000 AGXX40 KNHC 280800 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 400 AM EDT Tue Mar 28 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... Weak high ridging extending westward from the western Atlantic to the north-central gulf, with a weak high center located near 27N84W. It is providing gentle to moderate east to southeast winds throughout, except for light to gentle anticyclonic flow around its immediate vicinity. The fresh to strong east winds along the northern Yucatan Peninsula have diminished to moderate winds. Deepening low pressure is over the southern Plains. The ridge currently in place over the north-central waters will begin to shift eastward tonight and Wed as the low pressure advances eastward. With high pressure then becoming situated across the Bahamas, this will result in a tightening of the pressure gradient across the western Gulf beginning tonight and through Wednesday with fresh to strong southeast winds and seas building to around 9 ft, or possibly briefly to 10 ft. The highest of these seas will be in the northwest portion of the area. The low will send a cold front into the northwest gulf early on Thursday, and quickly move across the gulf while weakening as it reaches the eastern waters on Friday night. Strong southerly winds will precede the front over the far northern waters on Thursday through Friday. Scattered to numerous showers and thunderstorms are expected to spread east just ahead of this front. High pressure behind the front will shift eastward allowing for fresh to locally strong southeast flow to set up over the far western gulf on Saturday. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... A weak pressure pattern remains in control over the Caribbean due to a break down of the gradient attributed to low pressure east of the central Bahamas. Both Ascat and buoy data reveal gentle to moderate winds prevailing over the Caribbean. High pressure will become established across the Bahamas tonight as the low moves northeast then east over the central Atlantic. This pattern will help to increase the winds slightly across the Caribbean basin. The high will expand across the SW N Atlantic by Wednesday night which will cause fresh to strong winds to develop across the Gulf of Honduras through Friday. The high will then slide eastward by Friday night in response to a a cold front expected to approach the southeast U.S. This will allow for winds across the central Caribbean to increase to 15 to 20 kt during the Friday night through Saturday time period. Mainly 5 to 7 ft seas will prevail over the tropical N Atlantic forecast zones through the week along with moderate trade winds. Late this week, winds are expected to diminish as the low pressure passing north of the area brings a frontal trough near the region north of 15N. ...SW N ATLANTIC INCLUDING THE BAHAMAS... Broad and low pressure of 1005 mb near 27N67W has taken a more definitive northeast track during the past several hours. A warm front extends from the low to 29N64W to 28N58W. A trough trails from the low to the southeast Bahamas. Relatively weak high pressure of 1018 mb is present west of the low pressure, while strong high pressure is to its north and northeast. The 0124Z Ascat pass noted a swath of gale force winds northeast of the low within about 30 nm of a line from 30N64W to 29N67W to 27N69W. The Ascat pass also reveals that the gale force winds are embedded within a swath of 20-30 kt winds between 60 nm and 240 nm of the low in its northeast quadrant. Seas within the gale force wind area are in the 12-18 ft, while seas elsewhere east of the Bahamas are in the 8-11 ft range primarily due to a northeast swell. Higher seas of 10-15 ft are associated with the 20-30 kt winds. The low is on track, as stated in previous discussions, to exit the northeast zone AMZ115 this afternoon. North to northeast gale force winds will mainly confined to the northwest quadrant of the low over zone AMZ115, at a distance of 60 nm to 120 nm. The gale force winds will then shift east of the that zone this afternoon, but will remain over our high seas area. Strong to near gale force north to northeast winds will remain over the eastern part of zone AMZ115 tonight, before becoming northwest to north winds of 15-20 kt early on Wednesday. Seas of 8-13 ft in mixed will linger in the eastern part of the same zone tonight, then slowly subside to 8-10 ft on Wednesday, to 6-8 ft by late Wednesday afternoon, and to 5-6 ft on Thursday. Models in good agreement in depicting weak high pressure over the Bahamas to expand in coverage through Wednesday night. The high will then slide eastward beginning Thursday afternoon as a cold front approaches the northwest waters. Current forecast has the cold front reaching the northwest waters Friday night, with fresh to strong southerly winds developing on Friday over these waters well ahead of the front. Seas are expected to build to around 9 ft with these winds. The front is forecast to reach from near 31N75W to South Florida by Saturday evening. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... .AMZ115...ATLANTIC FROM 27N TO 31N BETWEEN 65W AND 70W... Gale Warning today. $$ *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.