MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 07W (DOKSURI) WARNING NR 02// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 07W (DOKSURI), LOCATED APPROXIMATELY 430 NM EAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 15 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED (IR) SATELLITE IMAGERY DEPICTS A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC) WITH IMPROVED CONVECTIVE BANDING WRAPPING INTO A MORE DEFINED LOW- LEVEL CIRCULATION CENTER (LLCC). THIS IMPROVED ORGANIZATION IS EVIDENT IN A 261116Z SSMIS IMAGE AND A 261417Z TRMM PARTIAL IMAGE, WHICH SHOW MULTIPLE DEEP CONVECTIVE BANDS WRAPPING INTO THE LLCC. A 261457Z OSCAT IMAGE SHOWS A WELL-DEFINED, SYMMETRIC CIRCULATION WITH PREDOMINANTLY 30-35 KNOT WINDS. THIS OSCAT IMAGE ALONG WITH A FORTUITOUS 26/12Z SHIP OBSERVATION NEAR 13.4N 130.1E (WINDS 250/23 KNOTS; LOCATED ABOUT 85 NM SSE OF THE 26/12Z CENTER POSITION) CLEARLY INDICATE THAT THE PREVIOUSLY ELONGATED SYSTEM HAS EVOLVED QUICKLY INTO ONE DOMINANT CIRCULATION. BASED ON THE OSCAT IMAGE AND IR ANIMATION, THERE IS INCREASED (GOOD) CONFIDENCE IN THE INITIAL POSITION. THE INITIAL INTENSITY OF 35 KNOTS IS ASSESSED SLIGHTLY HIGHER THAN THE 30 KNOT DVORAK ESTIMATES BASED ON THE OSCAT DATA AND THE SHIP OBSERVATION. UPPER-LEVEL ANALYSIS INDICATES THAT THE LLCC IS LOCATED WITHIN A GENERALLY FAVORABLE ENVIRONMENT CHARACTERIZED BY GOOD OUTFLOW AND WEAK (5-10 KNOTS) VERTICAL WIND SHEAR (VWS). ANIMATED WATER VAPOR IMAGERY REVEALS SOME PRESSURE ON THE NORTHWEST PERIPHERY OF THE SYSTEM; HOWEVER, EQUATORWARD OUTFLOW REMAINS VIGOROUS AND POLEWARD OUTFLOW HAS IMPROVED OVER THE PAST 24 HOURS. ADDITIONALLY, SEA SURFACE TEMPERATURES ARE HIGH (29-30 DEGREES CELSIUS). 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING. SYSTEM HAS BEEN UPGRADED TO TROPICAL STORM STRENGTH AND THE EXTENDED TAU TRACK SPEEDS HAVE BEEN INCREASED. B. TS 07W IS CURRENTLY STEERING ALONG THE SOUTHWESTERN PERIPHERY OF AN EAST-WEST ORIENTED DEEP SUBTROPICAL RIDGE (STR), WHICH EXTENDS WESTWARD TO TAIWAN. THE RECENT 26/12Z LAOG SOUNDING (NORTHERN LUZON) INDICATES OVERALL DEEP EASTERLY FLOW WITH SOUTHEASTERLY FLOW THROUGH THE LOW- TO MID-LEVELS, SUPPORTING A WEST-NORTHWESTWARD TRACK. TS 07W IS EXPECTED TO GRADUALLY INTENSIFY TO A PEAK INTENSITY NEAR 60 KNOTS BY TAU 36 DUE TO THE CURRENT AND FORECAST FAVORABLE CONDITIONS. INTERACTION WITH NORTHERN LUZON MAY SERVE TO SLIGHTLY WEAKEN OR HINDER DEVELOPMENT NEAR TAU 36 AND, OBVIOUSLY, A CLOSER TRACK TO LAND WILL SIGNIFICANTLY WEAKEN THE SYSTEM, THERFORE, THERE IS MARGINAL CONFIDENCE IN THE PEAK INTENSITY AT THIS POINT. THERE IS, HOWEVER, HIGH CONFIDENCE IN THE FORECAST TRACK DUE TO THE TIGHT GROUPING OF THE DYNAMIC MODEL VORTEX TRACKERS AS WELL AS ALL ENSEMBLE GUIDANCE. NOGAPS HAD BEEN THE SOLE OUTLIER WITH AN UNREALISTIC POLEWARD TRACK INTO THE STR BUT HAS RECENTLY (26/12Z RUN) SWITCHED TO A STRAIGHT-RUNNER TRACK. C. IN THE EXTENDED PERIOD, TS 07W IS FORECAST TO CONTINUE TRACKING WEST-NORTHWESTWARD AS IT APPROACHES THE WESTERN EDGE OF THE STR. DYNAMIC MODEL GUIDANCE IS CONSISTENT IN DEPICTING A SHORT-WAVE TROUGH DIGGING OVER EASTERN CHINA WHICH SHOULD SERVE TO WEAKEN AND RETROGRADE THE WESTERN STR, WHICH SHOULD RESULT IN A CONTINUED WEST- NORTHWESTWARD TRACK OVER OR NEAR HONG KONG. THERE IS LOW CONFIDENCE IN THE EXTENDED FORECAST DUE TO UNCERTAINTIES IN THE STRENGTH OF THE AFOREMENTIONED TROUGH AND WESTERN STR. TS 07W IS EXPECTED TO WEAKEN AS IT APPROACHES HONG KONG DUE TO INCREASING VWS AND LAND INTERACTION.// NNNN NNNN