WDPN31 PGTW 301500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 29W (KROSA) WARNING NR 07// RMKS// 1. FOR METEOROLOGISTS 2. 6-HOUR SUMMARY AND ANALYSIS: TROPICAL STORM 29W (KROSA), LOCATED APPROXIMATELY 374 NM EAST- NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 14 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS IMPROVED DEEP CONVECTIVE BANDING WRAPPING TIGHTLY INTO A CONSOLIDATED LOW-LEVEL CIRCULATION CENTER (LLCC). A 301059Z SSMIS IMAGE INDICATES THE BANDING HAS DEEPENED AS WELL AS REVEALS THE FORMATION OF A MICROWAVE EYE WITH THE LLCC CRADLED WITHIN THE CUSP FEATURE. THERE IS GOOD CONFIDENCE IN THE INITIAL POSITION BASED ON THE ABOVE ANIMATION AND THE MICROWAVE IMAGERY. THE INITIAL INTENSITY OF 60 KNOTS IS BASED ON THE HIGH END OF DVORAK ESTIMATES RANGING FROM 45 TO 65 KNOTS FROM PGTW, RJTD, AND KNES. OVERALL, THE UPPER-LEVEL ENVIRONMENT CONTINUES TO BE FAVORABLE FOR FURTHER DEVELOPMENT WITH GOOD POLEWARD AND EQUATORWARD OUTFLOW AS WELL AS WEAK TO MODERATE (10-15 KNOT) VERTICAL WIND SHEAR. TS 29W IS TRACKING WESTWARD UNDER THE STEERING INFLUENCE OF THE MID-LEVEL SUBTROPICAL RIDGE (STR) TO THE NORTH. 3. FORECAST REASONING: A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 29W IS FORECAST TO TRACK GENERALLY WEST-NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STR THROUGHOUT ITS LIFESPAN. FAVORABLE UPPER LEVEL CONDITIONS, IN ADDITION TO PERENNIALLY WARM SEA SURFACE TEMPERATURES IN THE PHILIPPINE SEA WILL ENSURE RAPID INTENSIFICATION THROUGH TAU 12 TO AN INTENSITY OF 75 KNOTS PRIOR TO MAKING LANDFALL INTO LUZON. AFTERWARDS, TS 29W WILL SLIGHTLY WEAKEN AS IT SKIRTS THE NORTHERN COAST OF THE ISLAND. ONCE THE SYSTEM EMERGES IN THE SOUTH CHINA SEA, IT WILL ONCE AGAIN BEGIN TO INTENSIFY, REACHING A PEAK INTENSITY OF 85 KNOTS BY TAU 72. C. IN THE EXTENDED TAUS, TRACKS SPEEDS WILL SLOW AS AN EXTENSION OF THE STR BUILDS IN NORTH OF THE SYSTEM. THIS EXTENSION WILL TURN THE SYSTEM SLIGHTLY WEST-SOUTHWEST AS IT DRAGS ACROSS HAINAN AND EVENTUALLY EMERGES IN THE GULF OF TONKIN BY TAU 120. INTERACTION WITH THE TOPOGRAPHY OF HAINAN WILL GRADUALLY ERODE THE SYSTEM. DYNAMIC MODEL GUIDANCE INDICATES THREE DISTINCT GROUPINGS: THE FIRST BEING JGSM, JENS, AND EGRR WHICH INDICATE A WEAKER SYSTEM AND A MORE WEST-SOUTHWESTWARD TRACK; THE SECOND BEING GFDN WHICH MAINTAINS A GENERALLY WESTWARD TRACK THROUGHOUT THE FORECAST PERIOD; AND LASTLY THE THIRD GROUPING WITH ECMF, NVGM, AND GFS WHICH INDICATE A STRONGER SYSTEM AND A MORE WEST-NORTHWESTWARD TRACK THROUGH TAU 72 FOLLOWED BY A TURN TO THE SOUTHWEST AS A RESULT OF THE BUILDING STR. THE JTWC FORECAST IS LAID CLOSE TO THE MULTI-MODEL CONSENSUS, BUT HEDGED TOWARD TO THE NORTHERN SOLUTIONS. GIVEN THE WELL-ESTABLISHED STEERING MECHANISM, THERE IS HIGH CONFIDENCE IN THE NEAR- TO MID-TERM PORTION OF THE JTWC TRACK FORECAST. HOWEVER, DUE TO THE UNCERTAINTY IN THE INTENSITY AND THE SPREADING OF THE MODEL GUIDANCE, THERE IS LOW CONFIDENCE IN THE EXTENDED PORTION OF THE FORECAST.// NNNN