WDXS31 PGTW 160900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02S (BHEKI) WARNING NR 005// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 14.0S 73.0E INITIAL INTENSITY: 75 KTS GEOGRAPHIC REFERENCE: 415 NM SOUTH OF DIEGO GARCIA MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 09 KTS SIGNIFICANT WAVE HEIGHT: 26 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL CYCLONE (TC) 02S (BHEKI) WITH A DEVELOPING BUT STILL RAGGED EYE-FEATURE, SURROUNDED BY PERSISTENT CONVECTIVE BANDING. IN ADDITION, CONVECTION HAS CONTINUED TO DEVELOP WITHIN THE PERIPHERY OF THE NORTHERN QUADRANT, WRAPPING CYCLONICALLY AROUND THE EASTERN FLANK, AND INTO THE SOUTHERN SEMICIRCLE. ON THE ANIMATED WATER VAPOR IMAGERY, IMPROVED UPPER-LEVEL OUTFLOW HAS BEEN OBSERVED OVER THE LAST FEW HOURS, ILLUSTRATED BY MODERATE RADIAL OUTFLOW EXPRESSED WITH CIRRIFORM STRIATIONS BURSTING AWAY FROM THE CENTER STRUCTURE. THE ENVIRONMENT CONTINUES TO BE FAVORABLE FOR FURTHER INTENSIFICATION AS THE SYSTEM APPROACHES THE SUBTROPICAL RIDGE (STR) AXIS, VERTICAL WIND SHEAR (VWS) FROM THE NORTHEAST REMAINS LESS THAN 15 KTS, AND SEA SURFACE TEMPERATURES (SSTS) CONTINUE BETWEEN 27 C TO 28 C. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED DEVELOPING EYE FEATURE OBSERVED ON ANIMATED EIR SATELLITE IMAGERY. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON SUBJECTIVE AGENCY DVORAK ESTIMATES ALIGNING AT T4.5, AND CIMSS OBJECTIVE ESTIMATES RANGING BETWEEN 68 KTS AND 81 KTS. INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE EAST-SOUTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.5 - 77 KTS KNES: T4.5 - 77 KTS DEMS: T4.5 - 77 KTS FMEE: T4.5 - 77 KTS CIMSS SATCON: 68 KTS AT 160530Z CIMSS ADT: 79 KTS AT 160600Z CIMSS AIDT: 80 KTS AT 160600Z CIMSS D-MINT: 76 KTS AT 152036Z CIMSS D-PRINT: 76 KTS AT 160600Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 15-20 KTS SST: 27-28 CELSIUS OUTFLOW: MODERATE RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 02S IS FORECASTED TO TRACK TO THE SOUTHWEST ALONG THE WESTERN PERIPHERY OF THE STR DIRECTLY TO THE EAST UNTIL TAU 48, AS A SHORTWAVE TROUGH ASSOCIATED WITH THE MID-LATITUDE WESTERLIES ASSISTS IN THE SOUTHWESTWARD PULL TOWARD LATITUDE 18S. AS THE SYSTEM TRACKS SOUTHWEST, A SOUTHEAST TO NORTHWEST ORIENTED STR BEGINS TO BUILD JUST SOUTHWEST OF TC BHEKI. FOLLOWING TAU 48, THE STR THAT BEGINS TO BUILD TO THE SOUTHWEST FLATTENS OUT THE TRACK, FORCING THE TROPICAL CYCLONE ON A GENERALLY WESTWARD TRACK UNTIL TAU 120. WITH REGARD TO INTENSITY, TC 02S IS EXPECTED TO CONTINUE INTENSIFYING UNTIL TAU 24 DURING THE APPROACH TOWARD THE STR AXIS. FOLLOWING TAU 24, SSTS BEGIN TO DROP TO LESS THAN 26 C, STARTING THE INITIAL WEAKENING PHASE. AS TC BHEKI CONTINUES SOUTHWESTWARD AFTER TAU 24, VWS INCREASES TO ABOVE 20 KTS, WEAKENING THE SYSTEM TO 75 KTS BY TAU 48. AT TAU 48, DRY AIR ENTRAINMENT INTO THE CORE AND VWS ABOVE 30 KTS WILL CONTINUE TO STEADILY ERODE THE TROPICAL CYCLONE, WITH FORECASTED INTENSITIES TO 35 KTS BY THE END OF THE FORECAST PERIOD AS THE ENVIRONMENT BECOMES NON-CONDUCIVE FOR TROPICAL CYCLONE SUSTAINMENT. MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT THROUGHOUT THE FORECAST PERIOD FOR TC 02S, WITH A CROSS-TRACK SPREAD OF 150 NM BY TAU 72, GRADUALLY INCREASING TO 244 NM BY TAU 120. THE JTWC FORECAST CONTINUES TO ALIGN CLOSELY WITH THE JTWC CONSENSUS MEAN AND PREVIOUS FORECAST, WITH A SOUTHWEST TRACK THROUGH THE NEXT 48 HOURS, BECOMING GENERALLY WESTWARD THEREAFTER. OF NOTE, ALTHOUGH THE UKMET ENSEMBLE INDICATES A WEST-NORTHWESTERLY TRACK AFTER TAU 72, AND ECMWF AND NAVGEM TRACK TC 02S FURTHER WEST-SOUTHWEST, THE JTWC FORECAST REMAINS VERY CLOSE TO THE JTWC CONSENSUS, GFS, AND THE UKMET DETERMINISTIC SOLUTIONS, LENDING HIGH CONFIDENCE WITHIN THE INITIAL 72 HOURS, AND MEDIUM CONFIDENCE AFTERWARD. WITH REGARD TO INTENSITY, ALL INTENSITY MEMBERS INDICATE A RELATIVELY SHORT INTENSIFICATION WINDOW IN THE INITIAL 24 HOURS, LENDING HIGH CONFIDENCE TO THE 0-72 INTENSITY FORECAST. FOLLOWING TAU 72, THERE IS MEDIUM CONFIDENCE IN THE INTENSITY FORECAST DUE TO ENVIRONMENTAL UNCERTAINTIES AS THE STR BEGINS TO BUILD SOUTHWEST OF TC 02S BETWEEN TAU 72 AND TAU 120. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN