WDPN32 PGTW 110300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 17W (LINFA) WARNING NR 
005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 17W (LINFA), LOCATED APPROXIMATELY 100 NM 
SOUTHEAST OF DA NANG, VIETNAM, HAS TRACKED WESTWARD AT 08 KNOTS 
(KTS) OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE 
IMAGERY (MSI) REVEALS A WELL-DEFINED LOW LEVEL CIRCULATION CENTER 
(LLCC) WITH CONVECTIVE BANDING WRAPPING IN FROM THE NORTH AND WEST. 
A 102350Z GMI 89 GHZ MICROWAVE IMAGE REVEALS DEEP CONVECTION 
WRAPPING INTO A DEFINED LLCC WHICH SUPPORTS THE INITIAL POSITION 
WITH HIGH CONFIDENCE. THE INITIAL INTENSITY REMAINS ASSESSED AT 40 
KTS BASED ON A 101824Z SATCON ESTIMATE OF 42 KTS AND A 102330Z 
ADVANCED DVORAK TECHNIQUE ESTIMATE OF T2.7 (39 KTS). DIFFLUENT FLOW 
ALOFT, WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURES (SST), AND LOW 
(<10 KT) VERTICAL WIND SHEAR (VWS) ESTABLISH AN OVERALL FAVORABLE 
ENVIRONMENT FOR DEVELOPMENT. TS 17W IS TRACKING WESTWARD UNDER THE 
STEERING INFLUENCE OF A SUBTROPICAL RIDGE (STR) POSITIONED TO THE 
NORTH 
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. TS 17W IS CURRENTLY POSITIONED JUST OFF THE COAST OF VIETNAM 
AND SHOULD MAKE LANDFALL SOUTH OF DA NANG, VIETNAM PRIOR TO TAU 12. 
AFTERWARDS, THE SYSTEM WILL TRACK GENERALLY WESTWARD THROUGH THE 
REMAINDER OF THE FORECAST ALONG THE SOUTHERN PERIPHERY OF THE 
AFOREMENTIONED LOW-LEVEL STR. TS 17W WILL BEGIN TO WEAKEN AS IT 
MAKES LANDFALL AND BEGINS TO TRACK ACROSS THE RUGGED TERRAIN OF 
VIETNAM. COMBINED WITH THE INCREASING VWS, DISSIPATION IS EXPECTED 
BY TAU 36. WITH THE EXCEPTION OF THE UKMET ENSEMBLE MEAN AND JGSM 
SOLUTIONS, NUMERICAL MODEL GUIDANCE REMAINS IN GOOD AGREEMENT 
THROUGHOUT THE FORECAST PERIOD WITH A 60 NM SPREAD AT TAU 24. THE 
JTWC FORECAST TRACK LIES NEAR THE MULTI-MODEL CONSENSUS AND THE 
ECMWF MODEL SOLUTION WITH GOOD CONFIDENCE.//
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