WTPN21 PGTW 252330
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 99W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
085 NM EITHER SIDE OF A LINE FROM 16.0N 161.9E TO 18.1N 163.7E
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 25 KNOTS. METSAT
IMAGERY AT 251800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 16.0N 162.0E. THE SYSTEM IS MOVING NORTH-NORTHWESTWARD AT 08
KNOTS.
2. REMARKS:THE AREA OF CONVECTION (INVEST 99W) PREVIOUSLY LOCATED NEAR 
15.3N 162.3E IS NOW LOCATED NEAR 16.0N 162.0E, APPROXIMATELY 330 NM 
SOUTHWEST OF WAKE ISLAND. ANIMATED ENHANCED INFRARED IMAGERY (EIR) 
DEPICTS DISORGANIZED BURSTS OF DEEP CONVECTION FULLY OBSCURING A LOOSELY 
DEFINED LOW-LEVEL CIRCULATION CENTER. THE 251441Z AMSR2 WINDSPEED 
PRODUCT REVEALED A COMPACT, ASYMMETRIC, AND WEAK WIND FIELD, WITH 15-20 
KT WINDS CONFINED TO BENEATH THE DEEP CONVECTION. THE 251807Z SSMIS 91 
GHZ DATA REVEALS FAINT LOW LEVEL CLOUD BANDING WRAPPING INTO THE CENTRAL 
DEPP CONVECTIVE PLUME. ENVIRONMENTAL ANALYSIS IS CONDUCIVE FOR 
DEVELOPMENT WITH LOW VERTICAL WIND SHEAR (10-15 KTS), WARM SEA SURFACE 
TEMPERATURES (29-30 C), ABUNDANT DEEPLAYER MOISTURE, AND STRONG POLEWARD 
OUTFLOW ALOFT. GLOBAL DETERMINISTIC AND ENSEMBLE MODELS ILLUSTRATE 
GRADUAL TO STEADY DEVELOPMENT OVER THE NEXT 24-36 HOURS AS THE SYSTEM 
TRANSITS GENERALLY NORTHWARD. MAXIMUM SUSTAINED SURFACE WINDS ARE 
ESTIMATED AT 18 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 
262330Z.
//
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