Tropical
Cyclones
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Tropical Cyclone LIN [Australian Region][South Indian Ocean][South Pacific Ocean][Southern Hemisphere] |
WTPS21 PGTW 20090404 00:30z MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/TROPICAL CYCLONE FORMATION ALERT// RMKS/ 1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 180 NM EITHER SIDE OF A LINE FROM 18.1S 163.5W TO 23.9S 160.9W WITHIN THE NEXT 06 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 161230Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 18.9S 163.2W. THE SYSTEM IS MOVING SOUTHWARD AT 06 KNOTS. 2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 11.2S 57.6E, IS NOW LOCATED NEAR 11.3S 57.0E, APPROXIMATELY 600 NM NORTH OF LA REUNION. ANIMATED INFRARED SATELLITE IMAGERY SHOWS A RAPIDLY CONSOLIDATING LOW LEVEL CIRCULATION CENTER (LLCC) WITH DEEP CONVECTIVE BANDING WRAPPING INTO THE CENTER. ANIMATED WATER VAPOR IMAGERY SHOWS A WELL DEVELOPED POLEWARD OUTFLOW CHANNEL ASSOCIATED WITH AN APPROACHING UPPER LEVEL TROUGH AND A DEVELOPING EQUATORWARD OUTFLOW CHANNEL. A 031841Z ASCAT PASS SHOWS AN ORGANIZED SURFACE CIRCULATION. 24 HOUR PRESSURE TRENDS IN THE AREA INDICATE A 2MB DROP. THE SYSTEM IS IN A FAVORABLE ENVIRONMENT WITH LOW VERTICAL WIND SHEAR, DIFFLUENCE ALOFT AND HIGH SEA SURFACE TEMPERATURES. THE SYSTEM IS IN A WEAK STEERING ENVIRONMENT. THE PRIMARY INFLUENCE IS THE NORTHERN FLANK OF THE SUB-TROPICAL RIDGE TO THE SOUTH SLOWLY STEERING THE SYSTEM TO THE WEST. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1002 MB. 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 050030Z. ========================================================================= WTPS31 PGTW 20090404 03:00z 1. TROPICAL CYCLONE 25P (LIN) WARNING NR 001 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 040000Z --- NEAR 17.7S 175.7W MOVEMENT PAST SIX HOURS - 150 DEGREES AT 13 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: 17.7S 175.7W --- FORECASTS: 12 HRS, VALID AT: 041200Z --- 18.9S 174.7W MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 150 DEG/ 09 KTS --- 24 HRS, VALID AT: 050000Z --- 20.5S 173.8W 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 045 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 155 DEG/ 10 KTS --- 36 HRS, VALID AT: 051200Z --- 22.3S 172.9W 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 040 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 155 DEG/ 13 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 060000Z --- 24.7S 171.8W MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT 045 NM SOUTHEAST QUADRANT 035 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT --- REMARKS: 040300Z POSITION NEAR 18.0S 175.4W. TC 25P (LIN), LOCATED APPROXIMATELY 330 NM EAST OF SUVA, FIJI, HAS MOVED SOUTH-SOUTHEASTWARD AT 13 KNOTS OVER THE PAST O6 HOURS. THE LOW LEVEL CIRCULATION CENTER (LLCC) HAS RAPIDLY CONSOLIDATED WHILE DEEP CONVECTION (ENHANCED BY MAXIMUM DIURNAL COOLING OVERNIGHT) AGGRESSIVELY BUILT IN OVER THE CENTER. A 031812Z QUIKSCAT IMAGE DEPICTS A STRONG AND TIGHTENED LLCC WITH WINDS NEAR THE CENTER AS HIGH AS 45 KNOTS; THOUGH MOST OF THESE WIND OBSERVATIONS ARE SUSPECT DUE TO THE INTENSE PRECIPITATION THAT IS FALLING. AS A RESULT, THE INITIAL FORECAST INTENSITY WEIGHS MORE TOWARDS THE 