000 AGXX40 KNHC 210613 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 213 AM EDT SAT MAR 21 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: 12Z ECMWF BLENDED WITH PREVIOUS OFFICIAL FORECAST. A BLEND OF THE TAFB NWPS AND 12Z EC WAVE WITH THE PREVIOUS FORECAST USED FOR WAVE PARAMETERS. MEDIUM-LOW CONFIDENCE. THE 00Z GFS AND 12Z ECMWF CONTINUE TO DIVERGE WITH THE STRENGTH OF THE LOW PRES SYSTEM MOVING FROM TEXAS EASTWARD THROUGH THE SOUTHERN PORTION OF THE GULF COASTAL STATES INTO NORTHERN FLORIDA SAT THROUGH MON. THE GFS IS FASTER AND WEAKER THAN THE 12Z ECMWF WITH THE LOW AND COLD FRONT. THE 12Z ECMWF MORE CLOSELY RESEMBLES THE OTHER 00Z MODELS. THE GEFS AND EC ENS MEANS SUPPORT THE OPERATIONAL RUNS. CONFIDENCE IS LOWER THAN AVERAGE. A BLEND OF THE PREVIOUS FORECAST AND THE ECMWF WAS USED FOR THE FORECAST. FOR WAVES...THE EC WAVE SOLUTION WAS ADDED TO THE MIX WITH THE TAFB NWPS IN ORDER TO ACCOUNT FOR THE BLEND USED FOR WINDS. 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 WED NIGHT. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: LATEST GFS AND 12Z ECMWF BLENDED WITH PREVIOUS OFFICIAL FORECAST. TAFB NWPS USED FOR WAVE PARAMETERS IN THE CARIBBEAN WITH THE 12Z EC WAVE BLENDED WITH THE PREVIOUS OFFICIAL FORECAST IN THE TROPICAL ATLC. MEDIUM 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 EACH NIGHT THROUGH TUE NIGHT...DIMINISHING TO 15-20 KT BY LATE MORNING. ON WED NIGHT...THE MODEL 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. THE 00Z GFS WAS USED TO POPULATE THIS AREA AS IT HAS THE HIGHEST RESOLUTION AND GENERALLY DOES BEST IN THIS AREA. THERE ARE SOME RESERVATIONS AS THE GFS IS NOT THE PREFERRED SOLUTION WITH THE NORTHERN STREAM PATTERN...BUT DIFFERENCES IN THE PRESSURE GRADIENT BETWEEN THE MODELS SHOULD BE SMALL ENOUGH TO OUTWEIGHED BY LOCAL IMPACT OF THE FUNNELING OF WINDS NEAR THE HIGH TERRAIN HERE. ELSEWHERE...THE 0326 UTC ASCAT PASS SHOWS A FRESH TO STRONG BREEZE IN THE GULF OF HONDURAS BETWEEN A WEAKENING RIDGE OVER THE SOUTHERN BAHAMAS AND LOWER PRES CENTERED SW OF THE GULF OF TEHUANTEPEC. THE RIDGE WILL ERODE TODAY AND THE PRES GRADIENT WILL RELAX. EXPECT THESE CONDITIONS TO RETURN WED NIGHT AS RIDGING BUILDS AGAIN IN THE SW N ATLC. AGAIN THE HIGHER RESOLUTION GFS WAS RELIED ON FOR THE FORECAST HERE. OTHERWISE...AS EXPLAINED IN THE GULF OF MEXICO SECTION...THE 12Z ECMWF WAS FAVORED FOR ADJUSTING THE FORECAST. THE NWPS WAS PRIMARILY RELIED ON FOR SEAS IN THE CARIBBEAN...BUT IT APPEARS LOW WITH SEAS IN THE TROPICAL N ATLC COMPARED TO OBSERVATIONS. THE EC WAVE WAS BLENDED WITH THE PREVIOUS FORECAST TO ADJUST FOR THE BOTH THE PREFERENCE TOWARD AN ECMWF-LIKE WIND SOLUTION IN THE NORTHERN STREAM AND THE LOW VALUES SEEN IN THE NWPS COMPARED TO BUOY OBSERVATIONS AND ALTIMETER PASSES INITIALLY. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: 00Z GFS FAVORED OVER NE WATERS TODAY THROUGH TONIGHT. OTHERWISE...THE 12Z ECMWF WAS BLENDED WITH THE PREVIOUS OFFICIAL FORECAST. A BLEND OF THE TAFB NWPS AND EC WAVE WITH THE PREVIOUS FORECAST USED FOR WAVE PARAMETERS. MEDIUM-LOW CONFIDENCE. THE GFS COMPARES BEST WITH THE 0236 UTC ASCAT PASS WHICH SHOWED 20-25 KT S WINDS AHEAD OF THE COLD FRONT STRETCHED OVER NW WATERS. THE STRONGER GFS IS PREFERRED WITH THE WINDS HERE THROUGH TONIGHT. OTHERWISE...THE 12Z ECMWF IS PREFERRED AMONG THE LATEST GLOBAL MODELS WITH THE LOW PRES SYSTEM MOVING OUT OF THE GULF OF MEXICO MON. AS THE LOW MOVES INTO THE ATLC...CONFIDENCE IN THE ECMWF WANES A BIT. IT BECOMES A STRONGER AND FASTER SOLUTION THAN THE MODEL CONSENSUS AND IS STRONGER AND FASTER THAN ITS ENS MEAN. BLENDING THE 12Z ECMWF WITH THE PREVIOUS FORECAST FLATTENS OUT THE SYSTEM OVER THE CENTRAL ATLC...ESPECIALLY AS IT DIVERGES SIGNIFICANTLY FROM THE OTHER FORECASTS BY TUE. THE GEFS SHOWS MORE WIGGLE ROOM TOWARD A DEEPER AND MORE NORTHERLY LOW TRACK LIKE THE ECMWF BY THIS TIME WHILE THE 00Z GFS IS LESS AMPLIFIED. THE 12Z EC WAVE AND LATEST TAFB NWPS WERE USED TO ADJUST THE SEAS. THE EC WAVE IS PERFORMING BETTER COMPARED TO OBSERVATIONS WITH THE NORTHERLY SWELL MOVING INTO THE REGION...AS IT GENERALLY DOES...VERSUS THE NWPS. THE NWPS WAS WEIGHED HEAVILY IN THE BAHAMAS WHERE ITS HIGH RESOLUTION BATHYMETRY IS ESPECIALLY IMPORTANT TO THE FORECAST. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.