UNCLAS //N03145// MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 04W WARNING NR/ 03// RMKS/ WDPN32 PGTW 191500 1. FOR METEOROLOGISTS. 2. PROGNOSTIC REASONING FOR 191200Z3 TO 221200Z7 MAY 03. A. TROPICAL STORM (TS) 04W, LOCATED APPROXIMATELY 115 NM WEST OF CHUUK, HAS TRACKED NORTHEASTWARD AT 04 KNOTS OVER THE PAST 06 HOURS. THE WARNING POSITION IS BASED ON 191130Z5 ENHANCED INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 25 TO 35 KNOTS. ANIMATED INFRARED AND RECENT MICROWAVE IMAGERY REVEALS THE LOW LEVEL CIRCULATION CENTER (LLCC) IS PARTIALLY EXPOSED TO THE EAST OF THE DEEP CONVECTION. B. TS 04W IS EXPECTED TO TRACK NORTH-NORTHEASTWARD IN THE EARLY PERIOD AS IT CONSOLIDATES AND THEN POLEWARD TOWARDS A DEVELOPING WEAKNESS IN THE LOW TO MID-LEVEL RIDGE NORTH OF THE SYSTEM. THIS WEAKNESS IS FORECAST TO BE ENHANCED BY A MID-LATITUDE TROUGH TRANSLATING EASTWARD FROM THE ASIAN CONTINENT. IN THE LATE PERIOD A MORE NORTH-NORTHWESTWARD TRACK IS FORECAST AS THE SYSTEM TRACKS POLEWARD AROUND THE WESTERN PERIPHERY OF THE LOW TO MID-LEVEL RIDGE IN THE WEAKNESS. THE AVAILABLE DYNAMIC AIDS CONSISTING OF NOGAPS, UKMET (EGRR), THE JAPANESE GLOBAL (JGSM), COAMPS, AND NCEP GFS, ARE IN ONLY FAIR AGREEMENT WITH THIS SCENARIO. GFS TRACKS THE SYSTEM MUCH MORE RAPIDLY TO THE NORTHWEST, CREATING A MUCH LARGER SYSTEM AND MODIFYING THE RIDGE NORTH OF THE SYSTEM. GFDN, NOGAPS, AND COAMPS HAVE A SLOWER TRACK SPEED EARLY IN THE FORECAST PERIOD AND DEVELOP THE SYSTEM MORE SLOWLY. OUR FORECAST IS BASED ON PERSISTENCE AND A BLEND OF THE AVAILABLE DYNAMIC AIDS. C. THE SYSTEM IS EXPECTED TO INTENSIFY AT A NEAR CLIMATOLOGICAL RATE IN A MODERATE TO FAVORABLE UPPER LEVEL ENVIRONMENT WITH GOOD POLEWARD OUTFLOW POTENTIAL AFTER THE EARLY PERIOD. D. CURRENT WIND RADII ARE BASED ON RECENT MICROWAVE DATA AND AN AIR FORCE RECON FLIGHT. FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE-SIZED SYSTEM. 3. RELEASED BY LT BRYANT, USN. FORECAST TEAM: BRYANT/NOREN/JACOBS/NUTONGLA// NNNN