000 AGXX40 KNHC 211726 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 1226 PM EST Tue Feb 21 2017 Marine Weather Discussion for the Gulf of Mexico, Caribbean Sea, and Tropical North Atlantic from 07N to 19N between 55W and 64W and the Southwest North Atlantic including the Bahamas ...GULF OF MEXICO... MODEL PREFERENCE: Global model consensus. Medium confidence. A cold front extends s from the Ms Delta to the Bay of Campeche with a secondary trough, or cold front, analyzed over the far nw gulf waters. A strong sw to w wind shift will accompany the trough today, while strong to near gale force nw to n winds are expected s of 24N within about 120 nm w of the cold front through this afternoon. The trough will merge into the front along a position from the Fl Panhandle to the Yucatan Peninsula tonight, with a frontal wave low developing along the merged front near 28N85W. The low will move se across the Fl Peninsula along 27N on Wed night into early Thu dragging the front through the Fl Straits on Fri night. Strong se to s winds will develop e of the low and it's trailing front on Wed, and strong nw winds will develop to the s of 23N just to the w of the front late Wed, and shift se across the Yucatan Channel on Wed night. Another cold front will move off the Tx coast on Fri morning and race e across the entire gulf waters through Sat night. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: Global model consensus. Medium confidence. A cold front extends sw across the ne Caribbean and is preceded by a broad surface trough that extends s to near 13N65W. Lightning data has been detecting tstms just ne of the Virgin Islands over the past 12 hours, with BKN/OVC low-mid level clouds and SCT RW further s along the front and the trough over the Caribbean, and this will be carried in the weather grids through tonight. Fresh to locally strong ne winds expected in and just downstream of the Windward Passage today. A cold front will move into the Yucatan Channel tonight initially accompanied by a fresh sw-w-nw wind shift. The gradient will tighten with the post-frontal flow increasing to a fresh to locally strong breeze early Wed, and continuing into late Wed night before diminishing. The front will reach along a position from Central Cuba to extreme ne Nicaragua on Thu, with strong southerly flow developing e of the front across the s approach to the Windward Passage. These conditions will continue through late Thu night before diminishing. The front will stall and gradually wash out from the Windward Passage to ne Nicaragua through early Sun. Strong nocturnal flow will resume along the nw coast of Colombia on Sat night. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: Global model consensus. Medium confidence. A surface low is centered near 24N63W and is trailing a cold front across the Virgin Islands. Broken to locally overcast low to mid level clouds are observed e of the the low and front, with lightning data detecting tstms well to the e along a line from 22N57W to 17N61W. This low is expected to lose identity through early tomorrow as a second cold front currently extending from 31N58W to 26N70W swings rapidly se and merges into a single frontal boundary along a position from 31N55W to 20N60W late tonight. Strong northerly winds are currently observed to the n of the secondary front. The merged front will stall from near 21N55W to across the Leewards on Wed night, and gradually dissipate on Thu. Expect strong to near gale force nw flow across the discussion waters to the n of 27N e of 63W early Wed, with these conditions shifting n of 31N on Wed night. A surface low is expected to develop tonight over the e Gulf of Mexico along a cold front. As the low moves e across Florida along about 27N on Wed the pressure gradient will tighten with strong se winds developing across most waters w of 78W. These conditions will spread e across the waters n of 23N w of 73W on Wed night. The gradient will further tighten on Thu as the low and trailing cold front move off the s Fl coast with minimal gale force winds embedded in a larger area of strong to near gale force winds e of the low and front to along 69W, with seas building to at least 11 ft just e of the Bahamas. The low will lift nne crossing near 31N78W on Fri night, with a band of strong to near gale force se winds spreading ne across Bermuda on Sat, with these conditions shifting n of 31N on Sun. Strong nw winds will develop w of the low across the waters n of Bahamas on Sat night. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... .AMZ111...ATLANTIC FROM 27N TO 31N W OF 77W... Gale Warning Thu. GALE CONDITIONS POSSIBLE Thu. .AMZ113...ATLANTIC FROM 27N TO 31N BETWEEN 70W AND 77W... GALE CONDITIONS POSSIBLE Thu night into Fri night. $$ *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.nhc.noaa.gov/marine $$ .Forecaster Nelson. National Hurricane Center.