000 AGXX40 KNHC 131841 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 241 PM EDT SUN APR 13 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: GFS BLENDED WITH THE PREVIOUS FORECAST FOR WIND. MWW3 AND EC WAVE BLENDED WITH PREVIOUS FORECAST FOR WAVES. MEDIUM CONFIDENCE. THE MOST CHALLENGING PART OF THE FORECAST CONTINUES TO BE THE EXPECTED GALE EVENT IN THE WESTERN GULF LATE MON NIGHT THROUGH TUE NIGHT. THE SREF AND GEFS FORECASTS SHOW A 100 PERCENT CHANCE OF GALES IN THE W CENTRAL GULF TUE MORNING AND IN THE SW GULF TUE AFTERNOON. THE 12Z GFS CARRIES 40 KT WINDS IN THE W CENTRAL GULF ALONG THE COAST LATE MON NIGHT/EARLY TUE MORNING AND INCREASES WINDS TO 45 KT IN THE SW GULF TUE AFTERNOON. THE ECMWF IS NOT QUITE AS BULLISH...SHOWING SHOWING A MAX OF 35 KT AND 40 KT IN THESE SPOTS...RESPECTIVELY. PAST PERFORMANCE DICTATES THAT THE STRONGER SOLUTION GENERALLY PREVAILS IN SUCH A PATTERN. THE MODEL TIMING IS NOT TERRIBLY DIFFERENT...WITH THE ECMWF SLIGHTLY FASTER CARRYING THE FRONT EASTWARD IN THE NORTHERN GULF THAN THE GFS. HOPEFULLY...THE MODELS ARE SETTLING ON A SOLUTION SINCE THE TREND YESTERDAY WAS TOWARD A SLOWER MOVING FRONT. THE FORECAST WAS ADJUSTED TOWARD A FASTER SOLUTION THAN THE PREVIOUS OFFICIAL FORECAST AND THE 12Z GFS IS GENERALLY A COMPROMISE BETWEEN THE PREVIOUS FORECAST AND THE FASTER ECMWF. FOR WAVE...THE NWPS AND MWW3 ARE AGAIN TOO FAST TO SUBSIDE THE SWELL BEHIND THE FRONT AND APPEAR TOO LOW WITH THE MAXIMUM WAVE HEIGHTS. THE MWW3 ENSEMBLE HIGHEST WAVES ARE MORE IN LINE WITH THE EC WAVE FORECAST. THE EC WAVE WAS USED TO HEDGE THE BLEND OF THE PREVIOUS FORECAST AND MWW3 TOWARD HIGHER MAXIMUM SEAS AND MORE PERSISTENT SWELL. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: GFS BLENDED WITH PREVIOUS FORECAST FOR WIND. NWPS BLENDED WITH PREVIOUS FORECAST FOR WAVES. HIGH CONFIDENCE. THE SUBTROPICAL RIDGE HAS MOVED NORTHWARD OVER THE PAST 24 HOURS AND IS EXPECTED TO SHIFT E AS A COLD FRONT MOVES INTO THE GULF OF MEXICO AND EVENTUALLY PASSES N OF THE CARIBBEAN INTO THE SW N ATLC TUE NIGHT. THIS WILL KEEP TRADES BELOW A STRONG BREEZE IN THE CARIBBEAN...EXCEPT FOR THE USUAL SPOT WHERE THE PRESSURE GRADIENT IS TIGHTEST OFF THE COLOMBIAN COAST. THERE IS GOOD AGREEMENT IN THE MODELS THAT THE FRONT WILL NOT MAKE IT INTO THE CARIBBEAN. THIS WILL LEAVE THE WEAK TRADE WIND REGIME IN PLACE THROUGH MID WEEK...WITH WINDS INCREASING SLIGHTLY BY THU NIGHT WHEN HIGH PRES BEHIND THE FRONT BUILDS N OF THE AREA. THE GFS FORECAST IS AS GOOD AS ANY...AND IS GENERALLY BETTER WITH THE STRONGER WINDS ALONG THE COAST OF COLOMBIA DRIVEN BY THE PRES GRADIENT BETWEEN THE SUBTROPICAL RIDGE AND LOW PRES OVER NW SOUTH AMERICA. THE HIGH RESOLUTION NWPS SOLUTION LOOKS GOOD HERE. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GFS BLENDED WITH THE PREVIOUS FORECAST THROUGH TUE NIGHT WITH THE ECMWF ADDED FOR WED THROUGH THU NIGHT. MWW3 AND EC WAVE BLENDED WITH THE PREVIOUS FORECAST. MEDIUM CONFIDENCE. INITIALLY...SOME ADJUSTMENTS WERE MADE TO THE GRIDS BASED ON OBSERVATIONS SHOWING STRONGER WINDS AND HIGHER SEAS NEAR A SURFACE ROUGH STRETCHED NORTHEAST FROM THE CENTRAL BAHAMAS...A REMNANT OF THE STATIONARY FRONT THAT TRAVERSED THE AREA YESTERDAY. WINDS AND SEAS SHOULD DIMINISH BELOW ADVISORY CRITERIA HERE OVER THE NEXT 24 HOURS AS THE TROUGH IS PICKED UP BY THE SOUTHERLY STEERING FLOW AHEAD OF THE COLD FRONT BEGINNING TO PUSH INTO THE GULF OF MEXICO. THE LARGER FORECAST PROBLEM IS WHAT TO DO WITH THIS FRONT AS IT MOVES INTO THE SW N ATLC. THE MODELS CONTINUE TO SHOW SOME DIFFERENCES WITH THE TIMING AND STRENGTH OF THE COLD FRONT. AS STATED ABOVE...THE GENERAL TREND WITH THE TIMING OF THIS FRONT IS TOWARD A FASTER SOLUTION AND THE 12Z GFS IS GENERALLY A COMPROMISE BETWEEN THE PREVIOUS FORECAST AND THE FASTER ECMWF. ONCE THE FRONT IS IN THE SW N ATLC...THE EC CONTINUES TO KEEP IT CLOSER TO THE COAST. THE EC ENSEMBLE MEAN AGAIN HEDGES TOWARD THE FASTER GFS. THE FORECAST WAS ADJUSTED SLIGHTLY MORE TOWARD THE GFS THAN THE ECMWF AS A RESULT...WITH FRESH TO STRONG WINDS BEHIND THE FRONT WED THROUGH THU. WAVES WERE ADJUSTED FOR THE PREFERRED WIND FIELD. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... .GMZ011...NW GULF INCLUDING STETSON BANK... GALE WARNING MON NIGHT. .GMZ017...W CENTRAL GULF FROM 22N TO 26N W OF 94W... GALE WARNING MON NIGHT INTO TUE. .GMZ023...SW GULF S OF 22N W OF 94W... GALE WARNING TUE. GALE CONDITIONS POSSIBLE TUE INTO TUE NIGHT. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.