WTPN21 PGTW 230400
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 91W) REISSUED//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/220351ZSEP26//
AMPN/REF IS TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 15.0N 139.3E TO 17.0N 134.8E
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 230000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 15.1N 139.0E. THE SYSTEM IS MOVING NORTHWESTWARD AT 13
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 91W) PREVIOUSLY LOCATED
NEAR 14.3N 140.0E IS NOW LOCATED NEAR 15.1N 139.0E, APPROXIMATELY
349NM WEST-NORTHWEST OF GUAM. MULTISPECTRAL SATELLITE IMAGERY (MSI) 
DEPICTS CURVED, DEEP CONVECTIVE BANDING, WITH A CONSOLIDATING, ELONGATED 
LOW LEVEL CIRCULATION CENTER (LLCC). THE MID-LEVEL CIRCULATION AND MOST 
OF THE CONVECTION ARE DISPLACED TO THE NORTH OF THE SURFACE CENTER. THE 
SYSTEM HAS SLOWLY BECOME BETTER ORGANIZED AND IS ON THE CUSP OF BECOMING 
A TROPICAL DEPRESSION. ENVIRONMENTAL ANALYSIS INDICATES A FAVORABLE 
CONDITIONS FOR DEVELOPMENT WITH LOW VERTICAL WIND SHEAR (10-15KTS), GOOD 
POLEWARD OUTFLOW, AND VERY WARM SEA SURFACE TEMPERATURES (29-30C). 
GLOBAL DETERMINISTIC AND ENSEMBLE MODELS AGREE ON TROPICAL CYCLONE 
FORMATION WITHIN 24 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. THIS SUPERSEDES REF A (WTPN21 
PGTW 230400).
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY 
240400Z.//
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