MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 01W (VONGFONG) WARNING NR 007// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 01W (VONGFONG), LOCATED APPROXIMATELY 465 NM EAST- SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS SYMMETRICAL, SPIRAL BANDS WRAPPING INTO A CENTER THAT CONTINUES TO BE OBSCURED BY CONVECTION. A DIMPLE IN THE CENTRAL CONVECTION HAS BEGUN TO FORM, HOWEVER. THIS FEATURE, ALONG WITH A COOLING TREND OF THE SYSTEM CENTER NOTED IN ANIMATED ENHANCED INFRARED (EIR) IMAGERY, INDICATES THAT EYE FORMATION IS IMMINENT. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE DIMPLE IN THE VISIBLE IMAGERY AS WELL AN EYE FEATURE NOTED IN THE EIR LOOP AND IS INLINE WITH FIXES FROM PGTW, RJTD AND RCTP. THE INITIAL INTENSITY OF 70 KNOTS IS HEDGED ABOVE THE PGTW CURRENT INTENSITY ESTIMATE OF T4.0 (65 KTS) DUE TO THE IMPENDING EYE FORMATION AND STRUCTURE OF THE SYSTEM. THE ENVIRONMENT REMAINS VERY FAVORABLE FOR ADDITIONAL RAPID INTENSIFICATION, WITH LOW (5-10 KTS) VWS, WARM SSTS (29-30 C) AND ROBUST RADIAL OUTFLOW ALOFT. TY VONGFONG IS STEERED BY A DEEP-LAYER SUBTROPICAL RIDGE POSITIONED TO THE EAST NEAR GUAM WHICH IS EXTENDING WEST TOWARD THE LUZON STRAIT. 3. FORECAST REASONING. A. THERE HAS BEEN NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS FORECAST BULLETIN. B. TY VONGFONG WILL CONTINUE TO TRACK WEST-NORTHWESTWARD THROUGH TAU 36 UNDER THE STEERING INFLUENCE OF A BUILDING STR TO THE EAST. CONDITIONS IN THE AREA WILL REMAIN HIGHLY FAVORABLE FOR RAPID INTENSIFICATION WITH CONTINUED WARM (29-30 C) SSTS, LOW (5-10 KTS) VWS AND DIVERGENCE ALOFT. THESE CONDITIONS WILL ALLOW THE SYSTEM TO INTENSIFY TO 100 KTS BY TAU 36 WHEREUPON IT WILL BEGIN TO CROSS OVER CATANDUANES ISLAND. A SLIGHT WEAKENING OF THE SYSTEM TO 95 KTS BY TAU 48 WILL OCCUR DUE TO THE FRICTIONAL EFFECTS OF LAND, HOWEVER THIS WILL BE OFFSET BY CONTINUED FAVORABLE CONDITIONS AND ROBUST OUTFLOW. AFTER TAU 48, TY VONGFONG WILL TURN NORTH-NORTHWEST AND ACCELERATE AS IT BEGINS TO RECURVE AROUND THE STR. BY TAU 72, THE SYSTEM WILL REACH LANDFALL FOR A SECOND TIME OVER LUZON WHEREUPON IT WILL WEAKEN TO 85 KTS DUE TO TERRAIN EFFECTS. DYNAMIC MODEL GUIDANCE IS IN FAIR AGREEMENT THROUGH TAU 48 WITH A SPREAD OF 167 NM. THE DEVIATION OF MODEL SOLUTIONS IS DUE TO THE DYNAMIC NATURE OF A REORIENTATION OF THE STEERING STR AND RESULTS IN ONLY FAIR CONFIDENCE IN THE TIMING AND LOCATION OF THE RECURVATURE. CROSS TRACK SPREAD IN MODEL SOLUTIONS INCREASE TO 350 NM BY TAU 72. GFS, NAVGEM AND JGSM MODEL SOLUTIONS ALL BRING THE SYSTEM OVER LUZON BY TAU 72 WHEREAS ECMWF, AFUM AND UKMET SOLUTIONS PROVIDE A MORE WESTWARD TRACK, BRINGING TY VONGFONG INTO THE SOUTH CHINA SEA. THE OFFICIAL JTWC FORECAST TRACK LIES ALONG THE EAST SIDE OF THE TIGHTEST GROUPING OF MODELS MENTIONED EARLIER (GFS, NAVGEM AND JGSM) AND JUST NORTH AND EAST OF THE MULT-MODEL CONSENSUS TRACK, LENDING OVERALL FAIR CONFIDENCE IN THIS PORTION OF THE FORECAST. C. AFTER TAU 72, TY VONGFONG WILL ROUND THE STR AXIS AND BEGIN A GENERALLY NORTH-NORTHEASTWARD TRACK. AS IT TRAVELS OVER LUZON AND REENTERS THE PHILIPINE SEA IT WILL WEAKEN TO 65 KTS BY TAU 96 DUE TO THE FRICTIONAL EFFECTS OF LAND AND INCREASING VWS (20-25 KTS), ALTHOUGH POLEWARD OUTFLOW IS EXPECTED TO REMAIN ROBUST AS IT TAPS INTO THE DEEP WESTERLY FLOW ALOFT. THIS WEAKENING TREND WILL CONTINUE AS THE SYSTEM TRAVELS INTO THE LUZON STRAIT, EVENTUALLY WEAKENING TO 50 KTS BY TAU 120, AT WHICH TIME IT WILL BEGIN EXTRATROPICAL TRANSITION. MODEL SOLUTIONS BEGIN TO DIVERGE FURTHER AFTER TAU 72 WITH A CROSS TRACK SPREAD OF 424 NM BY TAU 96. ADDITIONALLY, THE ALONG TRACK SPREAD OF MODEL SOLUTIONS INCREASES SIGNIFICANTLY BY TAU 120 WITH A SPREAD OF 898 NM WHEN ALL MEMBERS OF THE MULTI-MODEL CONSENSUS ARE INCLUDED. THE LARGE SPREAD IN BOTH ALONG AND CROSS TRACK MODEL GUIDANCE LENDS HIGH UNCERTAINTY DURING THIS PERIOD AND THUS LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.// NNNN NNNN