000 AGXX40 KNHC 271715 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 115 PM EDT SUN APR 27 2008 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... A SOUTHERN STREAM SHORT WAVE TROUGH ALOFT IS RESPONSIBLE FOR CLUSTERS OF THUNDERSTORMS OFF THE NE MEXICAN COAST THIS MORNING. FURTHER WEST...A DEEP LONG WAVE TROUGH EXTENDING FROM THE CENTRAL PLAINS THROUGH SOUTH TEXAS WILL PUSH A COLD FRONT OFF THE TEXAS COAST LATER TODAY. NUMEROUS THUNDERSTORMS ARE EXPECTED ALONG THIS FRONT...ESPECIALLY OFF THE SOUTH TEXAS COAST THIS EVENING. THE TIGHT GRADIENT BEHIND THE FRONT AND THE COLD AIR ADVECTION WILL ALSO SET UP A LATE SEASON GALE EVENT OFF THE MEXICAN COAST S OF TAMPICO TONIGHT AND EARLY MON. WINDS DIMINISH OVER THE WESTERN GULF THROUGH LATE MON...WITH FRESH TO STRONG NLY FLOW BEHIND THE FRONT OVER THE CENTRAL AND EASTERN GULF INTO TUE. THE FRONT WILL LOSE STEAM AS IT MOVES THROUGH GULF WATERS AS UPPER SUPPORT LIFTS OUT...AND LIMP INTO THE YUCATAN CHANNEL BY TUE NIGHT. HIGH PRES BUILDS BEHIND THE FRONT OVER THE NRN GULF COAST THROUGH MIDWEEK. SE RETURN FLOW PICKS UP OVER THE NW GULF BY WED AS THE HIGH PRES BUILDS INTO THE WESTERN ATLC. GLOBAL MODELS...ESPECIALLY THE GFS...SHOW SE FLOW INCREASING ACROSS THE CENTRAL AND WESTERN GULF THU AND FRI IN RESPONSE TO DEEPENING LOW PRES OVER THE PLAINS. CARIBBEAN AND TROP N ATLC... SCATTEROMETER DATA SHOW THE STRONGEST WINDS ARE IN THE EASTERN CARIBBEAN...ON THE ORDER OF 20 KT. THIS IS WHERE THE GRADIENT IS TIGHTEST ON SOUTH SIDE OF A 1022 MB SURFACE HIGH CENTERED N OF THE BAHAMAS. AN UPPER TROUGH N OF THE AREA ALONG WITH ABUNDANT DEEP LAYER MOISTURE IS KEEPING SCATTERED SHOWERS ACTIVE ACROSS THE EASTERN CARIBBEAN AS WELL...ALTHOUGH THIS IS STARTING TO TAPER OFF. A LOW AMPLITUDE SURFACE TROUGH EMBEDDED IN THIS AREA OF MOISTURE FROM ROUGHLY THE MONA PASSAGE TO CURACAO...WILL KEEP THE PRESSURE GRADIENT TIGHT ENOUGH TO SUPPORT FRESH TRADES ACROSS THE CARIBBEAN THROUGH TUE AS THE TROUGH PROGRESSES EWD. MEANWHILE A FRONT IN THE GULF OF MEXICO WILL MAKE SLOW PROGRESS TO THE SE AND THROUGH THE YUCATAN CHANNEL INTO THE NW CARIBBEAN MON INTO TUE. THE FRONT WILL BE FAIRLY DIFFUSE HOWEVER AND DISSIPATE OR SHIFT NWD BY WED. TRADES OVER THE EASTERN CARIBBEAN DIMINISH WED INTO THU AS THE HIGH TO THE NORTH WEAKENS AND SHIFTS E AHEAD OF THE ADVANCING FRONTAL BOUNDARY. WW3 MODEL DEPICTS 12 SECOND SWELL OF UP TO 6 FT PUSHING THROUGH THE MONA AND ANEGADA PASSAGES MON AND TUE...AND DECAYING BY WED. SW N ATLC... WATER VAPOR IMAGERY SHOWS AN UPPER TROUGH FROM BERMUDA THROUGH THE WINDWARD PASSAGE...FOLLOWED BY RIDGING BUILDING NORTH OF THE BAHAMAS. AT THE SURFACE...A 1022 MB HIGH PRES ASSOCIATED WITH THE UPPER RIDGE IS CENTERED NE OF THE BAHAMAS AND IS MAINTAING MODERATE TO FRESH TRADES ACROSS THE SOUTHERN BAHAMAS. SLY FLOW WILL INCREASE OFF THE FLORIDA AND GEORGIA COASTS TONIGHT AND EARLY MON AHEAD OF A COLD FRONT FORECAST TO MOVE OFF THE COAST BY LATE MON. THE FRONT WILL PUSH EWD THROUGH MID WEEK AND EXTEND FROM 31N65W TO CENTRAL CUBA BY LATE WED...FOLLOWED BY HIGH PRES BEHIND THE FRONT. WARNINGS... ATLC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... GALE WARNING S OF 25N W OF 94W TONIGHT AND MON. .FORECASTER CHRISTENSEN. TROPICAL PREDICTION CENTER.