WDPN31 PGTW 250300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (TRAMI) WARNING NR 019// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 16.9N 118.8E INITIAL INTENSITY: 50 KTS GEOGRAPHIC REFERENCE: 188 NM NORTHWEST OF MANILA, PHILIPPINES MOVEMENT PAST 6 HOURS: WESTWARD AT 05 KTS SIGNIFICANT WAVE HEIGHT: 19 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A CONSOLIDATING CENTRAL DENSE OVERCAST (CDO) THAT IS FULLY OBSCURING THE LLCC BENEATH. A 242235Z SSMIS 37GHZ MICROWAVE IMAGE INDICATES A WELL DEFINED LOW LEVEL CIRCULATION WITH THE MAJORITY OF DEEP CONVECTION TO THE SOUTH OF THE LLCC. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON EIR AND SSMIS IMAGERY. THE INITIAL INTENSITY OF 50 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE PREPONDERANCE OF INTENSITY GUIDANCE INDICATING 45-57KTS. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: COMBINED STEERING INFLUENCE OF THE NEAR-EQUATORIAL RIDGE (NER) TO THE SOUTHEAST AND A SUBTROPICAL RIDGE (STR) TO THE NORTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T3.5 - 55 KTS RJTD: T3.0 - 45 KTS RCTP: T3.0 - 45 KTS KNES: T3.0 - 45 KTS DEMS: T2.5 - 35 KTS CIMSS SATCON: 51 KTS AT 242226Z CIMSS ADT: 45 KTS AT 242330Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 15-20 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE EQUATORWARD ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TS 22W IS FORECASTED TO CONTINUE TRACKING WESTWARD UNDER THE COMBINED STEERING INFLUENCES OF A NER TO THE SOUTHEAST AND A STR TO THE NORTHEAST. WHILE THE OVERALL ENVIRONMENT IS CHARACTERIZED AS MODERATELY FAVORABLE, PERSISTENT MID-UPPER LEVEL VERTICAL WIND SHEAR IS FORECASTED TO PREVENT 22W FROM SIGNIFICANTLY INTENSIFYING. OVER THE NEXT 36 HOURS THE SYSTEM WILL STILL CLIMB TO 55KTS AND POSSIBLY HIGHER AS IT TRANSITS THE BASIN. NEAR TAU 48, A PASSING MID-LATITUDE TROUGH BREAKS DOWN THE STR WHILE AT THE SAME TIME THE NER RIDGE IS BUILDING. THE RESULT OF THESE ATMOSPHERIC FORCINGS IS THAT 22W IS FORECASTED TO MAKE AN ABOUT-FACE THROUGH TAU 96 AND STEADY UP ON A RECIPROCAL COURSE, AND TRACK EASTWARD INTO THE SCS. THROUGH THE ENTIRE COURSE CHANGE, VERTICAL WIND SHEAR CONTINUES TO INCREASE BEYOND 45KTS, RESULTING IN A STEADY WEAKENING TREND THROUGH TAU 120. MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT THAT 22W WILL APPROACH VIETNAM BEFORE TURNING SOUTH AND EVENTUALLY EASTWARD THROUGH TAU 120. THE TIMING AND NATURE OF THIS TURN IS NOT AGREED UPON HOWEVER. FOR THIS REASON, THE INITIAL JTWC TRACK FORECAST IS PLACED WITH HIGH CONFIDENCE AND WITH LOW CONFIDENCE THEREAFTER. RELIABLE MODEL INTENSITY GUIDANCE INDICATES GRADUAL INTENSIFICATION THROUGH TAU 36 AND STEADY WEAKENING THEREAFTER. THE TRACK GUIDANCE HAS AN IMMENSE IMPACT ON THE INTENSITY FORECAST DUE TO THE UNKNOWN EXTENT OF LAND INTERACTION, BECAUSE OF THIS, THE JTWC FORECAST INTENSITY IS PLACED INITIALLY WITH MEDIUM CONFIDENCE AND WITH LOW CONFIDENCE THEREAFTER. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN