000 AGXX40 KNHC 150456 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1255 AM EDT SUN MAR 15 2009 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... HIGH PRES IS BUILDING OVER THE TEXAS COAST...BEHIND A STATIONARY FRONT EXTENDING FROM SE LOUISIANA TO THE WESTERN BAY OF CAMPECHE NEAR 20N96W. LIGHT TO MODERATE SE TO S FLOW PREVAILS E OF THE FRONT. THE FRONT REMAIN STATIONARY MOST OF TODAY UNDER SW FLOW ALOFT...AHEAD OF A PAIR OF SHORT TROUGHS OVER THE CENTRAL PLAINS AND SOUTHERN ROCKIES. THE NORTHERN PORTIONS OF THE FRONT WILL SHIFT EAST AS THE SHORT WAVE ENERGY SHIFTS EASTWARD INTO THE SOUTHEAST U.S. THE FRONT BECOMES ORIENTED MORE EAST TO WEST TUE...FROM CENTRAL FLORIDA E THROUGH THE MIDDLE GULF TO THE WESTERN BAY OF CAMPECHE...WITH THE WESTERN PORTION OF THE FRONT DIMINISHING. AFTER WINDS AND SEAS DIMINISH OVER THE WESTERN GULF TODAY...GENERALLY MODERATE WINDS AND SEAS CAN BE EXPECTED BOTH AHEAD AND BEHIND THE FRONT THROUGH MID WEEK. CARIBBEAN SEA... 1027 MB HIGH PRES WILL REMAIN CENTERED NEAR BERMUDA THROUGH MONDAY...AND MAINTAIN GENERALLY 15 TO 20 KT TRADES ACROSS ALL BUT THE FAR NW CARIBBEAN THROUGH MONDAY. SHIP OBSERVATIONS SHOW UP TO 25 KT STILL ACTIVE OFF THE COLOMBIAN COAST. A JASON ALTIMETER PASS FROM AROUND 23Z NOTED 5 TO 7 FT SEAS BETWEEN DOMINICAN REPUBLIC AND VENEZUELA. SEAS TO 9 FT ARE LIKELY IN THE VICINITY OF THE MONA AND ANEGADA PASSAGES...WHERE NE SWELL WITH PERIODS TO 12 SECOND CONTINUE TO MOVE INTO THE AREA FROM THE ATLC. WINDS TAPER OFF IN THE CARIBBEAN TUE THROUGH THU AS THE HIGH PRES N OF THE AREA WEAKENS AND SHIFTS EAST AHEAD OF A COLD FRONT MOVING OFF THE SE U.S. COAST. IN ADDITION THE NE SWELL DAMPENS OUT...ALLOWING SEAS TO SUBSIDE. ATLANTIC S OF 31N W OF 55W... RECENT SHIP OBSERVATIONS SHOW A SWATH OF E TO SE WINDS AROUND 15 TO 20 KT FROM NE OF THE LEEWARDS...THROUGH THE SOUTHERN BAHAMAS...AND INTO SOUTH FLORIDA. THE WINDS ARE ON THE SOUTHERN PERIPHERY OF 1027 MB SURFACE HIGH PRES CENTERED NEAR 31N63W. BUOY OBSERVATIONS SHOW NE SWELL UP TO 10 FT WITH PERIODS TO 12 SECONDS S OF 22N. THE RIDGE STAYS IN PLACE THROUGH MONDAY...MAINTAINING THE FRESH TRADES. MOST OF THE LARGE NE SWELL GREATER THAN 8 FT WILL BE S OF THE 20N BY LATE MONDAY. CHANGE STARTS LATE MON AS A COLD FRONT DRIVEN BY SHORT WAVE ENERGY ALOFT PUSHES OF THE SOUTHEAST U.S. COAST MONDAY NIGHT...ASSOCIATED WITH SURFACE LOW PRES FORMING OFF THE CAROLINAS. SW TO W WINDS BETWEEN N FLORIDA AND BERMUDA INCREASE BETWEEN THE DEVELOPING LOW AND THE HIGH PRES TO THE SOUTH. GLOBAL MODELS SHOW THE LOW DEEPENING AND MOVING TO THE NE OF BERMUDA BY TUE...WITH THE FRONT ENTERING THE WATERS S OF 31N. MAIN FORECAST ISSUE WILL BE POTENTIAL FOR STRONG SW WINDS N OF 28N E OF THE FRONT...AND FRESH TO STRONG NORTHERLY FLOW N OF THE FRONT. THE FRONT EXTENDS FROM 31N55W TO THE CENTRAL BAHAMAS BY LATE TUE...AND FROM 28N55W TO THE SOUTHERN BAHAMAS WED...BEFORE DISSIPATING THU. STATIONARY FRONT EXTENDS FROM SE LOUISIANA COAST SW TO 25N94W AND TO A WEAK 1011 MB LOW JUST N OF VERACRUZ MEXICO. TO ITS E...A WEAK RIDGE EXTENDS W FROM THE WESTERN ATLC ACROSS THE NORTHERN GULF COAST TO NEAR 88W. CURRENT BUOY OBSERVATIONS W OF THE FRONT ARE SHOWING MOSTLY N WINDS OF 15 KT WITH SEAS IN THE 3-5 FT RANGE. A QUIKSCAT PASS FROM NEAR 1200 UTC THIS MORNING OVER THE WESTERN GULF BEHIND THE FRONT DEPICTED NW-NW WINDS OF 15 KT BEHIND THE FRONT OVER THE NW GULF...AND SLIGHTER STRONGER N WINDS OF 20-25 KT BEHIND THE FRONT IN THE SW GULF. THE WINDS IN THE SW GULF TURNED OUT TO BE HIGHER THAN ANTICIPATED AS A TIGHTER PRES GRADIENT RESULTING BETWEEN THE WEAK LOW AND HIGH PRES NOSING S OVER NORTHERN AND CENTRAL MEXICO WAS SUFFICIENT ENOUGH TO ACCOUNT FOR THESE WINDS. GFS GUIDANCE FROM YESTERDAY AND 12 UTC THIS MORNING DID HINT THAT THESE WINDS MY BE STRONGER FOR TODAY. LATEST SATELLITE IMAGERY SHOWS EXTENSIVE MOSTLY OVERCAST LAYERS OF MOSTLY LOW AND MID CLOUDS WITH EMBEDDED AREAS OF RAIN WITH EMBEDDED SCATTERED SHOWERS AND ISOLATED TSTMS ALONG AND W OF THE FRONT WITH MAJORITY OF THE ACTIVITY OCCURRING IN THE NW GULF. THIS ACTIVITY IS LIKELY TO PERSIST INTO MON MORNING AS A VERY PRONOUNCED UPPER LEVEL TROUGH CURRENTLY OVER THE WESTERN U.S. APPROACHES TEXAS AND THE FAR NW GULF COAST. ELSEWHERE ACROSS THE GULF...BUOY OBSERVATIONS FROM LATE THIS AFTERNOON AND EVENING HAVE NOTED...AND ARE CURRENTLY REPORTING SE-S WINDS OF 10-15 KT OVER THE REMAINDER OF GULF TO E OF THE FRONT...WITH THE EXCEPTION OF VARIABLE WINDS OF 5-10 KT IN THE NE PART AND AN AREA OF ENHANCED SE WINDS OF 15-20 KT IN THE SOUTHERN SECTION OF THE GULF S OF 23N BETWEEN 88W-91W. OBSERVED SEA STATE RANGES FROM 3-5 FT ELSEWHERE ACROSS THE GULF TO ABOUT 1 FT IN THE FAR NE PORTION. WAVEWATCH MODEL GUIDANCE FROM 1800 THIS PAST AFTERNOON AGAIN APPEARED REASONABLE WITH OBSERVED SEAS OVER THE GULF. BOTH 1200 AND 1800 UTC GLOBAL MODEL GUIDANCE AND THE REGIONAL NAM ARE IN PRETTY GOOD AGREEMENT WITH THE POSITION OF THE FRONT AND WITH DEPICTING WEAK LOW PRES ALONG IT. GFS ENSEMBLE GUIDANCE ALSO IS IN LINE WITH THE MODELS. THE UPPER LEVELS AS DEPICTED IN THE GLOBAL MODELS SUGGESTS THAT AFOREMENTIONED UPPER TROUGH WILL AMPLIFY AS IT SWINGS ACROSS NE TEXAS AND THE SE U.S. MON THROUGH WED INDUCING THE STATIONARY TO BECOME A COLD FRONT THAT STAGGERS INTO NE GULF MON THROUGH TUE. IT BECOMES DIFFUSE FROM NEAR FL PANHANDLE TO BAY OF CAMPECHE MON NIGHT AND TUE. AN ATLC BACKDOOR COLD FRONT IS FORECAST TO THEN DROP S INTO THE NE GULF MON NIGHT THROUGH TUE AS STRONG ATLC HIGH PRES NUDGES WSW INTO THE NORTHERN GULF IN ITS WAKE THROUGH WED BEFORE WEAKENING LATE WED INTO THU. WINDS WILL BE LIGHT ON EITHER SIDE OF THE FRONT AS IT MOVES ACROSS THE MIDDLE AND EASTERN GULF THROUGH THE FORECAST PERIOD...WITH SEAS REMAINING ON THE LOW SIDE. EXPECT WINDS TO BECOME NE-E 10-15 KT SUN THROUGH TUE OVER THE NE GULF...AND BRIEFLY INCREASING TO 15-20 KT EARLY WED THEN BECOME VARIABLE 5-10 KT LATE WED AND THU. CARIBBEAN SEA... AS THE PRES GRADIENT CONTINUES SURFACE HIGH PRES CONTINUES TO WEAKEN ACROSS THE SEA IN RESPONSE TO WEAKENING ATLC HIGH PRES TRADES WILL WEAKEN THROUGH SUN. WINDS WILL CONTINUE TO BE NE-E 20-25 KT NEAR THE COLOMBIAN COAST THROUGH MON...THEN WEAKENING TO 15-20 KT TUE AND WED. EXPECT SEAS TO ALSO LOWER OVER MUCH OF THE AREA AREA...EXCEPT REMAINING IN THE RANGE OF 8-10 FT NEAR THE COLOMBIAN COAST THROUGH TUE THEN DIMINISHING TO 6-9 FT LATE TUE...TO 5-7 FT WED AND 4-5 FT THU. SEAS ELSEWHERE WILL BE ON THE LOW SIDE THROUGHOUT THE SEA BY THU WITH RANGES OF 4-5 FT IN THE EASTERN PORTION...AND 2-3 FT IN THE WESTERN PORTION AND 3-4 FT OVER REMAINDER OF THE SW PORTION. SW N ATLANTIC AND TROPICAL N ATLC... HIGH PRES CONTINUING TO BUILD S ACROSS THE AREA IS CREATING A TIGHT PRES GRADIENT OVER THE SE PORTION OF THE SW N ATLC AND N TROPICAL N ATLC ALLOWING FOR NE WINDS OF 15-20 KT OVER THESE WATERS...EXCEPT MORE SUSTAINED AT 20 KT OVER THE SE WATERS OF THE SW N ATLC AS SHOWN BY A QUIKSCAT PASS FROM 1016 UTC THIS MORNING. SEAS AT BUOY 41043 NEAR 21N65W HAVE BEEN HOLDING STEADY AT 10 FT DURING THE AFTERNOON AND EVENING HOURS. LATEST NOAA WAVEWATCH MODEL GUIDANCE HAS TONED DOWN MAXIMUM SEA HEIGHTS EXPECTED THROUGH THE TROPICAL N ATLC ZONE FROM THE 10-13 FT OF EARLIER RUNS TO 9-11 FT. THIS IS MORE IN LINE WITH THE CURRENT SHIP OBSERVATIONS OF 8-11 FT ACROSS THESE WATERS. THESE SEAS WILL PERSIST IN THE NORTHERN TROPICAL N ATLC ZONE N OF ABOUT 16N THROUGH MON MORNING...THEN SUBSIDE TO 7-9 FT MON AFTERNOON TO 6-7 FT TUE AND 4-7 FT WED EXCEPT 6-8 FT S OF 17N...AND TO 3-5 FT THU. RIDGE FROM 29N65W TO CENTRAL FL AS DISPLAYED IN A QUIKSCAT PASS FROM 2240 UTC THIS EVENING WILL SLIDE SE TO ALONG 28N AS A STATIONARY FRONT N OF THE AREA DROPS S AS A COLD FRONT INTO THE NORTHERN WATERS MON NIGHT INTO TUE...AND FURTHER S FROM 31N65W TO NEAR WEST PALM BEACH TUE AND FROM 28N65W TO NW BAHAMAS WHERE IT WILL BECOME DIFFUSE TO S FL BY LATE WED AS HIGH PRES BUILDS S INTO THE AREA BEHIND IT...THEN SHIFTS TO E OF 70W BY LATE THU AS A WEAK TROUGH MOVES INTO THE WESTERN PORTION. HIGH PRES BUILDING S INTO THE AREA BEHIND THE FRONT WILL ALLOW FOR WINDS TO BECOME N-NE 15-20 KT N OF THE FRONT WITH STRONGER WINDS OF NW-N 20-25 KT E OF 72W DIMINISHING TO 15-20 KT LATE WED AND TO E 10 TO 15 KT THU. SEAS BEHIND THE FRONT BUILD UP TO 10 FT WED E OF 75W ...THEN SUBSIDE TO 8-9 FT BY LATE THU AS THE AREA OF HIGH PRES SHIFTS TO E OF ABOUT 70W AND THE FRONT BECOMES A DIFFUSE FRONTAL TROUGH OVER THE WESTERN PORTION OF THE SW N ATLC. WINDS WILL BE RELATIVELY LIGHT OVER THE REMAINDER OF THE SW N ATLC SUN THROUGH THU...WITH THE EXCEPTION OF THE FAR SE WATERS WHERE NE-E WINDS OF 15-20 KT AS STATED EARLIER WILL PREVAIL THROUGH MON NIGHT...THEN DIMINISH TO 10-15 KT TUE. SEAS WILL RANGE 3-5 FT IN A N SWELL...EXCEPT 4-6 FT E OF THE SE BAHAMAS AND 2-3 FT SW OF THE BAHAMAS. ANOTHER EXCEPTION WILL BE THE NE AND E PORTIONS OF THE SW N ATLC ON THU WHERE A LINGERING N SWELL MAY STILL INDUCE SLOW SUBSIDING SEAS OF 7-10 FT. ATLANTIC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER AGUIRRE. TROPICAL PREDICTION CENTER.