000 AGXX40 KNHC 141857 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 300 PM EDT SUN AUG 14 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... LATEST SURFACE ANALYSIS SHOWS A WEAK 1016 MB HIGH CENTERED OVER THE NW GULF NEAR 27N93W WITH A RIDGE NW TO NE TEXAS AND ANOTHER SE TO THE FAR SE PORTION. THIS WILL REMAIN THE DOMINATE FEATURE IN THE GULF THROUGH THE THE PERIOD. LATEST BUOY OBSERVATIONS THROUGHOUT CONTINUE TO SHOW LIGHT WINDS WINDS AND LOW SEAS ACROSS ALL ZONES...WITH SEAS AS LOW AS 0-1 FT OVER PARTS OF THE EASTERN ZONE. THE ONLY OTHER EXCEPTIONS TO THE FEATURES...BUT HAVING MINOR IMPACTS TO WINDS AND SEAS...IS A TROPICAL WAVE OVER THE FAR EASTERN BAY OF CAMPECHE WHICH IS ONLY PRODUCING ISOLATED TO WIDELY SCATTERED SHOWERS AND TSTMS AS IT MOVES WESTWARD NEAR 15 KT. A WEAK FRONTAL TROUGH OVER THE SE U.S. WILL SLOWLY SETTLE SOUTHWARD INTO THE NE GULF SUN THROUGH TUE AND DISSIPATE IN PLACE WED AS THE HIGH CONTINUES ITS DOMINANCE OVER THE GULF. CARIBBEAN SEA... WINDS IN THE CARIBBEAN ARE MAINLY DRIVEN BY THE PRESSURE GRADIENT BETWEEN THE 1016 MB HIGH PRES SYSTEM NEAR 26N70W AND LOWER PRESSURE OVER SOUTH AMERICA. THIS GRADIENT WILL MAINTAIN FRESH TO STRONG TRADES MAINLY OVER THE S CENTRAL AND SW CARIBBEAN FOR THE REST OF THIS AFTERNOON...THEN DIMINISH SOME TONIGHT AND MON AS THE RIDGE WEAKENS DUE TO RECENTLY UPGRADED TROPICAL STORM GERT IN THE ATLC NEAR 28.6N 63.1W AND ANOTHER LOW NEAR 23N59W IMPINGING UPON IT FROM THE EAST. THIS WILL WEAKEN THE PRESSURE GRADIENT OVER THE CARIBBEAN WITH MODERATE TO FRESH TRADES PREVAILING THROUGH TUE. FORESEEABLE CHANGES TO THE WINDS AND SEAS IN THE CARIBBEAN WILL BE ATTRIBUTED TO A TROPICAL WAVE CURRENTLY E OF THE AREA NEAR 45W/46W. THE WAVE IS PRECEDED BY A COMPLEX OF SHOWERS AND TSTMS RACING OUT AHEAD IT. GLOBAL MODEL RUNS FROM BOTH 06Z AND 12 UTC THIS MORNING ARE MORE CONSISTENT IN DEPICTING A WEAKER TROPICAL WAVE FEATURE THAT EVENTUALLY TRACKS INTO THE CARIBBEAN SEA THAN THE PREVIOUS MODEL RUNS. SATELLITE IMAGERY FROM THROUGHOUT THE DAY SHOWS WAVE THAT IS RATHER STRETCHED IN A NW TO SE FASHION UNDER FAST UPPER ELY WINDS WITH DRY AND STABLE AIR PRESSING INTO IT FROM THE NE AND E. MOST OF THE MODEL GUIDANCE IS NOT TOO DISCERNIBLE IN ITS INITIALIZATION OF THE WAVE...HOWEVER THE NEW 12 UTC EUROPEAN IS CLOSER TO THE WAVE POSITION ANALYZED AT 12 UTC THIS MORNING. SO BASED ON THESE CONCLUSIONS WILL PRETTY MUCH FOLLOW THE GFS AND EUROPEAN GUIDANCE...WHICH IS USED IN THE HPC/NHC MEDIUM RANGE GUIDEDANCE...FOR FORECASTING THE WAVE THROUGH THE CARIBBEAN SEA FOR THIS FORECAST PACKAGE. THE WAVE IS EXPECTED TO REACH NEAR 15N70W BY WED...16N76W