WTPN21 PHNC 171330
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (99E)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
145 NM EITHER SIDE OF A LINE FROM 12.6N 105.6W TO 15.2N 110.6W
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 23 TO 27 KNOTS. METSAT
IMAGERY AT 081712Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 12.9N 106.3W. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 11
KNOTS.
2. REMARKS: AN AREA OF CONVECTION (INVEST 99E) IS LOCATED NEAR 12.9N 
106.3W APPROXIMATELY 1329 NM SOUTH-SOUTHEAST OF SAN DIEGO. ANIMATED 
ENHANCED INFRARED (EIR) SATELLITE IMAGERY AND A 170820Z AMSR2 89 GHZ 
IMAGE DEPICT AN CONSOLIDATING LOW LEVEL CIRCULATION CENTER (LLCC) WITH 
CONVECTION TO THE NORTHWESTERN PERIPHERY TO THE CIRCULATION. 
ENVIRONMENTAL ANALYSIS INDICATES A FAVORABLE AREA FOR DEVELOPMENT WITH 
VERY WARM (29-30C) SEA SURFACE TEMPERATURES, LOW (5-10KT) VERTICAL WIND 
SHEAR, AND MODERATE EQUATORWARD OUTFLOW ALOFT. GLOBAL DETERMINISTIC AND 
ENSEMBLE MODELS ARE IN GOOD AGREEMENT THAT 99E WILL CONTINUE TO TRACK 
GENERALLY NORTHWESTWARD OVER THE NEXT 24 HOURS. MAXIMUM SUSTAINED SURFACE 
WINDS ARE ESTIMATED AT 23 TO 27 KNOTS. MINIMUM SEA LEVEL PRESSURE IS 
ESTIMATED TO BE NEAR 1002 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 
181330Z.
//
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