000 AGXX40 KNHC 131757 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 200 PM EDT THU MAR 13 2008 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... THE COLD FRONT...WHICH INCHED THROUGH THE SE GULF YESTERDAY IS NOW SE OF THE AREA...AND SFC OBS INDICATE THAT THE WRN END OF IT HAS LIKELY WASHED OUT. BEHIND THE FRONT...WEAK 1019MB HIGH PRES HAS MIGRATED E AND NOW RESTS OVER THE NE GULF AND N FL AND IS RESPONSIBLE FOR A GENERALLY LIGHT WIND REGIME GULF WIDE THIS MORNING. IN FACT...A 1202 UTC QUIKSCAT PASS...BUOY AND SHIP OBS INDICATED NE TO E WINDS OF 5 TO 10 KT ACROSS THE ERN HALF OF THE GULF AND SEAS OF 1 TO 3 FT. OVER THE WRN HALF OF THE GULF...SE TO S WINDS OF 10 TO 15 KT GENERALLY PREVAIL...BUT A DEVELOPING RETURN FLOW HAS ALREADY INCREASED TO 15 TO 20 KT N OF 22N W OF 94W. WITH THE STRONGER WINDS IN THE WRN HALF OF THE GULF...SEAS HAVE ARE BUILDING TO 3 TO 5 FT THIS MORNING...HIGHEST NEAR THE TX/NE MEXICAN COAST. THE NEXT SIGNIFICANT SYSTEM...A SRN STREAM SHORTWAVE MOVING ONTO THE SRN PLAINS THIS AFTERNOON...SHOULD QUICKLY TRACK THROUGH THE LOWER MS VALLEY EARLY FRIDAY AND DAMPEN OUT AS IT MOVES OFF THE SE CONUS COAST LATE IN THE DAY. MODEST HEIGHT FALLS AND A PATTERN OF UPR-LVL DIVERGENCE AHEAD OF THIS IMPULSE SHOULD LEAD TO LOWERING PRESSURES OVER THE SRN PLAINS TODAY...WHICH IN TURN SHOULD LEAD TO WARM AIR ADVECTION/ STRENGTHENING RETURN FLOW OVER THE WRN HALF OF THE GULF THIS AFTERNOON AND EVENING. GFS OUTPUT HAS BEEN CONSISTENT IN DEVELOPING SLY 20 TO 25 KT FLOW BY THIS EVENING...WITH WAVEWATCH III OUTPUT SUGGESTING WAVE HEIGHTS REACHING 8 FT JUST OFFSHORE THE TX COAST IN S SWELL BY EARLY FRI. MODELS ALSO INDICATE A WELL-DEFINED WARM FRONT LIFTING OUT OF THE SW GULF/NE MEXICO TONIGHT...WHICH SHOULD RAPIDLY LIFT NE TO THE NE/CENTRAL GULF COAST FRI AFTERNOON...WITH OVERRUNNING SHOWERS AND TSTMS POSSIBLY FORMING NEAR AND NE OF THE BNDRY. AFTER ITS PASSAGE...A STEADY S TO SW FLOW OF 15 TO 20 KT SHOULD PREVAIL ACROSS THE GULF...CAUSING SEAS TO BUILD TO 4 TO 7 FT IN S TO SW SWELL IN MOST AREAS...EXCEPT NEAR THE FL STRAITS AND S OF 20N IN THE BAY OF CAMPECHE..WHERE SEAS SHOULD REMAIN 1 TO 3 FT THROUGH EARLY SAT. NEXT...AMORPHOUS SHORTWAVE ENERGY IN THE SRN STREAM SHOULD ARRIVE OVER THE SRN/CENTRAL PLAINS LATE FRI AND COALESCE INTO A MORE AMPLIFIED BUT POSITIVELY-TILTED IMPULSE WHILE STREAKING ACROSS THE CENTRAL MS VALLEY SAT MORNING AND FINALLY REACH THE CAROLINA COAST BY SUN MORNING. THERE HAS BEEN A CONSISTENT SPREAD AMONGST THE GUIDANCE IN TERMS OF WHEN THE ASSOCIATED COLD FRONT MAKES IT TO THE NW GULF SAT. THE ECMWF AND UKMET CONTINUE TO BE SLOWER WITH THE SHORTWAVE AND HENCE SLOWER WITH THE ARRIVAL OF THE COLD FRONT...WHILE THE GFS/NAM ARE THE FASTEST TO