000 AGXX40 KNHC 210710 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 210 AM EST THU FEB 21 2008 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. LATEST SURFACE OBS...BUOY DATA...AND A 0216 UTC QUIKSCAT PASS INDICATE THAT THE BOUNDARY OVER THE SOUTHERN GULF THIS MORNING HAS LIFTED NORTH AS A WARM FRONT TODAY AND NOW LIES ALONG A LINE FROM 29N94W 28N88W 26N85W 25N80W. SOUTH OF THE FRONT A GENERAL SE TO S FLOW OF 10 TO 15 KT COVERS MUCH OF THE SOUTHERN GULF... WHILE AND E TO SE WIND OF 15 TO 20 KT LIES WITHIN ABOUT 120 NM TO THE NORTH. RADAR AND SATELLITE IMAGERY ALSO REVEAL OVERRUNNING CLOUD COVER AND LIGHT PRECIPITATION NEAR AND NORTH OF THE BOUNDARY...WITH AN AREA OF MODERATE CONVECTION IMMEDIATELY OFFSHORE THE LA COAST. DATA AND WAVE WATCH III GRIDS SUGGEST A TRANSITIONAL PERIOD IN THE GULF...AS SHORT PERIOD NE TO E SWELL OVER THE LAST DAY OR TWO BECOME MORE SE AND WAVE HEIGHTS OF 6 TO 9 FT EARLY YESTERDAY RELAX TO 4 TO 6 FT...EXCEPT 1 TO 3 FT OFFSHORE THE WEST COAST OF FL. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT A SOUTHERN STREAM SHORTWAVE OVER THE SW THIS MORNING WILL QUICKLY BE EJECTED ONTO THE SOUTHERN PLAINS AND CENTRAL MS VALLEY FRI...AS ANOTHER VIGOROUS SYSTEM BEGINS DIGGING INTO THE WEST. HEIGHT FALLS...LARGE-SCALE DIVERGENCE...AND PVA AHEAD OF THE FIRST SYSTEM SHOULD CAUSE THE WARM FRONT OVER THE GULF THIS MORNING TO CONTINUE NORTHWARD...WITH A LOW-LEVEL SE TO S FLOW OF 15 TO 20 KT BECOMING MORE S TO SW IN ITS WAKE BY FRI. WHERE THE SLY FLOW IS STRONGEST OVER THE WRN GULF...WAVE HEIGHTS COULD REBUILD TO 6 FT OR SO UNDER A SE SWELL WHILE 1 TO 3 FT SEAS REMAIN IN PLACE OFF THE FL WEST COAST. AN ASSOCIATED COLD FRONT SLIDING ACROSS THE NORTHERN GULF FRI AND SAT SHOULD SWEEP ACROSS THE NRN GULF...GENERALLY N OF 25N...BUT THE N TO NE FLOW FOLLOWING ITS PASSAGE SHOULD BE FAIRLY WEAK COMPARED TO PREVIOUS FRONTS. IN FACT...THE LIGHT N TO NE FLOW N OF THE BNDRY AND THE VARIABLE BUT LIGHT FLOW S OF IT SHOULD ALLOW WAVE HEIGHTS TO RELAX TO 2 TO 4 FT BY LATE SAT AND SUN. FROM SAT THROUGH MON...A SERIES OF SHORTWAVES COMING OUT OF THE SW SHOULD CAUSE THE WAVY FRONT ACROSS THE NRN GULF TO OSCILLATE BACK AND FORTH. THOUGH MODEL DIFFS DURING THIS TIME INCREASE... THERE SEEMS TO BE LITTLE IMPACT FOR MARINE INTERESTS OVER THE GULF SINCE WINDS AND SEA SHOULD REMAIN FAIRLY LIGHT GULF WIDE. IN FACT...WAVE HEIGHTS OF 1 TO 3 FT SHOULD BE COMMON OVER GULF WATERS SUN AND EARLY MON. HOWEVER...THE LAST SYSTEM THIS PERIOD MOVING FROM THE ROCKIES INTO THE PLAINS APPEARS THE STRONGEST OF THE LAST SEVERAL AND INDICATIONS ARE SUCH THAT...AS LOW PRESSURE DEVELOPS AGAIN OVER THE SRN PLAINS LATE MON AND TUE...A MODERATE TO FRESH SLY FLOW WILL REDEVELOP FROM WEST TO EAST ACROSS THE GULF. THIS SHOULD