WTPN21 PGTW 261500
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
120 NM EITHER SIDE OF A LINE FROM 8.6N 137.4E TO 11.9N 135.6E
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 261200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 8.7N 137.2E. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 07 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 99W) PREVIOUSLY LOCATED NEAR
8.3N 138.5E IS NOW LOCATED NEAR 8.7N 137.2E, APPROXIMATELY 77 NM
SOUTHWEST OF YAP. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A
PARTIAL 261216Z ASCAT PASS DEPICT A SWATH OF 25 KT WINDS ON THE WESTERN
AND SOUTHERN PERIPHERIES OF AN ELONGATED AREA OF ROTATION WHICH EXTENDS
FROM THE LOW LEVEL CIRCULATION CENTER (LLCC) TOWARDS THE SOUTHWEST
TOWARDS PALAU. ENVIRONMENTAL ANALYSIS REVEALS A FAVORABLE ENVIRONMENT
FOR DEVELOPMENT WITH MODERATE POLEWARD UPPER-LEVEL OUTFLOW, LOW TO
MODERATE VERTICAL WIND SHEAR (10-15 KTS), AND WARM SEA SURFACE
TEMPERATURES (29-30 C). GLOBAL DETERMINISTIC AND ENSEMBLE MODELS AGREE
ON 99W TRACKING GENERALLY NORTHWESTWARD OVER THE NEXT 24-48 HOURS AS IT
CONTINUES TO CONSOLIDATE AND STEADILY INTENSIFY. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 18 TO 23 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1005 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
271500Z.//
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