000 WTNT41 KNHC 052059 TCDAT1 HURRICANE TOMAS DISCUSSION NUMBER 31 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL212010 500 PM EDT FRI NOV 05 2010 THE CONVECTIVE STRUCTURE OF HURRICANE TOMAS HAS BEEN DISRUPTED THIS AFTERNOON. WHILE SOME OF THIS DISORGANIZATION MAY HAVE BEEN DUE TO MODERATE SOUTHERLY VERTICAL SHEAR...IT IS MORE LIKELY THAT TOMAS HAS BEEN AFFECTED BY HAVING SOME OF ITS CIRCULATION PASS OVER THE HIGHER TOPOGRAPHIC REGIONS OF EASTERN CUBA AND HAITI. THE HIGHEST FLIGHT-LEVEL WINDS REPORTED BY THE AIR FORCE HURRICANE HUNTERS IS 62 KT WITH PEAK SFMR SURFACE WINDS OF ABOUT THE SAME. THE CURRENT INTENSITY IS REDUCED TO 65 KT AND THIS MAY BE SLIGHTLY GENEROUS. AS TOMAS PROGRESSES NORTHEASTWARD DURING THE NEXT DAY...IT MOVES AWAY FROM THE GREATER ANTILLES AND HAS A BRIEF OPPORTUNITY TO REINTENSIFY. WHILE THE CYCLONE WILL LIKELY REMAIN OVER WARM WATERS FOR AT LEAST THE NEXT COUPLE OF DAYS...EXPECTED VERY STRONG VERTICAL SHEAR AND STABLE/DRY ATMOSPHERE SHOULD LEAD TO A FAIRLY RAPID WEAKENING. THE FORECAST INTENSITY IS BASED ON A BLEND OF THE SHIPS/LGEM/GFDL MODELS AND IS SLIGHTLY LOWERED FROM THE PREVIOUS ADVISORY. ALTERNATIVELY...IF THE INNER CORE OF TOMAS DOES NOT QUICKLY REORGANIZE...THE SYSTEM MAY SIMPLY CONTINUE TO WEAKEN FROM HERE ON IN. WHILE THE FORECAST HERE CALLS FOR THE CYCLONE TO BECOME A REMNANT LOW AT DAY 4...IT IS QUITE POSSIBLE THAT INSTEAD THE SYSTEM COULD EVOLVE INTO AN EXTRATROPICAL LOW AFTER INTERACTING WITH THE STRONG APPROACHING COLD FRONT. THE HURRICANE IS CURRENTLY MOVING AT 35/12...PRIMARILY DUE TO THE INFLUENCE OF COMBINED INFLUENCE OF A NORTH-SOUTH ORIENTED RIDGE TO ITS EAST AND A VIGOROUS SHORT-WAVE TROUGH TO ITS NORTHWEST. THE CYCLONE SHOULD CONTINUE TO MOVE NORTHEASTWARD AT ABOUT THE SAME SPEED FOR ABOUT THE NEXT 36 H AND NEARLY ALL TRACK MODEL GUIDANCE IS IN AGREEMENT WITH THIS. HOWEVER...BEYOND 36 H...THE MODEL SUITE SHOWS A TREMENDOUS DIVERGENCE THAT FALLS INTO TWO FACTIONS. THE NORTHERN GROUP...WITH MEMBERS AT FIVE DAYS JUST SOUTHEAST OF NEWFOUNDLAND...INCLUDE THE HWRF/GFDL/NOGAPS MODELS. THE ECMWF LIKELY WOULD HAVE ALSO BEEN EXPLICITLY INCLUDED HERE...BUT IT BECOMES ABSORBED BY A LARGE BAROCLINIC SYSTEM AFTER DAY THREE. THE SOUTHERN GROUP...WITH MEMBERS AT FIVE DAYS JUST NORTH OF THE CARIBBEAN...INCLUDE THE GFS/GFS ENSEMBLE/UKMET. THE FORECAST TRACK CHOSEN LEANS MORE TOWARD THE LATTER BUNCH AND IS CONSIDERABLY SOUTH OF THE MODEL CONSENSUS...WHICH IS AN UNREALISTIC PREDICTION...AND SOMEWHAT SOUTH OF THE PREVIOUS ADVISORY. IT ALMOST GOES WITHOUT SAYING...THE EXTENDED FORECAST OF THIS SYSTEM IS VERY UNCERTAIN. REGARDLESS OF THE EXACT TRACK AND INTENSITY OF TOMAS...THE MOST SIGNIFICANT THREAT FROM THIS TROPICAL CYCLONE SHOULD CONTINUE TO BE HEAVY RAINFALL...WHICH COULD PRODUCE FLASH FLOODING AND LIFE- THREATENING MUD SLIDES OVER PORTIONS OF HAITI AND THE DOMINICAN REPUBLIC DURING THE NEXT COUPLE OF DAYS. FORECAST POSITIONS AND MAX WINDS INITIAL 05/2100Z 20.3N 73.8W 65 KT 12HR VT 06/0600Z 22.0N 72.6W 70 KT 24HR VT 06/1800Z 23.9N 71.5W 80 KT 36HR VT 07/0600Z 24.8N 70.8W 75 KT 48HR VT 07/1800Z 25.4N 69.6W 55 KT 72HR VT 08/1800Z 26.5N 67.0W 30 KT 96HR VT 09/1800Z 26.5N 63.5W 25 KT...POST-TROP/REMNT LOW 120HR VT 10/1800Z 27.0N 61.0W 25 KT...POST-TROP/REMNT LOW $$ FORECASTER LANDSEA/BEVEN