WDPN32 PGTW 250900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 21W (MOLAVE) WARNING NR 
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 21W (MOLAVE), LOCATED APPROXIMATELY 238 NM 
EAST-SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 14 
KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL 
SATELLITE IMAGERY INDICATES A RAPIDLY CONSOLIDATING SYSTEM WITH 
TIGHTLY-CURVED BANDING WRAPPING INTO A DEFINED LOW LEVEL CIRCULATION 
CENTER (LLCC). A 250525Z GMI 89 GHZ MICROWAVE IMAGE SHOWS CONVECTIVE 
BANDING WRAPPING TIGHTLY INTO THE CLEARLY-DEFINED LLCC; THE 37 GHZ 
IMAGE DEPICTS A SYMMETRIC MICROWAVE EYE FEATURE, SUPPORTING THE 
INITIAL POSITION WITH GOOD CONFIDENCE. THE INITIAL INTENSITY IS 
ASSESSED AT 60 KTS HEDGED BETWEEN DVORAK CURRENT INTENSITY ESTIMATES 
OF T3.5 (55 KTS, RJTD) AND T4.0 (65 KTS, PGTW/KNES). FURTHERMORE, A 
250610Z ADVANCED DVORAK TECHNIQUE ESTIMATE OF T3.5 (55 KTS) AND A 
250340Z SATCON ESTIMATE OF 63 KTS LEND CONFIDENCE TO THIS INTENSITY. 
ENVIRONMENTAL ANALYSIS REVEALS EXCELLENT EQUATORWARD OUTFLOW AND 
IMPROVING POLEWARD OUTFLOW, LOW TO MODERATE (15-20 KTS) VERTICAL 
WIND SHEAR, AND WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURES (SST) 
CONTRIBUTING TO AN OVERALL FAVORABLE ENVIRONMENT FOR CONTINUED 
DEVELOPMENT. TS 21W IS TRACKING WESTWARD UNDER THE STEERING 
INFLUENCE OF A SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTHEAST 
WITH AN EXTENSION TO THE NORTH.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE 
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 21W IS EXPECTED TO CONTINUE INTENSIFYING AS IT TRACKS 
GENERALLY WESTWARD ALONG THE PERIPHERY OF THE STR. AS FAVORABLE 
CONDITIONS PERSIST, THE SYSTEM SHOULD INTENSIFY TO 65 KTS PRIOR TO 
MAKING LANDFALL OVER THE EASTERN PHILIPPINES NEAR TAU 06. AS IT 
TRANSITS OVER THE INNER SEAS SOUTH OF LUZON, THE SYSTEM SHOULD 
MAINTAIN INTENSITY UNTIL THE SYSTEM RE-EMERGES OVER THE SOUTH CHINA 
SEA WHERE IT IS EXPECTED TO RE-INTENSIFY. TS 21W IS EXPECTED TO 
INTENSIFY TO PEAK AT 85 KTS BY TAU 60 AND THEN GRADUALLY WEAKEN AS 
IT APPROACHES THE COAST. NUMERICAL GUIDANCE IS IN GOOD AGREEMENT 
THROUGH TAU 72 WITH A 112 NM SPREAD IN SOLUTIONS AT TAU 72. 
CONSEQUENTLY, THERE IS HIGH CONFIDENCE IN THIS PHASE OF THE FORECAST.
   C. SHORTLY AFTER TAU 72, NUMERICAL GUIDANCE DIVERGES SLIGHTLY AS 
THE SYSTEM MAKES LANDFALL OVER CENTRAL VIETNAM. TS 21W WILL WEAKEN 
SIGNIFICANTLY AS IT TRACKS INLAND OVER RUGGED TERRAIN. DUE TO THE 
TIGHTER AGREEMENT BETWEEN THE MODELS, THERE IS OVERALL HIGH 
CONFIDENCE IN THE JTWC FORECAST TRACK.//
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