MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (AERE) WARNING NR 13// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 22W (AERE), LOCATED APPROXIMATELY 180 NM EAST OF HONG KONG, HAS TRACKED NORTH-NORTHEASTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS FLARING DEEP CONVECTION OVER A DECAYING LOW-LEVEL CIRCULATION CENTER (LLCC). A 081835Z SSMI 85GHZ IMAGE REVEALS CONVECTIVE BANDING WRAPPING BROADLY AROUND THE NORTHERN PERIPHERY OF AN EXPOSED LLCC. DUE TO THE BROAD NATURE OF THE CENTER AND LACK OF MICROWAVE IMAGERY, THERE IS MODERATE CONFIDENCE IN THE CURRENT POSITION AND RECENT TRACK MOTION, WHICH APPEARS TO BE QUASI- STATIONARY IN NATURE. THE CURRENT INTENSITY IS ASSESSED AT 40 KNOTS BASED ON DVORAK INTENSITY ESTIMATES RANGING FROM 35 TO 55 KNOTS BUT HEDGED LOWER BASED ON THE MOST RECENT ASCAT IMAGE SHOWING 35 KNOT WINDS. UPPER-LEVEL ANALYSIS SHOWS A MARGINALLY-FAVORABLE ENVIRONMENT WITH SOUTHERLY VERTICAL WIND SHEAR OFFSET BY POLEWARD OUTFLOW AND LOW OCEAN HEAT CONTENT VALUES. TS 22W IS TRACKING QUASI-STATIONARY WITHIN A WEAK STEERING ENVIRONMENT. 3. FORECAST REASONING. A. NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. 34-KNOT WIND RADII HAVE BEEN ADJUSTED SMALLER BASED ON THE 081351Z ASACT IMAGE. B. TS AERE WILL REMAIN IN A WEAK STEERING ENVIRONMENT OVER THE NEXT 12 TO 24 HOURS EXHIBITING QUASI-STATIONARY TRACK MOVEMENT UNTIL A LOW-LEVEL RIDGE BUILDS TO THE NORTH. THIS RIDGE IS ASSOCIATED WITH A MODERATE NORTHEAST SURGE, WHICH IS EXPECTED TO ENHANCE WIND FLOW THROUGH THE TAIWAN STRAIT AND ADVECT COOLER, DRIER AIR INTO THE NORTHERN SOUTH CHINA SEA. THE OVERALL EFFECT WILL BE TO DRIVE TS 22W SOUTHWESTWARD WHILE SIGNIFICANTLY WEAKENING THE SYSTEM. NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT WITH THE BULK OF THE VORTEX TRACKERS INDICATING A SOUTHWESTWARD TRACK TOWARD HAINAN ISLAND. THE SYSTEM IS EXPECTED TO DISSIPATE OVER WATER BY TAU 72. OVERALL, THERE IS LOW CONFIDENCE IN THE JTWC FORECAST TRACK DUE TO THE TIMING OF THE TRACK CHANGE AND SIGNIFICANT DIFFERENCES IN TRACK SPEED AFTER TAU 24.// NNNN NNNN