Tropical Cyclones [Index]

Tropical Cyclone HETTIE [Australian Region][South Indian Ocean][South Pacific Ocean][Southern Hemisphere][Summaries and Track Data]

WTPS21 PGTW 20090128 02:00z
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
090 NM EITHER SIDE OF A LINE FROM 20.0S 177.0W TO 22.7S 179.6W
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 27 TO 32 KNOTS. METSAT IM-
AGERY AT 272330Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 20.2S 177.2W.  THE SYSTEM IS MOVING SOUTHWESTWARD AT 05
KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 17.3S
176.1W, IS NOW LOCATED NEAR 20.2S 177.2W, APPROXIMATELY 335 NM EAST-
SOUTHEAST OF NADI, FIJI. RECENT ANIMATED MULTISPECTRAL IMAGERY
CONTINUES TO INDICATE A WELL-DEFINED CIRCULATION, BUT THE LOW LEVEL
CIRCULATION CENTER (LLCC) HAS BECOME PARTIALLY EXPOSED OVER THE
PAST SIX HOURS. MICROWAVE IMAGERY INDICATES THAT THE CONVECTION IS
BEING SHEARED TO THE EAST OF THE LLCC. THE MOST RECENT QUIKSCAT AND
WINDSAT IMAGES INDICATE WINDS OF 25 TO 30 KNOTS NEAR THE CENTER OF
THE CIRCULATION AND 30 TO 35 KNOTS ALONG THE EASTERN PERIPHERY OF
THE LLCC. THE UPPER LEVEL ENVIRONMENT REMAINS MARGINAL WITH MODERATE
VERTICAL WIND SHEAR, HOWEVER, AN UPPER LEVEL TROUGH THAT HAS BEEN
LOCATED TO THE WEST OF THE SYSTEM CONTINUES TO TRACK EASTWARD. THIS
COULD ALLOW THE CURRENTLY STRONG SHEAR GRADIENT TO RELAX AND ALLOW
CONVECTION TO RE-BUILD OVER THE LLCC. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 27 TO 32 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 1000 MB. DUE TO THE WELL-DEFINED LLCC AND
POTENTIAL FOR A DECREASE IN VERTICAL WIND SHEAR, 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 290200Z.//
=========================================================================
WTPS31 PGTW 20090128 15:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 11P (HETTIE) WARNING NR 001//
RMKS/
1. TROPICAL CYCLONE 11P (HETTIE) WARNING NR 001
   01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
    ---
   WARNING POSITION:
   281200Z --- NEAR 21.7S 177.5W
     MOVEMENT PAST SIX HOURS - 195 DEGREES AT 07 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: 21.7S 177.5W
    ---
   FORECASTS:
   12 HRS, VALID AT:
   290000Z --- 22.7S 178.3W
   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 24 HR POSIT: 245 DEG/ 06 KTS
    ---
   24 HRS, VALID AT:
   291200Z --- 23.2S 179.4W
   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 36 HR POSIT: 260 DEG/ 06 KTS
    ---
   36 HRS, VALID AT:
   300000Z --- 23.4S 179.4E
   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 48 HR POSIT: 275 DEG/ 05 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   301200Z --- 23.3S 178.4E
   MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
281500Z POSITION NEAR 22.0S 177.7W.
TROPICAL CYCLONE (TC) 11P (HETTIE), LOCATED APPROXIMATELY 315 NM
SOUTHEAST OF SUVA, FIJI, HAS TRACKED SOUTH-SOUTHWEST AT 07 KNOTS
OVER THE PAST 06 HOURS. RECENT ANIMATED INFRARED IMAGERY AND A
280915Z AMSUB MICROWAVE IMAGE SHOWS DEEP CONVECTION FLARING ON THE
SOUTHEASTERN PERIPHERY OF THE LOW LEVEL CIRCULATION CENTER (LLCC).
