#6 Postby Chacor » Mon Mar 16, 2009 9:25 am
TCFA:
WTPS21 PGTW 161300
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
180 NM EITHER SIDE OF A LINE FROM 18.1S 163.5W TO 23.9S 160.9W
WITHIN THE NEXT 06 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 25 TO 30 KNOTS. METSAT IM-
AGERY AT 161230Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 18.9S 163.2W. THE SYSTEM IS MOVING SOUTHWARD AT 06 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 18.1S
163.1W, IS NOW LOCATED NEAR 18.9S 163.2W, APPROXIMATELY 240 NM NORTH-
WEST OF RAROTONGA. ANIMATED INFRARED SATELLITE IMAGERY AND A 16/0803Z
METOP-A IMAGE INDICATE A RAPIDLY CONSOLIDATING LOW-LEVEL CIRCULATION
CENTER (LLCC) WITH MULTIPLE DEEP CONVECTIVE BANDS SPIRALING INTO THE
CENTER. THIS SYSTEM, LIKE TC 20P, IS DEVELOPING FROM THE MID-LEVELS
DOWN TO THE SURFACE. HOWEVER, UNLIKE 20P, THIS SYSTEM HAS BETTER
RADIAL OUTFLOW WITH MORE RAPIDLY IMPROVING CONVECTIVE BANDING EVID-
ENT AT THIS EARLY STAGE OF DEVELOPMENT. DESPITE SURFACE DEVELOPMENT
LAGGING SLIGHTLY BEHIND CONVECTIVE ORGANIZATION, SCATTEROMETER DATA
HAS INCREASINGLY SUPPORTED A STRENGTHENING LLCC. A PARTIAL 160805Z
ASCAT IMAGE SHOWS 25-30 KNOT NORTHERLY FLOW OVER THE EASTERN SEMI-
CIRCLE. THESE WINDS WERE VERIFIED BY A 16/00Z SHIP OBSERVATION FROM
MYMX5 OF 340/22 KNOTS. THE OVERALL ENVIRONMENT IS VERY FAVORABLE
FOR FURTHER DEVELOPMENT. UPPER-LEVEL ANALYSIS AND ANIMATED WATER
VAPOR IMAGERY INDICATE AN ANTICYCLONE OVER THE LLCC WITH VERY GOOD
POLEWARD OUTFLOW ENHANCED BY TWO UPPER-LEVEL LOWS (SOUTHWEST AND
SOUTHEAST OF THE SYSTEM), AS WELL AS EXCELLENT EQUATORWARD OUTFLOW
ENHANCED BY STRONG CROSS-EQUATORIAL FLOW. THE SST OF 29C, OCEAN
HEAT CONTENT AND A DEEP MOISTURE ENVELOPE (> 60MM) SUPPORT CONTIN-
UED CONSOLIDATION. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED
AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE
NEAR 1000 MB. BASED ON THE FAVORABLE ENVIRONMENT CHARACTERIZED BY
EXCELLENT OUTFLOW AND A RAPIDLY ORGANIZING LLCC, 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 171300Z.//
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