WDXS31 PGTW 100300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 11S (FREDDY) WARNING NR 056// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 19.0S 38.6E INITIAL INTENSITY: 65 KTS GEOGRAPHIC REFERENCE: 212 NM NORTH-NORTHWEST OF EUROPA ISLAND MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 04 KTS SIGNIFICANT WAVE HEIGHT: 29 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THAT TROPICAL CYCLONE 11S (FREDDY) HAS CONTINUED TO SLOWLY CONSOLIDATE AND HAS OVER THE PAST 12 HOURS DEVELOPED A WEAK CENTRAL COLD COVER (CCC) FEATURE, SIGNIFYING A PERIOD OF ARRESTED, OR VERY SLOW, DEVELOPMENT. ANALYSIS OF TWO HIGH-RESOLUTION MICROWAVE IMAGES INCLUDING A 092223Z AMSR2 AND 092322Z GMI REVEALS A TILTED VORTEX STRUCTURE, WITH A WELL-DEFINED MICROWAVE EYE FEATURE IN THE 36-37GHZ IMAGES DISPLACED TO THE SOUTH OF A RAGGED UPPER-LEVEL CENTER EVIDENT IN THE 89GHZ CHANNEL. CIMSS SHEAR ANALYSIS SUGGESTS 0-5 KNOTS OF SHEAR, BUT HIGH-RESOLUTION GFS MODEL SOUNDINGS AND HWRF CROSS-SECTIONS SUGGEST A WEDGE OF MODERATE (15-20 KTS) SOUTHERLY SHEAR IS STILL IMPACTING THE CORE, WHICH WOULD SUPPORT THE TILTED VORTEX SEEN IN THE MICROWAVE IMAGERY. BASED ON THE MICROWAVE IMAGERY NOTED ABOVE, THE INITIAL POSITION IS ASSESSED SOUTHWEST OF THE BULK OF THE AGENCY FIX POSITIONS WITH MEDIUM CONFIDENCE. IN LIGHT OF THE CCC AND ARRESTED DEVELOPMENT, THE INITIAL INTENSITY IS HELD STEADY AT 65 KNOTS, SLIGHTLY HIGHER THAN THE MAJORITY OF THE OBJECTIVE INTENSITY TECHNIQUES BUT RIGHT AT THE AVERAGE OF THE AGENCY CURRENT INTENSITY ESTIMATES. AN AMSR2 WINDSPEED PASS SHOWED A MAXIMUM WIND BETWEEN 64-70 KTS, PROVIDING ADDITIONAL CONFIDENCE TO THE INTENSITY ASSESSMENT. OVERALL, THE ENVIRONMENT IS IMPROVING, AS THE ATMOSPHERE IS MOISTENING UP AND THE DRY AIR IS BEING PUSHED BACK BY AND EXPANDING RADIAL OUTFLOW ENVELOPE. UPPER-LEVEL OUTFLOW IS IMPROVING, WITH INCREASING EQUATORWARD AND EASTWARD OUTFLOW STARTING TO APPEAR IN THE WATER VAPOR IMAGERY. ADDITIONALLY, THE SYSTEM IS MOVING SLOWLY OVER AN AREA OF RELATIVELY HIGHER OHC, WHICH WILL PROVIDE A BOOST OF ENERGY FOR POTENTIAL INTENSIFICATION DOWN THE ROAD. THE MAIN HINDRANCE AT THE MOMENT REMAINS THE STUBBORN MID-LEVEL SHEAR. THE SYSTEM IS SLOWLY TRACKING THROUGH A COMPETING STEERING ENVIRONMENT, TRAPPED BETWEEN A NEAR EQUATORIAL RIDGE (NER) TO THE NORTHEAST AND A SUBTROPICAL RIDGE (STR) TO THE SOUTHWEST. INITIAL WIND RADII BASIS: PERSISTENCE AND AMSR2 WINDSPEED PRODUCT. CURRENT STEERING MECHANISM: COMPETING STEERING ENVIRONMENT BETWEEN THE NER AND STR, WITH THE STR CURRENTLY THE SLIGHTLY MORE DOMINANT FEATURE. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.0 - 65 KTS KNES: T3.5 - 55 KTS FMEE: T4.5 - 77 KTS CIMSS SATCON: 54 KTS AT 092203Z CIMSS ADT: 55 KTS AT 100030Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 0-5 KTS SST: 27-28 CELSIUS OUTFLOW: MODERATE RADIAL OTHER FACTORS: DEVELOPING EASTWARD AND EQUATORWARD OUTFLOW CHANNELS, AND MODERATE MID-LEVEL SHEAR. ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: HIGH INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THE FORECAST HAS BEEN EXTENDED TO 120 HOURS TO CAPTURE A SIGNIFICANT SLOW-DOWN IN TRACK SPEED AND THE POTENTIAL OF A LOOP BACK TO OPEN WATERS IN THE EXTENDED FORECAST PERIOD. FORECAST DISCUSSION: WHILE NOT A COMPLETE CHANGE IN FORECAST PHILOSOPHY, THE FORECAST TRACK OF TC FREDDY HAS CHANGED FAIRLY SIGNIFICANTLY WITH THIS FORECAST. THE FORECAST TRACK CONTINUES TO TAKE FREDDY TO A LANDFALL ALONG THE COAST OF MOZAMBIQUE NEAR QUELIMANE BUT THE