Tropical Storm DUJUAN Advisory 2月21日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 01W (DUJUAN)
WARNING NR 015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 01W (DUJUAN), LOCATED 658 NM SOUTHEAST
OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 13 KNOTS OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY
SHOWS A RAGGED LOW LEVEL CIRCULATION (LLC), INITIAL POSITION IS
PLACED WITH FAIR CONFIDENCE BASED ON THE EIR LOOP. THE INITIAL
INTENSITY OF 30KTS IS BASED ON DVORAK ESTIMATES OF T2.0/30KTS
(PGTW/RJTD) AND SUPPORTED BY THE ADVANCED DVORAK TECHNIQUE (ADT)
OBJECTIVE ESTIMATE OF T2.4/34KTS. ANALYSIS INDICATES WARM (29-30C)
ALONG-TRACK SST AND ROBUST WEST AND POLEWARD OUTFLOW ALOFT.
ADDITIONALLY, THE WARM MOIST AIR AHEAD OF THE TD IS OVERRUNNING THE
COLD NORTHEASTERLY WIND SURGE IN THE PHILIPPINE SEA. DEEP CONVECTION
REMAINS AHEAD OF THE DISPLACED LLC BY HIGH (30KT) SOUTHEASTERLY
VERTICAL WIND SHEAR (VWS). THE CYCLONE IS NOW TRACKING NORTHWESTWARD
AS THE SUBTROPICAL RIDGE (STR) STEERS IT TOWARDS THE PHILIPPINE
ISLANDS.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE IN THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TD 01W WILL CONTINUE TRACKING NORTHWESTWARD AS THE STEERING
STR TO THE NORTHEAST BUILDS, THE SYSTEM WILL MAKE INITIAL LANDFALL
OVER SAMAR, PHILIPPINES, JUST AFTER TAU 24 AND THEN ENTER THE
SIBUYAN SEA AND ENCOUNTER COOLER 27C SSTS. AFTER TAU 24, HIGH
RELATIVE VWS COMBINED WITH THE RUGGED TERRAIN OF THE MULTIPLE
ISLANDS WILL ERODE THE TD TO DISSIPATION BY TAU 48, POSSIBLY SOONER.
NUMERICAL MODELS DIVERGE SIGNIFICANTLY TO 250NM+ BY TAU 48. THIS
INDICATES UNCERTAINTY IN THE MODELS TRACKING A WEAK VORTEX, LENDING
OVERALL LOW CONFIDENCE IN THE JTWC TRACK FORECAST.//
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