000 AGXX40 KNHC 240634 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 234 AM EDT TUE MAR 24 2015 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: 00Z GFS BLENDED WITH PREVIOUS OFFICIAL FORECAST. A BLEND OF THE TAFB NWPS WITH THE PREVIOUS FORECAST USED FOR WAVE PARAMETERS. MEDIUM CONFIDENCE. WINDS AND SEAS ARE FORECAST TO REMAIN BELOW THE ADVISORY CONDITIONS OF 20-25 KT AND 8 FT...RESPECTIVELY...UNTIL AFTER A COLD FRONT MOVES INTO THE NW GULF LATE THU. THE 00Z GFS AND UKMET AND THE 12Z ECMWF AGREE THAT WINDS WILL BUILD BEHIND THE FRONT AFTER IT HAS MOVED INTO THE NW GULF AS SHORTWAVE ENERGY ALOFT THAT FIRST PASSES THROUGH THE SOUTHWESTERN U.S. MAKES ITS WAY INTO THE LEADING EDGE OF THE DEEP LAYERED TROUGH. THE 00Z GFS IS STRONGER WITH THE WINDS BEHIND THE FRONT INITIALLY THAN THE 12Z ECMWF...BUT BOTH MODEL AGREE ON SENDING THE SURGE OF STRONG WINDS IN BEHIND THE FRONT AROUND 06Z FRI. THE 00Z UKMET SHOWS BETTER AGREEMENT WITH THE ECMWF IN THESE REGARDS. THE GFS BRINGS WINDS TO 30 KT ALONG THE COAST OF VERACRUZ JUST N OF TAMPICO AT 06Z FRI WHILE THE ECMWF WAITS UNTIL 18Z TO SHOW 30 KT WINDS HERE. THE 03Z SREF SHOWS UP TO A 30 PERCENT CHANCE OF GALE FORCE WINDS HERE...BUT WITH THE GEFS SHOWING NO CHANCE AND THE GLOBAL MODELS CAPPING WINDS AT 30 KT HERE...WILL SIDE WITH THE GFS. THE GFS DOES ALLOW WINDS TO REACH GALE FORCE S OF 20N W OF 95.5W BRIEFLY AROUND 00Z SAT AND THEN QUICKLY DIMINISHES THE WINDS IN THE W GULF. THE 03Z SREF SHOWS AS HIGH AS A 25 PERCENT CHANCE OF GALES THROUGH THE END OF ITS FORECAST 12Z FRI...BUT AGAIN THE GEFS SHOWS NO CHANCE. SINCE THE GFS IS ONLY AT GALE FORCE FOR ONE PERIOD IN A SMALL AREA...WILL HOLD OFF ON FORECASTING GALES HERE. OTHERWISE...THE GFS SEEMS REASONABLE TO BLEND WITH THE OFFICIAL FORECAST. FOR WAVES...THE TAFB NWPS DID A BETTER JOB CAPTURING THE HIGHER SEAS IN THE AREA OF STRONG WINDS BEHIND THE FRONT THAN THE MWW3. IT WAS USED TO ADJUST THE WAVE FORECAST. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 00Z GFS BLENDED WITH PREVIOUS OFFICIAL FORECAST. TAFB NWPS USED FOR WAVE PARAMETERS IN THE CARIBBEAN WITH SOME MANUAL EDITS ALONG THE COAST OF COLOMBIA. A BLEND OF THE MWW3 AND EC WAVE WAS USED TO ADJUSTS THE WAVES IN THE TROPICAL N ATLC. HIGH CONFIDENCE. WEAK ATLC RIDGING N OF THE AREA COMBINED WITH LOW PRES OVER NW COLOMBIA WILL SUPPORT PULSES OF 20-25 KT NE WINDS WITHIN 90 NM OF THE COAST OF COLOMBIA TONIGHT...DIMINISHING TO 15-20 KT BY LATE MORNING. ON WED NIGHT...THE MODELS AGREE ON BUILDING HIGH PRES OVER