000 AXNT20 KNHC 190003 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 703 PM EST Sat Nov 18 2017 Tropical Weather Discussion for North America, Central America Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 1800 UTC surface analysis and satellite imagery through 2345 UTC. ...SPECIAL FEATURE... A cold front will reach the NW Gulf of Mexico tonight and will move across the remainder of the Gulf through Monday. Strong high pressure building behind the front will generate gale force winds over the SW Gulf waters S of 25N to the west of the front beginning 1200 UTC Sunday and persisting through Sunday night. See the latest high seas forecast under AWIPS/WMO headers HSFAT2/FZNT02 for more details. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 08N13W to 05N21W. The Intertropical Convergence Zone axis extends from 05N21W to 06N40W to 06N57W. Scattered moderate convection is from 03N to 06N between 16W and 35W. ...DISCUSSION... GULF OF MEXICO... A broad ridge extends from the SW N Atlc across the Florida Peninsula and into the Gulf approximately to 93W. The ridge supports light to gentle SSW winds E of 93W and SSW moderate flow westward ahead of the next cold front that is coming off the Texas and Louisiana coasts tonight. CIRA LPW and GOES-16 water vapor imagery continue to show deep layered dry air basin-wide, which is supporting clear skies. The cold front will sweep across the Gulf through Monday. Gale force winds are forecast over a portion of the SW Gulf Sunday behind the front. Please refer to the special features section for more details. CARIBBEAN SEA... The base of a middle to upper level trough extending from the W Atlc reaches the NW Caribbean where it support a weak surface trough from the NE Yucatan Peninsula near 20N87W to the Gulf of Honduras near 15N83W. Shallow moisture in this region of the basin support isolated showers 90 nm either side of the trough axis. Latest scatterometer data showed a low center just N of the Mona Passage from which a surface trough extends SW to 15N71W. In the south-central basin, a 1008 mb low is off the coast of Colombia near 11N74W from which a surface trough extends northward to southern Hispaniola. This elongated area of low pressure prevails underneath an upper level ridge that supports diffluent flow and thus scattered showers and tstms across the NE Caribbean, including Puerto Rico and the Virgin Islands. Isolated showers are between 68W and 74W, including Hispaniola and the Mona Passage. High pressure over the western Atlantic is supporting moderate to fresh NE winds over the northwestern Caribbean. Mainly light to gentle winds cover the remainder of the Caribbean. The area of low pressure in the southern basin will stall through early morning morning while it weakens to a surface trough that will move westward through the middle of the week. ...HISPANIOLA... Isolated showers are across the island tonight being supported by an elongated area of low pressure focused on a 1008 mb low just N of the Mona Passage with associated surface trough extending SW to southern Hispaniola adjacent waters. Showers will continue through Monday as the area of low pressure drifts NE over the Atlc waters. ATLANTIC OCEAN... A broad ridge over portions of the NW Atlc waters extends SW across the SW N Atlc supporting fair weather and NE to E moderate to fresh winds. Over the central Atlc forecast waters a stationary front extends from 30N40W to a 1008 mb low near 27N50W. A surface trough then extends from the low SW to another 1008 mb low pressure center located just N of the Mona Passage. These features are supporting a large area of showers N of 22N between 37W and 56W and S of 23N between 55W and 69W. High pressure of 1019 mb centered near 26N25W dominates the eastern Atlantic. Over the next 24 hours the lows will move NE with convection spreading east. SW winds will increase to 20 to 25 kt N of 30N east of 70W Sunday as a cold front approaches the region. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos