WDPN31 PGTW 130300 
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 03W (THREE) 
WARNING NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
    TROPICAL STORM(TS) 03W (THREE), LOCATED APPROXIMATELY 206 NM 
EAST OF DAVAO, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 06 
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE 
IMAGERY SHOWS THE SYSTEM CONSOLIDATING IN A FAVORABLE ENVIRONMENT 
CHARACTERIZED BY WARM (30C) SEA SURFACE TEMPERATURES AND LOW 
VERTICAL WIND SHEAR. THE INITIAL INTENSITY ASSESSMENT IS BASED ON A 
PGTW DVORAK ASSESSMENT OF T2.0 (30KT) FACTORED WITH A SHIP REPORT OF 
40KTS TO THE NORTHEAST OF THE LOW LEVEL CIRCULATION CENTER. A 
122141Z SSMIS PASS SHOWS CURVED BANDS OF DEEP CONVECTION OVER BOTH 
THE POLEWARD AND EQUATORWARD SEMICIRCLES. THE CONVECTION IS WEAKER 
OVER THE WESTERN SEMICIRCLE, HOWEVER, AND THE HIGHER FREQUENCY 
MICROWAVE BAND REVEALS A SLOT OF DRY AIR BETWEEN THE LLCC AND THE 
OUTER CONVECTIVE BAND. TS 03W IS MOVING STEADILY WESTWARD ALONG THE 
SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE. 700-850MB MEAN 
STEERING LAYER WINDS INDICATE A FIRM WESTWARD STEERING FLOW ALL THE 
WAY ACROSS MINDANAO. TOTAL PRECIPITABLE WATER LOOPS SHOW PRONOUNCED 
DRYING NORTH OF THE 10TH LATITUDE, WHERE VERTICAL WIND SHEAR RISES 
SHARPLY. 
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE 
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. THERE IS GOOD CONVICTION THAT TS 03W WILL CONTINUE TRACKING 
WEST-NORTHWESTWARD THROUGH THE NEXT 24 HOURS AND MAKE LANDFALL OVER 
THE SURIGAO DEL SUR PROVINCE OF MINDANAO, NEAR THE 8TH LATITUDE. FOR 
THE NEXT 24 HOURS THE ENVIRONMENT WILL REMAIN FAVORABLE, WITH LOW 
VWS, WARM SSTS AND MARGINAL OUTFLOW ALOFT, WHICH WILL ALLOW FOR THE 
SYSTEM TO STEADILY INTENSIFY TO A PEAK OF 45 KTS AT LANDFALL. MODELS 
ARE IN GOOD AGREEMENT THAT THE SYSTEM WILL TRANSLATE OVER THE RUGGED 
TERRAIN OF MINDANAO AND INTO THE SULU SEA AFTER TAU 36. AS 03W MOVES 
INTO THE SULU SEA AND RECONSOLIDATES, SUBSIDENCE AND INCREASING 
VERTICAL WIND SHEAR FROM AN UPPER-LEVEL TROUGH ENCROACHING FROM THE 
NORTHWEST WILL RETARD FURTHER DEVELOPMENT. THERE IS EXCELLENT 
CONFIDENCE IN THE TRACK FORECAST THROUGH THE FIRST 24 HOURS, BUT 
ONLY FAIR CONFIDENCE ONCE 03W MOVES INTO THE SULU SEA. THE TRACK 
THROUGH THE SULU SEA IS MUCH LESS CLEAR AT THIS POINT DUE TO THE 
UNCERTAINTY OF HOW MUCH WILL BE LEFT OF THE LOW LEVEL VORTEX, THE 
EFFECTS OF A MORE SUBSIDENT UPPER LEVEL ENVIRONMENT, AND A MORE 
AMBIGUOUS STEERING FLOW. THERE IS ALSO GOOD CONFIDENCE IN THE 
INTENSITY FORECAST THROUGH LANDFALL. AFTER LANDFALL, CONFIDENCE IN 
THE INTENSITY FORECAST DROPS PRECIPITOUSLY DUE TO THE EXACT POSITION 
AND INTENSITY OF THE UPPER LEVEL TROUGH DIGGING INTO THE SOUTH CHINA 
SEA. ANIMATED WATER VAPOR IMAGERY IS NOT YET REVEALING CONCLUSIVE 
SIGNS OF THE INTENSITY AND MOVEMENT OF THE UPPER LEVEL TROUGH AT 
THIS EARLY JUNCTURE.//
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