MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 24W (HALONG) WARNING NR 002// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 24W (HALONG), LOCATED APPROXIMATELY 676 NM EAST OF ANDERSEN AFB, GUAM, HAS TRACKED NORTHWESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A LARGE AND IRREGULAR AREA OF DEEP FLARING CONVECTION, WITH NO VISIBLE FORMATIVE BANDS. THE INITIAL POSITION IS TRACED FROM LOW CLOUD FEATURES IN THE EIR LOOP AND FROM A WEAK FORMATIVE IMPARTIAL CIRCULATION FEATURE IN THE 1532Z 36GHZ AMSR2 MICROWAVE IMAGE WITH LOW CONFIDENCE. THE INITIAL INTENSITY OF 35KTS IS BASED FROM THE DVORAK ESTIMATES OF T2.5/35KTS FROM PGTW AND RJTD. UPPER- LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH NEAR-RADIAL OUTFLOW AND LOW (<15KTS) VERTICAL WIND SHEAR (VWS). ADDITIONALLY, SST VALUES OF 29-30C ARE CONDUCIVE FOR DEVELOPMENT. TS 24W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) TO THE NORTHEAST. 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 24W WILL CONTINUE ON ITS CURRENT TRACK UP TO TAU 48. AFTERWARD IT WILL TURN MORE NORTHWARD AS IT ROUNDS THE STR. THE SYSTEM WILL INTENSIFY UNDER FAVORABLE CONDITIONS TO A PEAK OF 105 KNOTS BY TAU 72, POSSIBLY HIGHER, DUE TO ENHANCED POLEWARD OUTFLOW INTO THE MIDLATITUDE WESTERLIES. C. IN THE EXTENDED PERIOD, TS 24W WILL RECURVE AND ACCELERATE NORTHEASTWARD AND BEGIN EXTRA-TROPICAL TRANSITION (ETT) AS IT INTERACTS WITH THE MIDLATITUDE WESTERLIES. THE SYSTEM SHOULD COMPLETE ETT BY TAU 120 AS IT GAINS FRONTAL CHARACTERISTICS AND BECOMES EMBEDDED WITHIN THE MIDLATITUDE WESTERLIES. TS 24W WILL WEAKEN RAPIDLY DUE TO INCREASING VWS AND COOLER SST BY TAU 120 BUT WILL STILL BE A STORM FORCE COLD-CORE LOW, ALBEIT WITH AN EXPANSIVE WIND FIELD. DUE TO THE BROAD NATURE OF THE LLCC AND LARGE SPREAD IN SOLUTIONS IN THE EXTENDED PERIOD, THERE IS OVERALL LOW CONFIDENCE IN THE JTWC FORECAST TRACK.// NNNN NNNN