SURGE THE FRONT INTO THE GULF. MODEL TRENDS ARE FOR A SLIGHTLY SLOWER PROGRESSION...WHICH MAKES THE 12Z GFS LOOK TOO FAST. BASED UPON THIS...A HEALTHY S TO SW FLOW OF 20 TO 25 KT SHOW SPREAD FROM W TO E ACROSS THE GULF AHEAD OF THE COLD FRONT...WHICH SHOULD ARRIVE IN THE GULF SLIGHTLY SLOWER THAN THE 12Z GFS SUGGESTS. THESE WINDS SHOULD FAVOR WAVE HEIGHTS CRESTING AROUND 6 TO 9 FT IN S TO SW SWELL N OF 27N SAT WITH 3 TO 6 FT S OF 25N. THE FRONT SHOULD DROP AS FAR S AS 25N SUN MORNING...AS THE SRN STREAM SHORTWAVE SUPPORTING OUTRUNS IT. MODELS AGREE THAT A STRONG AND BROAD SFC RIDGE BUILDING IN BEHIND THE FRONT SHOULD LEAD TO AN INITIAL BRISK NW TO N FLOW...VEERING MORE NE TO E 20 TO 25 KT SUN-MON. THE LONG DURATION OF THE ELY FLOW SHOULD ALLOW WAVE HEIGHTS TO GROW TO 7 TO 10 FT OVER THE NW GULF BY MON AFTERNOON AND 3 TO 6 FT N OF 25N E OF 90W. THE FINAL SYSTEM OF CONSEQUENCE...A STRONG SRN STREAM CLOSED LOW....SHOULD REACH SRN/CENTRAL CA SAT NIGHT AND PASS THROUGH THE SW CONUS SUN-TUE. THE BULK OF THE MODEL GUIDANCE IS IN REMARKABLY GOOD AGREEMENT...SAVE FOR THE UKMET WHICH APPEARS AS A SLOW OUTLIER SOLN. GFS/NCEP ENS MEANS/ECMWF ARE ALL CLOSE TOGETHER...THOUGH THE ECMWF IS A TAD SLOWER THAN THE REST. STRONG HEIGHT FALLS AND LARGE-SCALE UPR-LVL DIVERGENCE AHEAD OF THIS SYSTEM SHOULD CAUSE THE STRONG AND STEADY ELY FLOW OVER THE NRN GULF TO VEER MORE E TO SE THEN SE TO S MON INTO TUE. AGAIN...THE EXTENDED DURATION OF STRONG WINDS OVER THE GULF SHOULD ALLOW SEAS TO BUILD TO 8 TO 13 FT IN SE SWELL OVER THE WRN HALF OF THE GULF BY TUE MORNING...WHILE 5 TO 8 FT SEAS PREVAIL OVER THE ERN GULF EXCEPT ALONG THE W FL COAST. THE ASSOCIATED COLD FRONT SHOULD REACH THE TX COAST LATE TUE MORNING OR AFTERNOON...WITH SLY 10 TO 15 FT SWELL DIRECTLY AHEAD OF THE FRONT. SW N ATLC... A WEAK FRONTAL WAVE HAS FORMED ALONG THE THE QUASI-STATIONARY FRONT OVER THE SW ATLC THIS MORNING. SATELLITE IMAGERY REVEALS A POORLY-DEFINED LEAD OF CLOUDS STREAKING FROM W TO E OVER THE NRN WATERS...ATTENDED BY BURSTS OF SCATTERED SHOWERS AND TSTMS. OVERALL THOUGH...THE WIND REGIME OVER THE SW ATLC REMAINS LIGHT ...WITH NO WINDS OVER 20 KT OBSERVED. IN GENERAL...SEAS RANGE FROM 3 TO 5 FT NEAR AND E OF THE BAHAMAS...WITH 2 TO 3 FT SEAS W OF THE BAHAMAS. HIGHER 4 TO 6 FT SEAS PREVAIL E OF 70W IN MIXED NW AND SE SWELL. MODEL GUIDANCE TAKES THE SFC WAVE NE OF THE BAHAMAS E OF THE AREA BY EARLY FRI AND LIFT THE WEAK STATIONARY FRONT DRAPED ACROSS THE AREA NWD AS A WARM FRONT DURING THE DAY FRI. A BRIEF BURST OF STRONG SWLY FLOW SHOULD FORM N OF 29N W OF 75W FRI AFTERNOON THROUGH SAT MORNING...AS THE GULF PORTION OF THE WARM FRONT LIFTS N OF THE AREA...WITH SEAS BUILDING TO 4 TO 6 FT. OTHERWISE...THE NEXT MAJOR SYSTEM TO