000 AGXX40 KNHC 070654 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 155 AM EST SUN NOV 7 2010 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLC...AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... WINDS HAVE DIMINISHED IN THE WESTERN GULF ASIDE FROM THE WESTERN BAY OF CAMPECHE WHERE FUNNELING WINDS TYPICALLY REMAIN HIGH LONGER AFTER A COLD FRONTAL PASSAGE THAN IN THE SURROUNDING AREA. THE SOUTHEASTERN GULF IS WHERE THE PRES GRADIENT BETWEEN HIGH PRES OVER THE WESTERN AND NORTHERN GULF AND THE COLD FRONT AND HURRICANE TOMAS IN THE SW N ATLC IS GREATEST. THE GFS IS IN REASONABLE AGREEMENT WITH THE NHC OFFICIAL FORECAST FOR TOMAS THROUGH SUN EVENING AND THEN BECOMES SLOWER AND MORE SOUTHERLY. THIS LIKELY KEEPS THE WINDS HIGHER IN THE SE GULF LONGER THAN THE OFFICIAL FORECAST SUGGESTS...SO ADJUSTMENTS WERE MADE TO THE GFS TO DROP THE 20 KT WINDS IN THE E GULF MORE QUICKLY ON MON. BY TUE...BOTH THE GFS AND ECMWF HINT AT BRIEFLY INCREASING SOUTHERLY RETURN FLOW TO 20 KT ALONG THE S TEXAS/NE MEXICO COAST...BUT THE 00Z GFS ENSEMBLES SHOW LESS THAN A 10 PERCENT CHANCE OF 20 KT WINDS. KEPT THE MENTION OF 20 KT WINDS OUT OF THE FORECAST FOR NOW. CARIBBEAN SEA... HURRICANE TOMAS WELL NORTH OF THE AREA CONTINUES TO DRAG A TROUGH TO ITS S TROUGH THE EASTERN CARIBBEAN. THIS TROUGH SEPARATES NW WINDS TO ITS W FROM SE WINDS ON ITS E SIDE. THE STRONGEST NORTHERLY WINDS ARE ASSOCIATED WITH A DISSIPATED COLD FRONT AND LIE W OF 75W ACCORDING TO THE 0230 UTC ASCAT PASS. THESE WINDS WILL DIMINISH TO LESS THAN 20 KT OVER MUCH OF THE WESTERN CARIBBEAN BY TUE. THE TROUGH WILL CONTINUE TO VERY SLOWLY NUDGE E AS TOMAS MOVES EASTWARD AND CONVECTION WILL CONTINUE TO BE FOCUSED NEAR AND E OF THIS TROUGH OVER THE NEXT FEW DAYS. BOTH THE GFS AND ECMWF DEVELOP A WEAK LOW PRES SYSTEM ON THE TROUGH BY WED AND BEGIN TO MOVE THE LOW AND TAIL END OF THE TROUGH W. CONFIDENCE IS LOW IN THIS WEAK LOW PRES SYSTEM DEVELOPING. THE FORECAST BROAD BRUSHES THIS IDEA FOR NOW. TROPICAL N ATLC... THE MODELS GENERALLY AGREE ON CARRYING THE UPPER LOW CURRENTLY N OF THIS ZONE SLIGHTLY WESTWARD TODAY BEFORE SHOVING IT BACK TO THE EAST AHEAD OF THE INTENSIFYING DEEP LAYER LOW OFF THE NE U.S. COAST. THE MODELS VARY WITH THE STRENGTH OF THE SYSTEM...WITH THE GFS ON THE WEAKER SIDE ALOFT COMPARED TO THE ECMWF. BASED ON ITS SATELLITE PRESENTATION...THE ECMWF SEEMS TO HAVE A BETTER HANDLE ON THIS PATTERN AND IT IS CLOSER TO THE OFFICIAL NHC FORECAST FOR TOMAS THAN THE GFS. AS A RESULT...THE ECMWF IS SLOWER TO BRING WINDS IN THE NW PORTION OF THE AREA TO 20 KT SE OF TOMAS THAN THE GFS. THE ECMWF WAS PRIMARILY USED FOR THE FORECAST HERE. SW N ATLC... HURRICANE TOMAS HAS MOVED NORTHEASTWARD AHEAD OF THE COLD FRONT A BIT FASTER THAN FORECAST THIS TIME LAST NIGHT. THE NHC OFFICIAL FORECAST AT 0300 UTC CONTINUES TO TURN TOMAS MORE EASTWARD AFTER 12Z SUN AND ALLOWS TOMAS TO REMAIN A TROPICAL STORM AS IT EXITS THE SW N ATLC ZONE MON. THIS GFS IS SLOWER AND MORE SOUTHERLY WITH THE TRACK OF TOMAS BY MON COMPARED TO THE OFFICIAL FORECAST WHILE THE 00Z ECMWF IS CLOSER TO THE OFFICIAL TIMING BUT FARTHER S BY ABOUT 2 DEGREES AS IT CROSSES E OF THE FORECAST AREA. THE ECMWF WAS RELIED ON MORE HEAVILY FOR THE FORECAST IN THE SW N ATLC BECAUSE ITS FORECAST IS CLOSER TO THE OFFICIAL FORECAST FOR TOMAS. WARNINGS... ATLC... .HURRICANE WARNING FROM 24N TO 27N E OF 71W...AMZ080. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER