000 AGXX40 KNHC 110709 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 309 AM EDT FRI SEP 11 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: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL. NWPS BLENDED WITH PREVIOUS OFFICIAL FOR WAVES. HIGH CONFIDENCE. TIMING AND STRENGTH OF THE COLD FRONTS EXPECTED TO MOVE INTO THE NORTHERN GULF OVER THE WEEKEND IS ONE OF THE FORECAST CHALLENGES THIS PERIOD. THE 12Z ECMWF IS SLIGHTLY FASTER TO LOWER HEIGHTS OVER THE NORTHERN GULF THAN THE 00Z GFS. THE GFS IS STRONGER AND SHOWS STRONGER NE WINDS BEHIND THE STRONGER FRONT OVERNIGHT SAT NIGHT INTO SUN MORNING. OVERALL...THE DIFFERENCES ARE REASONABLY MINOR AT THIS TIME. BY MON...BOTH MODELS SHOW THE BOUNDARY OVER THE WESTERN GULF BEGINNING TO INTERACT WITH THE NORTHERN END OF A TROPICAL WAVE...WITH SOME TROPICAL CYCLONE DEVELOPMENT SUGGESTED BY THE MODELS. THE 12Z ECMWF WAS ON THE STRONGER SIDE OF THE GUIDANCE HERE...WITH THE UKMET SHOWING NO CLOSED LOW-LEVEL CIRCULATION. THE 00Z GFS IS WEAKER AND MORE OPEN WITH THE LOW- LEVEL CIRCULATION THAN THE STRONGER 12Z ECMWF. THE NEW 00Z ECMWF IS LESS AGGRESSIVE THAN ITS PREVIOUS RUN. THE COMPROMISE GFS SEEMS BEST HERE FOR NOW. A THERMAL TROUGH WILL DEVELOP EACH AFTERNOON OVER THE YUCATAN PENINSULA. THE TROUGH WILL MOVE W-NW INTO THE SW GULF WATERS DURING THE EVENING THROUGH LATE NIGHT HOURS...THEN DISSIPATE BY LATE MORNING. THE GFS ALSO SEEMS REASONABLE HERE. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 00Z GFS BLENDED WITH PREVIOUS OFFICIAL. NWPS BLENDED WITH PREVIOUS OFFICIAL FOR WAVES. MEDIUM CONFIDENCE. THE 0144Z ASCAT-B PASS SHOWED A SOLID AREA OF 25 KT WINDS WITHIN ABOUT 90 NM OF THE TROPICAL WAVE ALONG 60W FROM 16.5N-19N. THE GFS IS ON THE LIGHTER SIDE OF THE MODEL GUIDANCE WITH THE STRENGTH OF THIS WAVE...THE REMNANTS OF GRACE...INITIALLY. HOWEVER...THE GFS CARRIES STRONGER WINDS ALONG THE N COAST OF HISPANIOLA AS THE WAVE PASSES THROUGH THAN THE ECMWF. THE GFS GENERALLY PERFORMS BETTER HERE UNDER EASTERLY FLOW. THE GFS SEEMS TO CATCH UP QUICKLY IN THE FORECAST PERIOD...LIKELY ON DAY 1. THE GFS SEEMS REASONABLE WITH THIS WAVE...EXCEPT BEEFED UP THE WINDS AND ASSOCIATED SEAS TODAY AND TONIGHT. THE MODELS ARE IN RELATIVELY GOOD AGREEMENT ON THE RIDGING N OF THE AREA DRIVING THE TRADE WINDS THROUGH MON. AFTER THIS TIME...THE FORECAST BECOMES MORE UNSURE. THE GFS IS A BIT OF AN OUTLIER WITH STRONG LOW PRES IT PUSHES E ALONG 50N...WELL N OF THE AREA...MON-WED. THIS MAY BE CAUSING IT TO BE TOO FAR N WITH HIGH PRES ALONG THE U.S. MID ATLC COAST THAN EXTENDS INTO THE SW N ATLC. HOWEVER...THE ECMWF IS AMONG THE STRONGEST SOLUTIONS WITH THIS RIDGING. THE GFS SEEMS TO BE IN SLIGHTLY BETTER AGREEMENT WITH THE GEFS AND ECMWF ENS MEANS THAN THE ECMWF OVER THE SW N ATLC AND CARIBBEAN WITH THE PRES GRAD. WHEN ALL THINGS ARE EQUAL...THE GFS GENERALLY PERFORMS BETTER WITH TOPOGRAPHICALLY ENHANCED TRADE WINDS ALONG THE COAST OF COLOMBIA. THERE IS ALSO DISAGREEMENT ON THE DEVELOPMENT OF A TROPICAL WAVE E OF THE AREA BY EARLY NEXT WEEK. THE GFS IS FASTER CARRYING THE SYSTEM W LIKE THE UKMET WHILE THE ECMWF IS THE SLOWEST OF THE MODELS BY TUE NIGHT. OVERALL...DO NOT SEE A GOOD REASON TO STRAY FROM THE GFS SOLUTION. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL. NWPS BLENDED WITH PREVIOUS OFFICIAL FOR WAVES. HIGH CONFIDENCE. RIDGING ALONG 27N...S OF HENRI...CONTINUES TO DOMINATE THE AREA. A COLD FRONT WILL MOVE OFF THE GEORGIA COAST EARLY SUN. THE MODELS ARE IN REASONABLE AGREEMENT WITH THIS TIMING AND STRETCH THE FRONT FROM 31N76W TO CAPE CANAVERAL SUN EVE. AS STATED IN THE SECTION ABOVE...THE GFS IS A BIT OF AN OUTLIER WITH STRONG LOW PRES IT PUSHES E ALONG 50N...WELL N OF THE AREA...MON-WED. THIS MAY BE CAUSING IT TO BE TOO FAR N WITH HIGH PRES ALONG THE U.S. MID ATLC COAST THAN EXTENDS INTO THE SW N ATLC. HOWEVER...THE ECMWF IS AMONG THE STRONGEST SOLUTIONS WITH THIS RIDGING. THE GFS SEEMS TO BE IN SLIGHTLY BETTER AGREEMENT WITH THE GEFS AND ECMWF ENS MEANS THAN THE ECMWF OVER THE SW N ATLC WITH THE PRES GRAD. WILL CONTINUE TO RELY ON THE GFS TO ADJUST 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.