000 AGXX40 KNHC 221739 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 140 PM EDT FRI MAR 21 2008 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... AN ILL-DEFINED SRN STREAM SHRTWV IS RACING THROUGH A NEARLY ZONAL FLOW OVER THE GOMEX...AHEAD OF A DEVELOPING LONGWAVE TROF BEGINNING TO DEVELOP OVER THE ERN CONUS. ALTHOUGH WEAK...THE IMPULSE HAS RE-ACTIVATED THE OLD BOUNDARY WHICH PASSED THROUGH FL AND THE SERN GOMEX LATE THIS WEEK AND HAS SPURRED THE DEVELOPMENT OF A WEAK 1015MB SFC WAVE MOVING ENE 20-25 KT NEAR 26.5N85W AT 15 UTC. FOR THE MOS PART...WEAK HIGH PRESSURE COVERING THE CTRL/WRN GOMEX W OF THE FRONT IS MAINTAINING WEAK WINDS AND FAIRLY TRANQUIL SEA STATE THIS AFTERNOON. BUOY AND SHIP DATA AS WELL AS THE WRN EDGE OF AN EARLIER QUIKSCAT PASSED SUGGESTED A GENERAL N-NE 5-10 KT FLOW W OF 90W ... WITH 2 TO 4 FT SEAS...HIGHEST OVER THE CTRL WATERS. E OF 90W... SIMILAR CONDITIONS EXIST...THOUGH THE SAME 1126 UTC QUIKSCAT PASSED INDICATED 15-25 KT WINDS WITHIN ABOUT 180NM OF THE NE QUADRANT OF THE SFC WAVE. NE OF THE CTR...SATELLITE AND RADAR IMAGERY SHOWS AN EXPANDING AREA OF SHOWERS AND TSTMS S OF 28N E OF 86W...PRODUCING LOCALLY STRONG...GUSTY WINDS AND SHIFTING SEAS. MODELS TRACK THE WEAK WAVE ACROSS THE CTRL FL PENINSULA LATER THIS AFTERNOON/EVENING...WITH THE ASSOCIATED COLD FRONT SLIDING SE OF THE AREA BY EARLY SUN MORNING. MEANWHILE...NRN STREAM SHRTWV ENERGY DROPPING INTO THE ERN CONUS TROF WILL SEND A SECONDARY SURGE THROUGH THE NRN GULF WATERS BY SUN MORNING...WITH THE STRONGER FRONT FADING INTO THE PRIMARY E OF THE AREA BY LATE/SUN/EARLY MON. THIS WILL BE FOLLOWED BY AN EVEN MORE POTENT SHRTWV DIGGING INTO THE SERN STATES MON...WITH THE GFS COMING AROUND TO THE MORE PROGRESSIVE/DEEPER ECMWF/CMC SOLNS. ONCE THIS OCCURS...MODEL GUIDANCE IS IN AGREEMENT THAT A REASONABLY STRONG SFC RIDGE SHOULD BUILD IN FROM THE CTRL MS VALLEY...RESULTING IN AN INCREASING N TO NE LOW-LVL FLOW OF 20-25 KT FROM N TO S ACROSS THE GOMEX FROM SUN INTO MON. THE BRISK N TO NE WINDS SHOULD LAST A LITTLE OVER 24 HR AND PUT ENOUGH STRESS ON THE OCEAN SFC FOR SEAS TO BUILD TO 7 TO 11 FT IN NE SWELL...FIRST FROM 23N TO 28N W OF 89W MON AFTERNOON AND THEN SPREADING SEWD INTO TUE. ALL THE WHILE...THE STRONG SFC RIDGE OVER THE MS VALLEY SHOULD BE MIGRATING EWD AND GRADUALLY WEAKENING ALONG WITH THE WINDS...WITH THE RIDGE EXPECTED TO LIE FROM N FL TO JUST OFF THE SERN COAST LATE TUE-WED. FROM LATE TUE THROUGH THU...THE SHRTWV WHICH QUICKLY DUG INTO THE SERN STATES SHOULD LIFT OUT...LEAVING A FLAT AND NEARLY ZONAL FLOW ACROSS MUCH OF THE SRN TIER OF THE CONUS. THE EWD SHIFT OF THE SFC RIDGE SHOULD CAUSE THE LOW-LVL SHOULD TO VEER MORE E-SE AND DIMINISH TO 10-15 KT E OF 90W EXCEPT THROUGH THE STRAITS OF FL AND EXTREME SERN GOMEX. W OF 90W THE FLOW SHOULD BECOME MORE SE-S 15 KT EXCEPT SLY 15-20 KT IMMEDIATELY OFFSHORE THE NE MEXICAN/S TX COASTS...WHERE SLY WINDS OF 20-25 KT SHOULD DEVELOP THU IN RESPONSE TO LOW PRES FORMING ACROSS THE SRN/CTRL PLAINS. WITH LITTLE IN THE WAY OF FORCING...SEAS OF 3 TO 6 FT N OF 25N AND 5 TO 8 FT N OF 25N LATE TUE SHOULD SUBSIDE FURTHER TO 3 TO 6 FT GULF-WIDE WED-THU. CARIBBEAN... LONG PERIOD NW TO N SWELL FROM THE LARGE AND POWERFUL STORM SYSTEM OVER THE WRN ATLC FROM EARLY THIS WEEK LEFT HAS PROPAGATED AWAY FROM ITS SOURCE REGION INTO THE CARIBBEAN AND MUCH OF THE NORTH ATLC MOST OF THIS WEEK. STILL THOUGH...RESIDUAL SWELL CONTINUES TO ARRIVE OVER THE NE CARIBBEAN WATERS THROUGH THE ATLC PASSAGES AROUND PUERTO RICO AND THE LESSER ANTILLES BUT SHOULD CONTINUE TO DIMINISH AS THE SWELL TRAIN PUSHES FARTHER SE. OTHERWISE...HIGH PRES EXTENDING FROM THE CTRL ATLC INTO THE ERN/CTRL CARIBBEAN IS PROMOTING MODERATE TO OCCASIONALLY FRESH TRADES TODAY AND THESE CONDITIONS SHOULD PERSIST WITH LITTLE CHANGE THROUGH AT LEAST TUE. 15-20 KT TRADES WILL BE MOST COMMON S OF 17N E OF 78W DURING THIS TIME WITH SEAS OF 4 TO 7 FT...WITH TYPICALLY HIGHER WINDS AND SEAS OFF THE COLOMBIAN COAST. HOWEVER...THE GULF COLD FRONT SLIDING SEWD TODAY SHOULD ENTER THE NW CARIBBEAN TONIGHT AND BE REINFORCED BY A SECONDARY SURGE MON...WITH THE FRONT RESTING FROM ERN CUBA TO NEAR CABO GRACIAS A DIOS NICARAGUA MON AFTERNOON. BRISK N TO NE FLOW FROM THE GULF SHOULD BEGIN SPREADING INTO THE NW CARIBBEAN MON AFTERNOON THROUGH TUE...WITH THE WORST CONDITIONS INITIALLY N OF 20N W OF 85W EARLY TUE AND THEN AFFECTING MOST AREAS N OF 18N BY TUE AFTERNOON. SEAS SHOULD BRIEFLY BUILD TO 6 TO 10 FT TUE AND THEN SUBSIDE TO 5 TO 8 FT WED AFTERNOON AS THE WINDS WEAKEN. WITH HIGH PRES OVER THE SRN CONUS MOVING OFFSHORE THE SERN COAST BY WED...A FRESH TRADE WIND REGIME SHOULD SET UP SHOP OVER MOST OF THE CARIBBEAN BASIN. LOCALLY STRONGER WINDS SHOULD ALSO PENETRATE THE TYPICAL ATLC