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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