MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (LEKIMA) WARNING NR 08// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 10W (LEKIMA), LOCATED APPROXIMATELY 479 NM SOUTH OF KADENA AB, HAS TRACKED SOUTHWESTWARD AT 03 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS THAT DEEP CONVECTION IS CONTINUING TO CONSOLIDATE AND IMPROVE IN STRUCTURE. THE INITIAL POSITION IS PLACED WITH GOOD CONFIDENCE AND IS BASED ON A 051716Z AMSR2 36GHZ MICROWAVE IMAGE, WHICH SHOWS THE IMPROVING STORM STRUCTURE. THE INITIAL INTENSITY ESTIMATE OF 45 KNOTS IS BASED ON DVORAK CURRENT INTENSITY (CI) ESTIMATES OF T3.0 (45 KNOTS) FROM PGTW AND RJTD. ENVIRONMENTAL ANALYSIS SHOWS THAT TS 10W IS EXPERIENCING FAVORABLE TO NEUTRAL (15 TO 20 KNOT) VERTICAL WIND SHEAR. TS 10W HAS A STRONG EQUATORWARD OUTFLOW CHANNEL AND A DEVELOPING POLEWARD OUTFLOW CHANNEL. SEA SURFACE TEMPERATURE ARE FAVORABLE FOR DEVELOPMENT WITH TEMPERATURES GREATER THAN 31 DEGREES CELSIUS. TS 10W IS DRIFTING NORTHWESTWARD WHILE POSITIONED BETWEEN A SUBTROPICAL RIDGE (STR) TO THE NORTH AND A NEAR EQUATORIAL RIDGE (NER) TO THE SOUTH. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE OVERALL FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. THROUGH TAU 48, TS 10W WILL TRACK NORTHWESTWARD AS THE AFOREMENTIONED RIDGES BUILD. FAVORABLE VERTICAL WIND SHEAR AND SEA SURFACE TEMPERATURES WILL ALLOW TS 10W TO STEADILY INCREASE IN INTENSITY, REACHING 65 KNOTS BY TAU 48. AS TS 10W TRACKS NORTHWESTWARD IT WILL MOVE AWAY FROM TD 11W AND TY 09W WHICH WILL ALLOW FOR IMPROVED UPPER LEVEL OUTFLOW. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK. C. SHORTLY AFTER TAU 72, TS 10W WILL MAKE LANDFALL IN NORTHERN TAIWAN. LAND INTERACTION WITH TAIWAN WILL CAUSE TS 10W TO DECREASE IN INTENSITY, REACHING 55 KNOTS BY TAU 96. ALSO BY TAU 96, THE STR TO THE NORTH WILL BECOME THE PRIMARY STEERING FEATURE AND CAUSE TS 10W TO TURN NORTHWARD. SHORTLY AFTER TAU 96, TS 10W WILL MAKE LANDFALL IN CENTRAL CHINA AND CONTINUE TO WEAKEN IN INTENSITY AS IT TRACKS NORTHWARD. DYNAMIC MODEL GUIDANCE HAS A SPREAD OF 340 NM BY TAU 120, THEREFORE, THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.// NNNN NNNN