WTPN21 PGTW 210600
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 98W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 3.8N 112.5E TO 10.4N 115.9E 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 210530Z INDICATES THAT 
A CIRCULATION CENTER IS LOCATED NEAR 4.4N 112.8E. THE SYSTEM IS MOVING 
NORTH-NORTHEASTWARD AT 07 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 98W) PREVIOUSLY LOCATED NEAR 
4.3N 113.0E IS NOW LOCATED NEAR 4.4N 112.8E, APPROXIMATELY 259 NM WEST 
OF BRUNEI. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A 202305Z SSMIS 
91GHZ MICROWAVE IMAGE DEPICT A MORE SYMMETRIC CIRCULATION, WITH 
FRAGMENTED, FORMATIVE BANDING ORGANIZING AROUND THE CIRCULATION, AND 
DEEP CONVECTION BUILDING OVER THE CENTER. ADDITIONALLY, A 210204Z ASCAT 
PASS SHOWS 15 KNOTS WRAPPING AROUND THE CIRCULATION, WITH STRONGER 30 
KNOT WINDS LOCATED AROUND THE SOUTHWEST PERIPHERY. ENVIRONMENTAL 
ANALYSIS REVEALS THAT INVEST 98W IS IN A FAVORABLE ENVIRONMENT FOR 
FURTHER DEVELOPMENT, WITH WARM (29-30C) SEA SURFACE TEMPERATURES, GOOD 
POLEWARD OUTFLOW ALOFT, OFFSET BY MODERATE TO HIGH VERTICAL WIND SHEAR 
(20-25KTS). GLOBAL MODELS ARE IN GOOD AGREEMENT THAT INVEST 98W WILL 
GENERALLY TRACK POLEWARD OVER THE NEXT 36 HOURS. MAXIMUM SUSTAINED 
SURFACE WINDS ARE ESTIMATED AT 18 TO 23 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 
220600Z.//
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