000 AGXX40 KNHC 290800 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 400 AM EDT FRI JUN 29 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... LIGHT TO MODERATE WINDS ARE EXPECTED TO PREVAIL ACROSS THE GULF WATERS THROUGH SAT WITH SEAS GENERALLY 3 FT OR LESS. LLVL TROUGH LINGERING ACROSS EXTREME S FLORIDA AND THE SE GULF AFTER THE PASSAGE OF DEBBY EXTENDS W THEN WNW TO THE W GULF...WHERE A LARGE CLUSTER OF DEEP CNVTN BLEW UP THIS EVENING DIRECTLY UNDER AN UPPER ANTICYCLONE. CONVECTION HAS SINCE DIMINISHED...WHILE THIS AREA OF CONSIDERABLE LLVL MOISTURE WILL GRADUALLY SHIFT NW ACROSS THE TEXAS COASTAL WATERS AND INLAND THROUGH SAT NIGHT. IN DOING SO...A WEAK 1018 MB HIGH CURRENTLY ACROSS THE E GULF WILL SETTLE SLIGHTLY S...WITH MODERATE SE RETURN FLOW EXPECTED ACROSS THE W HALF OF THE BASIN TONIGHT THROUGH THE WEEKEND. WINDS OF 10-15 KT ARE GENERALLY EXPECTED...HOWEVER AFTERNOON SEABREEZES WILL LIKELY YIELD WINDS NEAR 18-20 KT ACROSS PORTIONS OF THE W HALF...AS WELL AS THE TYPICAL YUCATAN LATE AFTERNOON TROUGH AND ITS WWD MIGRATION DURING THE EVENING WILL ALSO YIELD 20 KT WINDS. SEAS EXPECTED TO BUILD TO 4 FT ACROSS W PORTIONS SAT AND THEN 4-5 FT SAT NIGHT AND 4-6 ON SUN. UTILIZED A BLEND OF THE GFS/ECMWF IN THE FCST. SOUTHWEST NORTH ATLC S OF 31N W OF 65W... THE REMNANT LOW OF DEBBY WAS CENTERED JUST NW OF BERMUDA THIS MORNING...WITH A TIGHT AND WELL DEFINED CORE STILL PRODUCING MINIMAL GALES IN THE SE QUAD PER A RECENT 0414Z OSCAT PASS. NW SWELL AND SW WINDS AROUND 20 KT CONTINUE TO PRODUCE SEAS TO 8 FT CONFINED TO A SMALL AREA N OF 29N BETWEEN 67W AND 72W THIS MORNING AND WILL SHIFT NE OUT OF THE AREA TODAY. LONG PERIOD SWELL GENERATED FROM DEBBY AND ITS REMNANTS MADE IT ALL THE WAY TO THE SE FLORIDA COASTAL WATERS BUT HAS SINCE FADES...AND WILL CONTINUE TO DO SO FOR THE WATERS NE OF THE BAHAMAS THROUGH THIS EVENING. OTHERWISE...RIDGING WILL PREVAIL ACROSS MOST OF THE REST OF THE AREA...FROM A HIGH CENTERED ACROSS THE NE ATLC SW TO THE BAHAMAS...AND INTERRUPTED BY WEAK TROUGHING ALONG 60W. ANTICYCLONIC FLOW OF 10-15 KT GENERALLY EXPECTED TROUGH THE WEEKEND WITHE WLY TRADES TO NEAR 20 KT DEVELOPING BY SUN S OF 23N AND THROUGH THE SRN BAHAMAS. AGAIN A BLEND OF THE GFS AND ECMWF WAS USED IN THE WIND AND WAVE FIELDS. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... MODERATE TO FRESH E TO SE TRADES WILL PREVAIL ACROSS MUCH OF THE CARIBBEAN...WITH NOCTURNAL PEAKS TO NEAR 30 KT ALONG THE N COAST OF COLOMBIA AS A RIDGE BUILDS W ALONG 25N THROUGH SAT BEFORE SHIFTING TO 27N EARLY NEXT WEEK. A LARGE CLUSTER OF DEEP CONVECTION ACROSS THE SW CARIB AND ADJACENT EPAC APPEARS TO BE ASSOCIATED WITH THE S PORTION OF A TROPICAL WAVE ALONG ABOUT 82W ATTM. A LOWER TROPOSPHERIC JET LOOKS TO BE ENHANCING THE WAVE AND COULD ALLOW FOR A BRIEF PERIOD OF BAROTROPIC GROWTH AS IT SHIFTS W ACROSS CENTRAL AMERICA AND INTO THE EPAC NEXT 24 HOURS. ACTIVE CONVECTION ASSOCIATED WITH THE WAVE IS LIKELY TO CONTINUE TO PULSE AS IT SHIFTS ACROSS CENTRAL AMERICA. A BETTER DEFINED TROPICAL WAVE WAS ALONG 47/48W THIS MORNING...AND HAS LEFT BEHIND A LLVL CLOUD SWIRL THAT HAS BEEN CARRIED AS A SURFACE LOW ON PREVIOUS SURFACE MAPS. HOWEVER...RECENT SCATTEROMETER PASSES DID NOT SUGGEST A SURFACE LOW. THE WAVE IS ACCOMPANIED BY A LARGE AREA OF MOISTURE AND A BROAD AND WEAKENING MID LVL CYCLONIC CIRCULATION. THIS WAVE HAS BEGUN TO INTERACT ALREADY WITH MID TO UPPER LEVEL TROUGHING BETWEEN 55W AND 60W...WITH MOISTURE AND THE MID LVL VORT BEING DRAWN MORE NW. THIS WAVE IS DIFFICULT TO FOLLOW IN TRADITIONAL MODEL FORECAST FIELDS OF RH AND REL VORTICITY...BUT GLOBAL MODELS SEEM TO SUGGEST THAT THIS INTERACTION WILL SLOW DOWN THE WAVE NEXT 24-36 HOURS. ALTHOUGH THE WAVE WILL WEAKEN SOMEWHAT AS IT APPROACHES THE LESSER ANTILLES...THE UPPER TROUGH TO ITS W IS FORECAST TO SHIFT NW AND WILL MAINTAIN A MOIST AND UNSTABLE ENVIRONMENT ACROSS THE E CARIB. BASED ON GLOBAL MODEL CONSENSUS I HAVE THE WAVE NEAR 52W BY SAT 00Z...55/56W SUN 00Z...AND ALONG 61/62W BY MON 00Z. HOWEVER...LOOKING AT CURRENT STLT IMAGERY THIS COULD BE A BIT SLOW. LETS SEE IF THE WAVE SLOWS DOWN TODAY AS PER MODEL FORECASTS. PRESENTLY THERE IS JUST A RELATIVELY SMALL AREA OF 15-20 KT WINDS ACROSS THE N SEMICIRCLE OF THIS WAVE WITH SEAS 6-7 FT. MODELS SHOW SOME TIGHTENING OF GRADIENT ACROSS THE TOP LATE SAT AND SUN AND ATLC RIDGE BEGINS TO BUILD SW ACROSS THE REGION...AND WILL INCREASE WINDS TO 20 KT WITH SMALL POCKETS TO 25 KT...AND SEAS 6-8 FT. NOTE...GRIDDED MARINE OUTPUT IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE (LOWER CASE) GULF OF MEXICO... .NONE. CARIBBEAN SEA... .NONE. SW N ATLANTIC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER STRIPLING