Subject: Pacific-NW: Rmks/

From: SIU Weather Processor <[email-masked]>
Date: Sun, 19 Sep 2010 22:14:08 -0500

WTPN22 PGTW 200300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE FORMATION ALERT REISSUED//
REF/A/MSG/NAVMARFCSTCEN PEARL HARBOR HI/190251ZSEP2010//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
130 NM EITHER SIDE OF A LINE FROM 17.7N 147.0E TO 21.3N 143.9E
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 15 TO 20 KNOTS. METSAT IM-
AGERY AT 200000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 18.0N 146.7E.  THE SYSTEM IS MOVING NORTHWESTWARD AT 14
KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 13.9N
151.2E IS NOW LOCATED NEAR 18.0N 146.7E, APPROXIMATELY 175 NM NORTH-
NORTHEAST OF SAIPAN. RECENT ANIMATED MULTISPECTRAL SATELLITE IMAGERY
INDICATES A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC)
WITH EXTENSIVE DEEP CONVECTION FLARING ALONG THE EASTERN PERIPHERY
AND WEAK LOW LEVEL WESTERLIES ALONG THE SOUTHERN PERIPHERY. THE LLCC
IS LOCATED IN AN AREA OF MODERATE SOUTHEASTERLY VERTICAL WIND SHEAR
AND MODERATE POLEWARD AND EASTWARD UPPER LEVEL OUTFLOW IN THE
GRADIENT BETWEEN AN UPPER LEVEL ANTICYCLONE AND A TROPICAL UPPER
TROPOSPHERIC TROUGH (TUTT) TO THE NORTH. THE LLCC IS EXPECTED TO
BECOME MORE ORGANIZED AS THE TUTT SHIFTS NORTHWARD OVER THE NEXT 24
HOURS, REDUCING SUBSIDENCE INDUCED BY THE TROUGH AND IMPROVING
POLEWARD OUTFLOW. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT
15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR
1006 MB. BECAUSE UPPER LEVEL CONDITIONS ARE EXPECTED TO BECOME MORE
FAVORABLE, 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
210300Z.//

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