000 AGXX40 KNHC 120758 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 358 AM EDT THU MAR 12 2009 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO... CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... A COLD FRONT IS CURRENTLY DRAPED ACROSS THE FAR NW GULF... EXTENDING FROM SOUTH CENTRAL LOUISIANA TO SE TEXAS. THIS FRONT IS EXPECTED TO BECOME STATIONARY LATER TODAY AS THE UPPER FLOW DE-AMPLIFIES. THE ONLY EXCEPTION WILL BE ALONG THE COAST OF MEXICO...WHERE TERRAIN VARIATIONS OVER MEXICO WILL FORCE THE FRONT TO SURGE SOUTHWARD TODAY FOLLOWED BY NORTH WINDS UP TO 20 KT...WHICH IS HANDLED WELL BY THE NAM. ON FRIDAY...THE EASTERN PORTION OF THE FRONT IS FORECAST TO LIFT NORTH INTO THE SE CONUS AS A WARM FRONT AS A SURFACE WAVE DEVELOPS ALONG THE FRONT IN THE NW GULF WITH THE APPROACH OF A SHORTWAVE TROUGH FROM THE SW CONUS. CORRESPONDINGLY...THE COLD FRONT WILL BE REINFORCED OVER THE WESTERN GULF LATE IN THE WEEKEND...FOLLOWED BY N WINDS TO 25 KT ALONG THE COAST OF MEXICO. HOWEVER...THE FRONT WILL QUICKLY LOSE ITS DEFINITION BY EARLY NEXT WEEK AS AN UPPER RIDGE TRANSPORTS THE BULK OF THE UPPER SUPPORT NORTHWARD. OTHERWISE... GENERALLY TRANQUIL CONDITIONS WILL BE PRESENT ACROSS MUCH OF THE CENTRAL AND SOUTHEAST GULF...WHERE A SURFACE RIDGE EXTENDING SW FROM THE W ATLC IS PRESENT. THE RETURN FLOW AROUND THE RIDGE IS GENERATING E TO SE WINDS TO 10 TO 15 KT AROUND THE GULF SE OF THE FRONT BASED ON BUOY OBS. THE ONLY EXCEPTION IS AROUND THE COAST OF YUCATAN WHERE THE 12/0300 UTC ASCAT PASS IS SHOWING E WINDS UP TO 20 KT. THE RELATIVELY LIGHTER AHEAD OF THE FRONT WILL KEEP WAVE HEIGHTS IN THE 3 TO 5 FT RANGE...EXCEPT ACROSS THE E GULF WHERE SEA HEIGHTS OF UNDER 3 FT ARE EXPECTED. SEAS WILL DECREASE TO 1 TO 3 FT ACROSS MUCH OF THE GULF BY LATE WEEKEND WITH DECREASING WINDS AHEAD OF THE FRONT. HOWEVER...IN THE WAKE OF THE FRONT OVER THE W GULF...THE STRONGER WINDS WILL SUPPORT HIGHER SEAS...WITH WAVEWATCH GUIDANCE NOW SUGGESTING SEAS UP TO 8 FT IN THE WAKE OF THE FRONT BY SAT NIGHT. HOWEVER...AS THE FRONT BECOMES DIFFUSE AND POST FRONTAL WINDS DECREASE...SEAS WILL SUBSIDE IN THE WAKE OF THE FRONT BY EARLY NEXT WEEK. CARIBBEAN... THE SURFACE PRESSURE GRADIENT ACROSS THE CARIBBEAN CONTINUES TO SLOWLY WEAKEN AS THE SURFACE HIGH IN THE SW NORTH ATLC WEAKENS. IN RESPONSE...THE STRONG TRADE WIND FLOW IS FORECAST TO WEAKEN DURING THE NEXT FEW DAYS...WITH THE STRONGEST WINDS FOUND NEAR THE COAST OF COLOMBIA. NE TO E WINDS OF 20 TO 25 KT WILL PERSIST ACROSS PORTIONS OF THE SW AND E CARIBBEAN THROUGH LATE WEEK BEFORE DIMINISHING EVEN FURTHER THIS WEEKEND WITH THE APPROACH OF THE COLD FRONT OVER THE NW GULF OF MEXICO. CORRESPONDINGLY... WAVEWATCH GUIDANCE LOWERS THE MAX SEA HEIGHTS FOUND NEAR THE COAST OF COLOMBIA FROM 11 FT CURRENTLY TO 8 FT BY SAT. LIKEWISE...THE AREA OF GREATER THAN 8 FT SEAS OVER PORTIONS OF THE SW AND E CARIBBEAN HEIGHTS WILL CONTRACT THROUGH LATE WEEK. THE TRADES COULD PICK UP SOME EARLY NEXT WEEK IN RESPONSE TO A SURFACE RIDGE APPROACHING THE CARIBBEAN AHEAD OF THE FRONT. ATLANTIC... AT 12/0600 UTC...GALES CONTINUE IN THE WESTERN SEMICIRCLE OF THE 998 MB LOW IN THE CENTRAL ATLC NEAR 30N46W. THE ASCAT PASS NEAR 12/0100 UTC CONFIRMS THESE GALES MAINLY N OF 29N BETWEEN 50W-54W. THE LOW CONTINUES TO FILL AND SPIN DOWN AFTER HAVING LOST ITS FRONTAL STRUCTURE WITH THE CORRESPONDING UPPER LOW BEING DISASSOCIATED FROM ITS SURROUNDING JET SUPPORT. THUS THE GALE AREA WILL CONTINUE TO CONTRACT...WITH WINDS DIMINISHING OVER THE NEXT DAY. BY 13/1200 UTC...WINDS ASSOCIATED WITH THE LOW ARE EXPECTED TO HAVE FALLEN BELOW GALE FORCE AS THE LOW WEAKENS... DRIFTS EAST-SOUTHEASTWARD..AND THE WIND FIELD BROADENS. GIVEN THE JUXTAPOSITION OF THE DYNAMIC FETCH REGION AND ENHANCED WINDS IN THE SW SEMICIRCLE OF THE LOW...WAVEWATCH GUIDANCE IS INDICATING LARGE SWELLS OVER 14 FT ACROSS LOCATIONS E OF 65W TRACKING SOUTHWARD IN NW TO N SWELL ACROSS THE SW N ATLC AND TROPICAL N ATLC. MAX SEAS TO 22 FT ARE AFFECTING PORTIONS OF THE DISCUSSION AREAS IN THIS REGION BUT WILL DECREASE AS THE STRONGER WIND FIELD EXITS THE REGION. THE ASSOCIATED SWELL IS FORECAST TO AFFECT THE SW N ATLC AND N TROPICAL ATLC DURING THE NEXT FEW DAYS. IN THE WAKE OF THIS LOW...A SURFACE RIDGE WILL AFFECT MUCH OF THE REGION INTO THE WEEKEND...WITH ENHANCED TRADE WINDS CONFINED TO LOCATIONS S OF 22N...WHILE SEAS SUBSIDE TO BELOW 10 FT AREAWIDE BY SAT NIGHT. A PERSISTENT SURFACE RIDGE WILL SET UP INTO EARLY NEXT WEEK ALONG 28N...THOUGH A WEAK FRONT WILL MOVE SOUTHWARD INTO THE CENTRAL ATLC BY LATE MONDAY FOLLOWED BY INCREASED NORTHERLY WINDS. ATLANTIC... GALE WARNINGS IN W SEMICIRCLE OF 998 MB LOW NEAR 30N46W. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER COHEN. TROPICAL PREDICTION CENTER.