Tropical Cyclones [Index]

Tropical Cyclone 201215 Southern Hemisphere Summary

WTXS21 PGTW 20120229 08:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
130 NM EITHER SIDE OF A LINE FROM 12.3S 68.8E TO 16.4S 65.7E 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 28 TO 32 KNOTS. METSAT IMAGERY AT 290530Z
INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 12.9S 68.6E.
THE SYSTEM IS MOVING WEST-SOUTHWESTWARD AT 07 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 11.6S
69.4E, IS NOW LOCATED NEAR 12.9S 68.6E, APPROXIMATELY 400 NM
SOUTHWEST OF DIEGO GARCIA. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
SHOWS A TIGHTLY ORGANIZED LOW LEVEL CIRCULATION CENTER (LLCC) WITH
ACTIVE CONVECTIVE BANDS OVER BOTH SEMICIRCLES. A 290452Z METOP-A
MICROWAVE PASS SUPPORTS THE WELL DEFINED LLCC WITH DEEP CENTRAL
CONVECTION BUILDING. UPPER LEVEL ANALYSIS INDICATES A MID-LATITUDE
TROUGH HAS STARTED TO MOVE TO THE SOUTHEAST OF THE LLCC , HELPING TO
ENHANCE THE STRONG POLEWARD OUTFLOW OBSERVED IN ANIMATED WATER VAPOR
IMAGERY OVER THE PAST 12 HOURS. THE LLCC HAS BEEN SLOWLY TRACKING
TOWARDS THE AXIS OF AN UPPER LEVEL SUBTROPICAL RIDGE AND INTO AN
AREA OF WEAKER VERTICAL WIND SHEAR (LESS THAN 10 KNOTS). SEA SURFACE
TEMPERATURES ARE BETWEEN 29 AND 30 DEGREES CELSIUS, SUPPORTING THE
RECENT DEVELOPMENT AND FURTHER DEVELOPMENT OVER THE NEXT 24 HOURS.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 28 TO 32 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB. THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
010800Z.//
=========================================================================
WTXS32 PGTW 20120229 21:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 15S (FIFTEEN) WARNING NR 001//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/290751Z FEB 12//
AMPN/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. TROPICAL CYCLONE 15S (FIFTEEN) WARNING NR 001
   02 ACTIVE TROPICAL CYCLONES IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   291800Z --- NEAR 13.8S 67.3E
     MOVEMENT PAST SIX HOURS - 240 DEGREES AT 08 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: 13.8S 67.3E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   010600Z --- 14.5S 66.0E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT
                            045 NM SOUTHEAST QUADRANT
                            045 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 235 DEG/ 07 KTS
    ---
   24 HRS, VALID AT:
   011800Z --- 15.3S 64.8E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT
                            055 NM SOUTHEAST QUADRANT
                            055 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 220 DEG/ 05 KTS
    ---
   36 HRS, VALID AT:
   020600Z --- 16.1S 64.1E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT
                            055 NM SOUTHEAST QUADRANT
                            055 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 195 DEG/ 04 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   021800Z --- 16.9S 63.9E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
                            025 NM SOUTHEAST QUADRANT
                            025 NM SOUTHWEST QUADRANT
                            025 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
                            060 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 160 DEG/ 07 KTS
    ---
   72 HRS, VALID AT:
   031800Z --- 19.7S 65.0E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   VECTOR TO 96 HR POSIT: 190 DEG/ 06 KTS
    ---
   LONG RANGE OUTLOOK:
    ---
   96 HRS, VALID AT:
   041800Z --- 22.2S 64.5E
   MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
292100Z POSITION NEAR 14.0S 67.0E.
TROPICAL CYCLONE (TC) 15S (FIFTEEN), LOCATED APPROXIMATELY 490 NM
SOUTHWEST OF DIEGO GARCIA, HAS TRACKED WEST-SOUTHWESTWARD AT 08
KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY
AND A 291725Z AMSU MICROWAVE IMAGE SHOW INCREASED DEEP CONVECTION
TIGHTLY WRAPPING INTO A WELL-DEFINED LOW LEVEL CIRCULATION CENTER
(LLCC), FROM WHICH THE INITIAL POSITION WAS BASED. THE INITIAL
INTENSITY WAS BASED ON PGTW, KNES, AND FMEE DVORAK ESTIMATES RANGING
FROM 30 TO 35 KNOTS. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM IS
LOCATED DIRECTLY UNDER THE RIDGE AXIS IN AN AREA OF LOW VERTICAL
WIND SHEAR. AN UPPER LEVEL TROUGH TO THE WEST IS INCREASING OUTFLOW.
