WTPN21 PGTW 061930

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//

SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 96W)//

RMKS/

1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN

150 NM EITHER SIDE OF A LINE FROM 28.0N 162.3E TO 35.5N 151.4E

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 42 TO 48 KNOTS. METSAT

IMAGERY AT 061800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED

NEAR 28.2N 162.1E. THE SYSTEM IS MOVING NORTHWARD AT 09 KNOTS.

2. REMARKS: THE AREA OF CONVECTION (INVEST 96W) PREVIOUSLY LOCATED NEAR

27.2N 162.5E IS NOW LOCATED NEAR 28.2N 162.1E, APPROXIMATELY 1266 NM

EAST-SOUTHEAST OF MISAWA, JAPAN. THE SYSTEM IS CURRENTLY CLASSIFIED AS A

MONSOON DEPRESSION, GENERALLY CHARACTERIZED AS A LARGE CYCLONIC

CIRCULATION, GREATER THAN 600NM DIAMETER, WITH EXTENSIVE GALE-FORCE

WINDS AROUND THE PERIPHERY AND A WEAK CORE OF LIGHT WINDS. ANIMATED

ENHANCED INFRARED IMAGERY (EIR) DEPICTS FLARING CONVECTION ISOLATED TO

THE NORTHERN AND WESTERN PERIPHERY OF A PARTIALLY EXPOSED, BROAD LOW-

LEVEL CIRCULATION CENTER (LLCC). AN EXTENSIVE AREA OF CONVECTION

ASSOCIATED WITH THE HIGHEST WIND SPEEDS SURROUNDING THE CENTRAL VORTEX

ALSO EXTENDS POLEWARD AND EASTWARD OF THE LLCC. THE RADIUS OF MAXIMUM

WINDS REMAINS HIGH, ASSESSED TO BE AN AVERAGE OF 110 NM IN THE VICINITY

OF THE LLCC, BUT HAS DECREASED OVER THE PAST 12 HOURS. THE ENVIRONMENT

IS MARGINALLY FAVORABLE FOR DEVELOPMENT, WITH MODERATE VERTICAL WIND

SHEAR (15-25 KTS), WARM SEA SURFACE TEMPERATURES (26-28 C), AND GOOD

POLEWARD OUTFLOW ALOFT. GLOBAL MODELS INDICATE THE SYSTEM WILL SLOWLY

CONSOLIDATE AND TRANSITION INTO A WARM-CORE TROPICAL CYCLONE AS IT

TRACKS NORTHWESTWARD OVER THE NEXT FEW DAYS. FOR HAZARDS AND WARNINGS,

REFERENCE THE FLEET WEATHER CENTER SAN DIEGO HIGH WINDS AND SEAS PRODUCT

OR REFER TO LOCAL WMO DESIGNATED FORECAST AUTHORITY. MAXIMUM SUSTAINED

SURFACE WINDS ARE ESTIMATED AT 42 TO 48 KNOTS. MINIMUM SEA LEVEL

PRESSURE IS ESTIMATED TO BE NEAR 987 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

071930Z.//

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