THE SW N ATLC AND ALLOW A FRESH TO STRONG BREEZE TO EXPAND OVER A LARGER AREA OFF THE COAST OF COLOMBIA AND STRETCH OVER MUCH OF THE CENTRAL CARIBBEAN THU AND THU NIGHT BEFORE BEGINNING TO SHRINK AGAIN FRI AND SAT AS A PROGRESSIVE COLD FRONT IN THE GULF OF MEXICO SHOVES THE SUBTROPICAL HIGH E. WINDS WILL ALSO INCREASE IN THE GULF OF HONDURAS WED NIGHT AS THE SUBTROPICAL HIGH TO THE N STRENGTHENS. THESE WINDS SHOULD DIMINISH LATE FRI WHEN THE COLD FRONT IN THE GULF OF MEXICO DIMINISHES THE PRES GRADIENT OVER THE AREA. THE 00Z GFS WAS USED TO POPULATE THIS AREA AS IT HAS THE HIGHEST RESOLUTION AND GENERALLY DOES BEST IN THIS AREA AND IS REASONABLY CLOSE TO THE PREFERRED SOLUTION TO THE N. THE NWPS WAS PRIMARILY RELIED ON FOR SEAS IN THE CARIBBEAN WITH SOME MANUAL EDITS MADE ALONG THE COAST OF COLOMBIA TOWARD SLIGHTLY HIGHER SEAS CORRESPONDING TO THE STRONGER WINDS. THE NWPS IS 2-3 FT TOO LOW WITH SEAS IN THE TROPICAL N ATLC COMPARED TO OBSERVATIONS. THIS IS LIKELY DUE TO THE COLD START THAT WAS PERFORMED IN AN EARLIER RUN. SWELL IN THE MODEL NEEDS A FEW MORE CYCLES TO BUILD TO THE PROPER LEVELS. THE EC WAVE AND MWW3 WERE BLENDED WITH THE PREVIOUS FORECAST. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: THE 00Z GFS BLENDED WITH THE PREVIOUS OFFICIAL FORECAST. A BLEND OF MWW3 AND EC WAVE WITH THE PREVIOUS FORECAST USED FOR WAVE PARAMETERS. MEDIUM CONFIDENCE. THE 00Z GFS AND 12Z ECMWF ARE IN REASONABLE AGREEMENT WITH THE FRESH TO STRONG BREEZE BEHIND THE WAVY BOUNDARY OFF THE NE FLORIDA COAST WHICH IS CONFIRMED BY ASCAT. OBSERVATIONS SHOW SEAS ARE A BLEND OF THE HIGHER EC WAVE AND APPROXIMATELY 2 FT LOWER MWW3 BEHIND THE FRONT. AS IN THE TROPICAL N ATLC...THE NWPS IS TOO LOW WITH SEAS IN THE SW N ATLC COMPARED TO OBSERVATIONS. THIS IS LIKELY DUE TO THE COLD START THAT WAS PERFORMED IN AN EARLIER RUN. SWELL IN THE MODEL NEEDS A FEW MORE CYCLES TO BUILD TO THE PROPER LEVELS. BY LATE FRI...THE GFS APPEARS TO BE THE MIDDLE OF THE ROAD SOLUTION BETWEEN THE FASTER UKMET AND SLOWER ECMWF WITH THE TIMING OF THE COLD FRONT MOVING OFF THE NE FLORIDA COAST. THE GFS IS SLIGHTLY STRONGER WITH THE WINDS...BUT ITS STRONGER SOLUTION WAS FAVORED IN THE GULF OF MEXICO AND APPEARS TO BE A REASONABLE CHOICE FOR ADJUSTING THE WINDS. FORECAST SEAS WILL BE A BLEND OF THE PREVIOUS FORECAST WITH THE MWW3...WHICH USES THE PREFERRED GFS WIND SOLUTION...AND THE EC WAVE...WHICH IS SLIGHTLY HIGHER OVERALL AND USUALLY PERFORMS BETTER WITH SWELL. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.