TC 15S IS CURRENTLY TRACKING ALONG THE NORTHWESTERN PERIPHERY OF A
LOW- TO MID-LEVEL STEERING RIDGE. AFTER TAU 36, THE SYSTEM IS
EXPECTED TO TURN POLEWARD WHEN AN UPPER LEVEL TROUGH WEAKENS THE
STEERING RIDGE. TC 15S SHOULD SIGNIFICANTLY WEAKEN BY TAU 72, DUE TO
INCREASED VERTICAL WIND SHEAR ASSOCIATED WITH AN APPROACHING UPPER
LEVEL TROUGH. TC 15S WILL BEGIN TO TURN SOUTHWESTWARD AS THE LOW
LEVEL STEERING RIDGE REBUILDS IN TO THE SOUTH. THE SYSTEM WILL
DISSIPATE AS A SIGNIFICANT TROPICAL CYCLONE BY TAU 96. NUMERICAL
MODEL GUIDANCE SUPPORTS THE POLEWARD TURN AND DISSIPATION SCENARIO.
HOWEVER, SEVERAL MODELS INCLUDING GFDN, WBAR, AND EGRR EXTEND
FARTHER WESTWARD BEFORE TURNING POLEWARD IN THE EARLY TAUS. THIS
FORECAST IS IN AGREEMENT WITH ECMWF, NOGAPS, AND GFS. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 291800Z IS 8 FEET. NEXT WARNINGS AT
010900Z AND 012100Z. THIS WARNING SUPERSEDES AND CANCELS REF A,
JOINT TYPHOON WRNCEN 290751Z FEB 12 TROPICAL CYCLONE FORMATION ALERT
=========================================================================
WTXS32 PGTW 20120301 09:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 15S (FIFTEEN) WARNING NR 002//
REFER TO TROPICAL CYCLONE 14S (IRINA) WARNINGS (WTXS31 PGTW)
RMKS/
1. TROPICAL CYCLONE 15S (FIFTEEN) WARNING NR 002
   02 ACTIVE TROPICAL CYCLONES IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   010600Z --- NEAR 14.7S 64.8E
     MOVEMENT PAST SIX HOURS - 245 DEGREES AT 16 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: 14.7S 64.8E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   011800Z --- 15.8S 63.3E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT
                            045 NM SOUTHEAST QUADRANT
                            045 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 230 DEG/ 04 KTS
    ---
   24 HRS, VALID AT:
   020600Z --- 16.3S 62.7E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT
                            055 NM SOUTHEAST QUADRANT
                            055 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 195 DEG/ 04 KTS
    ---
   36 HRS, VALID AT:
   021800Z --- 17.0S 62.5E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT
                            055 NM SOUTHEAST QUADRANT
                            055 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 175 DEG/ 04 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   030600Z --- 17.8S 62.6E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
                            025 NM SOUTHEAST QUADRANT
                            025 NM SOUTHWEST QUADRANT
                            025 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
                            060 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 165 DEG/ 07 KTS
    ---
   72 HRS, VALID AT:
   040600Z --- 20.5S 63.4E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   VECTOR TO 96 HR POSIT: 215 DEG/ 07 KTS
    ---
   LONG RANGE OUTLOOK:
    ---
   96 HRS, VALID AT:
   050600Z --- 22.7S 61.7E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
010900Z POSITION NEAR 15.0S 64.4E.
