WDPN31 PGTW 141500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 02W (SURIGAE) WARNING 
NR 005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
    TROPICAL STORM (TS) 02W (SURIGAE), LOCATED APPROXIMATELY 74 NM
WEST-SOUTHWEST OF YAP, HAS TRACKED WEST-NORTHWESTWARD AT 03 KNOTS 
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE 
IMAGERY SHOWS THE SYSTEM HAS MAINTAINED OVERALL CONVECTIVE SIGNATURE 
WITH THE MAIN CONVECTION SLIGHTLY OFFSET WESTWARD FROM AN OBSCURED 
LOW LEVEL CIRCULATION. THE INITIAL POSITION AND INTENSITY OF 35KTS 
ARE BASED WITH HIGH CONFIDENCE ON THE 141127Z ASCAT BULLSEYE PASS. 
THE INITIAL INTENSITY IS ALSO SUPPORTED BY THE DVORAK ESTIMATES OF 
T2.5/35KTS FROM PGTW, RJTD AND THE OBJECTIVE ADT OF T2.3/33KTS AND 
REFLECTS THE SUSTAINED EIR CONVECTIVE SIGNATURE. ANALYSIS INDICATES 
A FAVORABLE ENVIRONMENT WITH ROBUST DUAL OUTFLOW, LOW TO MODERATE 
(10-20KT) VERTICAL WIND SHEAR (VWS), AND VERY WARM (30-31C) SEA 
SURFACE TEMPERATURE IN THE PHILIPPINE SEA. THE CYCLONE IS TRACKING 
ALONG THE SOUTHWEST PERIPHERY OF AN EXTENSION OF THE SUBTROPICAL 
RIDGE (STR) TO THE NORTHEAST. 
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE 
PREVIOUS PROGNOSTIC REASONING MESSAGE.   
   B. TS 02W WILL TRACK MORE NORTHWESTWARD UNDER THE STR. THE 
AFOREMENTIONED FAVORABLE ENVIRONMENT WILL FUEL STEADY 
INTENSIFICATION TO 70KTS BY TAU 48. AFTERWARD, RAPID INTENSIFICATION 
(RI) IS EXPECTED AS THE FAVORABLE CONDITIONS ARE FURTHER ENHANCED BY 
INCREASING POLEWARD OUTFLOW AND DECREASING VWS, AND BY TAU 72, REACH 
95KTS. NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH A GRADUAL SPREAD 
TO 130NM BY TAU 72 WITH EEMN AND ECMF THE NOTABLE LEFT-OF-TRACK 
OUTLIERS, LENDING HIGH CONFIDENCE IN THIS PORTION OF THE JTWC TRACK 
FORECAST THAT IS LAID JUST RIGHT OF THE MODEL CONSENSUS TO OFFSET 
THE LEFT OUTLIERS.
   C. AFTER TAU 72, A MIDLATITUDE TROUGH DIGGING IN FROM EASTERN 
ASIA WILL BREAK THE STR. IN RESPONSE, TS SURIGAE WILL TRACK MORE 
POLEWARD AS THE EASTERN SIDE OF THE RIDGE WILL ASSUME STEERING AND 
BY TAU 96, WILL DRIVE THE CYCLONE NORTH-NORTHEASTWARD TOWARD THE 
BREAK. CONCURRENTLY, THE HIGHLY FAVORABLE CONDITIONS WILL EXTEND THE 
RI AND BRING TS 02W TO A PEAK OF 120KTS. AFTERWARD, INCREASING VWS 
WILL GRADUALLY ERODE THE SYSTEM TO 110KTS BY TAU 120. NUMERICAL 
MODELS SPREAD OUT FURTHER TO 360NM BY TAU 120, LENDING FAIR 
CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC TRACK FORECAST.//
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