WTPN21 PGTW 090200
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 94W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
A 085 NM RADIUS OF 10.9N 127.0E 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 20 TO 25 KNOTS. METSAT IMAGERY AT 090000Z INDICATES THAT A
CIRCULATION CENTER IS LOCATED NEAR 10.9N 126.8E. THE SYSTEM IS
MOVING SOUTHWESTWARD AT 01 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 94W) PREVIOUSLY LOCATED 
NEAR 10.8N 126.8E IS NOW LOCATED NEAR 10.9N 126.8E, APPROXIMATELY 
220 NM SOUTHEAST OF LEGAZPI, PHILIPPINES. ANIMATED MULTISPECTRAL 
SATELLITE IMAGERY DEPICTS PERSISTENT CONVECTION OBSCURING A BROAD 
LOW LEVEL CIRCULATION (LLC). A 082149Z SSMIS 91GHZ PASS REVEALS 
RAGGED BANDING IN THE NORTHERN AND SOUTHERN PERIPHERY OF THE LLC. A 
082300Z OBSERVATION FROM GUIUAN REVEALS NORTH-NORTHEAST WINDS AT 
19KT. A 082300Z SHIP OBSERVATION NORTH-NORTHEAST OF GUIUAN FROM AN 
UNKNOWN ELEVATION REVEALS NORTHEAST WINDS AT 26KT. RECENT 
SCATTEROMETER DATA REVEALS 20-25KT WINDS AROUND THE LLC. 
ENVIRONMENTAL ANALYSIS INDICATES GENERALLY FAVORABLE CONDITIONS FOR 
DEVELOPMENT, CONSISTING OF ROBUST POLEWARD OUTFLOW ALOFT AND WARM 
(28-29C) SEA SURFACE TEMPERATURES, OFFSET BY LOW TO MODERATE (15-
20KT) VERTICAL WIND SHEAR. GLOBAL MODELS ARE IN GOOD AGREEMENT ON 
THE POSITION OF 94W BUT DIFFER ON INTENSIFICATION AND TRACK. GFS 
RAPIDLY INTENSIFIES 94W TO TROPICAL STORM STRENGTH WITHIN 18-24 
HOURS AND KEEPS IT RATHER SMALL AND TIGHTLY WOUND BEFORE BEING 
SLINGSHOT EASTWARD INTO THE SOUTHERN SEMICIRCLE OF 02W. HOWEVER, 
ECMWF SHOWS MUCH SLOWER DEVELOPMENT WITH A SLOW NORTHWARD MOTION 
OVER THE NEXT 36-48 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE 
ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED 
TO BE NEAR 1003 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A 
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED TO 
HIGH. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1003 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 
100200Z.
//
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