WTPN21 PGTW 161400
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
130 NM EITHER SIDE OF A LINE FROM 7.3N 135.0E TO 7.9N 131.0E
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 15 TO 20 KNOTS. METSAT
IMAGERY AT 161200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 7.4N 134.7E. THE SYSTEM IS MOVING WESTWARD AT 09 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 91W) PREVIOUSLY LOCATED 
NEAR 7.3N 135.6E IS NOW LOCATED NEAR 7.4N 134.7E, APPROXIMATELY 15 
NM EAST OF BABELTHUAP, PALAU, FSM. ANIMATED ENHANCED INFRARED (EIR) 
SATELLITE IMAGERY AND A 160927Z SSMIS 91GHZ SATELLITE IMAGE DEPICT 
FORMATIVE CONVECTIVE BANDING BEGINNING TO WRAP INTO AN OBSCURED LOW 
LEVEL CIRCULATION CENTER (LLCC). INVEST 91W IS IN A FAVORABLE 
ENVIRONMENT FOR DEVELOPMENT WITH LOW TO MODERATE (10-20 KT) VERTICAL 
WIND SHEAR (VWS), GOOD POLEWARD OUTFLOW, AND WARM (29-30C) SEA 
SURFACE TEMPERATURES (SST). GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 
91W WILL STRENGTHEN AND CONSOLIDATE AS IT TRACKS WEST-NORTHWESTWARD. 
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 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 
171400Z.//
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