MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 24W (SARIKA) WARNING NR 06// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 24W (SARIKA), LOCATED APPROXIMATELY 426 NM EAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS THAT THE SYSTEM IS STILL CONSOLIDATING WITH NASCENT FORMATIVE BANDING WRAPPING INTO AN INDISTINCT LOW LEVEL CIRCULATION CENTER (LLCC). A 131706Z GPM 89 GHZ MICROWAVE IMAGE DEPICTS THAT DEEP CONVECTION HAS INCREASED IN AREAL EXTENT, BUT IS LIMITED TO THE WESTERN PERIPHERY OF THE BROAD LLCC. THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON ANALYSIS OF SATELLITE FIXES FROM ALL AGENCIES IN CONJUNCTION WITH THE 1706Z GPM PASS. THE INITIAL INTENSITY ESTIMATE OF 35 KNOTS IS BASED ON DVORAK ESTIMATES FROM ALL AGENCIES REPORTING T2.5 (35 KNOTS). UPPER-LEVEL ANALYSIS SHOWS GOOD OUTFLOW TO THE NORTHWEST INTO A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) LOCATED TO THE NORTHWEST, ALONG WITH A GOOD EQUATORWARD CHANNEL. HOWEVER AN UPPER-LEVEL ANTICYCLONE LOCATED JUST NORTHEAST OF THE SYSTEM IS PROVIDING PRESSURE ON THE EAST SIDE OF THE SYSTEM, AND LIMITING INTENSIFICATION AT THE CURRENT TIME. SEA SURFACE TEMPERATURES ARE VERY FAVORABLE BETWEEN 30 AND 31 CELSIUS AND VERTICAL WIND SHEAR (VWS) IS CURRENTLY LOW AT 5-10 KTS. TD 24W IS TRACKING SLOWLY WEST-NORTHWESTWARD ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED EAST-WEST ORIENTED SUBTROPICAL RIDGE (STR) EXTENDING ACROSS THE ENTIRE WESTERN PACIFIC. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TD 24W WILL CONTINUE TO TRACK SLOWLY WEST-NORTHWESTWARD ALONG THE RIDGE EXTENSION TROUGH TAU 48. BY TAU 48 THE FAR WESTWARD PORTION OF THE RIDGE ARM WILL BUILD, DEVELOPING INTO THE DOMINANT STEERING RIDGE MOVING NORTH OF LUZON AND ACCELERATING TD 24W WESTWARD. SLOW AND STEADY INTENSIFICATION IS EXPECTED TROUGH TAU 24 AS THE AFOREMENTIONED UPPER-LEVEL ANTICYCLONE REMAINS IN PLACE AND CONTINUES TO PRODUCE PRESSURE ON THE EASTERN SIDE OF THE SYSTEM. BY TAU 36 AND THROUGH LANDFALL AFTER TAU 48, INTENSIFICATION RATES WILL INCREASE AS A POINT-SOURCE IS FORECAST TO DEVELOP IN CLOSE VICINITY TO TS SARIKA, IMPROVING UPPER-LEVEL OUTFLOW CONDITIONS, PEAKING AT 85 KTS AT TAU 48. ACTUAL INTENSITY WILL LIKELY BE SLIGHTLY HIGHER AS LANDFALL IS EXPECTED AFTER TAU 48, ALLOWING FOR ADDITIONAL INTENSIFICATION. TD 24W IS EXPECTED TO MAKE LANDFALL OVER LUZON AS A TYPHOON. C. IN THE EXTENDED FORECAST TD 24W IS EXPECTED TO RESURFACE OVER THE SOUTH CHINA SEA WEAKENED BUT LARGELY INTACT. THE STEERING RIDGE WILL BE FULLY DEVELOPED AND CONTINUE TO STEER TD 24 WEST- NORTHWESTWARD. ENVIRONMENTAL CONDITIONS IN THE SOUTH CHINA SEA WILL BE VERY FAVORABLE SUPPORTING ANOTHER ROUND OF INTENSIFICATION, PEAKING OUT AT 80 KNOTS BEFORE TRACKING OVER HAINAN NEAR TAU 120. THERE IS A POSSIBILITY OF ADDITIONAL INTENSIFICATION BETWEEN TAU 96 AND LANDFALL, AS ENVIRONMENTAL CONDITIONS ARE HIGHLY CONDUCIVE TO INTENSIFICATION IN THIS AREA. DYNAMIC MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT WITH REFERENCE TO THE TRACK WITH ONLY MINOR MODEL SPREAD IN THE NEAR TERM REFLECTING THE BROAD NATURE OF THE LLCC AT THIS TIME. WITH REFERENCE TO THE FORWARD SPEED, DYNAMIC MODELS SHOW SIGNIFICANT ALONG TRACK DIVERGENCE, DUE TO THE GENERALLY WEAK STEERING CURRENTLY IN PLACE. THIS PLACES A LARGE UNCERTAINTY IN THE TIMING OF LANDFALL AND THE AMOUNT OF TIME AVAILABLE FOR INTENSIFICATION. DUE TO THIS UNCERTAINTY THERE IS HIGH CONFIDENCE IN THE FORECAST TRACK BUT LOW CONFIDENCE IN THE FORECAST INTENSITY.// NNNN NNNN