000 AGXX40 KNHC 080620 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 120 AM EST MON DEC 8 2014 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... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS/OFFICIAL FORECAST. LATEST TAFB-NWPS USED TO ADJUST WAVE PARAMETERS. HIGH CONFIDENCE. WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW THE ADVISORY CRITERIA OF 20-25 KT AND 8 FT...RESPECTIVELY...THROUGH THE END OF THE FORECAST PERIOD ON FRI NIGHT. TROUGHING OVER THE CENTRAL N ATLC HAS WEAKENED THE SUBTROPICAL RIDGE AND WEAKENED THE PRESSURE GRADIENT OVER THE GULF OF MEXICO. A WEAK COLD FRONT STRETCHED FROM THE FLORIDA KEYS TO FAR NE MEXICO WILL DISSIPATE OVER THE GULF TODAY. THE MODELS ARE IN REASONABLE AGREEMENT WITH THE STRENGTH AND TIMING OF THIS FRONT AND SHOW LOWERING THICKNESSES IN THE EASTERN GULF LATE TUE AND WED AS A DEEP LAYERED TROUGH AMPLIFIES OVER THE U.S. EAST COAST. HIGH PRES CENTERED OVER THE MISSISSIPPI VALLEY WILL DOMINATE THE WINDS OVER THE GULF FRI. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS/OFFICIAL FORECAST. LATEST TAFB-NWPS USED TO ADJUST WAVE PARAMETERS. HIGH CONFIDENCE. ADVISORY CRITERIA ARE NOT EXPECTED TO BE MET OVER THE AREA UNTIL EARLY TUE MORNING WHEN DIURNALLY ENHANCED WINDS ALONG THE COAST OF COLOMBIA ARE FORECAST TO REACH 20-25 KT. THE PRES GRADIENT BETWEEN HIGH PRES OVER THE CENTRAL U.S. AND LOWER PRES OVER NW SOUTH AMERICA WILL ALLOW WINDS TO FLIRT WITH ADVISORY CRITERIA IN THE EARLY MORNING HOURS TUE THROUGH THU AND BECOME SLIGHTLY MORE WIDESPREAD FRI. THE GFS IS GENERALLY THE MODEL TO BEAT OFF COLOMBIA AND IS THE STRONGEST OF THE MODELS HERE. WILL LEAN TOWARD ITS SOLUTION WHEN ADJUSTING THE FORECAST. OTHERWISE...WINDS AND SEAS WILL REMAIN UNDER ADVISORY CRITERIA OVER THE ENTIRE AREA UNTIL WED WHEN 8-10 FT N SWELL IS EXPECTED TO SEEP INTO THE TROPICAL N ATLC WATERS...BLANKETING THE AREA E OF THE ISLANDS THU. THIS SWELL WILL SUBSIDE TO 8 FT OR LESS BY FRI NIGHT. ...SW N ATLANTIC S OF 31N W OF 55W INCLUDING THE BAHAMAS... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS/OFFICIAL. LATEST TAFB-NWPS USED TO ADJUST WAVE PARAMETERS. HIGH CONFIDENCE. RECENT RAPIDSCAT AND ASCAT PASSES SHOW WINDS ARE STRONGER THAN EARLIER ANTICIPATED ALONG THE NE FLORIDA COAST BEHIND THE COLD FRONT STRETCHES FROM 31N70W TO THE FLORIDA KEYS...WITH WIDESPREAD 25-30 KT WINDS REPORTED. THE STRONGER GFS AND UKMET HAVE A BETTER HANDLE ON THESE WINDS INITIALLY THAN THE ECMWF AND NAVGEM. ADJUSTMENTS TOWARD THE STRONGER GFS WERE MADE IN THE SHORT TERM. SEAS ARE BUILDING BEHIND THE FRONT. THE TROUGHING ALOFT SUPPORTING THIS COLD FRONT IS IN THE PROCESS OF OVERTAKING THE TROUGH CENTERED ALONG 57W. THIS TROUGH IS NOT EXPECTED TO AMPLIFY MUCH FURTHER...SLOWING THE COLD FRONT. THE FRONT SHOULD DISSIPATE OVER THE GULF OF MEXICO TODAY WHILE THE PORTION OVER THE SW N ATLC PROGRESSES EASTWARD AND WEAKENS...WITH NE SWELL OVER 8 FT OUT-RUNNING THE FRONT AND PUSHING ACROSS THE NEARLY ENTIRE AREA BY WED NIGHT. BY TUE...THE NWPS BECOMES FASTER SPREADING THE LEADING EDGE OF THE SWELL SOUTHEASTWARD. THIS IS IN BETTER AGREEMENT WITH THE ECMWF AND SEEMS REASONABLE GIVEN THE RAPIDLY INTENSIFYING LOW THAT IS EXPECTED N OF THE AREA. AN AMPLIFYING UPPER TROUGH IS EXPECTED TO PASS ONTO THE U.S. E COAST AND LOWER THICKNESSES OVER WESTERN WATERS TUE. THE ASSOCIATED COLD FRONT SHOULD STRETCH FROM 31N73W TO THE CUBAN COAST ALONG 80W BY TUE NIGHT. THE FRONT WILL WEAKEN AS THE ANCHOR LOW MOVES N...WITH THE DISSIPATING BOUNDARY LYING FROM 31N58W TO THE SOUTHERN BAHAMAS BY THU NIGHT. AGAIN...THE MODELS ARE IN RELATIVELY GOOD AGREEMENT ON THIS SCENARIO AND THE GFS/NWPS SEEM REASONABLE. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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://WWW.NHC.NOAA.GOV/MARINE/GRIDS.PHP FOR ADDITIONAL INFORMATION PLEASE VISIT: HTTP://WWW.HURRICANE WARNINGS.GOV/MARINE $$ .FORECASTER SCHAUER. NATIONAL HURRICANE CENTER.