WTPS21 PGTW 061730
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 98P)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
180 NM EITHER SIDE OF A LINE FROM 11.6S 171.9W TO 17.6S 165.0W
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
IMAGERY AT 061700Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 11.6S 171.9W. THE SYSTEM IS MOVING EAST-SOUTHEASTWARD AT 18
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 98P) PREVIOUSLY LOCATED NEAR 
10.4S 174.4W IS NOW LOCATED NEAR 11.6S 171.9W, APPROXIMATELY 179 NM 
NORTH-NORTHWEST OF PAGO PAGO, AMERICAN SAMOA. ANIMATED ENHANCED INFRARED 
SATELLITE IMAGERY AND A 061452Z SSMIS 91 GHZ MICROWAVE IMAGE DEPICT A 
RAPIDLY CONSOLIDATING SYSTEM WITH VERY SYMMETRIC DEEP CONVECTION OVER 
THE CENTER AND FORMATIVE BANDING ALONG THE SOUTHWESTERN PERIPHERY. 
ENVIRONMENTAL ANALYSIS INDICATES THAT 98P IS IN A FAVORABLE ENVIRONMENT 
FOR DEVELOPMENT WITH GOOD OUTFLOW ALOFT, LOW (10-15 KTS) VERTICAL WIND 
SHEAR, AND WARM (30-31 C) SEA SURFACE TEMPERATURES. GLOBAL MODELS ARE IN 
GOOD AGREEMENT THAT 98P WILL TRACK SOUTHEASTWARD, EAST OF AMERICAN 
SAMOA, OVER THE NEXT 24 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE 
ESTIMATED AT 25 TO 30 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 
071730Z.//
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