000 AGXX40 KNHC 251836 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 230 PM EDT FRI APR 25 2008 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... HIGH PRES RIDGE CURRENTLY EXTENDS SW FROM OFF THE MID-ATLC COAST TO ALONG THE NRN GULF COAST. AS A RESULT...E-SE RETURN FLOW IS BEING OBSERVED OVER THE ENTIRE GULF WITH THE EXCEPTION OF THE FAR WRN PART NEAR THE TEXAS COAST. WIND SPEEDS AS BEING REPORTED BY GULF BUOYS AND A FEW SHIPS THIS MORNING ARE IN THE RANGE OF 10-15 KT...WITH HIGHER SPEEDS IN 15-20 KT SLY RETURN FLOW ALONG THE TEXAS COAST. 12 UTC SEA STATE ANALYSIS FROM THIS MORNING ALONG WITH THAT OF RECENT OBSERVATIONS FROM SHIPS AND BUOYS SHOW VALUES REASONABLY CLOSE TO THE NOAA WAVEWATCH WITH RANGES OF 3-5 FT IN THE SOUTH CENTRAL MIDDLE SECTION...1-3 FT IN THE E SECTION WITH A MINIMUM OF 1 FT NEAR THE FLORIDA BIG BEND AND 5-6 FT ALONG THE TEXAS COAST. A SMALL POCKET OF 3-5 FT SEAS WAS ANALYZED OVER THE FAR SE GULF AND STRAITS OF FLORIDA. THE RIDGE IS STILL ON TRACK TO WEAKEN AND GRADUALLY SHIFT EWD THROUGH SUN AS THE PARENT HIGH CENTER MOVES S TO NEAR 29N BY SUN AFTERNOON. THIS WILL CAUSE THE E-SE FLOW TO BECOMES MORE SLY OVER MUCH OF THE GULF THROUGH SUN EVENING. LATEST RUNS OF THE GLOBAL MODELS INDICATE THAT A RATHER SIGNIFICANT COLD FRONT FOR LATE APRIL WILL PUSH INTO THE NW GULF COAST LATE SUN MORNING OR EARLY AFTERNOON PER CONCURRENCE OF GLOBAL MODELS. LATEST MODEL RUNS ARE IN FAIR AGREEMENT THAT WINDS WILL SHARPLY INCREASE BEHIND THE FRONT OVER THE WRN AND MIDDLE GULF. BOTH 10M AND 30M 12 UTC GFS GUIDANCE SHOWS N 30-35 KT WINDS SPREADING INTO THE WRN GULF WITH THE HIGH END OF THE RANGE IN THE SW GULF BEHIND THE FRONT PRIMARILY CLOSE THE MEXICAN COAST SUN NIGHT THROUGH MON AND QUICKLY DIMINISHING LATE MON. THIS IS SIMILAR TO LAST NIGHT'S RUNS OF 00 UTC EUROPEAN AND CANADIAN MODELS. EVEN THE 12 UTC RUN OF THE NOGAPS MODEL SHOWS 35-40 KT IN THE SW GULF WITH ONE 35 KT WIND BARB IN THE NW GULF NEAR THE MEXICAN COAST LATE SUN NIGHT THROUGH LATE MON. THE GFS AND GUNC ENS MEANS DON'T SHOW GALE WINDS FOR THESE TIME FRAMES. THE GUNC SHOWS 30 KT FOR HIGHEST WIND SPEED IN THE SW GULF ON MON...WHILE THE GFS MEAN SHOWS 25 KT WITH BOTH SHOWING WINDS QUICKLY DROPPING LATE MON AFTERNOON INTO MON NIGHT. GIVEN THAT HIGH PRES BEHIND THE FRONT THAT BUILDS SWD OVER TEXAS AND NRN MEXICO BEHIND WILL WEAKEN AS IT QUICKLY SLIDES EWD INTO THE NRN GULF TUE AND WED AND THAT THE AIR MASS BEHIND THE FRONT WON'T BE COLD ENOUGH FOR AMPLE MIXING TO OCCUR DOWN TO THE SURFACE...WILL STICK CLOSE WITH CURRENT FORECAST OF WINDS IN THE 20-30 KT RANGE BEHIND THE FRONT WITH GUSTS TO GALE FORCE IN THE SW PART BEHIND THE FRONT SUN NIGHT THROUGH MON AFTERNOON. FOR SEAS BEHIND THE FRONT...WILL GO WITH A RANGE OF 7-10 FT IN THE NW GULF ON MON AND 8-12 FT IN THE SW GULF BEHIND THE COLD FRONT. OF COURSE...THESE RANGES WILL BE SUBJECT FOR ADJUSTMENTS BASED ON FUTURE TRENDS OF THE MODEL WIND FIELDS OVER THE AREA BEHIND THE FRONT. AS FOR FORECAST PSNS OF FRONT...ONCE FRONT MOVES OFF THE TEXAS FRONT THEN WILL QUICKLY REACH FROM THE FLORIDA BIG BEND TO THE ERN BAY OF CAMPECHE BY LATE MON AND EXIT THE GULF LATE MON. WINDS WILL DIMINISH RAPIDLY BEHIND IT THROUGH TUE AS HIGH PRES SETTLES IN OVER THE NW PART. SW ATLC... LOW PRES OF 1011 MB ANALYZED E OF THE AREA NEAR 28N61W AT 12 UTC THIS MORNING IS MOVING NE 15 KT. THE LOW CONTINUES TO TRAIL A TROUGH SW TO NEAR 21N69W WITH A TIGHT PRES GRADIENT SQUEEZE NW OF THE LOW THROUGH TONIGHT AS HIGH PRES ALONG THE E COAST OF THE UNITED STATES BUILDS SE THROUGH SUN NIGHT AND WEAKEN. QUIKSCAT DATA FROM JUST PAST 10 UTC THIS MORNING ALONG WITH SEVERAL SHIP REPORTS SHOWED NE 20-25 KT WINDS W OF THE LOW WITH SEAS UP TO 10 FT. WINDS ELSEWHERE ACROSS THE AREA ARE LIGHT...IN THE 10-15 KT WITH WNW FLOW INDICATED BY THE SCATTEROMETER DATA OVER JUST ABOUT THE ENTIRE AREA EXCEPT THE E PORTION WHERE S-SE FLOW IS NOTED SE OF THE LOW AND E OF THE TROUGH WITH NE FLOW PRESENT NE OF THE LOW AND TROUGH. THE NE WINDS OF 20-25 KT NW OF THE LOW WILL DIMINISH TO 10-15 KT SAT MORNING. BY SUN AFTERNOON...WINDS WILL BE GENERALLY E-SE 10-15 KT...EXCEPT SE-S IN THE FAR NW PART THEN INCREASE TO 20 KT THERE ON MON AS THE GULF OF MEXICO COLD FRONT APPROACHES THE UNITED STATES SE COAST...AND THE HIGH SHIFTS TO THE FAR E PORTION. GLOBAL MODELS IN FAIR AGREEMENT THAT THE FRONT MOVES OFFSHORE THE NE FLORIDA COAST LATE MON AFTERNOON OR EARLY EVENING WITH THE 00 UTC CANADIAN RUN FROM LAST NIGHT SHOWING THE FRONT JUST ALONG THE UNITED STATES SE COAST AT 18 UTC...AND BOTH THE 12 UTC REGIONAL MODEL (NAM) AND 12 UTC NOGAPS BEING THE SLOWEST OF THE GUIDANCE WITH FRONT JUST INLAND THE UNITED STATES SE COAST BY EARLY MON EVENING. THIS IS IN LINE WITH THE GFS AND GUNC MEAN GUIDANCE. FOR THIS FORECAST PACKAGE WILL INTRODUCE COLD FRONT IN THE FAR NW WATERS MON NIGHT. THE COLD FRONT IS THEN FORECAST PER MODEL CONSENSUS TO MOVE TO A PSN FROM 31N77W TO THE WRN BAHAMAS AND S FL MON NIGHT INTO TUE MORNING THEN WEAKEN. FRONT THEN MOVES FROM 31N70W TO SE BAHAMAS BY LATE TUE. WINDS BEHIND THE FRONT ARE EXPECTED TO BE NW-N 20 KT LATE MON...WITH WINDS TO 25 KT POSSIBLY ALONG 30N...THEN WEAKEN TO 10-15 KT DURING TUE AFTERNOON AND TO LIGHT AND VARIABLE MOSTLY NLY ON WED. EARLIER CONCERN OF THE POSSIBILITY OF LARGE SWELLS MOVING INTO THE AREA BEHIND THE FRONT SEEMS LESS LIKELY AS IT NOWS SEEMS THAT THE SWELL TRAIN WILL LAG FAR ENOUGH TO THE N OF FORECAST WATERS THAT IT SHOULD BECOME DIFFUSE BEFORE IMPACTING THE AREA ON MON AND TUE. CARIBBEAN AND TROPICAL ATLC WATERS... TRADES REMAIN RATHER LIGHT THROUGHOUT WITH ONLY A SMALL POCKET OF NE-E 15-20 KT WINDS JUST ALONG THE COAST OF COLOMBIA. ALTHOUGH HIGHER THAN WHAT MODEL GUIDANCE SUGGESTS...THESE WINDS SHOULD LESSEN TO 10-15 KT ON SAT. WINDS REMAIN UNCHANGED THROUGH SUN AFTERNOON...EXCEPT OVER THE SE PART OF THE CARIBBEAN AS THE PRES GRADIENT OVER THE SE ATLC AND NE CARIBBEAN TIGHTENS. WINDS ALSO INCREASE BRIEFLY TO E 15-20 KT OVER THE SRN PORTION OF THE TROPICAL N ATLC LATE MON INTO TUE MORNING. THE GULF OF MEXICO COLD FRONT IS EXPECTED TO MOVE INTO THE YUCATAN CHANNEL AND FAR NW PART OF THE CARIBBEAN AS A WEAKENING FRONT EARLY MON EVENING AS THE GULF OF MEXICO HIGH BRIDGES OVER IT WITH NE WINDS IN THE RANGE OF 10-15 KT AS MOST OF THE GUIDANCE INDICATES. THERE COULD BE BRIEF SPELLS OF NE 15-20 KT THROUGH THE YUCATAN CHANNEL ON TUE IF THE HIGH IN GULF OF MEXICO STRENGTHENS SOME. WARNINGS... ATLC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. .FORECASTER AGUIRRE. TROPICAL PREDICTION CENTER.