UPPER LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT ALOFT WITH
STRONG DIFFLUENCE OVER THE STORM PROVIDING GOOD OUTFLOW, ALTHOUGH
MODERATE WESTERLY VERTICAL WIND SHEAR (VWS) CONTINUES TO LIMIT
SIGNIFICANT DEVELOPMENT OF THE SYSTEM. CURRENT INTENSITY IS BASED
UPON DVORAK ESTIMATES OF 35 KNOTS FROM PGTW ALONG WITH SCATTEROMETRY
DATA WHICH DEPICTS WINDS OF 30 TO 40 KNOTS NEAR THE CENTER. IN THE
NEAR TERM, THE SYSTEM WILL MAINTAIN INTENSITY IN THE MARGINALLY
FAVORABLE ENVIRONMENT WHILE TRACKING SOUTH-SOUTHWESTWARD UNDER THE
INFLUENCE OF THE SUBTROPICAL RIDGE TO THE SOUTHEAST. AFTER TAU 12, A
LOW- TO MID-LEVEL RIDGE BUILDING SOUTH OF THE STORM IS EXPECTED TO
BECOME THE DOMINANT STEERING INFLUENCE AND WILL TURN THE SYSTEM
WESTWARD. THE STORM WILL MAINTAIN INTENSITY THROUGH TAU 12 AND THEN
BEGIN TO WEAKEN AS VWS INCREASES AND CONVECTION IS SHEARED AWAY FROM
THE LLCC DUE TO AN APPROACHING MID- TO UPPER-LEVEL SHORTWAVE TROUGH.
THE STORM IS EXPECTED TO DISSIPATE OVER WATER BY TAU 36.  THIS
WARNING SUPERSEDES AND CANCELS REF A, NAVMARFCSTCEN 280151Z JAN 08
TROPICAL CYCLONE FORMATION ALERT (WTPS21 PGTW 280200) MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 281200Z IS 10 FEET. NEXT WARNINGS AT
290300Z AND 291500Z.
=========================================================================
WTPS31 PGTW 20090129 03:00z
1. TROPICAL CYCLONE 11P (HETTIE) WARNING NR 002
   01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
    ---
   WARNING POSITION:
   290000Z --- NEAR 22.5S 177.8W
     MOVEMENT PAST SIX HOURS - 190 DEGREES AT 05 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
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   REPEAT POSIT: 22.5S 177.8W
    ---
   FORECASTS:
   12 HRS, VALID AT:
   291200Z --- 23.4S 178.6W
   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: 245 DEG/ 05 KTS
    ---
   24 HRS, VALID AT:
   300000Z --- 23.8S 179.5W
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
290300Z POSITION NEAR 22.7S 178.0W.
TROPICAL CYCLONE (TC) 11P (HETTIE), LOCATED APPROXIMATELY 390 NM
SOUTHEAST OF NADI, FIJI, HAS TRACKED SOUTHWARD AT 07 KNOTS OVER
THE PAST 06 HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS
A FULLY EXPOSED AND WEAKENED LOW LEVEL CIRCULATION CENTER LOCATED
APPROXIMATELY ONE DEGREE TO THE NORTHWEST OF SIGNIFICANTLY WARMED
CLOUD TOPS/CONVECTION. TWELVE HOUR SATELLITE INTENSITY TRENDS FROM
PGTW, KNES AND FMEE REFLECT A WEAKENING SYSTEM WITH CURRENT
INTENSITY ESTIMATES RANGING FROM 30 TO 35 KNOTS. A 281754Z QUIKSCAT
IMAGE CONFIRMS A 30 TO 35 KNOT (FLAGGED) SYSTEM AS WELL. THE CYCLONE
IS FORECAST TO TRACK SOUTH TO SOUTHWESTWARD OVER THE NEXT 24 HOURS
WHILE REMAINING BELOW WARNING CRITERIA. THE SYSTEM WILL CONTINUE TO
CONTEND WITH EXCESSIVE VERTICAL WIND SHEAR AHEAD OF A SHORTWAVE
TROUGH TO THE WEST MAKING REGENERATION VERY UNLIKELY. 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 290000Z IS 10 FEET.