000 AGXX40 KNHC 150637 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 240 AM EDT SUN MAY 15 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... THE MODELS SHOW SOME DIFFERENCES ALOFT WITH THE DEVELOPMENT OF A CUT OFF LOW OVER THE EASTERN U.S. AND THE MULTIPLE VORTICES THAT ARE EXPECTED TO ROTATE ABOUT THE LOW AND SEND A SERIES OF SURFACE TROUGHS THROUGH FLORIDA. HOWEVER...DIFFERENCES WITH THE TIMING OF THE LEAD FRONT AND THE MULTIPLE TROUGHS REINFORCING IT ARE RELATIVELY SMALL. AT 0600 UTC...BUOY 41012 REPORTED 25 KT NEAR 30N80.5W. BOTH THE 00Z GFS AND ECMWF ARE WELL INITIALIZED WITH THE STRENGTH OF THE SW FLOW. DIFFERENCES BETWEEN THE MODELS COMES INTO PLAY EARLY TUE WHEN A SURGE OF W-NW WINDS ASSOCIATED WITH ONE OF THOSE VORTICES PASSES OFF THE FL E COAST. THE GFS IS STRONGER WITH THE WINDS HERE THAN THE ECMWF. THE UKMET SIDES WITH THE STRONGER GFS...SO GENERALLY FOLLOWED THE GFS FORECAST HERE. TROUGHING OVER THE SE U.S. COAST/WESTERN ATLC WILL BEGIN TO LIFT NORTHWARD BY WED...ALLOWING FOR WINDS TO DIMINISH FROM S TO N AND RIDGING TO BUILD ACROSS MUCH OF THE AREA AND LIGHT WINDS TO PREVAIL BY LATE THU. FARTHER E...WEAK MID LEVEL ENERGY AND SURFACE TROUGHING OVER THE N CENTRAL CARIBBEAN WILL BEGIN TO LIFT NORTHWARD INTO THE EASTERN PORTION OF THE SW N ATLC ZONE TODAY. THE MAIN IMPACT TO THE SENSIBLE WEATHER IS EXPECTED TO BE AN INCREASE IN SHOWERS NEAR THE SYSTEM. THE 00Z UKMET DEVELOPS A SURFACE LOW PRES SYSTEM WITH 20 KT WINDS TO ITS N BY MON EVENING ASSOCIATED WITH THIS ENERGY...BUT CONFIDENCE IS LOW IN ITS OUTLIER STRONG SOLUTION BY THAT TIME. THE GFS LOOKS REASONABLE WITH ITS WEAKER SURFACE TROUGH THAT SHOWS A SLIGHT WIND SHIFT AT THE SURFACE AND AN INCREASE IN PRECIPITATION WITH THE SYSTEM AS IT LIFTS THROUGH THE AREA TODAY THROUGH TUE NIGHT. CARIBBEAN SEA AND THE TROPICAL N ATLANTIC ... WHILE THE WEAKENING AND NORTHEASTWARD EJECTION OF THE DEEP LAYERED LOW OVER THE CENTRAL ATLC IS EXPECTED TO ALLOW FOR BUILDING OF THE SUBTROPICAL RIDGE...FRESH TRADE WINDS ARE NOT EXPECTED TO RETURN IN EARNEST TO THE EASTERN AND CENTRAL CARIBBEAN OR THE TROPICAL N ATLC THIS PERIOD. THE CULPRIT IS THE PERSISTENT TROUGHING OVER THE U.S. EAST COAST WHICH IS WEAKENING THE PRES GRADIENT OVER THE AREA. MOISTURE WILL CONTINUE TO POOL ON THE EASTERN SIDE OF THE DEEP LAYER TROUGHING THAT EXTENDS INTO THE CENTRAL CARIBBEAN...MAKING RAINFALL OVER THE EASTERN CARIBBEAN THE PRIMARY SENSIBLE WEATHER CONCERN FOR THE NEXT FEW DAYS UNDER THIS SOMEWHAT STAGNANT PATTERN. THE SURFACE TROUGHING TO THE N IS EXPECTED TO BEGIN TO DIMINISH ON WED. MEANWHILE...A LOW AMPLITUDE TROPICAL WAVE NEAR 40W S OF ABOUT 08N IS FORECAST TO MOVE THROUGH THE TROPICAL N ATLC ZONE TUE-WED AND LIFT SLIGHTLY N AS IT MOVES INTO THE EASTERN CARIBBEAN BY THU. THIS SHOULD REINFORCE THE PERSISTENT TROUGHING OVER THE CENTRAL CARIBBEAN. AT THE SAME TIME...SUBTROPICAL RIDGING IS EXPECTED TO BUILD TO THE N AS THE TROUGHING OVER THE EASTERN U.S./WESTERN ATLC SHIFTS NORTHWARD. THIS SHOULD ALLOW FOR AN INCREASE IN WINDS IN THE E ATLC. THE 00Z GFS SHOWS A WIDESPREAD AREA OF 20 KT WINDS HERE WED AND THU WHILE THE UKMET ONLY ALLOWS WINDS TO INCREASE TO 15 KT AND THE ECMWF IS GENERALLY WEAKER THAN THE GFS. CONFIDENCE IS SOMEWHAT LOW HERE AS BOTH THE GFS AND ECMWF BRING A THIRD SYSTEM INTO PLAY - A VORT OF UNDETERMINED ORIGINS OVER THE NE CARIBBEAN THAT IS AMPLIFIED AS THE WAVE REACHES IT WED/THU. WITH CONFIDENCE SOMEWHAT LOW...WILL KEEP AN AREA OF 20 KT WINDS IN THE FORECAST...BUT WILL REDUCE THE AREA CLOSED TO THAT OF THE ECMWF AND ITS TIMING. GULF OF MEXICO... OVERALL...LITTLE CHANGE IS EXPECTED IN THE WEATHER PATTERN OVER THE GULF OF MEXICO THROUGH TUE NIGHT WITH PERSISTENT TROUGHING EXPECTED OVER THE EASTERN GULF. THE COLD FRONT OVER THE EASTERN GULF THIS MORNING IS EXPECTED TO WEAKEN...BUT A SECONDARY SURGE WILL PUSH INTO THE NE GULF OVERNIGHT TONIGHT AND A THIRD SURGE WILL DO THE SAME ON MON EVENING ACCORDING TO THE GFS AND ECMWF. HIGH PRES IS FINALLY EXPECTED TO DROP INTO THE NW GULF BEHIND THE EASTERN GULF TROUGHING ON TUE NIGHT AND ALLOW SE RETURN FLOW TO INCREASE TO 20 KT IN THE WESTERN GULF BY THE EARLY MORNING HOURS AS THE GRADIENT BUILDS BETWEEN THIS RIDGING AND TROUGHING OVER THE SOUTHERN HIGH PLAINS INCREASES. THE MODELS AGREE ON SHIFTING THE EASTERN GULF TROUGHING NORTHWARD WED AND THU AND REPLACING IT WITH THIS HIGH PRES WHICH WILL SHIFT INTO THE NE GULF LATE IN THE PERIOD. FRESH RETURN FLOW WILL PERSIST IN THE WESTERN GULF TUE NIGHT THROUGH WED AND INCREASE TO FRESH TO STRONG ON THU AS A COLD FRONT MOVES INTO CENTRAL TX. THE MODELS ARE IN RELATIVELY GOOD AGREEMENT ON THIS SCENARIO. WARNINGS.. ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER