000 AGXX40 KNHC 251947 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 245 PM EST FRI JAN 25 2013 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... HIGH PRES PREVAILS ACROSS THE GULF...CENTERED ON A 1026 HIGH OVER THE NE GULF AT 29N85W WITH A RIDGE EXTENDING W-W TO MEXICAN COAST TO NEAR TUXPAN. LATEST BUOY AND PLATFORM OBSERVATIONS INDICATE THAT THE RESULTING PRES GRADIENT IS BRINGING MODERATE TO LOCALLY FRESH NE-E WINDS AND SEAS OF 4-7 FT IN THE SE PORTION OF THE GULF INCLUDING THE STRAITS OF FLORIDA. SOUTHEASTERLY RETURN FLOW REMAINS ESTABLISHED OVER THE WESTERN GULF AND WILL SPREAD EASTWARD SOME THROUGH EARLY THIS EVENING. LATEST MODEL GUIDANCE INDICATES THAT SUFFICIENT UPPER RIDGING WILL PREVAIL OVER THE GULF TO INHIBIT THE NEXT FEW FRONTAL BOUNDARIES FROM ENTERING THE GULF AS THEY SHOULD ONLY APPROACH NEAR 31N. AS STATED IN PREVIOUS FORECASTS...A WEAK BACKDOOR BOUNDARY MAY SINK INTO NE COASTAL WATERS SAT NIGHT BEFORE WASHING OUT SUN NIGHT AND LIFTING N. RETURN FLOW IS EXPECTED TO INCREASE TO 15-20 KT ACROSS W PORTIONS SAT NIGHT THROUGH SUN NIGHT AS LOW PRES DEEPENS ACROSS UPPER MS VALLEY. THE LOW PRES IS EXPECTED TO PUSH A THE NEXT COLD FRONT INTO THE NW GULF WED WITH STRONG FLOW BEHIND FRONT ALONG MEXICAN WATERS...WITH SLIGHT CHANCE FOR GALES THERE. CARIBBEAN SEA AND TROPICAL N ATLC S OF 22N W OF 55W... THE LEADING EDGE OF THE HIGH RESOLUTION ASCAT PASS FROM JUST PASSED 14 UTC THIS MORNING CAPTURED A SMALL AREA OF NE 20-25 KT WINDS IN THE FAR S CENTRAL CARIBBEAN S OF 13N BETWEEN 73W-76W. THE 1544 UTC ASCAT PASS SHOWED NE WINDS OF 20 KT OVER THE NW PART OF THE SEA N OF 16N W OF 81W. ELSEWHERE ACROSS THE CARIBBEAN AND TROPICAL N ATLC LIGHT TO MODERATE TRADES CONTINUE AS REPORTED BY BUOY/SHIP AND ASCAT DATA. THE SAME ASCAT PASS FROM JUST PAST 14 UTC REVEALED A RATHER WEAK SURFACE TROUGH ROUGHLY ALONG 60W/61W FROM 13N TO 20N WITH A NE TO SE WIND SHIFT VERY SIMILAR TO A TROPICAL WAVE. THE TROUGH IS ESTIMATED TO BE MOVING W ABOUT 16 KT. WIDELY SCATTERED SHOWERS ARE POSSIBLE WITHIN 75 NM EITHER SIDE OF THIS FEATURE. STRONG HIGH PRES WILL MOVE SE OFF THE E COAST OF U.S. TONIGHT THROUGH SUN NIGHT TIGHTENING UP THE PRES GRADIENT ACROSS THE SW CARIBBEAN SEA PORTION. THIS WILL EXPAND THE AREAL COVERAGE OF THE NE 20-25 KT WINDS OBSERVED THIS MORNING IN THAT PORTION OF THE SEA THROUGH DAY 5 (WED). EXPECT SEAS THERE TO BUILD FROM 9 FT TO 8 TO 10 FT THROUGH SUN...AND TO HIGHER RANGES OF ABOUT 10-13 FT PER BLEND TUE AND WED PER BLEND OF THE GRIDDED NOAA WAVEWATCH AND ECMWF WAVES. A PULSE OF N SWELL RECENTLY GENERATED BEHIND OLD W ATLC COLD FRONT TO REACH NE CARIB ISLANDS AND PASSAGES LATE THIS AFTERNOON AND EVENING...WITH SECOND LARGER PULSE EXPECTED SAT EVENING... BUILDING SEAS 8-9 IN THE PASSAGES SUN AND SUN NIGHT. THE ECMWF DIMINISHES THESE QUICKER THAN THE GRIDDED WAVEWATCH GUIDANCE EARLY NEXT WEEK...WILL HANG ON TO THEN LONGER SIMILAR TO THE ECMWF GUIDANCE FOR FOR DAYS 3-5. A SECOND PULSE OF IN THE TROPICAL N ATLC...SEAS OF 7-9 FT IN MIXED NNW AND NE SWELL WILL DOMINATE THE WATERS E OF THE LESSER ANTILLES THROUGH SAT NIGHT BEFORE A SECOND PULSE OF NNW SWELL ARRIVES SUN...BUILDING SEAS 9-10 FT IN THE THE NRN PORTION AND OVER MOST OF THE CENTRAL PORTION. THESE SWELLS SUBSIDE MON AND TUE...BUT YET ANOTHER BATCH OF NW SWELLS WITH SEAS ALSO IN THE 9-10 FT MAY MOVE INTO THE FAR NRN PORTION PER THE GRIDDED NOAA WAVEWATCH. SW N ATLC S OF 31N W OF 55W... THE 18 UTC PRELIMINARY SURFACE ANALYSIS HAS A WEAKENING COLD FRONT EXTENDING FROM 26N65W NW TO ACROSS THE NW BAHAMAS AND TO INLAND CENTRAL FLORIDA NEAR MELBOURNE AS STRONG HIGH PRES BUILDS SE TO ITS NW. THE ASCAT PASS FROM 14 UTC THIS MORNING REVEALED N TO NE WINDS OF 20-25 KT OVER THE ERN PORTION OF THE AREA WHERE SEAS ARE 9-12 FT IN NW SWELLS. THE UPPER TROUGH ASSOCIATED WITH THE COLD FRONT IS SHEARING OUT TO THE NE ACROSS THE CENTRAL AND WRN PORTION. BUOY OBSERVATIONS UPSTREAM FROM THE FORECAST WATERS INDICATE LARGE SEAS...UP TO 14 FT...IN THE NW SWELLS. THESE VALUES MATCH UP PRETTY WELL WITH THE ECMWF VALUES AS THE GRIDDED NOAA WAVEWATCH SEEMS ABOUT 4-5 FT TOO HIGH. WILL HIGHLIGHT THE LARGE SWELL TRAIN WITH ITS ASSOCIATED HIGH SEA STATE TO AFFECT THE ERN WATERS AND MAJORITY OF THE CENTRAL WATERS THROUGH SAT AFTERNOON...THEN INDICATE MORE OF QUICKER SUBSIDING TREND INTO NEXT WEEK. THE FRONT WILL DISSIPATE THROUGH SUN AS THE EXTENSIVE AND STRONG HIGH PRES BUILDS ACROSS THE ENTIRE BASIN. THE STRONGER PART OF THIS HIGH PRES AREA WILL BE PRECEDE BY A SECOND WEAK FRONT TO REACH FROM NEAR 27N65W TO 28N81W SUN BY EVENING...AND DISSIPATE ACROSS SE PORTION MON. THE LARGE AREA OF HIGH PRES WILL SHIFT SE ACROSS THE NRN WATERS THROUGH WILL GRADUALLY WEAKENING. EXPECT FRESH TRADES OVER THE SRN WATERS MON AND TUE...THEN TO BE CONFINED TO THE SE PORTION BY WED MAINLY E OF THE BAHAMAS. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE WARNINGS... GULF OF MEXICO... .NONE. CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. SW N ATLC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE