000 AXNT20 KNHC 182352 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 651 PM EST Thu Jan 18 2018 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 FEATURES... ...Atlantic Gale Warning... A cold front extends from a low pressure system deepening over NW Atlc waters. The front enters the SW N Atlc near 31N67W SW across eastern Cuba to Costa Rica. A strong pressure gradient between this low and a broad high pressure anchored over NE Louisiana supports gale-force winds north of 30N within 180 nm west of the front. These conditions will dissipate by 19/00Z. However, near gale-force winds will prevail through early Friday morning as the front weaken east of the Bahamas. Please read the latest NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC, and the latest NHC Offshore Waters Forecast, MIAOFFNT3/FZNT23 KNHC, for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic Ocean near 04N08W and continues to 0N21W. The ITCZ begins near 0N21W and continues along 0N40W to 0N50W. Scattered moderate convection is observed from 01S to 05N between 10W and 24W. Isolated showers are from 0N to 06N between 30W and 50W. ...DISCUSSION... ...GULF OF MEXICO... A surface ridge is established across the Gulf in the wake of a cold front that currently extends across the SW N Atlc, western Cuba to the Gulf of Honduras. A weakness in the ridge is analyzed as a surface trough in the far western Gulf from 27N96W to the western Bay of Campeche near 18N93W. Scatterometer data depicts moderate to fresh northerly winds across the basin with locally strong winds in the Straits of Florida. Winds will weaken during the next 24 hours as the pressure gradient relaxes across the basin. Fresh to locally strong southerly flow will set-up again across the western Gulf and persist early this weekend ahead on the next cold front forecast to reach the Texas coast Sunday night. ...CARIBBEAN SEA... The tail of a cold front extends across eastern Cuba SW to Costa Rica. This feature are underneath a mid-level divergent flow that along shallow moisture supports scattered showers S of 20N and W of 76W. Latest scatterometer data show fresh to near gale-force winds in the NW Caribbean behind the front. The cold front is forecast to stall across the Windward Passage SW to NE Nicaragua by Friday morning before dissipating Saturday morning. Strong trade winds will pulse near the coast of Colombia coast Friday night and then expand across much of the central Caribbean over the weekend as high pressure builds north of the area. ...HISPANIOLA... Partly cloudy skies and isolated showers prevail across the island as a cold front rapidly approaches from the west. The front is forecast to stall in the Windward Passage Friday morning and then dissipate during Sat morning. This scenario will allow for the continuation of cloudy skies and potential for scattered showers through Saturday. Fresh northeast winds are expected across the Windward Passage through Saturday night as high pressure builds across the western Atlantic in the wake of the above mentioned front. ...ATLANTIC OCEAN... A cold front is moving across the SW N Atlc waters with strong to gale-force winds west of it. See the Special Features section for more details about this front and the Gale Warning in effect. In the central Atlc, an upper-level low continue to support scattered moderate convection from 23N to 29N between 37W-43W. Otherwise, the Azores high dominates the remainder central and east Atlantic. Gale-force winds behind the front will decrease to 30 kt tonight as the front continue to move towards the central Atlc waters through Friday. The front will then dissipate over the central basin Saturday through Sunday. For additional information please visit http://www.hurricanes.gov/marine $$ NR/ERA