WTPN21 PGTW 152000
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 97W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 160 
NM EITHER SIDE OF A LINE FROM 13.5N 144.4E TO 19.7N 139.1E 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 18 TO 23 KNOTS. METSAT IMAGERY AT 151800Z INDICATES 
THAT A CIRCULATION CENTER IS LOCATED NEAR 13.7N 144.2E. THE SYSTEM IS 
MOVING NORTH-NORTHEASTWARD AT 04 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 97W) PREVIOUSLY LOCATED NEAR 
7.0N 126.0E IS NOW LOCATED NEAR 13.7N 144.2E, APPROXIMATELY 32 NM 
WEST-NORTHWEST OF GUAM. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY 
DEPICTS A BROAD AREA OF DISORGANIZED, DEEP, FRAGMENTED, AND FLARING 
CONVECTION THAT ARE OBSCURING THE LOW LEVEL CIRCULATION (LLC). ANALYSIS 
INDICATES A FAVORABLE ENVIRONMENT WITH LOW TO MODERATE (10-15 KNOTS) 
VERTICAL WIND SHEAR, STRONG EQUATORWARD OUTFLOW, AND VERY WARM (29-30 
C) SEA SURFACE TEMPERATURES. RECENT SCATTEROMETRY DATA INDICATE AN 
EXPANSIVE WIND FIELD WITH THE STRONGER WINDS ALONG THE NORTHEAST- TO 
EASTERN PERIPHERIES. GLOBAL MODELS INDICATE A NORTHWARD TRACK AWAY FROM 
THE MARIANAS AND EVENTUALLY NORTHWESTWARD AROUND THE PERIMETER OF AN 
EVOLVING GYRE-LIKE PATTERN THAT WILL EVENTUALLY EXTEND FROM THE 
NORTHERN PHILIPPINE SEA TO THE SOUTH CHINA, DOTTED BY AT LEAST THREE 
VORTICES, INCLUDING 97W. A STEADY INTENSIFICATION OVER THE NEXT 12-36 
HOURS IS EXPECTED WITH WINDS AWAY FROM THE LLC AND NOT NECESSARILY 
ASSOCIATED WITH CENTRAL WIND SPEED. MAXIMUM SUSTAINED SURFACE WINDS ARE 
ESTIMATED AT 18 TO 23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO 
BE NEAR 1005 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 
162000Z.
//
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