000 AGXX40 KNHC 210638 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 238 AM EDT MON JUL 21 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 OFFICIAL. MWW3 AND TAFB NWPS BLENDED WITH OFFICIAL. HIGH CONFIDENCE. A TRANQUIL PERIOD CONTINUES IN THE GULF OF MEXICO WITH WINDS EXPECTED TO REMAIN BELOW THE 20-25 KT THRESHOLD THROUGH FRI NIGHT. THE MODELS HAVE BACKED OFF ON THE CHANCE OF WINDS REACHING THE 20-25 KT THRESHOLD NEAR THE YUCATAN DURING THE OVERNIGHT AND IN THE BAY OF CAMPECHE IN THE EARLY MORNING HOURS AS THE THERMALLY DRIVEN TROUGHING MIGRATING W FROM THE YUCATAN EACH NIGHT BUILDS THE PRESSURE GRADIENT. MODEL DIFFERENCES HERE ARE RELATIVELY MINOR. THE GFS SOLUTION SEEMS REASONABLE FOR ADJUSTING THE FORECAST. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: GFS BLENDED WITH OFFICIAL. MWW3 AND TAFB NWPS BLENDED WITH OFFICIAL IN THE CARIBBEAN...MWW3 BLENDED WITH OFFICIAL IN ATLC. HIGH CONFIDENCE IN CARIBBEAN MEDIUM CONFIDENCE IN ATLC. THE MODELS CONTINUE TO HAVE PROBLEMS RESOLVING THE FORECAST FOR LOW PRES ALONG THE MONSOON TROUGH IN THE TROPICAL CENTRAL ATLC. GFS RUNS BEFORE 20/00Z HAS DEVELOPED A TROPICAL STORM AND MOVED IT NW TOWARD THE NE CORNER OF THE TROPICAL ATLC OFFSHORE WATERS WED. THIS WAS AN OUTLIER SOLUTION. THE GFS HAS BACKED OFF ON THIS IDEA...BUT THE LATEST 00Z RUN DEVELOPS ELONGATED LOW PRES AT THE INTERSECTION OF A TROPICAL WAVE AND THE MONSOON TROUGH...ALBEIT FROM DIFFERENT ORIGINS THAN PREVIOUS RUNS...AND BUILDS WINDS TO 25 KT AND SEAS TO 8 FT IN THE TROPICAL N ATLC OFFSHORE WATERS WED. THE 0030 UTC ASCAT PASS SHOWS STRONG TO NEAR GALE FORCE WINDS NEAR THE LOW PRES SYSTEM. THE 00Z GFS IS WEAK COMPARED TO THE ASCAT AS IS THE 00Z ECMWF...BUT THE ECMWF SHOWS A CLOSED LOW PRES SYSTEM HERE INITIALLY. THE ECMWF CAPS WINDS AT 20 KT AND NEVER ALLOWS SEAS TO BUILD OVER 7 FT...WITH THE STRONGEST WINDS/HIGHEST SEAS COMING IN THE FIRST 24 HOURS OF THE FORECAST. THE UKMET IS MORE IN LINE WITH THE GFS BY PROPAGATING A STRONGER SYSTEM INTO THE OFFSHORE WATERS. CONFIDENCE HAS INCREASED IN THE GFS SOLUTION GIVEN THE DEVELOPMENT OF THE LOW AND THE CHANGE IN THE UKMET FORECAST TO SUPPORT A STRONGER SYSTEM. ADJUSTMENTS WERE MADE PRIMARILY IN THE FIRST 24 HOURS TO ACCOUNT FOR THE STRONGER WINDS SEEN IN THE ASCAT PASS COMPARED TO THE GFS...BUT THE GFS WAS OTHERWISE USED TO ADJUST THE FORECAST. IN THE CARIBBEAN...LITTLE CHANGE IS EXPECTED IN THE DAY-TO-DAY FORECAST THROUGH FRI NIGHT. STRONG TO NEAR GALE FORCE WINDS WILL CONTINUE ALONG THE NE COAST OF COLOMBIA...WITH THE GFS SHOWING A BARB OF GALE FORCE WINDS LATE TUE NIGHT/EARLY WED. THE GFS FROM 20/00Z SHOWED THE SAME CONDITIONS. NOT INCLINED TO PULL THE TRIGGER ON A GALE WARNING JUST YET SINCE IT IS SO BRIEF AND SMALL IN SCALE IN THE GFS FORECAST. WINDS WILL CONTINUE TO PULSE TO A FRESH BREEZE IN THE EVENING/OVERNIGHT HOURS IN THE GULF OF HONDURAS THROUGH FRI...INCREASING TO A FRESH TO STRONG BREEZE IN THE EVENINGS AFTER A TROPICAL WAVE PASSAGE ON TUE NIGHT AND THU NIGHT. THE GFS IS THE STRONGEST SOLUTION. THE STRONGER GFS GENERALLY DOES BEST WITH THE LOCAL DIURNAL DRIVEN WINDS IN THE CARIBBEAN...BOTH HERE AND OVER S CENTRAL WATERS. GFS AND NWPS/MWW3 WERE USED TO ADJUST THE FORECAST IN THE CARIBBEAN. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GFS BLENDED WITH OFFICIAL. MWW3 AND TAFB NWPS BLENDED WITH OFFICIAL. HIGH CONFIDENCE. THE ONLY CHANCE OF WINDS EXCEEDING THE 20-25 KT THRESHOLD OVER THE SW N ATLC WILL COME IN THE EVENING HOURS ALONG THE N COAST OF HISPANIOLA. THE GFS IS THE STRONGEST SOLUTION HERE AND INITIALIZED BEST LAST NIGHT WHEN ASCAT HIT THE AREA AT THE TIME OF PEAK WINDS. WILL CONTINUE TO LEAN ON THE GFS FORECAST TO ADJUST THE GRIDS. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.