WTPN21 PGTW 131500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 90W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 12.7N 113.8E TO 14.6N 109.6E
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 131200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 13.0N 112.9E. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 09
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 90W) PREVIOUSLY LOCATED NEAR 
12.6N 114.1E IS NOW LOCATED NEAR 13.0N 112.9E, APPROXIMATELY 366 NM EAST-
SOUTHEAST OF HUE, VIETNAM. ENHANCED INFRARED IMAGERY AND A 131051Z SSMIS 
91GHZ MICROWAVE IMAGE DEPICT FRAGMENTED DEEP CONVECTIVE BANDING IN THE 
NORTHERN SEMICIRCLE WRAPPING INTO A BROAD LOW-LEVEL CIRCULATION CENTER 
(LLCC). ENVIRONMENTAL ANALYSIS INDICATES MARGINAL CONDITIONS FOR 
DEVELOPMENT AS INDICATED BY WARM (29-30C) SSTS, STRONG UPPER LEVEL 
DIVERGENCE, OFFSET BY 20-25 KNOTS OF VERTICAL WIND SHEAR. GLOBAL MODELS 
ARE IN AGREEMENT WITH A WEST-NORTHWESTWARD TRACK AND STEADY DEVELOPMENT 
AS THE NORTHEAST SURGE WINDS WRAP INTO THE SYSTEM. MAXIMUM SUSTAINED 
SURFACE WINDS ARE ESTIMATED AT 18 TO 23 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 
141500Z.//
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