WTPN21 PGTW 081530
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 93W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
220 NM EITHER SIDE OF A LINE FROM 12.6N 131.9E TO 17.7N 129.9E
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 30 TO 35 KNOTS. METSAT IMAGERY AT 
081500Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 12.6N 
131.9E. THE SYSTEM IS MOVING EAST-NORTHEASTWARD AT 06 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 93W) PREVIOUSLY LOCATED 
NEAR 12.4N 131.3E IS NOW LOCATED NEAR 12.6N 131.9E, APPROXIMATELY 
351NM NORTH-NORTHWEST OF PALAU. THIS SYSTEM IS CURRENTLY CLASSIFIED 
AS A MONSOON DEPRESSION WITH EXPANSIVE GALE-FORCE WINDS OVER THE 
EASTERN PERIPHERY OF THE SYSTEM. THE GALE-FORCE WINDS ARE LOCATED 
OVER 300NM FROM THE BROAD, POORLY-DEFINED SYSTEM CENTER. AS IS 
TYPICAL WITH MONSOON DEPRESSIONS, ANIMATED ENHANCED INFRARED 
SATELLITE IMAGERY AND A 080928Z SSMIS 91GHZ MICROWAVE IMAGE DEPICT 
EXTENSIVE AREAS OF INTENSE DEEP CONVECTION OVER THE WESTERN, 
SOUTHERN AND EASTERN PERIPHERIES WITH NO CENTRAL CONVECTION OVER THE 
BROAD, POORLY-DEFINED LOW-LEVEL CIRCULATION. A 081025Z ASCAT-A 
PARTIAL IMAGE REVEALS AN ELONGATED, WEAK CIRCULATION WITH 20-25 KNOT 
WESTERLY WINDS OVER THE SOUTHERN SEMICIRCLE AND SHARP TROUGHING 
EXTENDING NORTHEASTWARD INTO INVEST 94W, WHICH IS ROTATING AROUND 
THE PERIPHERY OF INVEST 93W. UPPER-LEVEL ANALYSIS INDICATES A 
MARGINAL ENVIRONMENT WITH CONVERGENT NORTHERLY FLOW OVER THE LLC AND 
LOW TO MODERATE (10-20 KTS) VERTICAL WIND SHEAR. GLOBAL MODELS 
INDICATE THAT THIS MONSOON DEPRESSION WILL STEADILY STRENGTHEN AS IT 
TRACKS NORTHWARD TO NORTHWESTWARD OVER THE NEXT TWO DAYS. THE SYSTEM 
IS EXPECTED TO GRADUALLY GAIN TROPICAL CYCLONE (WARM-CORE) 
CHARACTERISTICS WITH IMPROVED CENTRAL CONVECTION AND A RADIUS OF 
MAXIMUM WINDS LESS THAN 100NM. BASED ON THE PERIPHERAL WINDS IN 
RECENT ASCAT IMAGERY, MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED 
AT 30 TO 35 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE 
NEAR 996 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 
091530Z.//
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