000 AGXX40 KNHC 221917 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 315 PM EDT MON APR 22 2013 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W...AND THE SW N ATLANTIC INCLUDING THE BAHAMAS. GULF OF MEXICO... A WEAK SURFACE TROUGH IS ANALYZED ALONG 90W S OF 27N EARLY THIS AFTERNOON. ELSEWHERE RELATIVELY WEAK HIGH PRES IS PRESENT. RECENT AND LATEST AND CURRENT BUOY OBSERVATIONS SHOW NE-E WINDS OF 10 KT OVER MUCH OF THE MIDDLE AND ERN GULF...EXCEPT FOR NE WINDS OF 15-20 KT IN THE FAR NE PORTION WHERE A TIGHTER PRES GRADIENT THERE BETWEEN THE TROUGH AND HIGH PRES OVER THE ERN U.S. IS INDUCING SUCH CONDITIONS. OVER THE WRN PORTION...E-SE WINDS OF MAINLY 10 KT ARE NOTED...EXCEPT FOR N-NE WINDS OF 5-10 KT IN THE SW GULF. THE BUOY OBSERVATIONS CURRENTLY SHOW SEAS IN THE RANGE OF 3-5 FT E OF 91W...AND ABOUT 3-4 FT W OF 91W. THE 12 UTC RUN OF THE GRIDDED WAVEWATCH GUIDANCE IS VERY NEAR THESE REPORTED VALUES...AND SO WILL USE THIS GUIDANCE FOR THIS UPCOMING FORECAST. THE ACTIVE TSTM ACTIVITY OBSERVED SINCE YESTERDAY OVER THE SE GULF HAS DIMINISHED IN COVERAGE DURING THE DAY AS DRY AIR ALOFT HAS SETTLED IN THE WAKE OF THE PREVIOUS UPPER TROUGH. ISOLATED SHOWERS AND TSTMS ARE CURRENT OBSERVED OVER THE FAR SE PART OF THE GULF S OF ABOUT 25N AND E OF 87W. MOISTURE GUIDANCE SUGGESTS THAT THIS ACTIVITY WILL CONTINUE TO SHIFT EASTWARD THROUGH EARLY TUE WHILE DECREASING. THE FORECAST WILL ONLY HAVE SLIGHT MODIFICATIONS IN THE MEDIUM RANGE. FOR THE VERY NEAR TERM...THE TROUGH ALONG 90W IS STILL SCHEDULED TO DISSIPATE THROUGH TUE. HIGH PRES OVER THE SE U.S. AND MAINLY THE NRN PORTION OF THE GULF IS FORECAST BY THE MODELS TO SLIDE EASTWARD THROUGH WED IN RESPONSE TO THE NEXT COLD FRONT FORECAST TO APPROACH THE GULF. THE MODELS INDICATE THAT THIS NEXT FRONT WILL ENTER THE FAR NW GULF EARLY ON WED. ONCE THE FRONT ENTERS THE GULF...IT WILL BEGIN TO WEAKEN RATHER QUICKLY AS IT MOVES E. WILL FOLLOW THE GENERAL MODEL CONSENSUS OF THE FRONT WEAKENING AFTER IT ENTERS THE GULF. YESTERDAY IT APPEARED THAT THE GFS WAS TOO WEAK AND TOO FAR TO THE N WITH THE COLD FRONT POSN ONCE IT ENTERED THE GULF AND REACH THE MIDDLE AND ERN GULF LATER IN THE WEEK...SO THE ECMWF GUIDANCE WAS WAS GIVEN MORE WEIGHT FOR WED THROUGH FRI PERIODS AS IT BROUGHT THE FRONT MORE TO THE S OF THE GULF FOR THESE SAME PERIODS...AND ALSO INDICATED MORE N-NE 15-20 KT WINDS BEHIND IT OVER THE FAR WRN GULF WED. THE 12 UTC RUN LOOKS GOOD WITH THE BRIEF PERIOD OF N-NE 20-25 KT WINDS ALONG AND JUST OFFSHORE THE CENTRAL AND LOWER TEXAS COAST EARLY WED. WILL FORECAST THE COLD FRONT TO REACH A POSN FROM THE WRN FLORIDA PANHANDLE TO THE W CENTRAL AND SW GULF THU. THE FRONT WILL BECOME STATIONARY OVER THE NE AND CENTRAL WATERS THU...AND DISSIPATE FRI. WINDS BEHIND THE FRONT WILL BE RATHER LIGHT IN THE 10-15 KT RANGE FROM THE N-NE OVER THE NW GULF THROUGH LATE WED...THEN BECOME MOSTLY E-SE AT 10-15 KT OVER MUCH OF THE NRN AND CENTRAL PORTIONS THU AND FRI EXCEPT FOR 15-20 KT IN THE SE AND S CENTRAL PORTIONS WHERE A TIGHTER PRES GRADIENT IS EXPECTED. SEAS ARE NOT EXPECTED TO BUILD UP TOO MUCH BEHIND THE FRONT...AT MOST 5 OR 6 FT AND POSSIBLY TO 7 FT NEAR THE TEXAS COAST. HIGH PRES BUILDS WSW ACROSS THE NRN GULF LATE THU THROUGH SAT. CARIBBEAN SEA AND TROPICAL N ATLC S OF 22N W OF 55W... STRONG HIGH PRES IS CENTERED OVER THE CENTRAL ATLC. AN ASCAT PASS FROM THIS 1404 UTC THIS MORNING REVEALED NE WINDS OF 15 KT OVER A PORTION OF THE CENTRAL CARIBBEAN AND THE FAR ERN PORTION AS WELL. WINDS ARE SLIGHTER HIGHER OVER THE FAR NRN TROPICAL N ATLC FROM THE NE AT 15-20 KT. THE OBSERVATIONS SHOW SEAS IN THE 6-7 FT RANGE IN THE SW CARIBBEAN AND 6-8 FT IN THE NRN TROPICAL N ATLC. SEAS ARE MUCH LOWER IN THE 3-5 FT RANGE ELSEWHERE EXCEPT FOR 2-3 FT W OF 79W. THE RIDGE IS FORECAST SLIDE EASTWARD THROUGH WED ALLOWING FOR A WEAK PRES GRADIENT TO DEVELOP THROUGHOUT. THE NE SWELLS ACROSS THE TROPICAL N ATLC WILL SLOWLY SUBSIDE THROUGH TONIGHT ALLOWING FOR THE CURRENT SEAS OF 6-8 FT TO LOWER TO 6 OR 7 FT THROUGH MOST OF FRI. A NEW SET OF NE LARGE LONG PERIOD SWELLS IS BEING CONSISTENTLY FORECAST BY THE WAVEWATCH GUIDANCES TO PROPAGATE INTO THE NE TROPICAL N ATLC ON FRI AND SPREAD S AND SW TO THE CENTRAL PORTION OF THESE SAME ZONE DURING FRI. THESE SWELLS ARE EXPECTED TO UP THE SEAS TO THE 10-12 FT RANGE...BUT COULD POSSIBLY BE HIGHER. SW N ATLC S OF 31N W OF 55W... THE 18 UTC PRELIMINARY SURFACE ANALYSIS HAS A RIDGE OF HIGH PRES EXTENDING FROM 30N66W SW TO THE SE AND CENTRAL BAHAMAS. A WEAKENING STATIONARY FRONT EXTENDS FROM NEAR 31N77W TO 28N79W...AND BECOMES A TROUGH TO WEST PALM BEACH FLORIDA. THE ASCAT PASS FROM 1400 UTC THIS MORNING REVEALED NE WINDS OF 15-20 20 KT OVER THE SE PORTION...AND LIGHTER E-SE WINDS OF 10-15 KT OVER MOST OF THE WRN PORTION...WITH E-SE WINDS OF 15-20 KT OVER A PORTION OF THE CENTRAL WATERS. OBSERVED SEAS ARE GENERALLY 6-7 FT OVER THE FAR SRN WATERS E OF THE BAHAMAS AND ENE PORTIONS. SEAS ELSEWHERE ARE 5-6 FT...EXCEPT 3-5 FT W OF THE BAHAMAS AND 8-12 FT IN THE FAR NW PART WHERE AN ASCAT PASS FROM 1540 UTC THIS MORNING CLEARLY SHOWED NE WINDS OF 25-30 KT WITH GALE FORCE WINDS JUST N OF THE AREA. SEAS IN THE FAR NW CORNER ARE 9-13 FT PER BUOY OBSERVATIONS. THE FRONT/TROUGH WILL BEGIN TO SLOWLY DRIFT E WHILE WEAKENING REACHING TO NEAR OR JUST E OF 70W FRI AS A TROUGH...THEN BEGIN TO MOVE BACK TO THE W DURING FRI AND DAMPEN OUT SAT. THE VERY TIGHT PRES GRADIENT BETWEEN THE CURRENT FRONT/TROUGH AND HIGH PRES ALONG THE SE U.S. WILL CONTINUE TO HOLD THE PINCHED OFF GRADIENT OFF THE NE FLORIDA COAST RESPONSIBLE FOR THE NE 25-30 KT WINDS THROUGH TONIGHT BEFORE IT SLACKENS ON TUE TO ALLOW THE WINDS TO DIMINISH TO 15-20 KT. THE SEAS THERE WILL SLOWLY SUBSIDE TO 9 OR 10 FT TUE...AND TO 6 FT BY WED. .WARNINGS...ANY CHANGES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... GMZ011...NONE. GMZ013...NONE. GMZ015...NONE. GMZ017...NONE. GMZ019...NONE. GMZ021...NONE. GMZ023...GALE WARNING TONIGHT. GMZ025...NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... AMZ011...NONE. AMZ013...NONE. AMZ015...NONE. AMZ017...NONE. AMZ019...NONE. AMZ021...NONE. AMZ023...NONE. AMZ025...NONE. AMZ027...NONE. AMZ029...NONE. AMZ031...NONE. AMZ033...NONE. AMZ035...NONE. AMZ037...NONE. AMZ039...NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... AMZ111...NONE. AMZ113...NONE. AMZ115...NONE. AMZ117...NONE. AMZ119...NONE. AMZ121...NONE. AMZ123...NONE. AMZ125...NONE. AMZ127...NONE. *FOR DETAILED ZONE DESCRIPTIONS PLEASE VISIT: HTTP://WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF NOTE: GRIDDED MARINE FORECASTS ARE AVAILABLE IN THE NATIONAL DIGITAL FORECAST DATABASE (NDFD) AT: HTTP://PREVIEW.WEATHER.GOV/GRAPHICAL FOR ADDITIONAL INFORMATION PLEASE VISIT: HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE