WDPN32 PGTW 100900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 17W (SEVENTEEN) 
WARNING NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 17W (SEVENTEEN), LOCATED APPROXIMATELY 
307 NM EAST-SOUTHEAST OF DA NANG, VIETNAM, HAS TRACKED NORTHWESTWARD 
AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL 
SATELLITE IMAGERY DEPICTS A PARTIALLY-EXPOSED, DEFINED LOW-LEVEL 
CIRCULATION CENTER (LLCC) WITH FORMATIVE CONVECTIVE BANDING OVER THE 
WESTERN SEMICIRCLE. A 100224Z MHS 89GHZ MICROWAVE IMAGE REVEALS 
LIMITED CONVECTIVE BANDING WRAPPING INTO THE WESTERN QUADRANT WITH A 
WEAKLY-DEFINED LLCC, WHICH SUPPORTS THE INITIAL POSITION WITH FAIR 
CONFIDENCE. THE INITIAL INTENSITY IS ASSESSED AT 30 KNOTS BASED ON A 
100224Z ASCAT-B IMAGE SHOWING NUMEROUS 25-30 KNOT WINDS SURROUNDING 
A DEFINED CENTER. UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE 
ENVIRONMENT WITH DIFFLUENT FLOW AND LOW VERTICAL WIND SHEAR. SST 
VALUES ARE CONDUCIVE FOR FURTHER DEVELOPMENT AT 29-30C. TD 17W IS 
TRACKING NORTHWESTWARD 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. TD 17W WILL TRACK GENERALLY WESTWARD THROUGH THE REMAINDER OF 
THE FORECAST PERIOD ALONG THE SOUTHERN PERIPHERY OF THE 
AFOREMENTIONED LOW-LEVEL STR. TD 17W WILL STEADILY INTENSIFY TO A 
PEAK INTENSITY OF 45 KTS BY TAU 24. THE SYSTEM SHOULD MAKE LANDFALL 
NEAR TAU 30 SOUTH OF DANANG, VIETNAM. AFTERWARDS, INCREASING VWS AND 
THE RUGGED TERRAIN OF VIETNAM WILL STEADILY WEAKEN THE SYSTEM UNTIL 
DISSIPATION BY TAU 72. NUMERICAL MODEL GUIDANCE REMAINS IN GOOD 
AGREEMENT THROUGHOUT THE FORECAST PERIOD WITH A 70 NM SPREAD AT TAU 
36. THE JTWC FORECAST TRACK LIES NEAR THE MULTI-MODEL CONSENSUS AND 
THE ECMWF MODEL SOLUTION WITH FAIR CONFIDENCE.//
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