000 AGXX40 KNHC 170714 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 315 AM EDT TUE MAY 17 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 CONTINUE TO BE IN REASONABLY GOOD AGREEMENT ON THE FORECAST FOR THE DEEP LAYERED LOW CENTERED OVER THE U.S. MID ATLC STATES AND CENTRAL APPALACHIANS. THE SOUTHEASTERN VORT MAX ASSOCIATED WITH THE LOW CURRENTLY LIES OVER THE CAROLINAS AND IS EXPECTED TO LIFT NORTHWARD AND WEAKEN AND THE NORTHWESTERN VORT DROPS SE THROUGH THE OHIO VALLEY AND BECOMES THE DOMINANT LOW ALOFT OVER THE SOUTHERN APPALACHIANS BY TONIGHT. THE CENTER OF THIS BROAD LOW WILL WEAKEN THROUGH THE PERIOD AND SLOWLY MOVE NW BY WED. THE COLD FRONT WILL WEAKEN AND LIFT NORTHWARD BEGINNING TONIGHT AS A RESULT. THE REINFORCING SURFACE TROUGHS ASSOCIATED WITH THESE VORTICES ALOFT WILL PASS INTO NW WATERS LATER TODAY AND OVERNIGHT TONIGHT...RESPECTIVELY. BOTH THE 00Z GFS AND ECMWF AGREE ON FINALLY BRINGING WINDS BELOW 20 KT WED EVENING AND GENERALLY ALLOW THE SUBTROPICAL RIDGE TO BUILD ALONG 28N-30N THU INTO FRI. BOTH OF THESE MODELS ALSO CARRY SOME OF THE ENERGY ALOFT FROM THE CENTRAL CARIBBEAN NORTHWARD THROUGH WATERS E OF 70W THU-FRI AND THEN DEVELOP A SURFACE LOW JUST E OF THE AREA N OF 28N LATE FRI INTO SAT. CONFIDENCE IS SOMEWHAT LOW IN THE DAY 4-5 FORECAST FOR THE DEVELOPMENT OF A CLOSED LOW LEVEL CIRCULATION HERE. THE FORECAST FAVORS A TROUGH WHICH PREVENTS THE SUBTROPICAL RIDGE FROM BECOMING STRONG ENOUGH TO SUPPORT VIGOROUS TRADE WIND FLOW TO THE S. CARIBBEAN SEA AND THE TROPICAL N ATLANTIC ... PERSISTENT TROUGHING OVER THE U.S. EAST COAST EXTENDS ALOFT INTO THE CENTRAL CARIBBEAN. AT THE SURFACE...A TROUGH CONTINUES TO LIE OVER THE CENTRAL CARIBBEAN AND IS EXPECTED TO REMAIN THERE INTO WED WHEN THE TROUGHING ALOFT WEAKENS AND SHIFTS NORTHWARD AND THE SUBTROPICAL RIDGE IS ALLOWED TO GRADUALLY BUILD FROM THE CENTRAL ATLC TOWARD THE NE CARIBBEAN AND THEN ALONG 28N-30N ON THU THROUGH SAT. MODERATE EASTERLY TRADE WINDS WILL DOMINATE THE EASTERN AND CENTRAL CARIBBEAN FRI AND SAT AS A RESULT...WITH THE MOST LIKELY ARE FOR WINDS ABOVE ADVISORY CRITERIA LYING ALONG THE COAST OF VENEZUELA AND NE COLOMBIA SAT. 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. MEANWHILE...A LOW AMPLITUDE TROPICAL WAVE NEAR 49W S OF ABOUT 10N IS FORECAST TO MOVE THROUGH THE TROPICAL N ATLC ZONE TONIGHT THROUGH WED AND MOVE INTO THE EASTERN CARIBBEAN BY THU. WHERE IT WILL ENCOUNTER THE PREVALENT EASTERLY TRADE WIND FLOW. WHILE THE TROPICAL WAVE WILL BRING MORE MOISTURE TO SUPPLY SHOWERS AND TSTMS OVER THE EASTERN CARIBBEAN...ITS IMPACT ON THE WIND FIELD IS EXPECTED TO BE MINIMAL AS IT MOVES AWAY FROM THE SUBTROPICAL RIDGING THAT ALLOWED FOR A STRONG ENOUGH GRADIENT IN THE TROPICAL ATLC TO SUPPLY 20 KT WINDS AND 8 FT SEAS OVER S WATERS. THE GFS AND ECMWF AGREE ON THAT FORECAST. GULF OF MEXICO... PERSISTENT TROUGHING OVER THE EASTERN GULF WILL CONTINUE THROUGH WED. A REINFORCING TROUGH CURRENTLY LIES OVER THE EASTERN GULF WITH MULTIPLE PLATFORM OBSERVATIONS N OF THE TROUGH SHOWING WINDS ABOVE 20 KT. THE 00Z GFS AND ECMWF BOTH SHOW 20 KT WINDS N OF THE FIRST FRONTAL TROUGH CURRENTLY AND THEN DIMINISH THE WINDS BELOW ADVISORY CRITERIA BY 1200 UTC. A SECOND REINFORCING TROUGH IS EXPECTED TO DROP S INTO THE NE GULF OVERNIGHT TONIGHT. THE 00Z GFS AND ECMWF AGREE ON LIGHTER WINDS WITH THIS SECOND TROUGH. HIGH PRES OVER THE NW GULF TODAY WILL GRADUALLY MOVE EASTWARD ALLOWING SE RETURN FLOW TO INCREASE TO 20 KT IN THE WESTERN GULF BY THE WED EARLY MORNING HOURS AS THE GRADIENT BUILDS BETWEEN THIS RIDGING AND TROUGHING OVER THE SOUTHERN HIGH PLAINS. FRESH RETURN FLOW IS EXPECTED TO INCREASE TO FRESH TO STRONG IN THE EARLY MORNING HOURS OF FRI AND SAT AS A COLD FRONT SLOWLY MOVES THROUGH CENTRAL TX...INCREASING THE PRES GRADIENT. THE STRONGER GFS IS FAVORED AS IT VERIFIED BETTER WITH A SIMILAR SYNOPTIC SET UP OVER THE SE GULF A FEW WEEKS AGO. WARNINGS.. ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER