WTPN21 PGTW 171430
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
165 NM EITHER SIDE OF A LINE FROM 7.2N 140.1E TO 8.1N 130.3E
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 171200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 7.2N 137.9E. THE SYSTEM IS MOVING WESTWARD AT 17 KNOTS.
2. REMARKS:
THE AREA OF CONVECTION (INVEST 98C) PREVIOUSLY LOCATED NEAR 7.6N 
141.0E, IS NOW LOCATED NEAR 7.2N 139.8E, APPROXIMATELY 730NM EAST OF 
DAVAO CITY, THE PHILIPPINES. ANIMATED ENHANCED INFRARED IMAGERY AND 
A 171224Z 89GHZ AMSU-B MICROWAVE IMAGE SHOW A PERSISTENT MASS OF 
CONVECTION ABOVE A SLIGHTLY ELONGATED LLC. DESPITE SOME HIGH (25-30 
KTS) VWS TO THE WEST OF THE SYSTEM, WESTWARD UL OUTFLOW IS PROVIDING 
ENOUGH EXHAUST TO OFFSET THE SHEAR. SSTS REMAIN WARM (28-29C) IN THE 
PHILIPPINE SEA AND WILL SUPPORT FURTHER DEVELOPMENT. GLOBAL MODELS 
ALL PREDICT THE SYSTEM WILL REACH TROPICAL DEPRESSION STRENGTH AS IT 
TRACKS WEST-SOUTHWEST OVER THE NEXT 24 HOURS. HOWEVER, GFS IS 
SIGNIFICANTLY MORE AGGRESSIVE THAN THE OTHERS, CALLING FOR AN 
INTENSITY OF 50 KNOTS BY TAU 24. 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 
181430Z.//
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