AFFECT MARINE INTERESTS IN THE SW ATLC WILL BE A WELL-DEFINED COLD FRONT DIVING SEWD OFF THE FL/SE CONUS COAST EARLY SUN. SW 20-30 KT LOW-LVL FLOW SHOULD DEVELOP AHEAD OF THE FRONT AND SPREAD FROM W TO E N OF 27N SUN...WITH SEAS BUILDING TO 8 TO 13 FT IN SW SWELL WITHIN ABOUT 240NM E OF THE FRONT. W OF THE FRONT...NW WINDS OF 20 TO 30 KT BLOWING SUN GRADUALLY VEER MORE N TO NE MON-TUE AND WEAKEN BUT SHOULD INTRODUCE SIGNIFICANT NW SWELL OF 10 TO 15 FT...WITH SEAS AS HIGH AS 15-25 FT N OF 28N E OF 70W BY MON MORNING. STRONG HIGH PRES BUILDING BEHIND THE FRONT SHOULD KEEP A BRISK NE TO N WIND WITHIN ABOUT 300 NM NW OF THE FRONT THROUGH TUE....WITH A LARGE AREA OF N TO NE SWELL ARRIVING FROM THE FL E COAST THROUGH THE BAHAMAS AND WRN ATLC. THE SWELL EVENT SHOULD BE PEAKING TUE...WITH A LARGE AREA OF 10 TO 20 FT SEAS COVERING THE AREA NE OF BAHAMAS TUE AFTERNOON. CARIBBEAN AND TROPICAL N ATLC... AS HAS BEEN THE CASE THE LAST FEW DAYS...WEAK HIGH PRES ENE OF THE AREA IS MAINTAINING LIGHT TO MODERATE TRADES ACROSS THE CARIBBEAN BASIN AND THE TROPICAL N ATLC. THIS PATTERN IS BEING MAINTAINED BY THE CURRENT UPR-LVL PATTERN OF FLAT AND STRONG MID- TO UPPER-LEVEL RIDGING ACROSS THE CARIBBEAN....WITH AN AXIS ALONG 16-17N JUXTAPOSED WITH A FAST-PACED ZONAL FLOW RUNNING FROM THE SE GOMEX THROUGH THE WRN ATLC. THIS GENERAL PATTERN IS EXPECTED TO PREVAIL THROUGH SUN...AT WHICH TIME A STRONG FRONT DIVING INTO THE SWRN ATL SHOULD HERALD STRONG HIGH PRES BUILDING IN FROM THE NORTH LATE SUN-TUE. AS A RESULT...THE PATTERN OF GENERALLY WEAK TRADES SHOULD GRADUALLY BE REPLACED WITH STRONGER TRADES...FIRST OVER THE CENTRAL AND WRN CARIBBEAN SEA MON AND THEN BASIN WIDE BY TUE. CURRENT SEAS OF 1 TO 3 FT ACROSS THE NW CARIBBEAN SEA AND 4 TO 6 FT OVER THE REMAINDER OF THE BASIN ...EXCEPT FOR THE TYPICALLY HIGHER SEAS IMMEDIATELY OFFSHORE COLOMBIA. EXPECT WAVE HEIGHTS TO GENERALLY BUILD TO 4 TO 8 FT BY TUE ACROSS THE BASIN...WITH 6 TO 10 FT SEAS OFFSHORE COLOMBIA. OTHERWISE...AN INCREASING SE FLOW IS EXPECTED TO DEVELOP W OF 85 AND GENERALLY S OF 20N INCLUDING THE GULF OF HONDURAS LATE FRI THROUGH SUN MORNING. SE FLOW COULD REACH 25 KT AT TIMES...WHICH SHOULD RESULT IN WAVES BUILDING TO 5 TO 8 FT IN SE SWELL THIS WEEKEND. FINALLY...LONG DURATION AND STRONG NWLY FLOW BEHIND THE FRONT DESCENDING INTO THE SW ATLC SUN/MON SHOULD LEAD TO SIGNIFICANT NW TO N SWELL DEVELOPING LATE SUN N OF 25N BETWEEN 60W AND 75W. SWELL SHOULD BEGIN ARRIVING ACROSS THE NRN/NE CARIBBEAN EARLY TUE...WITH WAVE HEIGHTS BUILDING TO 8 TO 12 FT FROM THE NRN COAST OF HISPANIOLA THROUGH THE NRN LESSER ANTILLES LATE TUE...INCLUDING ALL ATLC PASSAGES. WARNINGS... ATLANTIC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER KIMBERLAIN