Tropical Storm DUJUAN Advisory dom, 21-02

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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