000 AGXX40 KNHC 251943 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 243 PM EST Wed Jan 25 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. High confidence through Friday, then average confidence thereafter for the far western and southwest portions. The weak high pressure cell that was located over the far south central gulf has shifted to east of the gulf to over the Bahamas, while the next cold front has just moved off the Tx coast, and as of 18Z stretches from near GLS to inland the northeast Mexico and southeast Tx border. A pre-frontal trough moved offshore the Tx and La coasts this morning, and as of 18Z extends along a position from just southeast of La to 27N94W and to 23N97W. Southerly winds have increased to the moderate to fresh category during the course of the morning and afternoon east of the trough as the pressure gradient between it and the high over the Bahamas tightens. Winds near the trough are southerly in the gentle to moderate range. Seas are in the 6-8 ft range in the western gulf zones per altimeter and buoy data, and 4-6 ft elsewhere except for lower seas of 2-3 ft north of a line from near Lake Charles La to 25N88W to Key West. The cold front will move over the northwest waters of the gulf during the remainder of this afternoon, and reach from northeast Fl to near 24N91W to the south-central Bay of Campeche Thursday afternoon. Models have been consistently suggesting that the front will become stationary over the southern portion of the gulf on Friday, and gradually become diffuse through the weekend. Fresh to strong northwest winds and building seas of 6-8 ft will follow in the wake of the front, except offshore of Veracruz where model guidance is indicating minimal gale force northwest winds on Thursday with seas building higher to possible maximum of around 11 ft. High pressure will build across the area Friday through Sunday. The pressure gradient is expected to tighten in some sections of the western gulf Friday evening through Sunday, with possible strong to near gale force north-northeast winds in the far west- central and central portions beginning Saturday night. These winds will shift southward into the southwest gulf late Saturday night into Sunday and diminish Sunday night through Monday as the high pressure settles in across the region. Although the GFS mean ensemble 34 kt winds probabilities valid 12Z are rather low for gale winds, there is a chance that these probabilities will trend to higher ranges. Will update forecast as required to account for this. In any event, seas are expected to build to around 11 or 12 ft in the far western gulf Saturday night into Sunday before subsiding. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: Global model consensus. High confidence. The strong cold front of the previous days has continued to weakened during the past 24-48 hours, and as of 18Z is analyzed as a frontal trough from just southwest of Puerto Rico to 16N74W to near 14N78W. The 1336Z Ascat pass from this morning depicted a trough over the eastern Caribbean along a position from the Leeward Islands to just north of Bonaire. Isolated showers are possible along this trough. Weak high pressure is present across the area. The Ascat pass from 1516Z this morning showed mainly gentle to moderate northeast to east winds west of about 70W, except for moderate east to southeast winds west of 82W and east to southeast moderate winds south of 15N east of 70W. Light to gentle variable are noted just along and southeast of the frontal trough. Models are in very good agreement that the frontal trough will gradually dissipate through tonight. As stated in previous discussions, fresh to strong trades will be concentrated in the central portions of the Caribbean, with strong to near gale force northeast to east winds expected along the coast of Colombia each night through Sunday night diminishing some on Monday night. Seas induced by these winds are expected to reach around 11 ft. Little overall changes are forecast for the tropical north Atlantic waters through Friday then a large set of northeast swell will begin to propagate into much of the eastern sections of the these waters Saturday through Monday with seas in the 7-9 ft range. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: Global model consensus. High confidence. Near gale to gale force winds in very pronounced northwest flow are occurring across the northeast portions of the offshore waters forecast zones. The gale warning for northwest 30-35 kt winds currently in effect for north of 29N east of 67W will be allowed to expire by early this evening as the gradient there begins to weaken. Both altimeter data and buoy observations just upstream the north- central forecast waters indicate large seas up to 19 ft. Seas of up to 16 ft have migrated southeastward into the far north- central waters as also noted in an altimeter pass from this morning. Cold-air instability in the northwest flow continues to bring scattered showers to the northeast part of zone AMZ115. Weak high pressure centered over the central Bahamas will slide eastward through Thursday, and to east of 65W Thursday night in response to a cold front that will move across the southeast United States. The cold front will emerge off the Georgia and northeast Fl coasts on Thursday afternoon, and reach from near 31N70W to southeast Fl early on Friday. The front will then weaken as it reaches from near 29N65W to the southeast Bahamas and east/central Cuba by early on Saturday night. High pressure will build across the area in the wake of the cold front through Sunday with a reinforcing cold front clipping portions of the northern waters Sunday afternoon through Monday. Strong westerly winds and seas of around 8-11 ft will follow in behind this front. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... .GMZ023...SW GULF S OF 22N W OF 94W... Gale Warning south of 21N W of 95W. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... .AMZ115...ATLANTIC FROM 27N TO 31N BETWEEN 65W AND 70W... Gale Warning N of 29N east of 67W through this afternoon. *For detailed zone descriptions, please visit: http://www.nhc.noaa.gov/abouttafbprod.shtml#OWF Note: gridded marine forecasts are available in the National Digital Forecast Database (NDFD) at: http://www.nhc.noaa.gov/marine/grids.php For additional information, please visit: http://www.nhc.noaa.gov/marine $$ .Forecaster Aguirre. National Hurricane Center.