MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (GUCHOL) WARNING NR 09// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 05W (GUCHOL), LOCATED APPROXIMATELY 135 NM EAST OF YAP, HAS TRACKED WESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY SHOWS CONVECTIVE BANDING WRAPPING INTO A LOW LEVEL CIRCULATION CENTER (LLCC). A 122321Z SSMIS MICROWAVE IMAGE DEPICTS IMPROVED CONVECTIVE ORGANIZATION FROM WHICH THE INITIAL POSITION WAS BASED WITH GOOD CONFIDENCE. THE INITIAL INTENSITY WAS BASED ON THE KNES AND PGTW DVORAK ESTIMATES OF 35 KNOTS. WATER VAPOR IMAGERY SHOWS IMPROVED RADIAL OUTFLOW WITH A SLIGHT PULL INTO A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELL TO THE NORTH. THE TOTAL PRECIPITABLE WATER PRODUCT INDICATES A SUBSIDENT, DRY REGION TO THE NORTHWEST IS WEAKENING. SEA SURFACE TEMPERATURES (28-29 DEGREES CELSIUS) ARE FAVORABLE FOR DEVELOPMENT. TS 05W IS CURRENTLY TRACKING ALONG THE SOUTHERN PERIPHERY OF A MID- LEVEL SUBTROPICAL RIDGE (STR) LOCATED TO THE NORTH. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 05W IS EXPECTED TO CONTINUE TRACKING ALONG THE SOUTHERN PERIPHERY OF THE STR. THE SYSTEM SHOULD BEGIN TO TURN WEST- NORTHWESTWARD TO NORTHWESTWARD THROUGH TAU 72, AS THE STR WEAKENS AHEAD OF AN APPROACHING MID-LATITUDE TROUGH, CURRENTLY DIGGING SOUTH OF CHINA. MODEL GUIDANCE IS IN TIGHT AGREEMENT TROUGH TAU 72; THEREFORE, THERE IS HIGH CONFIDENCE IN THE FORECAST TRACK. C. AFTER TAU 72, TS 05W IS FORECAST TO ROUND THE SOUTHWESTERN PERIPHERY OF THE WEAKENING STR AND TURN MORE POLEWARD. IN THE EXTENDED FORECAST, MODEL GUIDANCE SPREADS WITH NOGAPS AND GFDN MAKING THE FASTEST TURN POLEWARD SOUTH OF OKINAWA, JAPAN. UKMO AND GFS MAINTAIN A MORE NORTHWESTWARD TRACK AND SLOWLY TURN THE SYSTEM POLEWARD. THERE IS LOW CONFIDENCE IN THE RECURVATURE TIMING AND POSITION DUE TO THE MODEL SPREAD IN THE EXTENDED FORECAST. HOWEVER, THE JTWC FORECAST FAVORS A RECURVATURE SCENARIO BASED ON THE DEEPENING MID-LATITUDE TROUGH. TS GUCHOL SHOULD CONTINUE TO STEADILY INTENSIFY AS IT TRACKS OVER WARM WATER AND AS OUTFLOW INCREASES INTO THE MID-LATITUDE TROUGH. THIS INTENSITY FORECAST IS IN AGREEMENT WITH INTENSITY MODEL GUIDANCE.// NNNN NNNN