WDPN31 PGTW 071500 MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 08W WARNING NR 10// RMKS/ 1. FOR METEOROLOGISTS. 2. PROGNOSTIC REASONING FOR 071200Z TO 111200Z AUG 2006. A. TYPHOON (TY) 08W (SAOMAI), LOCATED APPROXIMATELY 420 NM NORTHWEST OF GUAM, HAS TRACKED NORTHWESTWARD AT 14 KNOTS OVER THE PAST SIX HOURS. A 062300Z TRMM IMAGE SHOWS THAT TY 08W A BANDING EYE HAS DEVELOPED OVER THE PAST 06 HOURS. B. TY 08W CONTINUES TO STEER NORTHWESTWARD ALONG THE SOUTHWESTERN PERIPHERY OF A DEEP LAYER STEERING RIDGE ANCHORED SOUTHEAST OF JAPAN. A BROAD UPPER LEVEL CYCLONIC CIRCULATION LOCATED WEST OF TY 08W IS ALSO CONTRIBUTING TO THIS NORTH- WESTWARD MOTION. THE FORECAST TRACK WILL REORIENT TOWARD THE WEST-NORTHWEST AFTER TAU 48 AS THE STEERING RIDGE BUILDS WESTWARD. INTERACTION WITH TS 10W MAY CAUSE A POLEWARD SHIFT IN THE FORECAST TRACK EARLY IN THE PERIOD. THE AVAILABLE DYNAMIC AIDS ARE IN GOOD AGREEMENT THROUGH TAU 36, BUT DECREASE THERE- AFTER. DIFFERENCES IN THE MODEL FORECASTS AFTER TAU 36 RESULT FROM VARIATION IN THE WESTWARD EXTENSION OF THE STEERING RIDGE. THE SOLE OUTLIER IS TCLAPS, WHICH FORECASTS A POLEWARD TRACK THROUGHOUT THE FORECAST PERIOD. THIS FORECAST IS BASED ON A CONSENSUS OF ALL AVAILABLE AIDS WITH LESS EMPHASIS ON TCLAPS. C. TY 08W IS FORECAST TO INTENSIFY AT A CLIMATOLOGICAL RATE THROUGH TAU 48. IMPROVING UPPER LEVEL OUTFLOW, HIGH SEA SURFACE TEMPERATURES AND LOW VERTICAL WIND SHEAR SUPPORT THIS CONTINUED INTENSIFICATION. INTRUSION OF DRY, CONTINENTAL AIR AND INCREASING VERTICAL WIND SHEAR WILL IMPEDE FURTHER INTENSIFICATION AFTER TAU 48. D. CURRENT WIND RADII ARE BASED ON A 062000Z QUIKSCAT IMAGE AND BUOY OBSERVATIONS. FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE-SIZED SYSTEM. E. AFTER TAU 72, THE STEERING RIDGE IS FORECAST TO WEAKEN SLIGHTLY, CAUSING TY 08W TO TRACK NORTHWESTWARD BRIEFLY BEFORE MAKING LANDFALL IN SOUTHEASTERN CHINA PRIOR TO TAU 96. DISRUP- TION OF THE LOW LEVEL INFLOW, INTRUSION OF DRY AIR AND INCREASED VERTICAL WIND SHEAR WILL RAPIDLY WEAKEN THE SYSTEM AS IT TRACKS OVER LAND. FORECAST TEAM: DELTA// NNNN HTTP/1.1 200 OK Date: Mon, 07 Aug 2006 08:25:29 GMT Server: Apache Content-Length: 0 Connection: close Content-Type: text/plain; charset=UTF-8