WTPS21 PGTW 121400
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 91P)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
125 NM EITHER SIDE OF A LINE FROM 8.4S 169.2E TO 13.3S 174.4E
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 28 TO 32 KNOTS. METSAT
IMAGERY AT 121130Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 8.6S 169.4E. THE SYSTEM IS MOVING SOUTHEASTWARD AT 12 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 91P) PREVIOUSLY LOCATED NEAR 
7.0S 167.8E IS NOW LOCATED NEAR 8.6S 169.4E, APPROXIMATELY 722 NM 
NORTHWEST OF NADI, FIJI. ANIMATED ENHANCED INFRARED (EIR) SATELLITE 
IMAGERY AND A 120710Z SSMIS 91 GHZ MICROWAVE IMAGE DEPICT A 
CONSOLIDATING, PARTIALLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) 
WITH PERSISTENT DEEP CONVECTION TO THE WEST-SOUTHWEST AND FORMATIVE 
BANDING IN THE EASTERN PERIPHERIES. ENVIRONMENTAL ANALYSIS INDICATES 
THAT 91P IS IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH STRONG 
RADIAL OUTFLOW ALOFT, WARM SEA SURFACE TEMPERATURES (29-30 C), AND LOW 
TO MODERATE VERTICAL WIND SHEAR (10-25 KTS). GLOBAL MODELS ARE IN GOOD 
AGREEMENT THAT 91P WILL TRACK SOUTHEASTWARD AND CONTINUE TO DEVELOP OVER 
THE NEXT 24 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 28 
TO 32 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 999 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 
131400Z.//
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