WTPS21 PGTW 291800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 99P)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 13.9S 167.4W TO 19.6S 164.5W
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 27 TO 33 KNOTS. METSAT
IMAGERY AT 291800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 13.7S 167.5W. THE SYSTEM IS MOVING EAST-NORTHEASTWARD AT 06
KNOTS.
2. REMARKS:THE AREA OF CONVECTION (INVEST 99P) PREVIOUSLY LOCATED NEAR 
13.4S 169.7W IS NOW LOCATED NEAR 13.7S 167.5W, APPROXIMATELY 120 NM 
EAST-NORTHEAST OF MANUA ISLANDS. ANIMATED ENHANCED INFRARED SATELLITE 
IMAGERY DEPICTS DEEP CONVECTION BUILDING OVER A SLOWLY CONSOLIDATING LOW 
LEVEL CIRCULATION CENTER (LLCC). ENVIRONMENTAL ANALYSIS FOR THE AREA 
INDICATES A FAVORABLE ENVIRONMENT WITH WARM SEA SURFACE TEMPERATURES 
(29-30 C), MINIMAL VERTICAL WIND SHEAR (LESS THAN 10 KTS), AND ROBUST 
POLEWARD OUTFLOW ALOFT. GLOBAL DETERMINISTIC AND ENSEMBLE MODELS ARE IN 
GOOD AGREEMENT THAT 99P WILL DEVELOP RAPIDLY OVER THE NEXT 24 HOURS.  
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 27 TO 33 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 
301800Z.
//
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