RESULT IN BUILDING WAVE HEIGHTS...WITH WAVE HEIGHTS PERHAPS STRONGER THAN WHAT 5 FT THE WAVE WATCH III MODEL HAS BE EARLY TUE. ELSEWHERE...THE SAME FRONT CURRENTLY OVER THE GULF EXTENDS FROM 31N63W THROUGH THE FLORIDA STRAITS AND IS STATIONARY S OF ABOUT 28N. SATELLITE IMAGERY CONTINUES TO INDICATE SCATTERED MODERATE CONVECTION N OF 28N ALONG AND E OF THE BNDRY WITH SEVERAL NON- FLAGGED QUIKSCAT WINDS ON A 2214 UTC PASS INDICATING 20 TO 25 KT SW WINDS NEAR AND DIRECTLY AHEAD OF IT. SEAS OF 5 TO 7 FT IN THE VICINITY OF THE FRONT SHOULD BEGIN TO SUBSIDE THU ONCE THE FRONT BEGINS LIFTING N AS A WARM FRONT. MODELS DO INDICATE A WAVE FORMING OFF THE SE CONUS COAST ALONG THE RETREATING FRONT FRI MORNING WHICH SHOULD CAUSE SLY FLOW OVER THE FAR NRN PART OF THE SW ATLANTIC TO INCREASE TO 20 TO 25 KT. ONLY THE 00Z GFS SHOWS THE POTENTIAL FOR NEAR GALE CONDITIONS AROUND THIS TIME CLOSE TO THE NRN BNDRY...WITH OTHER MODELS SHOWING WEAKER WINDS THANKS TO A MORE NRN PSTN OF THE SFC WAVE. THE NEXT FRONT SHOULD ARRIVE OVER THE SW ATLANTIC WATERS SUN MORNING...WITH WINDS AND SEAS PICKING UP IN ADVANCE AND DIRECTLY BEHIND IT. WAVEWATCH III INDICATES A NW SWELL WITH 6 TO 10 FT SEAS BUILDING IN THE VICINITY OF 30N70W BY LATE SUN...WITH SEAS FURTHER INCREASING NEAR 30N65W INTO MON. OTHERWISE...PERSISTENT LOW-LEVEL RIDGING FROM THE CTL ATLANTIC INTO THE CARIBBEAN SHOULD KEEP MODERATE TO SOMETIMES FRESH TRADES ACROSS THE REGION THROUGH SAT. THIS PATTERN SHOULD HELP MAINTAIN WAVE HEIGHTS OF 6 TO 9 FT UNDER A NE TO E SWELL ACROSS THE ERN AND CTL CARIBBEAN...WITH LOCALLY HIGHER WINDS AND SEAS NEAR THE COLOMBIAN COAST. A WEAKER SERLY FLOW OVER THE NW CARIBBEAN SHOULD FAVOR WAVE HEIGHTS IN THE 3 TO 6 FT RANGE. HOWEVER...THE RESILIENT MID-LVL RIDGE OVER THE NW CARIBBEAN/SW ATLANTIC IS EXPECTED TO WEAKEN...WITH MEAN HEIGHTS FALLING CONSIDERABLY BY EARLY NEXT WEEK. THIS SHOULD CAUSE THE LOW-LEVEL RIDGE TO SHIFT EAST AND WEAKEN THE GENERAL LOW-LEVEL FLOW ACROSS THE CARIBBEAN BASIN. ALL IN ALL...THIS SUGGESTS A COLLAPSE OF THE TRADES...WITH WAVE HEIGHTS OF 3 TO 6 FT ACROSS MUCH OF THE AREA BY MON/TUE...EXCEPT LOCALLY HIGHER OFF THE COAST OF COLOMBIA. FINALLY....HEIGHTENED SEAS OF 7 TO 11 FT CONTINUE TO ARRIVE NEAR PUERTO RICO...THE U.S. VIRGIN IS...AND THE ANTILLES NEWD IN THE ATLC THANKS TO WHAT WAS A GALE CENTER SW OF THE AZORES A FEW DAYS AGO. ALTHOUGH THAT SYSTEM HAS SINCE DISSIPATED...THE NE SWELL ASSOCIATED WITH IT SHOULD KEEP WAVE HEIGHTS HIGH OVER THESE AREAS FOR THE NEXT 12 TO 24 HRS BEFORE SUBSIDING CONSIDERABLY GOING INTO THE WEEKEND. AND...WITH THE RELAXATION OF THE LOW-LEVEL RIDGE...EXPECT SEAS TO DROP TO 4 TO 6 FT BY EARLY NEXT WEEK. WARNINGS... ATLC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER KIMBERLAIN