WTPN21 PGTW 141930
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 95W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
100 NM EITHER SIDE OF A LINE FROM 26.9N 139.5E TO 39.7N 141.1E
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 071930Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 27.2N 139.6E. THE SYSTEM IS MOVING NORTHWARD AT 12 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 95W) PREVIOUSLY LOCATED NEAR 
26.0N 139.5E IS NOW LOCATED NEAR 27.2N 139.6E, APPROXIMATELY 505 NM 
SOUTH OF TOKYO, JAPAN. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY 
(EIR) DEPICTS A COMPACT AREA OF DEEP CORE CONVECTION BUILT OVER THE 
CENTER OF THE SYSTEM. A 141048Z ASCAT-B PASS REVEALED A SHARP CUSP 
FEATURE AND 25-30 KNOT WINDS ISOLATED ALONG THE EASTERN QUADRANTS. THIS 
SMALL SYSTEM IS FORMING WITHIN AN EXTENSIVE SWATH OF ELEVATED (20-30 
KNOTS) SOUTHERLY WINDS TRAILING IN THE WAKE OF 06W. ENVIRONMENTAL 
ANALYSIS REVEALS A FAVORABLE ENVIRONMENT MOVING FORWARD WITH LOW 
VERTICAL WIND SHEAR OF 10-15 KNOTS, GOOD EQUATORWARD OUTFLOW ALOFT AND 
WARM (28-29 C) SEA SURFACE TEMPERATURES. DETERMINISTIC MODELS SHOW THE 
SYSTEM FAILING TO CLOSE OFF INTO A DEFINED CIRCULATION AS IT QUICKLY 
TRACKS TO THE NORTH, BUT WITH ENHANCED WINDS CONFINED TO THE EASTERN 
SEMICIRCLE. TRACK GUIDANCE IN GOOD AGREEMENT REGARDING THE TRAJECTORY OF 
THE SYSTEM WITH MINIMAL SPREAD IN ENSEMBLE MEMBERS.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1004 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 
151930Z.
//
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