TIMELINE HAS BEEN EXTENDED AS THE SYSTEM IS NOW EXPECTED TO MOVE AT A MUCH SLOWER PACE DUE TO THE OFFSETTING AND COMPETING STEERING INFLUENCES OF THE NER TO THE NORTHEAST AND THE STR TO THE SOUTHWEST. THE FORECAST NOW CALLS FOR THE SYSTEM TO SLOWLY TRACK TOWARDS THE COAST, BUT NOT MAKE LANDFALL UNTIL AROUND TAU 48, THEN CONTINUING INLAND AT AROUND 2-3 KNOTS THROUGH THE END OF THE FORECAST PERIOD. ENVIRONMENTAL CONDITIONS ARE STEADILY IMPROVING, AND MODEL GUIDANCE CONTINUES TO SHOW A WEAKENING OF THE MID-LEVEL SHEAR, WHICH WILL ALLOW FOR THE VORTEX TO SYMMETRIZE. ONCE THIS OCCURS, THE SYSTEM WILL INTENSIFY VERY QUICKLY TO A PEAK OF AT 90 KNOTS BY TAU 36, AND POTENTIALLY SLIGHTLY HIGHER JUST PRIOR TO LANDFALL AS IT MOVES OVER WARM, HIGH OHC WATERS ALONG THE COASTLINE. THE ULTIMATE PEAK INTENSITY WILL DEPEND ENTIRELY ON HOW LONG THE SYSTEM REMAINS OVER WATER AND HOW FAST IT CAN GET ITS VORTEX TOGETHER, AS THE ENVIRONMENT REMAINS PRIMED. ONCE ASHORE, THE SYSTEM WILL RAPIDLY WEAKEN OVER THE TERRAIN OF NORTHERN MOZAMBIQUE, ULTIMATELY DISSIPATING BELOW WARNING CRITERIA BY THE END OF THE FORECAST PERIOD. BUT FREDDY IS A LIKE A B-REEL HORROR MOVIE THAT NEVER ENDS AND AS DISCUSSED BELOW, IT MAY NOT STAY OVER LAND FOR LONG. MODEL DISCUSSION: TRACK GUIDANCE HAS SEPARATED INTO TWO DISTINCT GROUPINGS THROUGH TAU 48, WITH ONE MAJOR OUTLIER. THE UKMET, GALWEM AND EGRR MODELS MAKE UP ONCE GROUP, WHILE THE GROUP CONSISTS OF THE GFS, GEFS, ECMWF, NAVGEM AND COAMPS-TC WHILE THE HWRF IS THE SIGNIFICANT OUTLIER DIFFERENT THAN ALL THE OTHERS. THE DISAGREEMENT IN THE GUIDANCE STEMS FROM HOW EACH TREAT THE STEERING RIDGES, WHICH RIDGE, THE NER OR STR, WILL STRENGTHEN AND BY HOW MUCH, AND COMBINED WITH DISPARITY IN STORM INTENSITY, LEADS TO MAJOR DISCREPANCIES BETWEEN THE MODEL GUIDANCE. THROUGH THE FIRST 48 HOURS OF THE FORECAST, THE FIRST CAMP RACES OUT FRONT OF THE OTHERS, APPROACHING THE ZIMBABWE BORDER WHILE THE OTHER CAMP IS APPROACHING LANDFALL. THE BEYOND TAU 48, THE FIRST CONTINUES RACING AHEAD, WHILE THE OTHER CAMP SPLITS, WITH THE NAVGEM, ECMWF, ECENS AND COAMPS-TC (NAVGEM) TAKING A RELATIVELY LEISURELY TRACK TO THE NORTH THEN TURNING BACK TO THE EAST BY TAU 120 AND THE GFS, GEFS, AND COAMPS-TC (GFS) TOUCHING LAND FOR A BIT THEN RETURNING TO SEA BY TAU 96. THE HWRF IS DOING ITS OWN THING AND KEEPS THE SYSTEM OFFSHORE THE ENTIRE TIME, MAKING A HEAD-FAKE TOWARDS LAND THEN TURNING AWAY AND JOINING UP WITH THE GFS TRACK. NEEDLESS TO SAY, THE TRACK FORECAST IS A BIT COMPLICATED WITH VERY HIGH UNCERTAINTY. TO COMPOUND THE UNCERTAINTY, THE GEFS AND ECENS ENSEMBLE MEANS AND INCREASING NUMBERS OF INDIVIDUAL MEMBERS ARE NOW SHOWING A TRACK THAT RETURNS TO THE OPEN SEA PRIOR TO TAU 120. INTENSITY GUIDANCE IS IN RELATIVELY GOOD AGREEMENT, WITH THE COUPLED COAMPS-TC GUIDANCE INDICATING A PEAK BETWEEN 90-100 KNOTS PRIOR TO LANDFALL. THE COAMPS-TC ENSEMBLE GUIDANCE IS ALSO SHOWING A 30 PERCENT PROBABILITY OF RI PRIOR TO LANDFALL WHILE THE GEFS IS INDICATING 80 PERCENT CHANCE OF MODERATE INTENSIFICATION BEFORE LANDFALL. THE JTWC FORECAST LIES CLOSE TO THE COAMPS-TC GUIDANCE THROUGH THE FORECAST PERIOD. THE ALTERNATE, I AM LEGEND, SCENARIO SEES TC FREDDY DO A U-TURN AFTER MAKING A BRIEF PASSAGE OVER THE COAST OF MOZAMBIQUE, RETURNING TO WATER BY TAU 96 AND QUICKLY REINTENSIFYING. WHILE CONFIDENCE IN THIS SCENARIO REMAINS LOW, WITH INCREASING MODEL GUIDANCE INDICATING A LOOP BACK TO SEA, PROBABILITIES ARE INCREASING. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN