WTPN21 PGTW 152230
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 98W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 17.3N 130.5E TO 19.4N 125.8E
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 151800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 17.5N 130.0E. THE SYSTEM IS MOVING NORTHWESTWARD AT 10
KNOTS.
2. REMARKS:
(1) THE AREA OF CONVECTION (INVEST 98W) PREVIOUSLY LOCATED
NEAR 16.0N 132.9E, IS NOW LOCATED NEAR 17.5N 130.0E, APPROXIMATELY
521 NM SOUTHEAST OF ISHIGAKI-JIMA, JAPAN. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY SHOWS A LARGE AREA OF CONVECTION UNCOUPLED FROM
AND FAR TO THE WEST OF THE LOW LEVEL CIRCULATION (LLC). A 152029Z
SSMIS F-18 89GHZ SHOWS NO DEEP CONVECTION ABOVE THE LLC AND NO
INDICATION OF LOW-LEVEL WRAPPING. A 151303Z METOP-B ASCAT PASS
DEPICTS A BROAD LLC WITH TROUGHING EXTENDING TO THE SOUTHWEST AND
HIGH (20 TO 30 KNOT) WINDS GREATER THAN 100 NM DISTANT TO THE NORTH
AND SOUTH. 98W IS CURRENTLY IN A FAVORABLE ENVIRONMENT WITH VERY
GOOD WESTWARD AND POLEWARD UPPER LEVEL OUTFLOW, LOW (5 TO 10 KNOT)
VERTICAL WIND SHEAR, AND VERY WARM (30 TO 31 CELSIUS) SEA SURFACE
TEMPERATURES. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 98W WILL
TRACK GENERALLY WEST WHILE MAINTAING A VERY EXPANSIVE WIND FIELD
UNTIL IT BEGINS TO INTERACT WITH AN UPPER LEVEL TROUGH AROUND TAU
96, ELONGATING AND DEFORMING THE SYSTEM, PREVENTING FULL TROPICAL
CONSOLIDATION. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18
TO 23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 997
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
162230Z.//
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