WDPN31 PGTW 220300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 09W (VICENTE) WARNING 
NR 06//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 09W (VICENTE), LOCATED APPROXIMATELY 180 NM SOUTH-
SOUTHEAST OF HONG KONG, HAS TRACKED WEST-NORTHWESTWARD AT 10 KNOTS 
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY 
SHOWS CONTINUED DEVELOPMENT OF DEEP CONVECTIVE BANDING WRAPPING 
ALONG THE SOUTHERN AND WESTERN SECTORS. THE CURRENT POSITION IS 
BASED ON A 212250Z WINDSAT CORIOLIS 37 GHZ IMAGE WITH HIGH 
CONFIDENCE. THE CURRENT INTENSITY IS MAINTAINED HIGHER THAN THE 
SUBJECTIVE DVORAK ESTIMATES OF 25-35 KNOTS FROM PGTW, RJTD, AND 
KNES DUE TO THE OBJECTIVE 211900Z SATCON ESTIMATE OF 42 KNOTS AND 
DEEP CONVECTIVE SPIRAL BAND CURVATURE OVER THE WESTERN SEMI-CIRCLE 
OF THE LLCC. UPPER-LEVEL ANALYSIS CONTINUES TO SHOW A SMALL 
ANTICYCLONE BUILDING JUST NORTH THE LLCC, SUPPORTING THE EQUATORIAL 
VENTING OF THE SYSTEM. HOWEVER, INDUCED UPPER-LEVEL TROUGHING 
EXISTS BETWEEN THIS SMALLER ANTICYCLONE AND A POINT SOURCE OF 
DIVERGENCE TO THE SOUTHEAST OF THE SYSTEM WHICH IS INDUCING UPPER-
LEVEL CONVERGENCE EAST OF THE LLCC. TS 09W IS CURRENTLY BEING 
STEERED BY THE SOUTHERN PERIPHERY OF A ZONAL DEEP-LAYERED 
SUBTROPICAL RIDGE (STR) ANCHORED OVER EASTERN ASIA AND IS UNDER 
MODERATE 15-20 KNOT EASTERLY VWS.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. TS VICENTE WILL CONTINUE TO TRACK WEST-NORTHWESTWARDS UNDER 
THE SOUTHERN PERIPHERY THE STEERING STR FOR THE ENTIRE FORECAST 
PERIOD. THE RECENT WEST-NORTHWESTWARDS MOTION IS DUE TO THE 
INCREASED INTENSITY OF TS 09W WHICH ALLOWS THE SYSTEM TO SLIGHTLY 
WEAKEN THE RIDGE PERIPHERY VIA BETA-EFFECT PROPAGATION. TS 09W 
SHOULD CONTINUE TO GRADUALLY INTENSIFY AS UPPER-LEVEL CONDITIONS 
SHOULD REMAIN CONSISTENT, IF NOT BECOME SLIGHTLY BETTER, DURING THE 
NEXT 36-48 HOURS. BY TAU 48 THE LLCC WILL ENCOUNTER COMPETING 
INFLUENCES FROM LAND INTERACTION WITH THE COASTLINE WEST OF THE 
LUICHOW PENINSULA AND WARM SST (28-30 CELSIUS) IN THE GULF OF 
TONKIN BUT SHOULD BE ABLE TO MAINTAIN STRONG TS STRENGTH AS IT 
APPROACHES NORTHERN VIETNAM BY TAU 72.
   C. TS 09W SHOULD DISSIPATE OVERLAND BY TAU 96. NUMERICAL MODEL 
GUIDANCE REMAINS IN GOOD AGREEMENT IN REGARDS TO THE TRACK 
TRAJECTORY BUT THE NOGAPS, GFDN, JGSM, AND WBAR SEEM TOO SLOW IN 
TRACK SPEED FOR THE SYNOPTIC ENVIRONMENT. DESPITE THESE TRANSLATION 
SPEED DISCREPANCIES, HIGH CONFIDENCE REMAINS IN THE OFFICIAL JTWC 
TRACK FORECAST DUE TO THE WELL ESTABLISHED SYNOPTIC ENVIRONMENT AS 
ANALYZED FROM THE 211200Z UPPER-LEVEL SOUNDINGS IN THE AREA.//
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