000 AGXX40 KNHC 191854 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 255 PM EDT TUE OCT 19 2010 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... VERY WEAK PRES PATTERN PERSISTS ACROSS THE GULF WITH POSSIBLY TWO WEAK HIGHS ACROSS THE N GULF...WITH RIDGING SW TO THE MEXICAN COAST ALONG 22N. A WEAK LLVL TROUGH...POSSIBLY AT THE SURFACE WAS ACROSS THE SE GULF FROM NEAR 28N85W TO NE COAST OF YUCATAN. PROGRESSIVE FLOW ACROSS N AMERICA WILL TRANSPORT A SERIES OF WEAK FRONTAL BOUNDARIES SWEEPING E ACROSS THE GULF COAST STATES NEXT FEW DAYS AND DRAG VERY WEAK BOUNDARIES ALONG THE NE GULF COASTS. THE LLVL TROUGH ACROSS THE SE GULF WILL DRIFT SLOWLY E AND ACROSS S FLORIDA BY END OF THE WEEK...WITH INDUCED NELY FLOW BEHIND IT ACROSS THE SE GULF YIELDING NE WINDS NEAR 15 KT AND SEAS 3-4 FT BY THU MORNING. OTHERWISE...MILD WINDS AND SEAS. A LARGE HIGH ACROSS THE ERN U.S. THU AND FRI WILL SHIFT E AND INDUCE SLY RETURN FLOW ACROSS THE W HALF OF THE BASIN...WITH S-SE WINDS 15-20 KT ACROSS THE NW GULF BY FRI WITH SEAS BUILDING 4-6 FT. HIGH TO SHIFT FURTHER E OVER THE WEEKEND AND RIDGE ACROSS THE SW N ATLC AND ENTIRE GULF BASIN TO BRING ABOUT MODERATE TO FRESH E TO SE WINDS...POTENTIALLY UP TO 25 KT IN THE STRAITS. CARIBBEAN... SHEAR LINE HAS MOVED TO JUST S OF 20N BETWEEN 50W AND 60W...AND HAS BEGUN TO LIFT NW ACROSS THE BAHAMAS...WITH 20 KT WINDS AND SEAS 6-8 FT WITHIN 180 NM TO THE N OF THIS OLD BOUNDARY. CUT OFF LOW HAS SUNK S OVER THE SE CARIB AND HELP TO REDUCE GRADIENT FLOW AND WEAKENED WINDS TO 5-15 KT ACROSS THE BASIN E OF 70W. LOW STILL PRODUCE SUBSIDENCE ACROSS THE CENTRAL CARIB..WITH SHALLOW SCATTERED SHOWERS E CARIB. MEANWHILE...MONSOONAL GYRE ACROSS THE W CARIB AND INTO THE FAR TROPICAL EPAC HAS BECOME MORE N-NE TO S-SW ALIGNED PAST 24 HOURS...WITH VERY ACTIVE CNVTN OCCURRING IN BANDS OF DEEP TSTMS ACROSS THE NW CARIB AND OFF THE COAST OF NICARAGUA. STLT IMAGERY THIS MORNING SUGGESTED THE MID LEVEL TURNING NEAR 17N83W MAY BE THE FOCAL POINT OF A NEW CENTER DEVELOPING...BUT RECENT 1454 UTC ASCAT PASS JUST CAME IN TO CONFUSE THE MATTER...WITH AMBIGUITIES OF NO HELP. TWO CENTERS MAY EXIST NEAR THE SURFACE...WITH A THIRD IN THE EPAC NEAR 09N86W. AS WOULD BE EXPECTED WITH THE DEVELOPMENT OF A MONSOONAL LOW EMBEDDED WITHIN A GYRE...ANY SIGNIFICANT DEVELOPMENT IS GOING TO BE SLOW. MODEL CONSENSUS AT 12Z WAS FOR A SLOW DRIFT OR REDEVELOPMENT TO THE N NEXT 24 HOURS THEN AN ANTICYCLONIC LOOP OVER NEXT COUPLE OF DAYS AND THEN SW INTO CENTRAL AMERICA. AS WOULD BE EXPECTED WITH A MONSOONAL LOW...STRONGEST WINDS WILL OCCUR AROUND PERIPHERY OF THE GYRE...WITH WEAK WINDS NEAR CENTER OF LOW. HAVE THUS CONTINUED WITH 15-20 KT AND SEAS 4-6 FT IN LONGEST FETCHES AROUND THE PERIPHERY OF BROAD CIRCULATION...AND IN GENERAL AGREEMENT WITH GUIDANCE. HIGH PRES MOVING INTO W ATLC OVER THE WEEKEND WILL STRENGTHEN GRADIENT ACROSS THE E HALF OF THE BASIN TO BRING ABOUT A RETURN TO MODERATE TRADES. ACROSS THE SW N ATLC...WEAKENING SHEARLINE ALONG 19N OR SO WILL SINK A BIT FURTHER S NEXT 24 HOURS AND WASH OUT...WITH NEAR 20 KT REMAINING N OF LINE AND REMNANTS THROUGH 48 HOURS. FRESHENING TRADES TO RETURN N PORTIONS OVER THE WEEKEND DUE TO BUILDING HIGH ACROSS THE ATLC. ATLC... SHEARLINE DESCRIBED ABOVE DENOTES TO STRONGEST WINDS ACROSS THE AREA...WITHIN 180 NM N PER GUIDANCE AND RECENT ASCAT PASSES. N-NW SWELL HAS MOVED THROUGH E HALF OF AREA OVERNIGHT AND THIS MORNING AND NOW SLOWLY FADING...BLEEDING THROUGH CARIB PASSAGES. ATLC RIDGE TO N OF SHEARLINE...WITH HIGH CENTERED SE OF BERMUDA IS SHIFTING SLOWLY E...WITH FLOW OPENING UP OFF THE MID ATLC STATES...BUT STILL LESS THAN 20 KT OVER FORECAST WATERS. MODELS STILL SHOW SOME ELONGATION OF LLVL TROUGHING CURRENTLY ACROSS NW HALF OF BAHAMAS...AND FORCE IT NE NEXT FEW DAYS WITH TWO UPPER TROUGHS FORECAST TO MOVE OFF SE U.S. COAST AND INTO W ATLC. STILL LOOKS AS THROUGH THERE IS A CHANCE FOR S TO SW WINDS OF 20 KT ON E SIDE OF THIS TROUGH ACROSS NE PORTIONS OF FORECAST WATERS THU AND THEN OUT OF AREA FRI. HIGH PRES BUILDING ACROSS THE AREA FROM THE NW OVER THE WEEKEND WILL BRING MODERATE ELY TRADES TO THE AREA...AND 20-20 KT ACROSS THE BAHAMAS AND THROUGH THE STRAITS OF FLORIDA. WARNINGS... ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER STRIPLING