WDPN31 PGTW 150300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 02W (SURIGAE) WARNING 
NR 007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
    TROPICAL STORM (TS) 02W (SURIGAE), LOCATED APPROXIMATELY 105 NM
WEST-SOUTHWEST OF YAP, HAS TRACKED WEST-NORTHWESTWARD AT 04 KNOTS 
OVER THE PAST SIX HOURS. ANIMATED MULTI-SPECTRAL SATELLITE IMAGERY 
(MSI) SHOWS FORMATIVE BANDING WRAPPING INTO A PARTIALLY EXPOSED LOW 
LEVEL CIRCULATION WITH PERSISTANT DEEP CONVECTION OVERHEAD. THE 
INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON A 142111Z 
SSMIS 37GHZ IMAGE WHICH DEPICTS LOW LEVEL BANDING WRAPPING INTO THE 
LOW LEVEL CIRCULATION CENTER. THE INITIAL INTENSITY OF 50 KTS IS 
AVERAGED BETWEEN THE DVORAK INTENSITY ESTIMATES OF T3.5/55KTS FROM 
PGTW AND T3.0/45KTS FROM RJTD AND ALSO THE OBJECTIVE ADT OF 
T3.3/51KTS. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH ROBUST 
DUAL OUTFLOW, LOW TO MODERATE (10-20KT) VERTICAL WIND SHEAR (VWS), 
AND VERY WARM (29-30C) SEA SURFACE TEMPERATURE (SST) IN THE 
PHILIPPINE SEA. TS 02W IS CURRENTLY 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 CONTINUE TO TRACK WEST-NORTHWESTWARD UNDER THE STR 
AND WILL CONTINUE TO STEADILY INTENSIFY AS IT CONTINUES TO 
CONSOLIDATE WITHIN A FAVORABLE ENVIRONMENT, REACHING 95 KTS BY TAU 
72. THERE IS SOME UNCERTAINTY IN INTENSIFICATION BETWEEN TAU 36 AND 
TAU 72 DUE TO THE CONSISTENT SHEAR AND PRESSURE ON THE EASTERN SIDE 
OF TS 02W. NUMERICAL MODELS CONTINUE TO BE IN GOOD AGREEMENT WITH A 
DECREASE IN THE CROSS-TRACK SPREAD TO 130NM AT TAU 72 LENDING TO 
HIGH CONFIDENCE IN THE EARLY PORTION OF THE JTWC TRACK FORECAST 
WHICH IS IN LINE WITH THE CURRENT MODEL CONSENSUS.
   C. AFTER TAU 72, A MIDLATITUDE TROUGH NORTH OF THE STR WILL BEGIN 
TO DEEPEN, CAUSING A BREAK IN STR. ONCE THE STR BREAKS, TS SURIGAE 
WILL  BEGIN TO TURN POLEWARD, TRACKING AROUND EASTERN PORTION OF THE 
RIDGE. THE FAVORABLE ENVIRONMENT WILL CONTINUE AND BRING TS 02W TO A 
PEAK OF 115KTS AT TAU 96 AND WEAKENING SLIGHTLY AFTERWARDS AS COOLER 
SST PREVAIL. NUMERICAL MODEL CROSS-TRACK SPREAD HAS DECREASED TO 
250NM AT TAU 120 OVER THE PAST SIX HOURS, LENDING FAIR CONFIDENCE IN 
THE EXTENDED PORTION OF THE JTWC TRACK FORECAST.//
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