MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (GUCHOL) WARNING NR 08// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 05W (GUCHOL), LOCATED APPROXIMATELY 175 NM EAST OF YAP, HAS TRACKED WESTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY SHOWS CONVECTIVE BANDING WRAPPING INTO A LOW LEVEL CIRCULATION CENTER (LLCC). THERE WAS LOW CONFIDENCE IN THE POSITION, WHICH WAS BASED ON A 121655Z AMSU MICROWAVE IMAGE DEPICTING A CONVECTIVE BAND WRAPPING ALONG THE SOUTHERN PERIPHERY OF THE LLCC. THE INITIAL INTENSITY WAS BASED ON KNES AND PGTW DVORAK ESTIMATES OF 35 KNOTS. WATER VAPOR IMAGERY SHOWS WEAK SYMMETRIC OUTFLOW WITH A SLIGHT PULL INTO A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELL TO THE NORTH. THE SUBSIDENT REGION ASSOCIATED WITH THE TUTT TO THE NORTHWEST IS INHIBITING OUTFLOW. ALTHOUGH, THE TOTAL PRECIPITABLE WATER PRODUCT INDICATES THIS SUBSIDENT, DRY REGION 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. MODEL GUIDANCE SPREADS WITH NOGAPS AS THE FASTEST RECURVER AND GFS, GFDN, AND ECMWF CONTINUING TO TRACK THE SYSTEM FARTHER NORTHWESTWARD. THERE IS LOW CONFIDENCE IN THE RECURVATURE TIMING AND POSITION DUE TO THE MODEL SPREAD. 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 SEA SURFACE TEMPERATURES AND AS OUTFLOW IMPROVES INTO THE MID-LATITUDE TROUGH. THIS INTENSITY FORECAST IS IN AGREEMENT WITH INTENSITY MODEL GUIDANCE.// NNNN NNNN