WTPN21 PGTW 151930
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 91W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 26.6N 152.7E TO 26.9N 155.1E
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 30 TO 35 KNOTS. METSAT
IMAGERY AT 151800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 26.7N 153.4E. THE SYSTEM IS MOVING EAST-NORTHEASTWARD AT 05
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 91W) PREVIOUSLY LOCATED NEAR 
26.3N 152.9E IS NOW LOCATED NEAR 26.7N 153.4E, APPROXIMATELY 879 NM 
EAST-SOUTHEAST OF YOKOSUKA, JAPAN. ANIMATED ENHANCED INFRARED SATELLITE 
IMAGERY DEPICTS A FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH 
EXPANSIVE CONVECTIVE BANDING DISPLACED ON THE WESTERN PERIPHERY. UPPER-
LEVEL ANALYSIS REVEALS A FAVORABLE ENVIRONMENT, WITH WARM (27-28C) SEA 
SURFACE TEMPERATURES, AND DECENT EQUATORWARD OUTFLOW; MAKING 91W A GREAT 
CANDIDATE FOR TRANSITIONING INTO A TROPICAL CYCLONE. GLOBAL MODELS ARE 
IN AGREEMENT THAT THE SYSTEM WILL LOSE JET SUPPORT, TAKE ON MORE 
TROPICAL CHARACTERISTICS AND INTENSIFY WHILE TRACKING EAST-NORTHEAST. 
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 30 TO 35 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1001 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 
161930Z.
//
NNNN