WDXS32 PGTW 030300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 09S (GRANT) WARNING NR 034// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 14.6S 65.5E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 574 NM NORTHEAST OF PORT LOUIS, MAURITIUS MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 06 KTS SIGNIFICANT WAVE HEIGHT: 15 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: THE STRUGGLE TO FIND SOMETHING INTERESTING TO SAY ABOUT TROPICAL CYCLONE GRANT INCREASES AFTER 20 DAYS OF IT BEING A VIABLE CIRCULATION AND ANOTHER 15 DAYS OF BEING AT OR ABOVE TROPICAL CYCLONE STRENGTH. GRANT CAME THROUGH TODAY, HOWEVER, SHOWING YET ANOTHER BURST OF CYCLIC CONVECTION BETWEEN 18Z AND 21Z. ALAS, THE VAST CDO OVER THE CORE COLLAPSED ALMOST AS QUICKLY AS IT FORMED, AND AT ANALYSIS TIME ANOTHER SMALL COMPLEX OF THUNDERSTORMS IS FLARING UP OVER THE CORE. A NUDGE TO THE NORTHWEST FROM THE MID-LEVEL STEERING RIDGE OVER THE PAST TWO DAYS HAS BROUGHT THE SYSTEM INTO 28C WATERS AND VERTICAL WIND SHEAR IS LIGHT, ALLOWING THE SYSTEM TO BEGIN PERIODIC EPISODES OF CYCLIC CONVECTION ONCE THE DRIER AIR MOVING INTO THE CORE BECOMES SATURATED ENOUGH TO ALLOW FOR IT. TOTAL PRECIPITABLE WATER LOOPS FROM CIMSS VERIFY THAT DRY AIR HAS MADE IT OVER THE TOP OF THE SYSTEM AND IS FURTHER CUTTING OFF THE MOISTURE SOURCE. IT IS DRY AIR, NOT VERTICAL WIND SHEAR OR COOLING OCEAN TEMPS THAT IS ACTING AS AN IMPEDIMENT TO THIS SYSTEM. ANIMATED WATER VAPOR IMAGERY SHOWS IMPINGED OUTFLOW OVER THE SOUTHEAST QUADRANT BUT OTHERWISE VERY GOOD OUTFLOW OVER THE REST OF THE SYSTEM. TROPICAL CYCLONE GRANT IS APPROACHING THE END OF ITS EQUATORWARD JAUNT AND WILL SOON ENTER ITS TERMINAL LEG TOWARDS MADAGASCAR. INITIAL WIND RADII BASIS: PERSISTENCE AND CLIMATOLOGY. CURRENT STEERING MECHANISM: THE SUBTROPICAL RIDGE, WHICH IS ANCHORED IN AN ANTICYCLONE OVER 15S 80E. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.5 - 35 KTS CIMSS SATCON: 42 KTS AT 02130Z CIMSS ADT: 47 KTS AT 030000Z CIMSS AIDT: 37 KTS AT 030000Z CIMSS D-MINT: 29 KTS AT 022034Z CIMSS D-PRINT: 27 KTS AT 030000Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 5-15 KTS SST: 27-28 CELSIUS OUTFLOW: MODERATE EQUATORWARD OTHER FACTORS: SUBSTANTIAL DRY AIR ENTRAINMENT. ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: WITH EACH SUCCESSIVE MODEL RUN, THE QUESTION OF WEATHER OR NOT TC 09S WILL MAKE IT TO MADAGASCAR BECOMES LESS CERTAIN. THE UPSTREAM ENVIRONMENT IS SIMPLY TOO HARSH TO ALLOW GRANT A FINAL HOO-RAH AND CONSIDERING THE CURRENT STATE OF THE INDIAN OCEAN DIPOLE AND MADDEN JULIAN OSCILLATION, CONCERNS THAT A DISCERNABLE VORTEX WILL CROSS MADAGASCAR AND RE-INVIGORATE OVER THE MOZAMBIQUE CHANNEL CAN BE ASSUAGED. SO ALTHOUGH IT WAS FUN FOR A WHILE, THE UNAVOIDABLE PARALLELS WITH FREDDY ARE FADING. AT THIS POINT THE ISSUE IS WHETHER OR NOT A DISCERNABLE VORTEX WILL EVEN MAKE IT TO THE EASTERN SHORES OF MADAGASCAR. DURING THE NEXT TWO DAYS TC 09S GRANT WILL TURN TO THE SOUTHEAST, BECOMING FURTHER SEPARATED FROM ITS MONSOON TROF MOISTURE SOURCE, AND STRUGGLE ALONG TOWARDS THE COAST OF MADAGASCAR. AS IT DOES SO IT WILL LIKELY CONTINUE TO SHOW CYCLIC BURSTS OF CONVECTION, WITH EACH SUCCESSIVE EPISODE BECOMING LESS VIGOROUS. MODEL DISCUSSION: TRACK GUIDANCE HAS CONGEALED OVER A LANDFALL SOUTH OF TOMASINA OR A DISSIPATION OFF-SHORE ALONG THAT TRACK. INTENSITY GUIDANCE, THOUGH WIDELY SPREAD, HAS GIVEN UP ON A BIG SURGE IN INTENSITY. THE JTWC TRACK FORECAST STAYS BETWEEN THE ECMWF ENSEMBLE AND THE NEW AI TRACKERS, WHILE THE INTENSITY FORECAST HUGS THE CONSENSUS MEAN, WHICH MEETS THE HFAS AT A PEAK OF 45 KNOTS AT TAU 72. FORECAST CONFIDENCE: TRACK 00-72 HR: MEDIUM TRACK 72-120 HR: MEDIUM INTENSITY 00-72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN