WDPN31 PGTW 200900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 01W (DUJUAN) 
WARNING NR 013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 01W (DUJUAN), LOCATED APPROXIMATELY 355 
NM EAST OF DAVAO, PHILIPPINES, HAS TRACKED NORTHEASTWARD AT 06 KNOTS 
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY 
SHOWS A FULLY EXPOSED, RAGGED, LOW LEVEL CIRCULATION (LLC) THAT IS 
DECOUPLED 100NM+ SOUTHEASTWARD FROM THE MAIN CONVECTION. THE INITIAL 
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE LLC IN THE 
ABOVE ANIMATION. THE INITIAL INTENSITY OF 30KTS IS HEDGED ON THE 
HIGH END OF AGENCY DVORAK ESTIMATES RANGING FROM T1.5/25KTS (KNES) 
TO T2.0/30KTS (PGTW/RJTD) AND SUPPORTED BY THE ADT ESTIMATE OF 
27KTS. ANALYSIS INDICATES WARM (29-30C) ALONG-TRACK SST AND STRONG 
WESTWARD AND POLEWARD OUTFLOW ALOFT. ADDITIONALLY, THE WARM MOIST 
AIR AHEAD OF THE TD IS OVERRUNNING THE COLD NORTHEASTERLY WIND SURGE 
IN THE PHILIPPINE SEA. THIS COMBINATION IS FUELING THE EXPLOSIVE 
DEEP MAIN CONVECTION EVEN THOUGH IT IS DISPLACED BY HIGH (30KT) 
SOUTHEASTERLY VERTICAL WIND SHEAR (VWS). THE NET EFFECT IS AN 
OVERALL UNFAVORABLE ENVIRONMENT. THE CYCLONE IS LODGED JUST TO THE 
SOUTH OF A COL BETWEEN THE DEEP LAYERED SUBTROPICAL RIDGES (STR) TO 
THE NORTHEAST AND NORTHWEST.   
3. FORECAST REASONING.
   A. THE FORECAST IS NOW TERMINATED AT TAU 48 IN ANTICIPATION OF AN 
EARLIER DISSIPATION, OTHERWISE, THERE IS NO SIGNIFICANT CHANGE IN 
THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING 
MESSAGE.
   B. TD 01W WILL SLOWLY TRACK NORTHWESTWARD AS THE STR TO THE 
NORTHEAST ASSUMES STEERING, MAKING LANDFALL OVER LEYTE, PHILIPPINES, 
AFTER TAU 36. THE HARSH ENVIRONMENT, MOSTLY DUE TO THE STRONG VWS, 
WILL FURTHER WEAKEN THE TD TO 25KTS BY TAU 12. AFTERWARD, AS THE 
STORM MOTION BECOMES MORE IN-PHASE WITH THE UPPER LEVEL WIND FLOW 
AND AS THE NORTHEAST COLD SURGE ABATES, THE VWS WILL RELAX A BIT AND 
ALLOW A SLIGHT INTENSIFICATION TO 30KTS BY TAU 24. AFTERWARD, LAND 
INTERACTION WILL GRADUALLY ERODE THE TD TO DISSIPATION BY TAU 48. 
NUMERICAL MODELS DIVERGE SIGNIFICANTLY TO 240NM+ BY TAU 48. THIS, 
PLUS THE UNCERTAINTY IN THE EVENTUAL NORTHWESTWARD MOTION, LEND LOW 
CONFIDENCE IN THE JTWC TRACK FORECAST.//
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