously mentioned 500-mb trough was just west of Babiola and was interacting with the system, which was becoming extratropical. MFR issued their last bulletin on Babiola at 1800 UTC, downgrading the system to below gale intensity and locating the center approximately 800 nm southeast of Rodrigues Island. Tropical Cyclone Connie (TC-08S / SIO #04) 25 January - 2 February ------------------------------------------- An area of convection appeared on 24 Jan about 315 nm east of northern Madagascar. SSM/I data indicated a fully-exposed LLCC with disorganized convection. The next day the persistent convection had become more organized and MFR initiated Tropical Disturbance Bulletins at 0600 UTC for disturbance #04. The rapidly strengthening disturbance was upgraded to a tropical depression six hours later and to Moderate Tropical Storm Connie at 1800 UTC with 40-kt winds. Connie was centered about 325 nm northwest of Mauritius at that time. (JTWC issued a Formation Alert at 1000 UTC, and their first warning was issued at 1800 UTC, giving a MSW estimate of 35 kts (1-min).) Convective organization was increasing in an environment of good outflow and weak vertical shear. TRMM microwave imagery depicted banding of deep convection in the northeast through southwest quadrants. The storm had been quasi-stationary for several hours but was forecast to track southwestward under the influence of a mid-level ridge to the south. Connie, however, remained more or less stationary, and actually moved (or was relocated) northward a bit on 26 Jan while slowly strengthening. A TRMM pass at 26/0703 UTC revealed what appeared to be a 27-nm wide eye. At 1800 UTC Connie's intensity had reached 45 kts (55 kts 1-min avg from JTWC) and was still quasi-stationary about 380 nm north-northwest of Mauritius. By 0600 UTC on 27 Jan the by-now severe tropical storm with 60-kt winds was moving south- eastward at 6 kts. A SSM/I pass at 0141 UTC revealed an irregular eye 20 nm in diameter with the eyewall surrounding approximately 4/5 of the vortex. Multi-spectral imagery showed a significant convective band entering the LLCC from the southern half of the system. At 1200 UTC Connie's center was about 300 nm north-northwest of Mauritius and MFR upgraded the storm to cyclone status with 80-kt MSW. (JTWC's concurrent 1-min avg MSW was 85 kts at the time.) The eye diameter by this time had shrunk to 11 nm and convective features were continuing to develop and build in toward the LLCC from the southeast and northeast. With an upper-level HIGH located over the cyclone, the outflow continued to improve and Connie began to strengthen rapidly. By 1800 UTC Connie's well-defined 15-nm wide eye was located approximately 235 nm northwest of Mauritius and had moved south at 7 kts over the previous six hours. There was a surface synoptic report of 10-min avg winds of 31 kts from WMO 61986, located about 140 nm due east of the cyclone. Throughout Connie's life center position estimates between JTWC and MFR were in excellent agreement, and intensity estimates agreed fairly well except that on 28 and 29 Jan, when the cyclone was at its peak, there was some divergence of opinion regarding the cyclone's intensity. At 27/1800 UTC JTWC increased the MSW (1-min) to 115 kts, which equates to T6.0 on the Dvorak scale. MFR's 10-min MSW estimate was 90 kts--equivalent to a Dvorak rating of T5.5--and as everyone in the business knows, a difference in Dvorak analysis of 0.5 T-number represents good agreement. At 28/0600 UTC JTWC began to gradually bring down Connie's MSW while MFR's value held steady at 90 kts. At 1800 UTC Reunion increased its MSW estimate to a peak of 100 kts (T6.0 on the Dvorak scale) while JTWC had brought its value down to 105 kts (T5.5). Remarks in the JTWC warning indicated that this was based upon CI estimates of 102 kts and 127 kts (T5.5 and T6.5). Connie's eye had remained well-defined, but cloud tops had warmed somewhat over the cyclone's center. MFR maintained the 100-kt intensity through 29/0600 UTC and then brought the MSW down to 85 kts at 29/1200 UTC. JTWC's estimates had continued to slowly decline and had reached 80 kts (1-min) by 1200 UTC. The minimum CP in Connie's history as estimated by MFR was 928 mb at 28/1800 UTC. By 0000 UTC on the 29th Connie was centered about 130 nm northwest of Mauritius. The cyclone was maintaining a 10-nm diameter eye, but was showing signs of shearing to the south. Water vapor imagery indicated a weak TUTT to the southwest of the storm which was causing the increase in vertical shear. By 1800 UTC on 28 Jan Connie was moving to the southwest on a track which carried it about 100 nm west of Reunion Island around 1800 UTC on 29 Jan. The MSW was down to 80 kts (both MFR and JTWC) as the eye was no longer apparent and drier air from the TUTT was being injected into the storm's inflow. At 30/0000 UTC Connie was located approximately 145 nm west-southwest of Reunion and moving southwest at 11 kts--a motion which had increased to 18 