Subject: Pacific-NW: Rmks/

From: SIU Weather Processor <[email-masked]>
Date: Wed, 22 Sep 2010 21:02:06 -0500

WTPN21 PGTW 230200
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE FORMATION ALERT REISSUED//
REF/A/MSG/NAVMARFCSTCEN PEARL HARBOR HI/220151ZSEP2010//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
165 NM EITHER SIDE OF A LINE FROM 13.5N 156.0W TO 14.5N 162.0W
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 IM-
AGERY AT 222332Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 13.6N 156.4W.  THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 09
KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 12.2N
153.0W IS NOW LOCATED NEAR 13.6N 156.4W, APPROXIMATELY 370 NM SOUTH-
SOUTHWEST OF HILO. RECENT ANIMATED MULTISPECTRAL SATELLITE IMAGERY
SHOWS AN EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH FLARING
CONVECTION LOCATED ALONG THE EASTERN PERIPHERY. ALSO, A 230002Z AMSU
IMAGE DEPICTS IMPROVED LOW LEVEL CONVECTIVE BANDING. UPPER LEVEL
ANLAYSIS INDICATES A TROUGH IS CAUSING SUBSIDENCE ALOFT AS WELL AS
INCREASED VERTICAL WIND SHEAR ALONG THE NORTHWESTERN PERIPHERY.
HOWEVER, THE SYSTEM IS CURRENTLY LOCATED IN AN AREA OF MODERATE
VERTICAL WIND SHEAR (15 TO 20 KNOTS) WITH GOOD DIVERGENCE ALOFT
FAVORABLE FOR DEVELOPMENT. THE SYSTEM IS EXPECTED TO CONTINUE
TRACKING WESTWARD. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT
17 TO 22 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 REMAINS GOOD. THIS
SUPERSEDES REF A.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
240200Z.//

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