000 AGXX40 KNHC 291854 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 255 PM 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... HIGH PRES HAS SETTLED ACROSS THE E HALF OF THE GULF WITH LIGHT AND VARIABLE WINDS OVER THE REGION WITH SEAS GENERALLY AROUND A FOOT. STRONG UPPER LEVEL DIFLUENT FLOW ALOFT COUPLED WITH LOW LEVEL CONVERGENCE HAS RESULTED IN A RATHER LARGE AREA OF TSTMS OVER THE GULF N OF 23N W OF 90W WITH RECENT LIGHTNING DATA INDICATING NUMEROUS LIGHTNING STRIKES ACROSS A BROAD SWATH OF THE NW GULF. THIS AREA OF ACTIVITY IS EXPECTED TO CONTINUE NW AND IMPACT THE NW GULF WATERS TONIGHT INTO SAT AND SAT NIGHT WITH LOCALLY STRONGER WINDS AND HIGHER SEAS. THE WEAK HIGH PRES WILL SETTLE SE...WITH MODERATE SE RETURN FLOW EXPECTED ACROSS THE W HALF OF THE BASIN SAT 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 GRIDDED FIELDS. SOUTHWEST NORTH ATLC S OF 31N W OF 65W... THE REMNANT LOW OF DEBBY WAS CENTERED N OF BERMUDA THIS AFTERNOON WITH A FAIRLY TIGHT AND WELL DEFINED SYMMETRIC CORE. THE SYSTEM WAS PRODUCING MINIMAL GALES WELL N OF THE AREA PER A 1052Z WINDSAT PASS. NW SWELL AND SW WINDS AROUND 20 KT CONTINUE TO PRODUCE SEAS TO 0 FT CONFINED TO A SMALL AREA N OF 29N BETWEEN 67W AND 72W THIS AFTERNOON BUT ARE SLATED TO SHIFT N OF THE AREA BY EARLY TONIGHT. LONG PERIOD SWELL GENERATED FROM DEBBY AND ITS REMNANTS MADE IT ALL THE WAY TO THE SE FLORIDA COASTAL WATERS BUT HAS SINCE FADED...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 PREVAIL ACROSS MUCH OF THE CARIBBEAN...WITH LOCAL PEAKS TO NEAR 30 KT ALONG THE N COAST OF COLOMBIA PER THE EDGE OF A MUCH EARLIER WSAT PASS. AS THE ATLC SFC RIDGE BUILDS W ALONG 25N THROUGH SAT BEFORE SHIFTING TO 27N EARLY NEXT WEEK EXPECT CONDITIONS TO CONTINUE. 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 84W/85W ATTM. 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 49/50W THIS AFTERNOON...AND HAS LEFT BEHIND A LLVL CLOUD SWIRL THAT HAD BEEN CARRIED AS A SURFACE LOW ON PREVIOUS SURFACE MAPS. 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 VORTICITY CENTER 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 AS IT APPROACHES THE WIND WARD ISLANDS AND E CARIBBEAN NEXT 36 TO 48 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 THE WAVE SHOULD BE NEAR 54/55W 12Z SAT...59/60W 12Z SUN AND 63W 12Z MON. THE WAVE WILL CARRY AN AREA OF 20 KT WINDS ACROSS THE N SEMICIRCLE WITH SEAS 6-8 FT AS IT TRAVERSES WWD. LOOKING AHEAD FOR TUE AND WED...GLOBAL MODELS INDICATE THE AREA OF ENHANCED TRADES WITH THE WAVE WILL MERGE WITH EXISTING TRADES OVER THE CENTRAL CARIBBEAN AND PRODUCE A BROAD AREA OF 20-25 KT TRADES OVER MOST OF THE CARIBBEAN BY THEN. 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 COBB