kts by 0600 UTC. The storm's intensity was down to near minimal cyclone force by this time, and Connie was beginning to recurve to the south-southeast. By 1800 UTC on 30 Jan the storm was moving southward about 265 nm east of the southern tip of Madagascar with 55-kt winds (60 kts 1-min avg from JTWC). Earlier in the day a SSM/I pass had indicated a spiral band of convection to the west of the LLCC, but a TRMM pass at 1331 UTC indicated only isolated convection to the south of the center and Connie was forecast to continue weakening. On 31 Jan Connie began to move in a southeasterly direction, steered by a mid-level subtropical ridge to the northeast and the approaching trough to the southwest. The storm, however, held on to its intensity with the MSW remaining at 55 kts through most of the day. JTWC actually increased its 1-min avg MSW to 65 kts briefly at 1800 UTC based upon satellite intensity estimates. However, any re-intensification was short-lived. Animated visible imagery early on 1 Feb showed a fully-exposed LLCC with rapidly weakening convection about 70 nm to the east of the center. Infrared imagery depicted a rapid warming of cloud tops as well as a significant decrease in the areal extent of deep convection. MFR issued its final warning at 01/0000 UTC since Connie appeared to be rapidly losing strength and was taking on extratropical characteristics. JTWC continued to track the rapidly weakening storm through 0600 UTC on 2 Feb when the MSW was estimated at only 25 kts and the center was located about 725 nm south of Reunion Island. SSM/I data indicated a fully-exposed LLCC with weakening convection displaced about 75 nm northeast of the center. The remnants of Connie were forecast to continue moving southeastward and weaken. Jean Marc de Maroussem, a resident of Mauritius, sent me some observations he'd made during Connie's closest approach to the island. The lowest pressure reported by Jean Marc was 1000.6 with several wind gusts exceeding 55 kts and a peak gust of 65 kts. The average rainfall for the entire island was about 200 mm--a bit of relief for the drought-stricken island but not enough. As far as Reunion Island goes, Patrick Hoareau reported that he'd been listening to the official radio on the internet and wind gusts of around 60-80 kts had been reported. Also 16,000 people were without power. Press reports indicated that Connie was responsible for two deaths on Reunion. One hundred homes were reportedly destroyed with at least 600 persons homeless. *********************************************************************** AUSTRALIAN REGION (AUG) - From Longitude 90E Eastward to Longitude 160E Activity for January: 2 tropical LOWs 1 hybrid LOW 1 severe tropical cyclone NOTE!!! The Australian Region was covered in the first installment of the January summary which was issued on 6 March. *********************************************************************** SOUTHWEST PACIFIC (SWP) - South Pacific Ocean East of Longitude 160E Activity for January: 2 tropical depressions 2 tropical cyclones of storm intensity NOTE!!! The South Pacific basin was covered in the first installment of the January summary which was issued on 6 March. *********************************************************************** 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, 1998 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 January as an example: jan00.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: jan00.sum, for example. Back issues can also be obtained from the following websites (courtesy of Michael Bath, Michael V. Padua, Tom Berg, Michael Pitt, and Rich Henning): Another website where much information about tropical cyclones may be found is the website for the UK Meteorological Office. Their site contains a lot of statistical information about tropical cyclones globally on a monthly basis. The URL is: TROPICAL CYCLONE REPORTS AVAILABLE 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). Also, tracks only for the 1998 tropical cyclones are currently available. The URL is: Also, TPC/NHC has available on its webpage nice "technicolor" tracking charts for the 1999 Atlantic and Eastern North Pacific tropical cyclones; also, preliminary storm reports for all the 1999 Atlantic and most of the Eastern North Pacific cyclones are now available. The URL is: Prepared by: Gary Padgett E-mail: garyp@alaweb.com Phone: 334-222-5327 (nights & weekends) / 850-882-2594 (weekdays) *********************************************************************** *********************************************************************** +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ To unsubscribe from WX-ATLAN send e-mail to LISTSERV@PO.UIUC.EDU with "unsub wx-atlan" in the body of your message. For help with the WX-ATLAN or WX-TALK discussion groups write to chris@siu.edu or see http://www.inlink.com/~landmb/intro.html. For more information on tropical weather products, see the NCEP Products Homepage at: http://www.nhc.noaa.gov