000 AGXX40 KNHC 231836 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 235 PM EDT SAT JUN 23 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... ELONGATED MONSOONAL LIKE CIRCULATION PERSISTING ACROSS THE GULF THIS MORNING...WITH MAJORITY OF WEATHER AND WIND CONFINED TO E SIDE OF CIRCULATION. STRONG SLY FLOW ON THIS E SIDE WAS VERIFIED BY SEVERAL SHIP OBS AND WITH BUOY 42003 FLUCTUATING MID 20'S TO BRIEF MINIMAL GALE CONDITIONS...AND SEAS UP TO 15 FT. BASED ON THIS AND VERY UNSTABLE ENVIRONMENT ACROSS THIS AREA...AND WITH GLOBAL MODELS IN AGREEMENT ON GALE FORCE WINDS IN BL...HAVE ISSUED GALE WARNING FOR THE E SEMICIRCLE OF LOW THIS AFTERNOON...AND SPREADING ACROSS N QUADRANT THIS EVENING. AS WOULD BE EXPECTED WITH THIS MONSOONAL TYPE EVOLUTION...GALE FORCE OR STRONGEST WINDS INITIALLY WILL REMAIN ON PERIPHERY OF THE CIRCULATION...AND GRADUALLY FILL IN ACROSS N AND NW QUADS AS MOISTURE WRAPS IN TOWARD THE CENTER. LLVL SWIRL CLEARLY EVIDENT IN VIS IMAGERY THIS AFTERNOON WILL LIKELY BE SHED TO THE SW WITH ANOTHER CENTER LIKELY TO BECOME THE DOMINANT CENTER TO THE NE OF THIS SWIRL...AND CLOSER TO THE CONVECTION. ALTHOUGH ALL THE GLOBAL MODELS SHOW ELONGATED STRETCHING OF MOISTURE FIELD OF THIS SYSTEM OVER THE NEXT 48 HOURS...ONLY THE GFS REMAINS ADAMANT IN SHEARING OUT SIGNIFICANT LLVL VORTICITY TO THE NE...WITH GFS ENSEMBLE MEMBERS FROM THE 00Z RUN PRETTY EVENLY DISTRIBUTED ALL ALONG THE MOISTURE AXIS BY 96 HOURS. HAVE THUS CREATED WIND AND PRES GRIDS STRONGLY WEIGHTED ON ECMWF...AND USED A 50-50 BLEND OF ECWAVE AND WWIII FOR SEAS. IT MAY TAKE A FULL 48 HOURS FOR THIS SYSTEM TO ATTAIN A TRULY TROPICAL TC APPEARANCE...BUT GALE FORCE OR NEAR GALE WINDS...WITH SHOWERS SQUALLS AND TSTMS WILL CONTINUE TO DOMINATE THE E AND NE PORTION OF THIS SYSTEM FOR THE NEXT 24-48 HOURS AND SPREAD ACROSS THE NE AND N CENTRAL GULF COASTAL WATERS AND COASTAL ZONES. BUOY 42003 NOW REPORTING 14 FT SEAS AT 9 SECONDS WHICH WILL PROPAGATE INTO THE N CENTRAL GULF COASTLINES...AND COMBINE WITH STRONG E TO SE WIND FLOW FOR HIGH WATER LEVELS LEADING TO SOME COASTAL FLOODING AND EROSION. INTERESTS ALONG THE UNITED STATES GULF COAST SHOULD MONITOR THE PROGRESS OF THIS LOW THROUGH THE WEEKEND. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... NARROW AND WEAK ATLC RIDGE EXTENDS FROM 1028 MB HIGH ACROSS NE ATLC SW INTO CENTRAL ATLC...AND SECONDARY HIGH 1018 MB JUST SW OF BERMUDA. HIGH OPENING UP INTO MONSOONAL CIRCULATION IN GULF OF MEXICO TO YIELD FRESH FLOW ACROSS CENTRAL CARIB AND FRESH TO STRONG S TO SE FLOW W AND NW CARIB. AS INDICATED ABOVE... FORECAST STRONGLY WEIGHTED TOWARD ECMWF. WITH SLOW WWD MOTION OF THE LOW IN GULF MON-WED...LITTLE SIGNIFICANT CHANGES EXPECTED IN OVERALL CONDITIONS ACROSS THE CARIB...WITH SEAS TO 9 FT IN S SSE SWELL ACROSS YUCATAN...WITH SEAS FLATTENING IN THE CURRENT. TROPICAL WAVE ACROSS CENTRAL ATLC EXPECTED TO MOVE INTO TROPICAL ATLC WATERS LATE MON NIGHT-TUE WITH MODEST INCREASE IN WINDS AND SEAS AND MUCH SAL BEHIND. SOUTHWEST NORTH ATLC S OF 31N W OF 55W... MAINLY LIGHT WINDS DOMINATE THE AREA UNDER THE INFLUENCE OF A WEAK ATLC RIDGE...WITH 1018 MB HIGH JUST SW OF BERMUDA. AS LOW IN GULF DEEPENS NEXT 72 HOURS...PRES GRADIENT WILL INCREASE BY SUN-MON ACROSS STRAITS OF FLORIDA UP FLORIDA COAST AND THROUGH THE BAHAMAS...TO YIELD S TO SE WNDS NEAR 20 KT WITH ISOLATED SPOTS TO 25 KT. SEAS OFFSHORE OF JAX COULD BUILD TO 8 FT BY MON NOON IN THIS FLOW. ECMWF SHOWS DRIER AIR IN CARIB ADVECTING NW AND N LATE SUN INTO MON AND WILL STABILIZE WEATHER ACROSS BAHAMAS AND S FLO WATERS BY THEN. WINDS GRIDS STRONGLY WEIGHTED TO ECMWF...AND USED A 50-50 BLEND OF ECWAVE AND WWIII FOR SEAS. NOTE...GRIDDED MARINE OUTPUT IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE (LOWER CASE) GULF OF MEXICO... .GALE WARNING GMZ015-021. CARIBBEAN SEA... .NONE. SW N ATLANTIC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER STRIPLING