000 AXNT20 KNHC 221732 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1232 PM EST Fri Dec 22 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 1200 UTC surface analysis and satellite imagery through 1715 UTC. ...ITCZ/MONSOON TROUGH... The monsoon trough enters the Atlantic Ocean through Sierra Leone and continues to 05N20W. The ITCZ extends from 05N20W to 03N30W to 01N40W to 00N51W. Scattered moderate convection is from 02N-06N between 13W-25W. ...DISCUSSION... GULF OF MEXICO... A ridge extending from the SE CONUS dominates the Gulf waters producing a gentle to moderate southerly return flow. These winds are forecast to increase to 15-20 kt across the western Gulf later today ahead of the next cold front that will enter the Gulf waters tonight. The front will reach from SE Louisiana to near Tampico, Mexico Saturday morning, and from the western Florida Panhandle to 23N94W to the central Bay of Campeche by Saturday night. Fresh to strong northerly winds and building seas of 8 or 9 ft are expected in the wake of the front on Saturday, with winds diminishing to 10-15 kt by Saturday night. Weak high pressure behind the front will be reinforcing by stronger high pressure on Sunday, pushing the front to a position from Tampa, Florida to 23N94W to the central Bay of Campeche by Sunday night. At that time, expect fresh to strong winds across the northern Gulf waters, mainly N of 27N with seas of 6-7 ft. The front is then forecast to extend from south Florida to near 22N96W to 22N96W to 18N94W on Monday while weakening. Patches of dense fog were noted this morning near the northern Gulf coast from eastern Texas to the Big Bend of Florida due to a moist onshore flow. Aloft, a ridge dominates the Gulf region, and the State of Florida. Moderate to strong upper level subsidence and implied dry air mass is noted within the ridge. CARIBBEAN SEA... The most recent scatterometer data provided observations of fresh to strong winds across the central Caribbean, and mainly fresh NE winds in the lee of eastern Cuba, and in the Windward Passage. Patches of low level clouds, embedded in the trade wind flow, are noted across the basin producing isolated to scattered passing showers. High pressure N of the region will maintain strong trade winds over the central and southwest Caribbean, with near gale force winds near the coast of Colombia each night through this weekend. Fresh to strong NE winds are expected through the Windward Passage as well. ...HISPANIOLA... A broad mid to upper-level ridge along with deep layer dry air continues to result in mostly fair weather conditions over the island. High pressure over the west Atlantic will support pulses of fresh to locally strong winds across the Windward Passage through the weekend. Low-topped trade wind showers will continue to affect the island from time to time. ATLANTIC OCEAN... A cold front extends from a weak 1016 mb low pressure located near 32N56W to 26N70W to another 1008 mb low pressure situated near 32N78W. This front will drift south and dissipate rapidly through early Sat. Recent scatterometer data indicate fresh to strong winds in the wake of the front but N of 30N between 62W and 70W. An area of showers is ahead of the front N of 27N between 54W and 58W. The easternmost low pressure is forecast to move SE into the forecast area, and open up into a trough early on Saturday. The remainder of the western Atlantic is under the influence of a ridge anchored by a 1026 mb high pressure located over the Carolinas. E of the front, a 1044 mb high pressure centered NE of the Azores extends a ridge across most of the E and central Atlantic. The pressure gradient between this strong high pressure and lower pressure in the vicinity of the monsoon trough/ITCZ is supporting fresh to strong winds N of 11N between the coast of Africa and 40W. For additional information please visit http://www.hurricanes.gov/marine $$ GR