WTXS21 PGTW 110300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 96S)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
080 NM EITHER SIDE OF A LINE FROM 16.1S 118.6E TO 19.9S 119.2E
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 28 TO 33 KNOTS. METSAT
IMAGERY AT 110300Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 16.4S 118.8E. THE SYSTEM IS MOVING SOUTHWESTWARD AT 11
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 96S) PREVIOUSLY LOCATED
NEAR 16.0S 120.6E IS NOW LOCATED NEAR 16.4S 118.8E, APPROXIMATELY
239 NM NORTH OF PORT HEDLAND, AUSTRALIA. ANIMATED MULTISPECTRAL SATELLITE 
IMAGERY (MSI) AND DATA FROM THE 101351 ASCAT METOP-B 25KM SHOW A 
DISORGANIZED LOW-LEVEL CIRCULATION (LLC), WITH DEEP CONVECTION FORMING IN 
FLARING, RADIAL PLUMES OVER THE OBSCURED LLC. A RECENT OBSERVATION FROM 
PORT HEDLAND INTERNATIONAL AIRPORT (YPPD) INDICATES A WIND SHIFT FROM 190 
TO 150 AND A PRESSURE FALL FROM 1002 HPA TO 999 HPA OVER THE PAST SIX 
HOURS, THOUGH PRESSURE HAS SINCE RISEN TO 1003 HPA. ENVIRONMENTAL 
CONDITIONS APPEAR FAVORABLE FOR DEVELOPMENT, WITH LOW VERTICAL WIND SHEAR 
(VWS) OF 10-15 KNOTS, STRONG EQUATORWARD UPPER-LEVEL OUTFLOW, AND WARM 
SEA SURFACE TEMPERATURES (SST) OF 29-30 C. BOTH DETERMINISTIC AND 
ENSEMBLE MODELS PREDICT CYCLOGENESIS. BOTH THE GFS AND ECMWF ENSEMBLES 
DEPICT A VARIETY OF POTENTIAL TRACKS THAT THE SYSTEM MAY TAKE, LEADING TO 
A LOT OF UNCERTAINTY WHETHER THE SYSTEM WILL REMAIN OVER WATER OR MOVE 
TOWARDS LAND. ADDITIONALLY, THE EXTENT TO WHICH THE SYSTEM WILL INTENSIFY 
AS CYCLOGENESIS OCCURS IS HIGHLY DEPENDENT ON HOW LONG THE SYSTEM REMAINS 
OVER THE WARM WATER ON THE CONTINENTAL SHELF. MAXIMUM SUSTAINED SURFACE 
WINDS ARE ESTIMATED AT 28 TO 33 KNOTS. MINIMUM SEA LEVEL PRESSURE IS 
ESTIMATED TO BE NEAR 998 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 
120300Z.//
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