000 AGXX40 KNHC 050648 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 148 AM EST FRI DEC 5 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 THROUGH MON THEN ECMWF ADDED TO THE BLEND. 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 TUE 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 WILL MOVE INTO THE NW GULF SAT EVENING AND IS EXPECTED TO STRETCH FROM FORT MYERS FLORIDA TO CORPUS CHRISTI TEXAS SUN EVENING. THE FRONT WILL DISSIPATE OVER THE W GULF WHILE THE EASTERN PORTION IS EXPECTED TO SLOWLY INCH S ALONG THE FL PENINSULA MON. THERE ARE SOME DIFFERENCES IN THE MODELS WITH THE TIMING AND STRENGTH OF THE BOUNDARY OVER S FLORIDA MON AND TUE...WITH THE 12Z/04 ECMWF DEVELOPING A STRONGER SURFACE LOW ON THE N EDGE OF THE FRONT OFF THE MID ATLC COAST WHICH ALLOWS THE BOUNDARY TO BE MORE PROGRESSIVE THAN THE GFS. THE DEEPER ECMWF HAS MORE SUPPORT FROM THE OTHER GLOBAL MODELS MON NIGHT AND TUE. THE GEFS SUPPORTS EARLIER DEVELOPMENT OF A MORE NORTHERLY LOW PRES SYSTEM OFF THE MID ATLC THAN THE 00Z GFS...MORE IN LINE WITH THE OTHER GLOBAL MODELS. DESPITE THESE DIFFERENCES...THE WIND AND SEAS ARE WELL BELOW ADVISORY CRITERIA. ADDED IN A SIGNIFICANT AMOUNT OF ECMWF TO THE BLEND MON THROUGH TUE NIGHT. ...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. SHIP 9HA2583 HAS REPORTED 20-25 KT WINDS AND 9 FT SEAS IN THE WINDWARD PASSAGE FROM 03Z-05Z. THIS IS CONSISTENT WITH EARLIER ASCAT PASSES OVER THE AREA. THE GFS IS THE STRONGEST MODEL HERE AND IN BEST AGREEMENT WITH THE OBSERVATIONS...BUT STILL APPEARS SLIGHTLY WEAK. IT WAS USED TO ADJUST THE FORECAST...BUT WINDS WERE STILL BUMPED UP SLIGHTLY BOTH HERE AND IN THE LEE OF CUBA WHERE THE MODELS AGREE ON WINDS INCREASING THROUGH SAT. THE NWPS WAS SLIGHTLY HIGHER THAN THE MWW3 HERE AND WAS USED TO ADJUST THE WAVE FORECAST. OTHERWISE...WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA THROUGH THE FORECAST PERIOD. ...SW N ATLANTIC S OF 31N W OF 55W INCLUDING THE BAHAMAS... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS/OFFICIAL FORECAST UNTIL SAT THEN THE ECMWF ADDED TO THE BLEND. LATEST TAFB-NWPS AND MWW3 USED TO ADJUST WAVE PARAMETERS. MEDIUM CONFIDENCE. INITIALLY...THE NWPS WAS TOO LOW WITH THE NE SWELL NEAR BUOY 41046 IN ZONE AMZ121 AND 41049 NEAR 27N63W AT 00Z...BOTH OF WHICH SHOWED 8 FT SEAS. THE NWPS IS RUNNING ABOUT A FOOT LOWER THROUGH MUCH OF THE SW N ATLC INTO SUN. GIVEN THE MWW3 WAS A BETTER MATCH FOR THE OBSERVATIONS...IT WAS RELIED ON MORE HEAVILY WHEN ADJUSTING THE SHORT RANGE FORECAST. LOW PRES IS EXPECTED TO FORM ALONG THE INVERTED TROUGH IN THE VICINITY OF 62W SOMETIME FRI...WITH THE 00Z GFS ON THE STRONG SIDE OF THE GUIDANCE ENVELOPE. THE 00Z GFS APPEARS TO HAVE GRID SCALE FEEDBACK ISSUES JUST N OF THE DEVELOPING LOW CENTER BEGINNING AT 06Z SAT. THE GFS DEVELOPS GALE FORCE WINDS ON THE N SIDE OF THE LOW AT THIS TIME. THE GRID SCALE FEEDBACK LIKELY CAUSES THE GFS TO EXPAND THE TROUGHING NORTHWARD MORE QUICKLY THAN THE OTHER MODELS. THE GEFS MEAN IS MORE IN LINE WITH THE ECMWF AND EC ENS MEAN AND THEIR WEAKER PRESSURE GRADIENTS OVER N WATERS SAT ONWARD. DESPITE GALE FORCE WINDS SEEN IN THE OPERATIONAL GFS...THE 00Z GEFS SHOWS NO CHANCE OF GALE FORCE WINDS IN THE SW N ATLC OR ELSEWHERE IN THE HIGH SEAS FORECAST AREA BETWEEN 29-31N W OF 35W THROUGHOUT THE PERIOD. 12Z/04 ECMWF IS ALSO THE FAVORED SOLUTION WITH THE SURFACE LOW OFF THE MID ATLC COAST SUN THROUGH TUE WHICH ALLOWS THE BOUNDARY TO BE MORE PROGRESSIVE THAN THE GFS. THE DEEPER ECMWF HAS MORE SUPPORT FROM THE OTHER GLOBAL MODELS MON NIGHT AND TUE...BUT IS A BIT DEEPER WITH THE LOW ON SUN. GRADUALLY ADDED MORE 12Z/04 ECMWF TO THE FORECAST AFTER SAT AS A RESULT. WOULD HAVE BLENDED IN THE EC WAVE TO THE FORECAST...BUT IT WAS NOT AVAILABLE. MANUAL ADJUSTMENTS WERE MADE TO THE NWPS/MWW3/OFFICIAL BLEND TOWARD THE ECMWF AFTER SAT. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.