000 AGXX40 KNHC 241821 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 220 PM EDT THU APR 24 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 THE NE CONUS TO ALONG THE NRN PORTION OF THE GULF. AS A RESULT...E-SE RETURN FLOW IS BEING OVER THE THE ENTIRE GULF WITH THE EXCEPTION OF ERN GULF WHERE WIND DIRECTION IS MORE NE-E. WIND SPEEDS AS BEING REPORTED BY GULF BUOYS AND A FEW SHIPS THIS MORNING ARE IN THE RANGE OF 15 KT...WITH HIGHER SPEEDS IN 20-25 KT SLY RETURN FLOW ALONG THE TEXAS COAST. CURRENT SEA STATE BEING OBSERVED IS RATHER CLOSE TO NOAA WAVEWATCH GUIDANCE WITH RANGES OF 3-5 FT IN THE SOUTH CENTRAL MIDDLE SECTION...2-3 FT IN THE E SECTION AND 5-7 FT ALONG THE TEXAS COAST. THE EXCEPTION IS SEAS ALONG THE TEXAS COAST MAY BE ABOUT 1-2 FT HIGHER THAN GUIDANCE VALUES. WILL ACCOUNT FOR THIS IN THE FIRST TWO PERIODS OF THE AFTERNOON PACKAGE. THE RIDGE IS STILL ON TRACK TO WEAKEN AND GRADUALLY SHIFT EWD THROUGH SAT AS THE PARENT HIGH CENTER MOVES SEWD TO ALONG 30N BY SAT NIGHT. THIS WILL CAUSE THE E-SE FLOW TO SPREAD E ACROSS THE MIDDLE WATERS TO THE FL COAST BY FRI NIGHT. A COLD FRONT IS PROGGED TO PUSH INTO NW GULF COAST LATE SUN MORNING OR EARLY AFTERNOON PER CONCURRENCE OF GLOBAL MODELS. PRIOR TO THIS... THE E-SE FLOW WILL BECOME SLY OVER THE FAR WRN GULF SAT NIGHT. 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 BEHIND THE FRONT SUN NIGHT INTO MON AND QUICKLY DIMINISHING LATE MON. THIS IS SIMILAR TO BOTH THE 00 UTC RUNS OF THE EUROPEAN AND CANADIAN MODELS. THE 12 UTC MEAN GFS ENSEMBLE SHOWS MUCH LESS WIND SPEEDS FOR THE SAME TIME FRAMES WITH WINDS OF 20 KT AND DECREASING QUICKLY TO 15-20 KT BY LATE MON NIGHT. GIVEN THAT HIGH PRES BEHIND THE FRONT APPEARS TO BE RATHER WEAK AND THAT MODEL RUNS MAY BE ON JUMPING ON THE HIGH SIDE WITH RESPECT TO THESE FORECAST WINDS...WILL STICK CLOSER WITH CURRENT FORECAST OF WINDS IN THE 20-30 KT RANGE BEHIND THE FRONT AND STRESS THAT THE STRONGER OF THESE WINDS WILL BE IN THE SW GULF DUE TO PINCHED OFF TIGHT PRES GRADIENT NORMALLY SEEN BEHIND FRONTS DROPPING SWD ALONG THE COAST OF THE FAR WRN GULF. AS STATED IN PREVIOUS DISCUSSIONS WILL LEAVE OF POSSIBILITY OPEN TO POSSIBLE GALE WINDS BEHIND FRONT PENDING FUTURE MODEL GUIDANCE. FOR SEAS BEHIND THE FRONT...WILL GO WITH A RANGE OF 8-11 FT FOR MON IN THE WRN GULF WITH THESE NUMBERS ALSO BEING OPEN FOR ADJUSTMENT BASED ON FUTURE TRENDS OF THE MODEL WINDS. 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 WITH WINDS DIMINISHING RAPIDLY BEHIND IT MON AND TUE AS HIGH PRES SETTLES IN OVER THE NW PART. SW ATLC... A SOMEWHAT OF A PERTURBED SYNOPTIC PATTERN IS IN PLACE AS LOW PRES OF 1009 MB CENTERED NEAR 28N71W MOVES ESE. THE LOW CONTINUES TO TRAIL A TROUGH SW TO THE N COAST OF HISPANIOLA WITH A TIGHT PRES GRADIENT SQUEEZE NW OF THE LOW AS HIGH PRES OVER THE E COAST OF THE UNITED STATES BUILDS SE THROUGH FRI NIGHT. SCATTEROMETER DATA FROM THIS MORNING ALONG WITH A FEW SHIP REPORTS SHOWED NE 20-25 KT WINDS W OF THE LOW WITH SEAS UP TO 9 FT. WINDS ELSEWHERE ACROSS THE AREA ARE LIGHT...IN THE 10-15 KT WITH WNW FLOW INDICATED BY THE SCATTEROMETER DATA OVER ABOUT JUST THE ENTIRE AREA EXCEPT THE E PORTION WHERE S-SE FLOW IS NOTED SE OF THE LOW AND E OF THE TROUGH...AND NE FLOW IS PRESENT NE OF THE LOW AND TROUGH. LATEST SATELLITE LOOPS SHOW SCATTERED TSTMS JUST EXITING THE NE PART AHEAD OF THE LOW AND TROUGH. THE LOW IS FORECAST TO MOVE E OF THE AREA FRI MORNING AS THE HIGH BUILDS SEWD INTO THE AREA. NE 20-25 KT WINDS W OF THE LOW WILL DIMINISH TO 10-15 KT BY SAT. WINDS WILL BE E-SE 10-15 KT OVER MUCH OF THE AREA SUN...EXCEPT SE-S IN THE FAR NW PART THEN INCREASE TO 20 KT THERE ON MON AS THE GULF OF MEXICO COLD FRONT APPROACH THE UNITED STATES SE COAST AND THE HIGH SHIFTS TO THE FAR E PORTION. THE COLD FRONT IS EXPECTED TO MOVE ALONG A PSN FROM 31N77W TO S FLORIDA BY EARLY TUE MORNING...AND WEAKEN FROM 31N70W TO NEAR HISPANIOLA BY LATE TUE. WINDS BEHIND THE FRONT ARE EXPECTED TO BE N ABOUT 20 KT AND 20-25 KT N OF ABOUT 29N ON MON...THEN WEAKEN TO 10-15 KT ON TUE. MAIN ISSUE WITH THIS FRONT WILL BE THE ARRIVAL OF LARGE SEAS (UP TO 11 FT) IN A NW SWELL BEHIND THE FRONT OVER FAR NRN WATERS 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 ALONG THE COAST OF COLOMBIA. ALTHOUGH HIGHER THAN MODEL GUIDANCE...THESE WINDS SHOULD LESSEN TO 10-15 KT TONIGHT AND FRI. WINDS REMAIN UNCHANGED THROUGH SUN AFTERNOON ...THEN INCREASE OVER THE SE PART OF THE CARIBBEAN SUN AFTERNOON 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. THE GULF OF MEXICO COLD FRONT IS EXPECTED TO MOVE INTO THE YUCATAN CHANNEL AND FAR NW PART OF THE CARIBBEAN EARLY MON EVENING THEN WEAKENS 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...BUT MAY BE HIGHER IF THE HIGH IN GULF STRENGTHENS. WARNINGS... ATLC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. .FORECASTER AGUIRRE. TROPICAL PREDICTION CENTER.