MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 04W (FOUR) WARNING NR 05// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 04W (FOUR), LOCATED APPROXIMATELY 564 NM EAST OF MANILA, PHILIPPINES, HAS TRACKED NORTHWESTWARD AT 06 KNOTS OVER THE PAST SIX HOURS. THE CURRENT POSITION IS BASED ON RECENT MICROWAVE SATELLITE IMAGERY INCLUDING A 291659Z AMSR2 AND A 291521Z GMI IMAGE. THE INTENSITY OF 35 KNOTS IS CONSISTENT WITH DVORAK CURRENT INTENSITY ESTIMATES OF T2.5 FROM PGTW AND KNES AND SUPPORTED BY EARLIER ASCAT-C DATA INDICATING A MAXIMUM OF 30 TO 35 KNOT WINDS ASSOCIATED WITH THE CIRCULATION. THE REDUCTION IN INTENSITY FROM THE PREVIOUS WARNING IS NOT INDICATIVE OF A WEAKENING TREND, AS NEW DATA INDICATE THE SYSTEM WAS LIKELY A BIT WEAKER SIX HOURS AGO THAN PREVIOUSLY ESTIMATED. TD 04W HAS MAINTAINED ITS STRUCTURE OVER THE PAST SIX HOURS WHILE TRACKING NORTHWESTWARD ALONG THE PERIPHERY OF A SUBTROPICAL STEERING RIDGE SITUATED TO THE NORTH AND EAST. THE AFOREMENTIONED MICROWAVE SATELLITE IMAGES SHOW A PARTIALLY-EXPOSED LOW LEVEL CIRCULATION WITH THE PRIMARY DEEP CONVECTION OFFSET TO THE SOUTHWEST DUE TO PERSISTENT MODERATE NORTHEASTERLY VERTICAL WIND SHEAR (VWS). STRONG DIFFLUENCE ALOFT HAS FUELED CONVECTIVE DEVELOPMENT DESPITE THE NEGATIVE IMPACT OF VWS OVER THE CIRCULATION CENTER. SEA SURFACE TEMPERATURES ARE VERY SUPPORTIVE AT ABOUT 30 DEGREES CELSIUS. 3. FORECAST REASONING. A. THERE IS NO MAJOR CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS WARNING. B. TS 04W WILL CONTINUE TRACKING GENERALLY NORTHWESTWARD FOLLOWING THE STEERING FLOW ASSOCIATED WITH THE SUBTROPICAL STEERING TO THE NORTH AND EAST FOR THE NEXT 72 HOURS. VWS IS EXPECTED TO DECREASE SLIGHTLY THROUGH TAU 48, WHICH SHOULD ALLOW THE SYSTEM TO INTENSIFY SLOWLY WITH THE SUPPORT OF VERY WARM SEA SURFACE TEMPERATURES AND STRONG DIFFLUENCE ALOFT. BY TAU 72, INCREASING VWS AND PASSAGE OVER COOLER WATER WILL LIKELY INDUCE A WEAKENING TREND. NUMERICAL MODEL TRACK FORECAST GUIDANCE COME INTO BETTER ALIGNMENT, WITH THE MAJORITY OF AVAILABLE MODELS NOW INDICATING A TRACK NEAR SOUTHERN TAIWAN OR SLIGHTLY TO THE SOUTH. THE JTWC TRACK FORECAST IS PLACED NEAR THE MULTI-MODEL CONSENSUS THROUGH TAU 72, WITH FAIR CONFIDENCE. C. IN THE EXTENDED RANGE, TS 04W IS EXPECTED TO TRACK INLAND AND DISSIPATE OVER SOUTHEASTERN CHINA. NUMERICAL GUIDANCE DIVERGES AFTER TAU 72, ALTHOUGH ALL MODELS SUPPORT DISSIPATION. BECAUSE MOTION OF THE WEAKENED SYSTEM IS LESS CERTAIN DURING THIS PERIOD, CONFIDENCE IN THE EXTENDED FORECAST PORTION OF THE JTWC TRACK FORECAST IS LOW.// NNNN NNNN