MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 04W (MERBOK) WARNING NR 02// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION 04W (MERBOK), LOCATED APPROXIMATELY 298 NM WEST-NORTHWEST OF MANILA, PHILIPPINES, HAS TRACKED NORTH- NORTHWESTWARD AT 11 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM CONTINUING TO CONSOLIDATE WITH CONVECTIVE BANDING WRAPPING INTO PERSISTENT CONVECTION LOCATED TO THE SOUTHEAST OF THE LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS BASED ON THE MSI AND EXTRAPOLATION FROM AN 110204Z METOP-B AMSU 89GHZ MICROWAVE IMAGE. THE INITIAL INTENSITY OF 30 KNOTS IS BASED ON MULTI AGENCY DVORAK ESTIMATES OF T2.0 AND AN 110205Z METOP-B ASCAT PASS SHOWING 30 KNOT WIND BARBS IN THE EASTERN SEMI-CIRCLE. ENVIRONMENTAL ANALYSIS INDICATES FAVORABLE CONDITIONS FOR FURTHER DEVELOPMENT WITH LOW VERTICAL WIND SHEAR VALUES (10-15 KNOTS), STRONG EQUATORWARD OUTFLOW, AND WARM SEA SURFACE TEMPERATURES (30-31 C). TROPICAL DEPRESSION (TD) 04W IS CURRENTLY TRACKING TO THE NORTHWEST ALONG THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE. 3. FORECAST REASONING. A. NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TD 04W IS EXPECTED TO CONTINUE TO TRACK TO THE NORTHWEST ALONG THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR). THE SYSTEM IS FORECAST TO MAKE LANDFALL TO THE EAST OF HONG KONG JUST BEFORE TAU 36. ONCE 04W MAKES LANDFALL IT WILL ROUND THE NORTHWESTERN EDGE OF THE STR, EXIT INTO THE EAST CHINA AND ACCELERATE NORTHEASTWARD. THE CURRENT FAVORABLE ENVIRONMENT WILL CAUSE THE SYSTEM TO GRADUALLY INTENSIFY, PEAKING AT 40 KNOTS JUST PRIOR TO LANDFALL. POST LANDFALL, LAND INTERACTION WILL CAUSE TD 04W TO RAPIDLY DISSIPATE. C. AFTER TAU 72, TD 04W WILL CONTINUE TO DETERIORATE AS IT TRACKS TO NORTHEAST. DYNAMIC MODEL GUIDANCE IS IN STRONG AGREEMENT THAT THE SYSTEM WILL TURN TO THE EAST, WITH VARIATION IN HOW RAPIDLY THE TURN OCCURS. THE CONSENSUS HAS THE SYSTEM TRACKING NORTH OF OKINAWA WHICH IS WHERE THE JTWC OFFICIAL FORECAST TRACK IS LOCATED. JTWC HAS HIGH CONFIDENCE IN ITS FORECAST TRACK UNTIL TAU 72 WHEN THE VARIATIONS IN TRACK LOCATION BY THE DYNAMIC MODEL GUIDANCE LENDS LOW CONFIDENCE IN THE JTWC TRACK FORECAST.// NNNN NNNN