000 AXNT20 KNHC 042340 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 640 PM EST Thu Jan 4 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 2230 UTC. ...SPECIAL FEATURES... A cold front extends into the discussion area from the hurricane- force 950 mb low centered off the mid-Atlc coast near 39N70W. The cold front reaches from 32N63W S-SW to 22N72W through the Windward Passage. Near gale to gale force W-NW winds are occurring generally N of 29N between 64W-75W, diminishing below gale force by later this evening as the low pressure area moves northward towards the eastern tip of Maine and western Nova Scotia. See the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. A tight pressure gradient and reinforcing cold air filtering in across the SW Caribbean Sea continues to support near gale to gale force NW-N winds generally S of 13N W of 80W. The wind field is forecast diminish below gale force later this evening. See the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the coast of Africa near 05N9W to 05N15W. The Intertropical Convergence Zone axis extends from 05N15W to 06N21W to the Equator near 40W. Only isolated convection is occurring, mainly N of the axis. ...DISCUSSION... GULF OF MEXICO... Surface ridging prevails across central Arkansas. Moderate to fresh northerly winds are expected to persist through Friday night, locally fresh to strong S of 20N and W of 92W. Thereafter, the ridging will weaken slightly and slide eastward across the SE CONUS shifting winds E-NE Saturday and E-SE on Sunday as the next area of low pressure develops across the Texas and Oklahoma panhandles. The associated cold front is expected to emerge off the Texas and Louisiana coasts late Sunday night into Monday morning. CARIBBEAN SEA... A middle to upper level trough is noted on water vapor imagery over the western North Atlc and NW Caribbean with axis extending from 32N67W to a base over eastern Cuba. This troughing has lifted northward from the NW Caribbean allowing for a surface cold front to stall from the Windward Passage to across Jamaica to central Panama. A 1010 mb low is centered at the southern extent of the front with a pre-frontal trough extending NE from the low to SW Haiti near 18N74W. The front along with the low and troughing are providing focus for scattered showers and tstms occurring generally within 360 nm E of the front, and within 180 nm in the NW semicircle of the low. Early data suggested that near gale to gale force NW-N winds were persisting from 10N to 13N W of the front, however, they will diminish below gale force later this evening. Moderate to locally strong northerly winds prevail elsewhere W of the front, with moderate to fresh trades noted across the remainder of the basin E of the surface trough. The stationary front will linger through Friday, gradually dissipating Saturday into Sunday. Fresh to strong winds are expected W of the boundary through the upcoming weekend. ...HISPANIOLA... Scattered showers and isolated tstms are expected through Friday across Hispaniola as a cold front is analyzed just to the NW of northern Haiti. The front is expected to stall across the island Friday with NE winds increasing through the Windward Passage and northern coastal exposures, persisting through Monday. ATLANTIC OCEAN... Outside of the Special Features cold front across the SW North Atlc, the remainder of the central and eastern Atlc is under the influence of a surface ridge anchored by a 1034 mb high centered S-SW of the Azores near 33N37W. For additional information please visit http://www.hurricanes.gov/marine $$ Lewitsky