000 AGXX40 KNHC 210803 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 403 AM EDT THU JUN 21 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO AND SW N ATLC S OF 31N W OF 55W... A WEAK SURFACE LOW WAS ANALYZED NEAR 25N85W AT 21/00Z...BUT THIS IS NOT EVIDENT ON A 0328 UTC ASCAT PASS...WHICH INSTEAD SHOWS A TROUGH FROM NE YUCATAN TO W CENTRAL FLORIDA. THE GOOD NEWS IS THAT GLOBAL MODELS ARE IN BETTER AGREEMENT IN THE SHORT TERM SHOWING THE DEVELOPMENT ALONG THE TROUGH OFF THE N COAST OF YUCATAN AND MOVING INTO THE S CENTRAL GULF LATER TODAY. BY EARLY SAT...THE CONSENSUS OF THE OPERATIONAL AND ENSEMBLE GFS AND ECMWF ARE DECENT AGREEMENT SHOWING THE LOW POSITION NEAR 24N90W WITH AN MSLP AROUND 1005 MB...WITH A SLOW DRIFT N INTO SUN. GIVEN THE POSITION OF THE LOW OVER THE WARMER LOOP CURRENT WATERS AND THE FACT THAT UPPER SHEAR IS EXPECTED TO MINIMAL...CONVECTION WILL PERSIST OVER MUCH OF THE GULF...PARTICULARLY AROUND THE EASTERN AND NE PORTIONS. THE MODELS DIVERGE CONSIDERABLY BEYOND SAT UNFORTUNATELY. THE GFS SHOWS A SHORT WAVE TROUGH DIGGING INTO THE NE GULF BY LATE SUN DRAWING THE LOW FURTHER TO THE NE. THE GFS CONTINUES TO EXHIBIT LIKELY CONVECTIVE FEEDBACK ISSUES AND DEEPENS A NEW LOW OFF THE NE FLORIDA COAST MON...AHEAD OF THE SHARP MID/UPPER TROUGH...REACHING TROPICAL OR SUBTROPICAL STRENGTH BY MON NIGHT. THE NOGAPS FOLLOWS A SIMILAR TREND. THE ECMWF MEANWHILE SHOWS A WEAKER SHORT WAVE TROUGH DIGGING THROUGH THE LOWER MISSISSIPPI VALLEY ON SUN...DRAWING THE SURFACE LOW INTO THE NE GULF. THE CONVECTIVE FEEDBACK AFFLICTING THE GFS APPEARS TO BE CONTAGIOUS AS THE ECMWF PROCEEDS TO DEEPEN THE LOW IN PLACE OVER THE NE GULF. THE UKMET MEANWHILE HAD BEEN THE ONLY MODEL SHOWING THIS NE TURN IS NOW INDICATING THE SURFACE LOW WILL SHIFT THE NW GULF. THE OFFICIAL FORECAST DISCOUNTS BOTH THE GFS SOLUTION SHOWING A DEEPENING LOW OF NE FLORIDA IN THE ATLC...AND THE ECMWF SOLUTION WITH A DEEPENING LOW IN THE NE GULF...AND INSTEAD FOLLOWS THE GEFS...ALTHOUGH CONTINUES THE GFS/ECMWF TREND OF MOVING THE SURFACE FURTHER EAST THROUGH EARLY NEXT WEEK. WINDS WILL REACH 25 KT OVER THE EASTERN GULF AND OFF THE NE FLORIDA COAST...BETWEEN THE LOW PRES AND THE ATLC RIDGE TO THE EAST. FORECAST SEAS ARE LOWER THE MWW3 GUIDANCE WHICH IS TIED TO THE CONVECTIVE FEEDBACK PRONE GFS... AND SEAS WILL REACH 10 FT NE OF THE BAHAMAS EARLY NEXT WEEK IN THE FRESH TO STRONG SW FLOW. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... CONVECTION OVER THE NW CARIBBEAN IS MOVING INTO THE SE GULF. FARTHER EAST...FRESH TRADE WINDS ARE OVER PRIMARILY THE EASTERN AND CENTRAL CARIBBEAN IN ADVANCE OF A TROPICAL WAVE ALONG 67W AT 21/00Z NOW APPEARS TO BE LOSING DEFINITION AS IT MOVES THROUGH THE CENTRAL CARIBBEAN. RECENT OBSERVATION SHOW THE WINDS AROUND 15 TO 20 KT FROM 55W TO THE CENTRAL CARIBBEAN...WITH 25 KT ALONG THE NORTHERN COAST OF SOUTH AMERICA. WINDS OVER THE CARIBBEAN WILL HINGE ON THE EVOLUTION OF THE SUBTROPICAL RIDGE TO THE N WHICH WILL BE HIGHLY DEPENDENT ON THE FORECAST FOR THE LOW IN THE GULF OF MEXICO. THE GEFS MEAN IS PREFERRED WHICH WILL KEEP MODERATE TO FRESH WINDS OVER MUCH OF THE CARIBBEAN THROUGH EARLY NEXT WEEK. NOTE...GRIDDED MARINE OUTPUT IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE (LOWER CASE) GULF OF MEXICO... .NONE. CARIBBEAN SEA... .NONE. SW N ATLANTIC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER CHRISTENSEN