WDPN31 PGTW 140900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 02W (SURIGAE) WARNING NR 004// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 02W (SURIGAE), LOCATED APPROXIMATELY 55 NM SOUTHWEST OF YAP, HAS TRACKED NORTHWESTWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM HAS MAINTAINED OVERALL CONVECTIVE SIGNATURE WITH THE MAIN CONVECTION SLIGHTLY OFFSET WESTWARD FROM A PARTIALLY EXPOSED LOW LEVEL CIRCULATION. THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE USING LOW CLOUD-TRACING IN THE MSI LOOP INTO AN OBSCURED CIRCULATION CENTER THAT LINED UP WELL WITH A DEFINED LLC FEATURE IN THE 140400Z AMSR2 36GHZ IMAGE. THE INITIAL INTENSITY OF 35KTS IS SUPPORTED BY THE DVORAK ESTIMATES OF T2.5/35KTS FROM PGTW, RJTD AND THE OBJECTIVE ADT AND REFLECTS THE SUSTAINED 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 A SUBTROPICAL RIDGE (STR) EXTENSION 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 NORTHWESTWARD UNDER THE STR. THE AFOREMENTIONED FAVORABLE ENVIRONMENT WILL PROMOTE STEADY INTENSIFICATION TO 85KTS BY TAU 72. NUMERICAL MODELS ARE IN OVERALL GOOD AGREEMENT WITH A GRADUAL AND EVEN SPREAD TO 185NM BY TAU 72 WITH EEMN ON THE LEFT- AND JGSM ON THE RIGHT-MARGIN OF THE ENVELOPE, LENDING FAIR CONFIDENCE IN THIS PORTION OF THE JTWC TRACK FORECAST THAT IS LAID CLOSE TO THE MODEL CONSENSUS. C. AFTER TAU 72, A MIDLATITUDE TROUGH DIGGING IN FROM EASTERN ASIA WILL BREAK THE STR. THE EASTERN SIDE WILL ASSUME STEERING AND BY TAU 96, WILL DRIVE TS 02W NORTHWARD TOWARD THE BREAK. A RAPID INTENSIFICATION IS EXPECTED AS THE FAVORABLE CONDITIONS ARE FURTHER ENHANCED BY INCREASED POLEWARD OUTFLOW AND DECREASING VWS. BY TAU 120, TS 02W WILL SURGE TO 120KTS, POSSIBLY HIGHER. NUMERICAL MODELS SPREAD OUT EVEN MORE TO 300NM BY TAU 120, MAINTAINING FAIR CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC TRACK FORECAST.// NNNN