WTPN21 PGTW 181530
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 97W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 9.0N 161.2E TO 11.9N 150.4E
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 181200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 9.2N 160.2E. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 20
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 97W) PREVIOUSLY LOCATED 
NEAR 8.0N 163.8E, IS NOW LOCATED NEAR 9.2N 160.2E, APPROXIMATELY 950 
NM EAST-SOUTHEAST OF ANDERSEN AFB, GUAM. ANIMATED ENHANCED INFRARED 
SATELLITE IMAGERY DEPICTS A LARGE AREA OF FLARING CONVECTION 
OBSCURING A CONSOLIDATING LOW LEVEL CIRCULATION. AN 181041Z ASCAT 
PASS SHOWS A SWATH OF 20-25KT WINDS BELOW THE CONVECTION AND A WEAK 
RETURN FLOW, CONSISTENT WITH THE FORMATIVE NATURE OF THE LOW LEVEL 
ENVIRONMENT. ENVIRONMENTAL CONDITIONS ARE OVERALL FAVORABLE, WITH 
LOW (5-10KT) VWS, GOOD DIVERGENCE ALOFT, AND 29-31C SSTS. GLOBAL 
MODELS ARE IN BETTER AGREEMENT, WITH GFS AND ECMWF SHOWING 
DEVELOPMENT IN THE NEAR TERM, AND NAVGEM AND UKMO HOLDING OFF ON 
DEVELOPMENT UNTIL THE MID-LATE TAUS. TRACK SOLUTIONS ARE IN GOOD 
AGREEMENT THROUGH TAU 72, ANTICIPATING A WEST-NORTHWESTWARD TRACK 
TOWARDS GUAM/CNMI. 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 
191530Z.//
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