000 AGXX40 KNHC 201943 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 240 PM EST SAT NOV 20 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... HIGH PRES CENTERED OVER NE GEORGIA EXTENDS A RIDGE SW TO THE N CENTRAL AND TO THE SW BAY OF CAMPECHE. BUOY OBSERVATIONS FROM EARLY THIS AFTERNOON SHOW RELATIVELY LIGHT WINDS ACROSS THE AREA WITH WIND DIRECTION FROM E TO SE OVER THE EASTERN AND CENTRAL GULF ZONES TO SE TO S OVER THE FAR NW PORTION...WITH THE EXCEPTION OF THE SE PORTION WHERE BOTH HIGH RESOLUTION ASCAT AND A COUPLE OF SHIP OBSERVATIONS SHOWED NE WINDS OF 20 TO 25 KT DUE TO A CONTINUING TIGHT PRES GRADIENT BETWEEN THE RIDGE AND SLIGHTLY LOWER PRES JUST SE OF THE GULF IN THE NW CARIBBEAN SEA. SEA STATE ANALYSIS FROM THIS MORNING AND EARLY AFTERNOON INDICATED SEAS IN THE 1 TO 3 FT RANGE N OF 24N...AND 4 TO 6 FT S OF 24N E OF ABOUT 89W. THE 1200 UTC RUN OF THE NOAA WAVEWATCH MODEL APPEARS REASONABLE WITH RESPECT TO THESE REPORTED VALUES SO WILL STAY CLOSE TO GUIDANCE OVERALL FOR THIS FORECAST...BUT MAY HAVE NOTCH UP SEAS IN THE FAR SE CORNER NEAR STRAITS OF FLORIDA BASED ON IMPACT THAT E SWELLS THAT PROPAGATE FROM THE SW ATLC WATERS THROUGH THE STRAITS OF FLORIDA HAVE ON THESE SEA OVER THE NEXT 36-48 HOURS. AS FOR THE FORECAST...THE RIDGE WILL SHIFT EASTWARD AND WEAKEN THROUGH WED AS MODELS CONTINUE TO BE IN AGREEMENT WITH THIS SCENARIO. THIS WILL ALLOW FOR WINDS ACROSS THE AREA TO REMAIN ON THE RATHER LIGHT SIDE WHILE VEERING AROUND TO THE SE TO S... HOWEVER WINDS OVER THE FAR WESTERN PORTION N OF 24N AND W OF 94W BEGIN TO INCREASE TO 15 TO 20 KT TONIGHT IN RETURN FLOW AS LOW PRES OVER THE GREAT INTERACTS WITH THEW RIDGE. THESE WINDS THEN DECREASE SOME LATE TUE INTO WED AS A COLD FRONT ASSOCIATED WITH THE LOW PRES APPROACHES THE TEXAS COAST ON THU AFTERNOON...AND TO JUST OFFSHORE THE TEXAS AND SW LOUISIANA COASTS THU EVENING BASED ON CONSENSUS OF LATEST NWP MODEL OUTPUT. OF NOTE...THE 1200 UTC GFS RUN AGAIN FASTER (ABOUT 18 HOURS) WITH FRONTAL TIMING OFF THE COAST AGAIN. CARIBBEAN SEA AND TROPICAL N ATLC... WEAKENING STATIONARY FRONT EXTENDS FROM CENTRAL CUBA TO INLAND COAST OF HONDURAS AT 16N86W EARLY THIS AFTERNOON. A HIGH RESOLUTION ASCAT PASS FROM THIS MORNING SHOWED A RATHER STEADY SWATH OF NE 20 KT WINDS N OF THE FRONT AND SW OF CUBA...WITH BUOY 42056 NEAR 20N85W REPORTING NE WINDS OF 15 TO 20 KT. A COUPLE OF RECENT SHIP OBSERVATIONS THROUGH THE WINDWARD PASSAGE SHOWED NE 20 KT WINDS. THE FRONT WILL GRADUALLY DISSIPATE THROUGH SUN AS STRONG ATLC HIGH PRES BUILDS SOUTHWARD INCREASE THE NE WINDS ACROSS MUCH OF THE AREA THROUGH TUE...THEN DECREASE SOME WED AND THU AS THE PARENT ATLC HIGH SHIFTS SE OVER THE CENTRAL ATLC AND WEAKENS. SW N ATLC S OF 31N AND W OF 65W... A COLD FRONT EXTENDS FROM 21N65W TO 22N73W THEN DISSIPATING STATIONARY TO CENTRAL CUBA EARLY THIS AFTERNOON AS STRONG HIGH PRES BUILDS SE ACROSS THE AREA TO ITS N. A PARTIAL ASCAT PASS FROM THIS MORNING REVEALED A SWATH NE 20 TO 25 KT WINDS N OF THE FRONTAL BOUNDARY TO 26N AND E OF THE BAHAMAS...WITH SEAS TO 9 FT AS REPORTED BY BUOYS 41046 NEAR 24N71W AND BUOY 41049 NEAR 27N63W. THESE WINDS ARE ALSO BEING CHANNELED TO THE S OF THE SE BAHAMAS AND SW THROUGH THE WINDWARD PASSAGE...AND ALSO TOWARDS THE COAST OF CUBA. THE FRONT IS FORECAST TO WEAKEN AND GRADUALLY DISSIPATE THROUGH SUN AS PUSHES TO JUST SE OF THE AREA AND INTO THE NORTHERN TROPICAL N ATLC. THE WESTERN MOST EXTENSION OF THE FRONT WILL LAG BEHIND AS A DISSIPATING STATIONARY FRONTAL BOUNDARY ACROSS NORTHERN HISPANIOLA AND EASTERN CUBA BY MON BEFORE COMPLETELY DISSIPATING. THE MAIN MARINE CONCERN AGAIN WILL BE THE VERY TIGHT PRES GRADIENT INDUCED BY THE HIGH PRES AREA THAT DOMINATES THE ENTIRE AREA THROUGH THE NEXT FEW DAYS. THIS GRADIENT WILL BE SEEN AFFECTING THE SOUTHERN PORTION OF THE SW N ATLC WITH NE TO E WINDS OF 20 TO 25 KT INCLUDING ALL EXPOSED PASSAGES. WAVEWATCH MODEL BUILDS SEAS UP TO 11 FT TO THE E OF THE BAHAMAS DURING THIS TIME PERIOD. WINDS REMAIN RATHER LIGHT OVER THE NORTHERN AND CENTRAL PORTIONS THROUGH DAY 5 AS THE HIGH CENTER SHIFTS SE TO OVER THOSE WATERS AND TO JUST SE OF THE AREA BY EARLY THU. A COLD FRONT MOVING THROUGH THE SE U.S. WILL BE PRECEDED BY INCREASING SW WINDS OVER THE FAR NORTHERN WATERS THU...WITH SPEEDS POSSIBLY REACHING 20 KT. WARNINGS... ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE