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 
17.0N 126.0E IS NOW LOCATED NEAR 13.7N 144.2E, APPROXIMATELY 32 NM 
WEST-NORTHWEST OF GUAM. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY 
DEPICTS A LOW LEVEL CIRCULATION, WITH CONVECTION BUILDING OVER THE 
CENTER. UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH 
LOW TO MODERATE (10-15 KNOTS) VERTICAL WIND SHEAR, EQUATORWARD OUTFLOW 
ALOFT, AND WARM (29-30 C) SEA SURFACE TEMPERATURES. GLOBAL MODELS 
INDICATE A NORTHWARD TRACK AWAY FROM THE MARIANAS AND EVENTUALLY 
NORTHWESTWARD UNDER THE STEERING INFLUENCE OF A SUBTROPICAL RIDGE WITH 
STEADY INTENSIFICATION FOR THE NEXT 12-36 HOURS. 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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