WTPN21 PGTW 260500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
140 NM EITHER SIDE OF A LINE FROM 17.4N 114.6E TO 22.3N 114.8E
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 17 TO 22 KNOTS. METSAT
IMAGERY AT 260146Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 17.6N 114.6E. THE SYSTEM IS MOVING NORTH-NORTHEASTWARD AT 07
KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 16.9 N
114.4E, IS NOW LOCATED NEAR 17.6N 114.6E, APPROXIMATELY 280 NM
SOUTH OF HONG KONG. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
DEPICTS AN AREA OF DEEPENING CONVECTION AND SIGNIFICANT
CONSOLIDATION OVER THE LAST SIX HOURS FORMING A LOW LEVEL
CIRCULATION CENTER (LLCC). THE INCREASE IN BROAD CIRCULATION
EXHIBITS AN IMPROVING VORTICITY SIGNATURE OF THE SYSTEM WITH
VERTICAL WIND SHEAR BECOMING MORE FAVORABLE OVER THE PAST SIX HOURS
(10-15 KNOTS). A 260146Z METOP-B ASCAT PASS IDENTIFIES THE WELL
DEFINED CIRCULATION CENTER, GIVING HIGH CONFIDENCE TO THE INITIAL
POSITION, AND ALSO SHOWS 20 KNOT WIND BARBS DISPLAYED IN THE
SOUTHEAST QUADRANT WRAPPING INTO THE LLCC. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 17 TO 22 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 1004 MB. BASED ON RECENT CONSOLIDATION AND
FAVORABLE ENVIRONMENTAL CONDITIONS, 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
270500Z.
//
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