Subject: Pacific-NW: 1. Formation Of A Significant Tropical Cyclone Is Possible Within

From: SIU Weather Processor <[email-masked]>
Date: Sat, 11 Dec 2010 13:32:04 -0600

WTPN21 PGTW 111930
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 7.8N 114.3E TO 11.0N 109.4E
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 111800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 8.2N 113.7E.  THE SYSTEM IS MOVING SOUTHWESTWARD AT 05
KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 9.7N
116.0E IS NOW LOCATED NEAR 8.2N 113.7E, APPROXIMATELY 435 NM EAST-
SOUTHEAST OF HO CHI MINH, VIETNAM. RECENT ANIMATED INFRARED
SATELLITE IMAGERY SHOWS INCREASED DEEP CENTRAL CONVECTION OVER A
DEVELOPING LOW LEVEL CIRCULATION CENTER (LLCC). A 111414Z AMSU
MICROWAVE IMAGE DEPICTS WEAK LOW LEVEL BANDING AND A 111413Z ASCAT
PASS SHOWS STRONGER 20-KNOT WINDS WRAPPING AROUND THE NORTHERN AND
WESTERN PERIPHERIES WITH WEAKER 10-KNOT WINDS AROUND THE
SOUTHEASTERN QUADRANT OF THE LLCC. SHIP OBSERVATIONS APPROXIMATELY
100 NM TO THE SOUTHEAST INDICATE PRESSURES OF 1006 TO 1007 MB. UPPER
LEVEL ANALYSIS INDICATES THE SYSTEM IS CURRENTLY LOCATED JUST SOUTH
OF THE SUBTROPICAL RIDGE AXIS IN AN AREA OF MODERATE VERTICAL WIND
SHEAR (20 KNOTS) WITH GOOD DIVERGENCE ALOFT. SEA SURFACE
TEMPERATURES ARE FAVORABLE FOR DEVELOPMENT. HOWEVER, DRY,
NORTHEASTERLY FLOW ALONG THE NORTHWESTERN PERIPHERY OF THE LLCC IS
EVIDENT IN RECENT MICROWAVE IMAGERY AND IN THE TOTAL PRECIPITABLE
WATER PRODUCT, WHICH MAY HINDER DEVELOPMENT OR ONLY ALLOW WEAK
DEVELOPMENT.  DUE TO INCREASE CENTRAL CONVECTION, FAVORABLE SEA
SURFACE TEMPERATURE AND DIVERGENCE ALOFT, THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS GOOD.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
121930Z.//

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