2.0 DVORAK FROM PGTW AND NFFN, RATHER THAN THE QUIKSCAT SOLUTION, AS WELL AS SEA LEVEL PRESSURE OBSERVA- TIONS FROM NEARBY FIJI. ENHANCED INFRARED SATELLITE IMAGERY INDICATES THAT THE DEEPEST CONVECTION IS STILL ORIENTED LINEARLY ALONG THE MONSOON TROUGH, RATHER THAN SYMMETRICALLY ABOUT THE LLCC. THE SYSTEM IS FORECAST TO CONTINUE TO STRENGTHEN UNDER LOW TO MODERATE VERTICAL WIND SHEAR AND DUAL OUTFLOW CHANNELS FOR THE NEXT 12 HOURS. AFTER WHICH, EXCESSIVE VERTICAL WIND SHEAR ASSOCIATED WITH A MID TO UPPER-LEVEL TROUGH THAT HAS BEEN DIGGING EQUATORWARD FOR THE LAST 2 DAYS, WILL WEAKEN THE CYCLONE. MODEL GUIDANCE IS INITIALIZING THE SYSTEM VERY POORLY DUE TO THE RAPID CONSOLIDATION OF THE LLCC AND IT BEING EMBEDDED IN VERY TIGHT TROUGHING. HOWEVER, THE ENERGY ASSOCIATED WITH THIS PART OF THE MONSOON TROUGH QUICKLY TRACKS SOUTH-SOUTHEASTWARD OUT AHEAD OF THE MID-LEVEL TROUGH IN A HIGH AMPLITUDE PATTERN. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 040000Z IS 15 FEET. NEXT WARNINGS AT 041500Z AND 050300Z. ========================================================================= WTPS31 PGTW 20090404 15:00z MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/TROPICAL CYCLONE 25P (LIN) WARNING NR 002// RMKS/ 1. TROPICAL CYCLONE 25P (LIN) WARNING NR 002 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 041200Z --- NEAR 19.7S 176.2W MOVEMENT PAST SIX HOURS - 175 DEGREES AT 13 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: 19.7S 176.2W --- FORECASTS: 12 HRS, VALID AT: 050000Z --- 22.0S 175.8W MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY VECTOR TO 24 HR POSIT: 165 DEG/ 14 KTS --- 24 HRS, VALID AT: 051200Z --- 24.7S 175.0W MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL VECTOR TO 36 HR POSIT: 150 DEG/ 15 KTS --- 36 HRS, VALID AT: 060000Z --- 27.3S 173.2W MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY EXTRATROPICAL RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT --- REMARKS: 041500Z POSITION NEAR 20.3S 176.1W. TC 25P (LIN), LOCATED APPROXIMATELY 380 NM EAST-SOUTHEAST OF NADI, FIJI, HAS TRACKED SOUTHWARD AT 13 KNOTS OVER THE PAST O6 HOURS. ANIMATED INFRARED IMAGERY INDICATES THAT THE LOW LEVEL CIRCULATION CENTER (LLCC) HAS TAKEN A MORE SOUTHWARD TRACK THAN PREVIOUSLY FORECAST. ADDITIONALLY, OVER THE PAST 12 HOURS DEEP CONVECTION HAS CONTINUED TO INCREASE OVER THE LLCC. TC 25P IS QUICKLY TRACKING ALONG THE WESTERN PERIPHERY OF A MID-LEVEL RIDGE LOCATED TO THE EAST OF THE SYSTEM. UPPER LEVEL ANALYSIS INDICATES THAT THE LLCC IS BEING SUPPORTED BY DUAL OUTFLOW CHANNELS BUT IS IN MODERATE LEVELS OF VERTICAL WIND SHEAR. TC 25P IS FORECAST TO CONTINUE TRACKING TOWARD HIGHER LEVELS OF VERTICAL WIND SHEAR AND DECREASING SEA SURFACE TEMPERATURES WHICH WILL KEEP TC 25P FROM DEVELOPING OVER THE NEXT 24 HOURS. FROM TAU 24 THROUGH TAU 36 TC 25P WILL BEGIN EXTRATROPICAL TRANSISTION AND IS EXPECTED TO INCREASE IN INTENSITY AS AN EXTRATROPICAL SYSTEM. MODEL GUIDANCE IS IN FAVORABLE AGREEMENT WITH THE CURRENT FORECAST REASONING. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 041200Z IS 15 FEET. NEXT WARNINGS AT 050300Z AND 051500Z.