000 AGXX40 KNHC 211814 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 115 PM EST MON NOV 21 2011 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLC...AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. SW N ATLC W OF 55W... A GALE WARNING IS IN EFFECT FOR THE FAR NE WATERS BETWEEN THE SURFACE LOW NEAR 27N52W AND 1025 MB HIGH PRES CENTERED NEAR THE GA/SC COAST. THE ASCAT PASSES AT 1238 UTC AND 1416 UTC MISSED MUCH OF THE AREA WHERE GALES ARE BELIEVED TO LIE. HOWEVER...SHIP VRZT5 REPORTED 30 KT WINDS NEAR 31N48W AND THE 1238 UTC ASCAT PASS SHOWED GALE FORCE WINDS EXIST WITHIN 150 NM N OF THE LOW ON THE EDGE OF THE SWATH. THESE CONDITIONS ARE NEAR OR SLIGHTLY STRONGER THAN THE 12Z GFS AND 00Z ECMWF. THE GFS HAS BEEN SLOWER THAN OBSERVATIONS CARRYING THE LOW TO THE N AND IT CONTINUES TO BE ON THE SLOWER AND STRONGER EDGE OF THE GUIDANCE AS THE SYSTEM MOVES N OF THE AREA OVER THE NEXT 48 HOURS. THE 12Z UKMET QUICKLY PHASES THE SYSTEM WITH A NORTHERN STREAM TROUGH WHILE THE ECMWF IS SOMEWHERE BETWEEN THE GFS AND UKMET...HEDGING TOWARD THE MORE PHASED/FASTER UKMET SOLUTION. WITH THE TWOAT SUGGESTING SUBTROPICAL DEVELOPMENT OF THE SYSTEM...THE FORECAST SIDES WITH A BLEND OF THE GFS AND THE ECMWF...LEANING MORE TOWARD THE GFS. THIS LOW WILL HAVE A LARGE SAY IN THE PROGRESSION OF THE COLD FRONT MOVING THROUGH WESTERN PORTIONS OF THE SW N ATLC WED NIGHT THROUGH SAT. BECAUSE OF ITS SLOW AND STRONG SOLUTION WITH THIS LOW...THE GFS IS SLOWER THAN THE 00Z ECMWF WITH THE EASTWARD PROGRESS OF THE COLD FRONT MOVING THROUGH THE GULF WED AND THU AND THE SW N ATLC WED NIGHT THROUGH FRI. THE GFS AND UKMET BOTH PINCH OFF A DEEP LAYER LOW NEAR BERMUDA LATE THU THAT LINGERS THROUGH SAT. THIS FURTHER GUMS UP THE NORTHERN STREAM OVER WATERS N OF 20N. THE NOGAPS IS ALSO SHOWING SOME RESEMBLANCE TO THIS SOLUTION WHILE THE 00Z ECMWF IS PROGRESSIVE. WILL CONTINUE TO FAVOR THE GFS THROUGH THE END OF THE WEEK AS EVEN THE 00Z ECMWF ENSEMBLE MEAN IS DEEPER AND SLOWER THAN ITS OPERATIONAL RUN BY FRI NIGHT/SAT. GULF OF MEXICO... BUOY DATA SHOW MODERATE RETURN FLOW OVER THE SW GULF SE OF A 1025 MB HIGH CENTERED NEAR THE GA/SC COAST WITH FRESH E WINDS S OF THE LOW IN THE STRAITS OF FL. THE SE FLOW OVER THE NW GULF WILL INCREASE TO FRESH TONIGHT AS THE FRONT APPROACHES...THEN VEER SW AND DIMINISH TUE NIGHT AHEAD OF THE FRONT. THE FRONT WILL PUSH OFF THE TEXAS COAST OVERNIGHT TUE NIGHT...WEAKEN FROM FORT MYERS FLORIDA TO THE BAY OF CAMPECHE THU MORNING AND DISSIPATE BY FRI. THE COOL DENSE AIR BEHIND THE FRONT WILL ALLOW N WINDS TO 20 KT TO FUNNEL DOWN THE MEXICAN COAST WED...REACHING VERACRUZ BY WED NIGHT. AT THE SAME TIME...THE SUPPORTING UPPER TROUGH LIFTS OUT TO NEW ENGLAND BY LATE WED...AND RIDGING BUILDS OVER THE CENTRAL PLAINS...THUS DEPRIVING THE FRONT UPPER SUPPORT OVER THE WESTERN GULF. AS A RESULT...THE FRONT WILL PUSH AS FAR AS THE FLORIDA KEYS BY EARLY THU OVER THE EASTERN GULF...BUT BECOME DIFFUSE OVER THE WESTERN GULF THROUGH THU AFTERNOON. THIS TIMING IS IN LINE WITH THE 12Z GFS AS OPPOSED TO THE FASTER 00Z ECMWF. THE FORECAST REASONING FOR THIS TIMING IS EXPLAINED IN THE SW N ATLC SECTION ABOVE. THE RIDGE PROGRESSES E TO THE CAROLINAS BY FRI...ALLOWING FRESH SE RETURN FLOW TO SET UP OVER THE NW GULF AND MAINTAINING FRESH E FLOW ACROSS MUCH OF THE EASTERN GULF BY FRI NIGHT. A STRONG FRONT SHOULD PUSH OFF THE TX COAST SAT AFTERNOON...WITH GALE CONDITIONS POSSIBLE BEHIND THE FRONT IN THE WESTERN GULF BY SAT NIGHT. THERE ARE STILL SOME CONSIDERABLE MODEL DIFFERENCE HERE...BUT THE BULK OF THE SOLUTIONS ARE IN LINE WITH THIS THINKING WHICH IS CLOSE TO THE GFS. MAY HOLD OFF ON THE MENTION OF GALES THIS PACKAGE GIVEN THE UNCERTAINTY...ESPECIALLY WITH THE TIMING NEAR THE END OF THE PERIOD. CARIBBEAN SEA AND TROPICAL N ATLC S OF 19N W OF 55W... THE PRESSURE GRADIENT BETWEEN HIGH PRESSURE N OF THE AREA...AND LOW PRESSURE ASSOCIATED WITH THE MONSOON TROUGH OVER THE SW CARIBBEAN IS SUPPORTING FRESH NE TO E WINDS AS DEPICTED BY THE LATEST ASCAT SCATTEROMETER PASS AT 1420 UTC...INCLUDING 20 TO 25 KT WINDS THAT WERE PUSHING THROUGH THE WINDWARD PASSAGE. THE GRADIENT WILL WEAKEN BY MIDWEEK AS THE RIDGE OF HIGH PRESSURE SHIFTS EASTWARD. WINDS WILL DIMINISH AND NE SWELL WILL DECAY TO LESS THE 8 FT BY WED AFTERNOON. NE WINDS WILL INCREASE TO 20 KT N OF 18N BY FRI...AS HIGH PRES BUILDS N OF THE AREA. WARNINGS... GULF OF MEXICO... .NONE. .CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. .SW N ATLC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER/CHRISTENSEN