000 AXNT20 KNHC 212358 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 658 PM EST Thu Dec 21 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. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 07N12W to 05N20W. The Intertropical Convergence Zone axis extends from 05N20W to 02N30W to 02N40W to 01S48W. Scattered moderate convection is from 01N-08N between 06W-19W and within 150 nm either side of the ITCZ. ...DISCUSSION... GULF OF MEXICO... Middle to upper level ridging is noted on water vapor imagery over the entire basin along with deep layer dry air, which is supporting clear skies and fair weather. Otherwise, surface high pressure anchored by a 1019 mb high over the central Bahamas extends a ridge axis across the Florida peninsula and the Gulf. Light to gentle variable winds dominate the eastern half of the basin while mainly moderate S-SE winds are observed in the western half of the Gulf. The next cold front is forecast to come off the coast of Texas Friday night, extend from the Florida Big Bend SW to Veracruz, Mexico early Sunday morning and from south Florida to Tampico, Mexico Monday near sunrise. Fresh to near gale force northerly winds will follow the front starting on Saturday. CARIBBEAN SEA... Broad middle to upper level ridging prevails over the Caribbean basin with water vapor imagery indicating very dry and stable air aloft supporting fair weather at the surface. A surface ridge anchored across the central Bahamas continues to support a tighter pressure gradient across the central Caribbean, thus resulting in fresh to strong trades. However, strong to near gale force winds are expected along the coast of Colombia. Little change in the synoptic pattern is expected through early next week. ...HISPANIOLA... Broad middle to upper level ridging along with deep layer dry air continue to support fair weather conditions. High pressure over the SW N Atlc anchored by a 1019 mb high over the central Bahamas support pulses of fresh to strong winds across the Windward Passage during the weekend. While overall tranquil conditions are expected, isolated low-topped trade wind showers are possible during the weekend along the north and eastern island. ATLANTIC OCEAN... A stationary front is N of the SW N Atlc waters associated with a pair of low pressure centers. A pre-frontal trough attached to one of these lows extends from 30N67W SW to 28N74W then W to near Melbourne, Florida. There is no convection associated with this trough, however scattered showers are noted SE of the lows N of 28N between 51W and 64W. Otherwise, the remainder SW N Atlc is under the influence of a surface ridge anchored by a 1019 mb high centered across the Bahamas. Farther east, a middle to upper level low supports a weak surface trough from 27N36W to 19N39W. Isolated showers and tstms are occurring primarily within 120 nm east of the trough. The remainder of the eastern Atlc is under the influence of a surface ridge anchored by a 1042 mb high centered W-NW of the Iberian peninsula near 43N17W. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos