Tropical
Cyclones
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Tropical Cyclone GABRIELLE [Australian Region][South Indian Ocean][South Pacific Ocean][Southern Hemisphere][Summaries and Track Data] |
WTXS21 PGTW 20090301 14:00z SUBJ/TROPICAL CYCLONE FORMATION ALERT// RMKS/ 1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 180 NM EITHER SIDE OF A LINE FROM 11.6S 102.6E TO 15.0S 107.2E WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME. WINDS IN THE AREA ARE ESTIMATED TO BE 25 TO 30 KNOTS. METSAT IM- AGERY AT 011300Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 12.1S 103.3E. THE SYSTEM IS MOVING SOUTHEASTWARD AT 14 KNOTS. 2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 11.0S 101.1E, IS NOW LOCATED NEAR 12.1S 103.3E, APPROXIMATELY 375 NM EAST OF COCOS ISLAND. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A WELL-DEFINED, EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH DEEP CONVECTION RE-DEVELOPING JUST WEST OF THE CENTER. A 01/1226Z SSMIS IMAGE INDICATED AN IMPROVING LLCC WITH ISOLATED CONVECTION NEAR THE CENTER. EARLIER SCATTEROMETER SUPPORTS 25-30 KNOT WINDS WRAPPING INTO THE CENTER. HIGH VERTICAL WIND SHEAR (VWS) REMAINS THE PRIMARY LIMITING FACTOR WITH 30-40 KNOTS OVER THE SYSTEM. HOWEVER, VWS IS EXPECTED TO DECREASE SIGNIFICANTLY WITHIN THE NEXT 12 HOURS AS THE SYSTEM BEGINS TO TURN SOUTHEASTWARD, TRACKING UNDER THE UPPER- LEVEL RIDGE AXIS AND REDUCED VWS. ADDITIONALLY, AN APPROACHING SHORTWAVE TROUGH CURRENTLY SOUTHWEST OF THE SYSTEM IS FORECAST TO SHIFT EAST PROVIDING AN IMPROVED POLEWARD OUTFLOW CHANNEL WITHIN THE NEXT 24 HOURS. SST AND OCEAN HEAT CONTENT ARE FAVORABLE FOR FURTHER DEVELOPMENT. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1002 MB. BASED ON THE FORECAST TRACK SOUTHEASTWARD TO SOUTH- WARD, THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS GOOD. 3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY 021400Z.// ========================================================================= WTXS31 PGTW 20090302 03:00z COR MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/TROPICAL CYCLONE 17S (SEVENTEEN) WARNING NR 001 CORRECTED// RMKS/ 1. TROPICAL CYCLONE 17S (SEVENTEEN) WARNING NR 001A CORRECTED 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 020000Z --- NEAR 13.2S 105.6E MOVEMENT PAST SIX HOURS - 115 DEGREES AT 11 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY REPEAT POSIT: 13.2S 105.6E --- FORECASTS: 12 HRS, VALID AT: 021200Z --- 14.2S 107.1E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 180 DEG/ 04 KTS --- 24 HRS, VALID AT: 030000Z --- 15.0S 107.1E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 245 DEG/ 05 KTS --- 36 HRS, VALID AT: 031200Z --- 15.4S 106.2E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 245 DEG/ 07 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 040000Z --- 16.0S 104.9E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT --- REMARKS: 020300Z POSITION NEAR 13.5S 106.0E. TROPICAL CYCLONE (TC) 17S (SEVENTEEN), LOCATED APPROXIMATELY 515 NM EAST OF THE COCOS ISLANDS HAS TRACKED EAST-SOUTHEASTWARD AT 11 KNOTS OVER THE PAST 06 HOURS. THE CYCLONE HAS A WELL DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC) AND DVORAK ESTIMATES SUGGEST THE 35-KNOT THRESHOLD HAS BEEN REACHED. A 01/2243Z SSMI/S IMAGE CONTINUES TO SHOW THE MAIN CONVECTION SHEARED TO THE SOUTHWEST OF THE LLCC. TC 17S HAS BEEN TRACKING EAST-SOUTHEASTWARD IN RESPONSE TO A MIDLATITUDE TROUGH WEST OF AUSTRALIA. BY TAU 24, THIS TROUGH WILL MOVE EASTWARD, ALLOWING AN ANTICYCLONE TO BUILD IN SOUTH OF THE SYSTEM. THIS ANTICYCLONE WILL CAUSE TC 17S TO TURN BACK TO THE WEST. TC 17S IS CURRENT IN A REGION OF MODERATE VERTICAL WIND SHEAR. HOWEVER, AS THE PREVIOUSLY MENTIONED MIDLATITUDE TROUGH MOVES OUT, THE WIND SHEAR GRADIENT IS FORECAST TO RELAX, ALLOWING FOR SLOW INTENSIFICATION THROUGH THE FORECAST PERIOD. THE AVAILABLE OBJECTIVE AIDS ARE IN GOOD AGREEMENT WITH THE TRACK FORECAST. THIS WARNING SUPERSEDES AND CANCELS REF A, NAVMARFCSTCEN 011351Z MAR 09 TROPICAL CYCLONE FORMATION ALERT (WTXS21 PGTW 011400 ) MAXIMUM SIGNIFICANT WAVE HEIGHT AT 020000Z IS 12 FEET. NEXT WARNINGS AT 021500Z AND 030300Z. JUSTIFICATION FOR CORRECTION: CHANGED DIRECTION CONVECTION WAS SHEARED FROM SOUTHEAST TO SOUTHWEST. ========================================================================= WTXS31 PGTW 20090302 15:00z SUBJ: TROPICAL CYCLONE 17S (GABRIELLE) WARNING NR 002 1. TROPICAL CYCLONE 17S (GABRIELLE) WARNING NR 002 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 021200Z --- NEAR 14.4S 106.5E MOVEMENT PAST SIX HOURS - 130 DEGREES AT 05 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY REPEAT POSIT: 14.4S 106.5E --- FORECASTS: 12 HRS, VALID AT: 030000Z --- 14.9S 106.9E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 225 DEG/ 04 KTS --- 24 HRS, VALID AT: 031200Z --- 15.5S 106.3E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 065 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 245 DEG/ 08 KTS --- 36 HRS, VALID AT: 040000Z --- 16.1S 104.8E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 065 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 245 DEG/ 10 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 041200Z --- 16.9S 102.9E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT --- REMARKS: 021500Z POSITION NEAR 14.5S 106.6E. TROPICAL CYCLONE (TC) 17S (GABRIELLE), LOCATED APPROXIMATELY 565 NM EAST-SOUTHEAST OF THE COCOS ISLANDS HAS TRACKED SOUTHEASTWARD AT 05 KNOTS OVER THE PAST 06 HOURS. ANIMATED INFRARED SATELLITE IMAGERY AND A 021212Z SSMI/S IMAGE DEPICT A STRUGGLING SYSTEM WITH A PART- IALLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH WEAK DEEP CONVECTIVE BANDING WRAPPING INTO THE WESTERN QUADRANT OF THE STORM. A 021114Z QUIKSCAT IMAGE INDICATES 30-35 KNOT UNFLAGGED WINDS OVER THE WESTERN SEMI-CIRCLE, WHICH ALONG WITH DVORAK INTENSITY ESTIMATES RANGING FROM 35-45 KNOTS, SUPPORT THE CURRENT INTENSITY OF 35 KNOTS. AS EXPECTED, THE SYSTEM HAS MOVED UNDER THE UPPER-LEVEL SUBTROPICAL RIDGE AXIS AND INTO LOWER VERTICAL WIND SHEAR (10-20 KNOTS), HOW- EVER, OVERALL OUTFLOW HAS REMAINED WEAK. ANIMATED WATER VAPOR IMAGERY SHOWS A WEAK POLEWARD OUTFLOW CHANNEL, ENHANCED SLIGHTLY BY A FILLING MIDLATITUDE SHORTWAVE TROUGH PROPAGATING INTO SOUTHWEST AUSTRALIA. DUE TO THIS WEAKENING TROUGH, THE LOW- TO MID-LEVEL SUBTROPICAL STEERING RIDGE IS EXPECTED TO STRENGTHEN SOUTH OF THE SYSTEM IN THE NEXT 12 HOURS AND WILL ALLOW THE SYSTEM TO CONTINUE SLOWING AND TO TRACK WEST-SOUTHWESTWARD (AND ACCELERATE). THE AVAILABLE DYNAMIC GUIDANCE IS IN GOOD AGREEMENT WITH THIS TRACK. THE SYSTEM IS FORECAST TO SLOWLY INTENSIFY OVER THE NEXT 36 HOURS UNTIL IT TRACKS INTO COOLER SST BY 48. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 021200Z IS 14 FEET. NEXT WARNINGS AT 030300Z AND 031500Z.// ========================================================================= WTXS31 PGTW 20090303 03:00z MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/TROPICAL CYCLONE 17S (GABRIELLE) WARNING NR 003// RMKS/ 1. TROPICAL CYCLONE 17S (GABRIELLE) WARNING NR 003 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 030000Z --- NEAR 13.7S 107.5E MOVEMENT PAST SIX HOURS - 090 DEGREES AT 03 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY REPEAT POSIT: 13.7S 107.5E --- FORECASTS: 12 HRS, VALID AT: 031200Z --- 14.5S 107.9E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 235 DEG/ 08 KTS --- 24 HRS, VALID AT: 040000Z --- 15.4S 106.6E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 065 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 245 DEG/ 10 KTS --- 36 HRS, VALID AT: 041200Z --- 16.2S 104.7E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 065 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 235 DEG/ 16 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 050000Z --- 18.0S 102.0E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT --- REMARKS: 030300Z POSITION NEAR 13.9S 107.6E. TROPICAL CYCLONE (TC) 17S (GABRIELLE), LOCATED APPROXIMATELY 630 NM EAST OF THE COCOS ISLANDS HAS TRACKED EASTWARD AT 03 KNOTS OVER THE PAST 06 HOURS. ANIMATED INFRARED SATELLITE IMAGERY AND A 022231Z SSMI/S IMAGE INDICATE THE LOW LEVEL CIRCULATION CENTER (LLCC) HAD BECOME COMPLETELY EXPOSED OVER THE PAST 12 HOURS, BUT IN THE PAST 4 TO 6 HOURS HAS TRACKED TOWARDS DEEPENING CONVECTION THAT HAS QUICKLY STARTED TO ORGANIZE. THE LLCC HAS BEEN ABLE TO MAINTAIN ITS STRUCTURE AND AN EDGE OF SWATH QUIKSCAT PASS INDICATES 30-35 KNOTS OF UNFLAGGED WINDS ON THE WESTERN PERIPHERY. UPPER LEVEL ANALYSIS INDICATES TC 17S IS UNDER THE AXIS OF AN UPPER LEVEL SUBTROPICAL RIDGE, PROVIDING AN ENVIRONMENT WITH DECREASING VERTICAL WIND SHEAR AND A RAPIDLY DEVELOPING POLEWARD OUTFLOW. TC 17S WILL BEGIN TO TRACK ALONG THE NORTHWESTERN PERIPHERY OF A LOW TO MID-LEVEL RIDGE THAT IS BEGINNING TO RE-ORIENT AND BUILD OVER WESTERN AUSTRALIA AS A MID-LATITUDE SHORTWAVE TROUGH TRACKS EASTWARD ACROSS AUSTRALIA. THE INCREASED OUTFLOW AND FAVORABLE SEA SURFACE TEMPERATURES WILL PROVIDE SOME INTENSIFICATION THROUGH TAU 36, BUT AS THE SYSTEM TRACKS INTO STRONGER VERTICAL WIND SHEAR AND COLDER SST, IT WILL WEAKEN BEYOND TAU 36. THE AVAILABLE DYNAMIC GUIDANCE IS IN GOOD AGREEMENT WITH THIS TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 030000Z IS 12 FEET. NEXT WARNINGS AT 031500Z AND 040300Z.// ========================================================================= WTXS31 PGTW 20090303 15:00z 1. TROPICAL CYCLONE 17S (GABRIELLE) WARNING NR 004 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 031200Z --- NEAR 15.0S 107.7E MOVEMENT PAST SIX HOURS - 190 DEGREES AT 05 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY REPEAT POSIT: 15.0S 107.7E --- FORECASTS: 12 HRS, VALID AT: 040000Z --- 15.7S 106.4E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 245 DEG/ 09 KTS --- 24 HRS, VALID AT: 041200Z --- 16.5S 104.7E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 065 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 245 DEG/ 11 KTS --- 36 HRS, VALID AT: 050000Z --- 17.4S 102.5E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 235 DEG/ 15 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 051200Z --- 19.1S 99.9E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY --- REMARKS: 031500Z POSITION NEAR 15.2S 107.4E. TROPICAL CYCLONE (TC) 17S (GABRIELLE), LOCATED APPROXIMATELY 660 NM EAST-SOUTHEAST OF THE COCOS ISLANDS HAS TRACKED SOUTHWARD AT 05 KNOTS OVER THE PAST 06 HOURS. RECENT ANIMATED INFRARED SATELLITE IMAGERY SHOWS THAT THE LOW LEVEL CIRCULATION CENTER HAS MOVED BACK UNDER THE DEEPEST AND MOST PERSISTENT CENTRAL CONVECTION, INCREASING DVORAK SATELLITE INTENSITY ESTIMATES TO AROUND 35 KNOTS FROM PGTW, KNES, AND APRF. VERTICAL WIND SHEAR WILL CONTINUE TO EASE OVER THE NEXT DAY AS THE TC APPROACHES THE SUBTROPICAL RIDGE AXIS TO THE SOUTH, ALLOWING FOR MODEST INTENSIFICATION. THE LACK OF STRONG OUTFLOW ALOFT AND LOW OCEAN HEAT CONTENT FURTHER SUPPORTS MINIMAL INTENSIFICATION OVER THE NEXT 24 HOURS. BEYOND 24 HOURS SEA SURFACE TEMPERATURES WILL DROP BELOW SUSTAINABLE LEVELS, VERTICAL WIND SHEAR WILL AGAIN INCREASE, AND THE ATMOSPHERE WILL BECOME LESS MOIST. COMBINED, ALL THESE CONDITIONS WILL PROMOTE WEAKENING, AND BY TAU 48, TC 17S WILL REMAIN A MINIMAL TC. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 031200Z IS 13 FEET. NEXT WARNINGS AT 040300Z AND 041500Z. ========================================================================= WTXS31 PGTW 20090304 03:00z MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/TROPICAL CYCLONE 17S (GABRIELLE) WARNING NR 005// RMKS/ 1. TROPICAL CYCLONE 17S (GABRIELLE) WARNING NR 005 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 040000Z --- NEAR 14.7S 106.0E MOVEMENT PAST SIX HOURS - 290 DEGREES AT 09 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER REPEAT POSIT: 14.7S 106.0E --- FORECASTS: 12 HRS, VALID AT: 041200Z --- 15.2S 103.4E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER VECTOR TO 24 HR POSIT: 245 DEG/ 16 KTS --- 24 HRS, VALID AT: 050000Z --- 16.5S 100.3E MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 040300Z POSITION NEAR 14.8S 105.4E. TROPICAL CYCLONE (TC) 17S (GABRIELLE), LOCATED APPROXIMATELY 550 NM EAST-SOUTHEAST OF THE COCOS ISLANDS, HAS TRACKED WEST-NORTHWESTWARD AT 09 KNOTS OVER THE PAST 06 HOURS. RECENT ANIMATED INFRARED SATELLITE IMAGERY SHOWS THAT THE LOW LEVEL CIRCULATION CENTER (LLCC) IS SHEARED FROM THE DEEPEST CONVECTION. RECENT POLAR ORBITING SATELLITE DATA INDICATES THAT THE LLCC HAS BROADENED WITH CONTINUED WEAK CONVECTIVE BANDING WRAPPING IN FROM THE SOUTHERN QUADRANTS. THE SYSTEM HAS TURNED NORTH OF WEST UNDER THE INFLUENCE OF AN EXTENSION OF LOW LEVEL RIDGING TO THE SOUTH. MARGINAL SEA SURFACE TEMPERATURES AND LOW TO MODERATE VERTICAL WINDSHEAR HAVE PREVENTED THE INTENSIFICATION PREVIOUSLY FORECAST. TC 17S IS EXPECTED TO CONTINUE TO TRACK WEST TO WEST-SOUTHWESTWARD UNDER THE INFLUENCE OF THE RIDGING TO THE SOUTH AND CONTINUE TO WEAKEN. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 040000Z IS 13 FEET. NEXT WARNINGS AT 041500Z. ========================================================================= WTXS31 PGTW 20090304 09:00z 1. TROPICAL CYCLONE 17S (GABRIELLE) WARNING NR 006 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 040600Z --- NEAR 16.0S 104.9E MOVEMENT PAST SIX HOURS - 215 DEGREES AT 15 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER REPEAT POSIT: 16.0S 104.9E --- FORECASTS: 12 HRS, VALID AT: 041800Z --- 17.1S 102.6E MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER VECTOR TO 24 HR POSIT: 245 DEG/ 16 KTS --- 24 HRS, VALID AT: 050600Z --- 18.3S 99.5E MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 040900Z POSITION NEAR 16.3S 104.3E. TROPICAL CYCLONE (TC) 17S (GABRIELLE), LOCATED APPROXIMATELY 520 NM EAST-SOUTHEAST OF THE COCOS ISLANDS, HAS TRACKED SOUTH-SOUTHWESTWARD AT 15 KNOTS OVER THE PAST 06 HOURS. RECENT ANIMATED MULTISPECTRAL IMAGERY SHOWS A BROADENING, PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER EQUATORWARD OF MODERATELY SHEARED AND WEAKENED CONVECTION. THE TC IS TRACKING GENERALLY SOUTHWESTWARD ALONG THE NORTHWESTERN PERIPHERY OF A STRENGTHENING LOW TO MID-LEVEL SUBTROPICAL RIDGE TOWARDS COOL WATER AND INCREASED VERTICAL WIND SHEAR. AS SUCH, THE TC IS FORECAST TO CONTINUE TO WEAKEN WELL BELOW THE WARNING THRESHOLD OF 35 KNOTS. THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WARNING CENTER (NAVMARFCSTCEN). THE SYSTEM WILL BE CLOSELY MONITORED FOR SIGNS OF REGENERATION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 040600Z IS 13 FEET.
Document: gabrielle.htm
Updated: 5th March 2009 |
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