000 AGXX40 KNHC 121833 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 230 PM EDT FRI AUG 12 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. GULF OF MEXICO... A WEAK RIDGE OF HIGH PRESSURE WILL PREVAIL ACROSS THE GULF OF MEXICO THROUGH THE FORECAST PERIOD. LATEST OBSERVATIONS INDICATE LIGHT TO MODERATE WINDS ACROSS THE GULF WITH SEAS GENERALLY 1 TO 3 FT. WITH THE RIDGE PREVAILING THROUGH THE FORECAST PERIOD...THESE GENERAL CONDITIONS ARE EXPECTED TO CONTINUE. THE EXCEPTION IS FRESH WINDS W OF THE YUCATAN PENINSULA EACH EVENING/NIGHT DUE TO DIURNALLY DRIVEN LOCAL EFFECTS. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... A TROPICAL WAVE IN THE WESTERN CARIBBEAN WILL SHIFT W OF THE AREA BY LATE SAT. THIS WAVE WILL NOT HAVE A SIGNIFICANT AFFECT ON THE WINDS ACROSS THE WESTERN CARIBBEAN BUT SHOULD CONTINUE TO CARRY PRECIPITATION WESTWARD WITH IT. WINDS IN THE CARIBBEAN ARE MAINLY DRIVEN BY THE PRESSURE GRADIENT BETWEEN THE RIDGE OVER THE SW N ATLC ALONG 26N AND LOWER PRESSURE OVER SOUTH AMERICA. THIS GRADIENT WILL MAINTAIN FRESH TO STRONG TRADES MAINLY OVER THE CENTRAL CARIBBEAN THROUGH THE FIRST HALF OF THE WEEKEND. THE TRADES ARE EXPECTED TO DIMINISH AS THE RIDGE OVER THE SW N ATLC WEAKENS AND A SURFACE LOW...POSSIBLY A TROPICAL CYCLONE...MOVES INTO THE TROPICAL N ATLC EARLY NEXT WEEK. THIS WILL WEAKEN THE PRESSURE GRADIENT OVER THE CARIBBEAN WITH MODERATE TO FRESH TRADES PREVAILING. LOW PRESSURE CENTERED NEAR 18N45W AT 12 UTC HAD PULLED WESTWARD AWAY FROM THE MONSOON TROUGH THIS MORNING...AND BASED ON THE LATEST ASCAT PASS...THE CIRCULATION HAS OPENED UP INTO A TROUGH. THIS TROUGH MAY STILL RE-ACQUIRE A CLOSED CIRCULATION AND DEVELOP INTO A TROPICAL CYCLONE. WINDS ASSOCIATED TO THIS FEATURE ARE FORECAST TO BE 20-25 KT OVER THE NE PORTION OF THE TROPICAL N ATLC ZONE AS THE SYSTEM MOVES THROUGH SUN/MON. A SECOND AREA OF LOW PRESSURE...STILL CURRENTLY EMBEDDED IN THE MONSOON TROUGH...WILL APPROACH THE CENTRAL PORTION OF THE TROPICAL N ATLC BY MID WEEK. THIS LOW ALSO HAS THE POTENTIAL TO BECOME A TROPICAL CYCLONE. INTERESTS IN THE E CARIBBEAN SHOULD CONTINUE TO MONITOR THE PROGRESS OF BOTH OF THESE DISTURBANCES DURING THE NEXT WEEK. SOUTHWEST N ATLC... A 1018 MB HIGH PRES IS POSITIONED NEAR 26N65W WITH A RIDGE EXTENDING TO THE NORTHERN BAHAMAS. A DEEP LAYER TROUGH LIES JUST OFF THE SE U.S. COAST AND THE TAIL OF THE STATIONARY BOUNDARY AT THE SURFACE ASSOCIATED WITH THIS DEEP LAYER TROUGHING WAS FROM 31N74W TO NEAR CENTRAL FLORIDA 12Z. THIS TROUGHING IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS. THIS TROUGHING WILL LINGER OVER THE SAME GENERAL AREA THROUGH SAT AND BRING ADDITIONAL RAINFALL TO FLORIDA...CUBA AND THE WESTERN BAHAMAS. THE HIGH WILL HOLD NEARLY STATIONARY THROUGH EARLY SAT BEFORE IT WEAKENS SOME WITH THE RIDGE SHIFTING TO THE NW-N EARLY NEXT WEEK. WITH THIS SCENARIO...EXPECT LIGHT TO MODERATE WINDS AND FAIRLY TRANQUIL SEAS THROUGH THE WEEKEND. AN AREA OF LOW PRES...A POSSIBLE TROPICAL CYCLONE...MAY ENTER THE EASTERN PORTION BY TUE...BUT CONFIDENCE IS VERY LOW ON THE STRENGTH OR TRACK OF THE SYSTEM BY THAT TIME. WARNINGS... GULF OF MEXICO... .NONE. CARIBBEAN AND TROPICAL N ATLC... .NONE. SW N ATLC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER AL