000 AGXX40 KNHC 221814 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 215 PM EDT THU APR 22 2010 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W GULF OF MEXICO... A RIDGE OF HIGH PRES REMAINS OVER THE GULF WATERS WITH 1015 MB HIGH PRES CENTERED NEAR 29N87W. SOUTHERLY RETURN FLOW HAS INCREASED TO 15-20 KT OVER THE W GULF AS INDICATED BY BUOYS LOCATED OFFSHORE OF TEXAS AND BY AN EARLIER WINDSAT SCATTEROMETER PASS. THE HIGH CENTER WILL SHIFT TO THE E INTO THE ATLC AND THE PRES GRADIENT WILL STRENGTHEN FURTHER AS A COLD FRONT APPROACHES THE TEXAS COAST. A FRONT WILL MOVE OFF THE TEXAS COAST LATE FRI NIGHT INTO EARLY SAT REACHING FROM SW LOUISIANA TO 20N96W IN THE SW BAY OF CAMPECHE WITH S-SW WINDS OF 20-25 KT AHEAD OF THE FRONT. THE FRONT WILL SHIFT E TO NEAR 30N90W TO 20N93W SAT NIGHT THEN WILL WEAKEN AS IT REACHES FROM THE FLORIDA PANHANDLE TO THE YUCATAN PENINSULA SUN NIGHT THEN EVENTUALLY MOVES INTO THE FAR SE GULF MON WHILE A WEAK TROUGH OF LOW PRES DEVELOPS IN THE BAY OF CAMPECHE. CARIBBEAN SEA AND TROPICAL N ATLC FROM 07N TO 22N W OF 55W... THE PRES GRADIENT IN THE CARIBBEAN SEA WILL TIGHTEN LATER TODAY AND EASTERLY TRADES WILL INCREASE FROM THE GENTLE TO MODERATE BREEZE RANGE TO THE MODERATE TO STRONG RANGE OVER THE CENTRAL AND E CARIBBEAN. E-SE WINDS IN THE W CARIBBEAN WILL ALSO INCREASE TO THE 15-20 KT RANGE. THE DURATION AND LENGTHENING OF THE FETCH OF THESE STRONGER WINDS WILL ALSO RESULT IN SHORT PERIOD SEAS BUILDING ACROSS THE BASIN. THE STRONGEST WINDS AND THE LARGEST SEAS WILL OCCUR NEAR THE COAST OF COLOMBIA. THESE CONDITIONS WILL PERSIST THROUGH THE FORECAST PERIOD. OTHERWISE A WEAK SHEAR LINE/AXIS OVER THE SE CARIBBEAN IS PRODUCING SCATTERED SHOWERS TODAY. THIS FEATURE WILL DISSIPATE DURING THE NEXT 24 HOURS. MEANWHILE IN THE TROPICAL N ATLC...A SERIES OF WEAK FRONTAL TROUGHS WILL MOVE ACROSS THE BASIN N OF 16N DURING THE NEXT SEVERAL DAYS. WINDS WILL SHIFT TO THE NE-E AT 10-15 KT BEHIND EACH OF THESE FEATURES. LONG PERIOD NW SWELL UP TO 11 FEET WILL PROPAGATE INTO THE NORTHERN PORTION OF THE BASIN SUN AND MON. S OF 16N...NE-E WINDS OF 10-15 KT WILL INCREASE TO 15-20 KT SUN THROUGH MON AS THE PRES GRADIENT TIGHTENS. SW N ATLANTIC S OF 31N W OF 55W... 1012 MB LOW PRES IS POSITIONED NEAR 26N62W WITH A TROUGH EXTENDING TO THE S-SW OF THE LOW. THE LOW WILL DISSIPATE DURING THE NEXT 24 HOURS AS IT MOVES TO THE E OF 55W. ANOTHER TROUGH IS SKIRTING ACROSS THE NORTHERN PORTION OF THE BASIN EXTENDING FROM 31N70W TO 27N77W WITH A DEVELOPING COLD FRONT BRINGING A REINFORCING SURGE OF COLDER AIR AND STRONGER WINDS AT THE SURFACE FORMING JUST BEHIND THE TROUGH. SCATTERED SHOWERS ARE OCCURRING ALONG AND AHEAD OF THESE FEATURES. THE COLD FRONT WILL MERGE WITH THE TROUGH DURING THE NEXT 24 HOURS AND THE 20-25 KT WIND FIELD BOTH AHEAD OF AND BEHIND THE FRONT WILL EXPAND AS A PARENT LOW PRES SYSTEM WELL N OF THE AREA STRENGTHENS. HIGH PRES WILL BUILD IN BEHIND THE FRONT LATE TONIGHT THROUGH SAT. SOUTHERLY RETURN FLOW WILL STRENGTHEN ALONG THE FLORIDA COAST SAT NIGHT THROUGH SUN AS THE HIGH PRES CENTER SHIFTS TO THE E AND AS THE NEXT COLD FRONT APPROACHES THE AREA. THE FRONT WILL SLOW DOWN AS IT MOVES TOWARD THE GEORGIA/FLORIDA COASTS MON EVENTUALLY MOVING OFFSHORE LATE MON NIGHT INTO EARLY TUE. THE FRONT WILL EXTEND FROM NEAR 31N79W TO E CENTRAL FLORIDA LATE MON NIGHT THEN FROM 31N70W TO THE TURKS AND CAICOS BY LATE TUE. HIGH PRES RETURNS BEHIND THE FRONT THEREAFTER. WARNINGS... ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER LEWITSKY