PASSAGES...RESULTING IN LOCALLY HIGHER SEAS NEAR AND DOWNSTREAM OF THOSE AREAS. SOUTHWEST ATLC... SURFACE OBS INDICATE THAT THE FRONT...WHICH STALLED IN THE WRN ATLC FROM THE CENTRAL BAHAMAS TO THE FL STRAITS...IS RETURNING AS A WARM FRONT THIS AFTERNOON. MODEL OUTPUT SHOWS THE FRONT RETREATING N OF THE AREA OVERNIGHT...WITH A GENERAL SE TO S LOW-LVL FLOW OF 10-15 KT PREVAILING ACROSS THE AREA EXCEPT E-SE 15-20 KT S OF 23N. SEAS ARE GENERALLY RUNNING 4 TO 7 FT NE OF THE BAHAMAS EXCEPT 6 TO 10 FT IN NW SWELL THIS AFTERNOON N OF 25N E OF 74W. OVERNIGHT...THE WEAK SFC WAVE OVER THE E CTRL GULF THIS AFTERNOON SHOULD BE EMERGING OFF THE E FL COAST AND RIDING UP THE SEWD-MVG COLD FRONT. WITHIN ABOUT 150NM OF THE E QUADRANT AND 90 NM NW... WINDS OF LOCALLY 20-25 KT IN SCATTERED TO LOCALLY NUMEROUS SHOWERS AND TSTMS ARE EXPECTED...WITH THE LOW PASSING NE OF THE AREA SUN AFTERNOON. INDICATIONS ARE THAT THE FRONT MAY BRIEFLY HESITATE SUN UNTIL SHRTWV ENERGY DIVING INTO THE SERN CONUS MON PUSHES THE FRONT WELL SE INTO THE SW ATLC...IN RESPONSE TO A SECONDARY AND RE- INFORCING COLD FRONT OVERTAKING THE PRIMARY. INITIALLY LIGHT NLY FLOW WILL DOMINATE THE AREA BEHIND THE FRONT SUN WITH 2 TO 4 FT SEAS BUT NW TO N WINDS OF 20-30 KT SHOULD DEVELOP MON EVENING INTO TUE...AS DEEPENING LOW PRESSURE FORMS OFF THE CAROLINA COAST. AS WAS THE CASE IN THE GOMEX...THE WIND EVENT SHOULD BE OF RATHER SHORT DURATION BUT SHOULD BE SUFFICIENTLY STRONG TO PRODUCE A SIGNIFICANT RESPONSE. OTHER MODEL DATA AND ENSEMBLE GUIDANCE SHOW NO INDICATION OF GALE FORCE CONDITIONS OVER THE EXTREME NRN WATERS IN THE WAKE OF THE DEVELOPING SFC NOW N OF THE AREA. HOWEVER... PREVIOUS RUNS DID HINT AT SUCH A POSSIBILITY. FOR NOW WILL EXCLUDE ANY MENTION OF GALE CONDITIONS...WITH GUIDANCE PRETTY EMPHATIC THAT WINDS SHOULD NOT REACH THAT LEVEL. SEAS SHOULD RAPIDLY BUILD TO 8 TO 13 FT W OF THE FRONT N OF 27N BY TUE MORNING...WITH THE NLY FLOW DRIVING 6 TO 9 FT SEAS EVEN W OF THE BAHAMAS. THE NLY FLOW GOING AGAINST THE GULF STREAM SHOULD RESULT IN SOME FAIRLY STEEP AND ROUGH SEAS BETWEEN THE FL COAST THROUGH THE WRN BAHAMAS DURING THE DAY TUE. WINDS AND SEAS SHOULD BEGIN TO DIMINISH WED...BUT THE NLY SWELL GENERATED BY THIS EVENT SHOULD BEGIN ARRIVING FROM HISPANIOLA INTO THE NRN ANTILLES THU. WARNINGS... ATLANTIC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER KIMBERLAIN