TROPICAL CYCLONE (TC) 15S, LOCATED APPROXIMATELY 525 NM NORTHEAST OF
PORT LOUIS, MAURITIUS, HAD TRACKED WEST-SOUTHWESTWARD AT 16 KNOTS
OVER THE PAST SIX HOURS. A RECENT 12-HOUR ANIMATED MULTISPECTRAL
SATELLITE IMAGERY SHOWS THE CONVECTIVE BANDING HAS MAINTAINED DEPTH
EVEN AS ITS OVERALL STRUCTURE ELONGATED IN RESPONSE TO A MID-
LATITUDE TROUGH APPROACHING FROM THE SOUTHWEST. THE INITIAL POSITION
WAS EXTRAPOLATED FROM A 010432Z AMSU-B MICROWAVE IMAGE AND THE
INITIAL INTENSITY WAS BASED ON CONGRUENT DVORAK ESTIMATES FROM PGTW
AND FMEE. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM IS UNDER A
NARROW RIDGE AXIS IN AN AREA OF LOW (05-10 KNOT) VERTICAL WIND SHEAR
(VWS). TC 15S IS, AT THE MOMENT, TRACKING ALONG THE NORTHWEST
PERIPHERY OF A LOW- TO MID-LAYERED SUBTROPICAL RIDGE (STR). BY TAU
36, THE AFOREMENTIONED MID-LATITUDE TROUGH WILL ERODE THE STEERING
RIDGE AND CAUSE THE CYCLONE TO TRACK POLEWARD. BY TAU 72, A
SECONDARY STR WILL ASSUME STEERING AND DEFLECT A WEAKENED SYSTEM
SOUTHWESTWARD. TC 15S WILL SEE MODERATE INTENSIFICATION OVER THE
NEXT 48 HOURS WITH FAVORABLE VWS AND IMPROVED POLEWARD OUTFLOW
ASSOCIATED WITH THE APPROACHING TROUGH. AFTER TAU 48, RAPIDLY
INCREASING VWS ASSOCIATED WITH THE PREVAILING WESTERLIES WILL ERODE
THE SYSTEM, CAUSING ITS EVENTUAL DISSIPATION BY TAU 96. THE
AVAILABLE NUMERICAL GUIDANCE IS IN LOOSE AGREEMENT WITH WBAR AS THE
SOLE RIGHT OUTLIER. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 010600Z IS 9
FEET. NEXT WARNINGS AT 012100Z AND 020900Z. REFER TO TROPICAL
CYCLONE 14S (IRINA) WARNINGS (WTXS31 PGTW) FOR TWELVE-HOURLY UPDATES.
=========================================================================
WTXS32 PGTW 20120301 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 15S (FIFTEEN) WARNING NR 003//
REFER TO TROPICAL CYCLONE 14S (IRINA) WARNINGS (WTXS31 PGTW)
RMKS/
1. TROPICAL CYCLONE 15S (FIFTEEN) WARNING NR 003
   02 ACTIVE TROPICAL CYCLONES IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   011800Z --- NEAR 15.3S 63.7E
     MOVEMENT PAST SIX HOURS - 245 DEGREES AT 07 KTS
     POSITION ACCURATE TO WITHIN 040 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
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   REPEAT POSIT: 15.3S 63.7E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   020600Z --- 15.9S 62.7E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   VECTOR TO 24 HR POSIT: 200 DEG/ 04 KTS
    ---
   24 HRS, VALID AT:
   021800Z --- 16.6S 62.4E
   MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
012100Z POSITION NEAR 15.4S 63.4E.
TROPICAL CYCLONE (TC) 15S, LOCATED APPROXIMATELY 460 NM NORTHEAST OF
PORT LOUIS, MAURITIUS, HAS TRACKED WEST-SOUTHWESTWARD AT 07 KNOTS
OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY
INDICATES THAT TC 15S HAS WEAKENED SIGNIFICANTLY OVER THE PAST 12
HOURS WITH DISORGANIZED DEEP CONVECTION FLARING SOUTH OF THE CENTER.
A 011704Z ASCAT IMAGE SHOWS A DEFINED CIRCULATION; HOWEVER, WINDS
HAVE DECREASED TO 20-25 KNOTS WITH ONE ISOLATED 30-KNOT WIND
DISPLACED OVER 60 NM SOUTH OF THE CENTER. A SHIP OBSERVATION AT
01/20Z, LOCATED APPROXIMATELY 45 NM EAST, SHOWED SLP NEAR 1003 MB
AND WINDS 070/30 KNOTS. THIS WEAKENING IS FURTHER EVIDENT IN A
011729Z TRMM IMAGE SHOWING WEAK LOW-LEVEL CONVECTIVE BANDING WITH AN
ISOLATED AREA OF DEEP CONVECTION SHEARED SOUTH OF CENTER.
ADDITIONALLY, DVORAK ESTIMATES HAVE DECREASED TO 25-30 KNOTS. TC 15S
IS FORECAST TO TRACK WEST-SOUTHWESTWARD TO SOUTHWARD WHILE
MAINTAINING A 25-30 KNOT INTENSITY. DYNAMIC MODEL GUIDANCE INDICATES
A SLIGHT POSSIBILITY OF REGENERATION BUT OVERALL ENVIRONMENTAL
CONDITIONS ARE MARGINAL. THIS IS THE FINAL WARNING ON THIS SYSTEM BY
THE JOINT TYPHOON WARNING CENTER. THE SYSTEM WILL BE CLOSELY
MONITORED FOR SIGNS OF REGENERATION. MAXIMUM SIGNIFICANT WAVE HEIGHT
AT 011800Z IS 7 FEET. REFER TO TROPICAL CYCLONE 14S (IRINA) WARNINGS
(WTXS31 PGTW) FOR TWELVE-HOURLY UPDATES.//