000 AGXX40 KNHC 201754 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 154 PM EDT FRI APR 20 2007 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... SFC HIGH PRES CENTERED OVER MICHIGAN AND A RIDGE AXIS STRETCHING SSW INTO THE WRN GULF OF MEXICO IS BEING REINFORCED BY A WEAK COLD FRONT MOVING S ACROSS CENTRAL FL AND THE NE GULF WATERS. NE WINDS OVER THE FAR NE GULF ARE INCREASING TO 20 KT BEHIND THE FRONT AND IT IS POSSIBLE THAT WINDS COULD BE AS HIGH AS 25 KT FOR A BRIEF PERIOD TONIGHT WITH SEAS BUILDING TO 6 FT JUST OUTSIDE THE TAE/TBW COASTAL WATERS BY SUNRISE (AS PER THE 00 UTC UKMET WAVE MODEL WHICH USUALLY DOES A BETTER JOB AT THE INITIAL BUILD-UP OF SEAS). THE FRONT IS EXPECTED TO DISSIPATE BY SAT AS IT MOVES S TOWARDS CUBA...AND STRONGER ELY FLOW WILL DEVELOP ON THE S SIDE OF THE BUILDING HIGH. SCATTERED AREAS OF 20 KT WILL OCCUR SAT THROUGH SUN NIGHT MAINLY OVER THE FAR ERN AND FAR WRN GULF WATERS. ELY WINDS BECOME MORE CONSISTENTLY 20 KT OVER THE S HALF OF THE REGION BEGINNING MON...THEN AS SE RETURN FLOW OFF THE TEXAS COAST ON TUE. A DEVELOPING STORM SYSTEM OVER THE CENTRAL U.S. PLAINS WILL ALLOW THE STRONGER SE WINDS TO EXPAND OVER MUCH OF THE W GULF BY WED AND WOULD EXPECT SEAS TO BUILD TO A MAXIMUM OF 8 FT OFF THE TEXAS COAST. SW N ATLC... AN INTERESTING FEATURE IS NOTED IN VIS SATELLITE IMAGERY JUST OFF THE NE COAST OF FLORIDA. AN AREA OF LOW PRES IS CENTERED NEAR 29.2N 78.9W AS OF ABOUT 1700 UTC...MOVING SSE AT ABOUT 10-15 KT. THE LOW CLOUDS AROUND THE FEATURE HAVE GIVEN IT AN ALMOST EYE-LIKE APPEARANCE AND IT IS FLANKED ON ITS N SIDE BY A SWATH OF NE WINDS 20-25 KT OVER THE TPC OFFSHORE WATERS. THE LOW WILL DROP S AND SHOULD DISSIPATE AS IT APPROACHES GRAND BAHAMA ISLAND AND THE SWATH OF HIGHER WINDS WILL EXPAND S TO ABOUT 27N W OF 75W BY SAT AFTERNOON. LARGE SWELLS UP TO 10 FT WILL BE GENERATED IN THIS SWATH N OF THE BAHAMAS...AND WILL THEN PROPAGATE SW TOWARDS THE FLORIDA/BAHAMAS COASTS WITH MAXIMUM PERIODS OF 10 SEC REACHING THE COAST IN A FIRST WAVE TONIGHT...THEN A SECOND WAVE SAT NIGHT. ELSEWHERE...A COLD FRONT IS MOVING E OVER THE SE PART OF THE AREA FROM 24N65W TO SE CUBA. THE FRONT WILL MOVE SE OF THE REGION BY SAT MORNING WITH SOME 6-8 FT NLY SWELL CONTINUING E OF THE BAHAMAS. HIGH PRES BUILDS OVER THE AREA BEGINNING SAT WITH WINDS INCREASING TO 20 KT OVER THE S AND SW PARTS SUN NIGHT THROUGH WED. SWELLS OVER THE N PART OF THE AREA WILL CONTINUE TO SUBSIDE WITH WEAKER WINDS...BUT WAVES WILL BUILD TO AT LEAST 8 FT OVER THE S PART WITH THE INCREASED GRADIENT. CARIBBEAN AND TROPICAL N ATLC... THE TRADES REMAIN ANOMALOUSLY ABSENT OVER THE W/CENTRAL CARIBBEAN AT THE MOMENT WITH A SURFACE TROUGH CENTERED ALONG 71W AND A DISSIPATING COLD FRONT SAGGING ACROSS THE NW CARIBBEAN WATERS. WINDS ARE N/NE 5-10 KT W OF THE TROUGH AND SE/S 10-15 KT E OF THE TROUGH TO THE LESSER ANTILLES AND THIS PATTERN WILL HOLD UNTIL SAT NIGHT WHEN THE TROUGH BEGINS TO DISSIPATE. HIGH PRES BUILDS OVER THE W ATLC ON SUN AND THIS WILL CAUSE WINDS TO INCREASE TO 20 KT NEAR CUBA AND THE WINDWARD PASSAGE SUN NIGHT AND MON...THEN OVER 20 KT ACROSS A GOOD CHUNK OF THE CARIBBEAN WATERS TUE AND WED. BY WED THE GRADIENT COULD BE STRONG ENOUGH FOR WINDS TO BE AS HIGH AS 30 KT OFF THE COLOMBIAN COAST. OVER THE TROPICAL N ATLC WATERS...THE W ATLC COLD FRONT WILL SAG INTO THE N PART BY SAT MORNING THEN STALL FROM 22N57W TO PUERTO RICO SAT NIGHT THROUGH MON. SEAS WILL GENERALLY SUBSIDE WITH A LACK OF SWELLS ACROSS THE TROPICAL ATLC ALTHOUGH WIND WAVES MAY STILL BUILD JUST N OF THE FRONT MON/TUE WHEN WINDS INCREASE TO 20 KT. WARNINGS... ATLANTIC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER BERG