// ========================================================================= WTPS31 PGTW 20090405 03:00z 1. TROPICAL CYCLONE 25P (LIN) WARNING NR 003 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 050000Z --- NEAR 21.3S 175.3W MOVEMENT PAST SIX HOURS - 170 DEGREES AT 09 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT REPEAT POSIT: 21.3S 175.3W --- FORECASTS: 12 HRS, VALID AT: 051200Z --- 23.5S 174.9W MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 160 DEG/ 13 KTS --- 24 HRS, VALID AT: 060000Z --- 25.9S 174.0W MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY EXTRATROPICAL --- REMARKS: 050300Z POSITION NEAR 21.9S 175.2W. TC 25P (LIN), LOCATED APPROXIMATELY 20 NM WEST OF FUA'AMOTU, TONGA, HAS TRACKED SOUTHWARD AT 09 KNOTS OVER THE PAST O6 HOURS. THE LOW LEVEL CIRCULATION CENTER (LLCC) IS JUST OFF- SHORE OF FUA'AMOTU (NFTF). AT 04/2300Z STATION SEA LEVEL PRESSURE (SLP) DROPPED TO IT'S LOWEST RECORDED READING OF 987 MB, AND SURFACE WINDS WERE LOGGED AT 35 KNOTS, GUSTING TO 52 KNOTS (10-MINUTE AVERAGE). MORE RECENT SPECI METAR REPORTS AT NFTF INDICATE THAT SLP HAS BEGUN TO RISE AS THE LLCC TRACKS SOUTH, AND AWAY FROM THE TONGAN ISLAND. LIN IS TRACKING DOWN THE SURFACE TROUGH IN A HIGH AMPLITUDE PATTERN TOWARDS HIGH VERTICAL WIND SHEAR AND SEA SURFACE TEMPERATURES BELOW 26 DEGREES CELSIUS. THESE FACTORS, COUPLED WITH A STRONG BAROCLINIC BOUNDARY, WILL LEAD TO RAPID EXTRATROPICAL TRANSITIONING WITHIN THE NEXT 24 HOURS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 050000Z IS 17 FEET. NEXT WARNINGS AT 051500Z. ========================================================================= WTPS31 PGTW 20090405 15:00z MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/TROPICAL CYCLONE 25P (LIN) WARNING NR 004// RMKS/ 1. TROPICAL CYCLONE 25P (LIN) WARNING NR 004 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 051200Z --- NEAR 24.8S 174.3W MOVEMENT PAST SIX HOURS - 165 DEGREES AT 22 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 BECOMING EXTRATROPICAL RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT REPEAT POSIT: 24.8S 174.3W --- FORECASTS: 12 HRS, VALID AT: 060000Z --- 29.3S 172.7W MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY EXTRATROPICAL --- REMARKS: 051500Z POSITION NEAR 25.9S 173.9W. TC 25P (LIN), LOCATED APPROXIMATELY 630 NM SOUTHEAST OF NADI, FIJI, HAS TRACKED SOUTH-SOUTHEASTWARD AT 22 KNOTS OVER THE PAST O6 HOURS. ANIMATED INFRARED IMAGERY DEPICTS A LOW LEVEL CIRCULATION CENTER (LLCC) THAT HAS STARTED EXTRATROPICAL TRANSITION (ET), BECOMING ELONGATED TO THE SOUTHEAST. CURRENT INTENSITY ESTIMATES HAVE RAPIDLY DECREASED FOR THE SYSTEM AS THE CONVECTION ASSOCIATED WITH TC 25P HAS BECOME SHEARED FROM THE LLCC TO THE SOUTHEAST. RAPIDLY INCREASING VERTICAL WIND SHEAR ASSOCIATED WITH A LONG WAVE TROUGH SOUTHWEST OF LIN HAS BEEN THE PRIMARY FACTOR IN TC 25P UNDERGOING ET. SEA SURFACE TEMPERATURES HAVE CONTINUED TO DECREASE AS LIN CONTINUES TRACKING TO THE SOUTH-SOUTHEAST AND HAVE BECOME UNFAVORABLE FOR FURTHER DEVELOPMENT. THESE FACTORS, COUPLED WITH A STRONG BAROCLINIC BOUNDARY, WILL LEAD TO RAPID ET IN THE NEXT 12 HOURS. THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WARNING CENTER (NAVMARFCSTCEN). THE SYSTEM WILL BE CLOSELY MONI- TORED FOR SIGNS OF REGENERATION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 051200Z IS 17 FEET.//
Document: lin.htm
Updated: 5th April 2009 |
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