BY THU AND 16N80W BY FRI. TROPICAL N ATLC W OF 55W... A RATHER WEAK LOW PRES SYSTEM IS JUST NW OF THE AREA NEAR 24N60W MOVING NW AT 15 KT. THIS SYSTEM WILL CONTINUE TO MOVE AWAY FROM TROPICAL N ATLC ZONE THIS AFTERNOON AND TONIGHT...AND BEGIN TO TURN MORE NORTHWARD AS IT MOVES AWAY FROM THE AREA AND STRENGTHENS...POSSIBLY TO A TROPICAL CYCLONE. MEANWHILE...THE MODELS HAVE BACKED OFF ON THE POTENTIAL DEVELOPMENT OF THE TROPICAL WAVE CURRENTLY ALONG 40W. AS DISCUSSED ABOVE UNDER CARIBBEAN SEA THE MODELS ARE IN BETTER AGREEMENT THAT SYSTEM WILL NOT ORGANIZE INTO A LOW PRES SYSTEM AS IT ENTERS THIS ZONE MON AFTERNOON...AND PASSES ACROSS THE LEEWARD ISLANDS LATE TUE INTO WED. THE PRIMARY EFFECTS ON THE AREA'S WINDS AND SEAS WILL BE ATTRIBUTED TO THE TIGHTER PRES GRADIENT TO ITS N DUE TO THE WAVE AND ATLC HIGH PRES IN THE CENTRAL ATLC. THE GRADIENT IS ALLOWING FOR E-E 20 KT WINDS. THIS GRADIENT WILL FOLLOW THE WAVE AS IT TRACKS WESTWARD OVER THE NEXT FEW DAYS. SOUTHWEST N ATLC... THE PRELIMINARY SURFACE ANALYSIS HAS A 1016 MB HIGH NEAR 26N70W ...AND A SURFACE TROUGH FROM 24N65W TO NORTHERN DOMINICAN REPUBLIC. SATELLITE IMAGERY AND MODEL GUIDANCE SHOWS A WEAKENED DEEP LAYER TROUGH JUST OFF THE SE U.S. COAST THAT IS EXPECTED TO AMPLIFY THROUGH TUE. NEWLY UPGRADE TROPICAL STORM GERT IS NEAR 28.6N 63.1W MOVING NNW OR 335 DEG AT 6 KT. GERT IS EXPECTED TO WEAKEN THE E SIDE OF THE HIGH. THE HIGH IS STILL FORECAST TO SHIFT NE AND DISSIPATE THROUGH MON MORNING. GERT IS FORECAST TO MOVE TO NEAR 30.5N 63.5W BY LATE TONIGHT ...BEFORE MOVING N OF 31N INTO MON MORNING. THIS WILL REQUIRE ADJUSTMENTS TO THE WINDS AFFECTING THE NEARBY WATERS OF THE NE CORNER OF THE AREA TONIGHT INTO MON MORNING. HOWEVER...THE STRONGEST WINDS ARE EXPECTED TO LIE IN THE E SEMICIRCLE WHERE THE PRES GRADIENT IS HIGHEST BETWEEN IT AND THE SUBTROPICAL HIGH. ELSEWHERE...THE SURFACE TROUGH WILL MIGRATE WESTWARD THROUGH THE BAHAMAS DURING MON THROUGH TUE NIGHT...AND OVER TO FLORIDA WED AND THU. E-SE WINDS OF 15-20 KT ARE EXPECTED TO ITS E S OF ABOUT 24N WHILE AHEAD OF IT PRECIPITATION WILL BE ITS MAIN SENSIBLE WX IMPACT. ANOTHER AREA OF LOW PRES...A POSSIBLE TROPICAL CYCLONE IN THE NEXT 48 HOURS...IS EXPECTED TO PASS TO THE E OF THE ZONE THROUGH TUE NIGHT. A COLD FRONT THAT MOVES OFF THE NE FL COAST MON AND TUE SHOULD STEER THIS LOW TO THE N. THIS LOW SHOULD HAVE LITTLE IF ANY EFFECTS ON WINDS IN THE ZONE AS THE MAIN AND STRONGEST OF THE WINDS WILL BE TO ITS E. A RIDGE WILL THEN BUILD ALONG 29N IN THE WAKE OF THIS SYSTEM ON WED...THEN SHIFT SLIGHTLY N THU AND FRI. 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 AGUIRRE