000 AXNT20 KNHC 132331 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 623 PM EST Wed Dec 13 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 2315 UTC. ...SPECIAL FEATURES... A tight pressure gradient between a 1033 mb high pressure located just south of the Azores and a low pressure system over western Africa is resulting in strong to mimimal gale force winds in the High Seas Forecast area called Agadir, along the coast of Morocco. Very rough seas are within the area of these winds. Winds and seas are forecast to gradually diminish tonight into Thu. Please, refer to the Meteo-France High Seas Forecast for more details. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 07N12W to 06N18W. The Intertropical Convergence Zone axis continues from 06N18W to the coast of NE Brazil near 03N51W. Scattered moderate convection is within about 60 nm N of the ITCZ axis between 23W- 30W. ...DISCUSSION... GULF OF MEXICO... A reinforcing and dry cold front is dissipating along 22N. A 1019 mb high pressure has developed over the NE Gulf while a 1023 mb high pressure is near Tampico, Mexico. Under this weather pattern, mainly light to gentle winds are noted across the Gulf region with the exception of moderate northerly winds across the SE waters, including the Yucatan Channel. Broken cold air stratocumulus clouds are still noted over the eastern Gulf in the wake of the dissipating front. Water Vapor imagery shows a band of transverse high clouds over northern Mexico and the NW Gulf in association with a subtropical jet, that is drawing upper level moisture from the EPAC region into the Gulf of Mexico. Looking ahead, another cold front is forecast to enter the northern Gulf Thu, then reach from the Florida Big Bend area in the NE Gulf to near Tampico Mexico by Fri afternoon, then stall from Tampa to the Bay of Campeche on Sat before lifting back to the W and NW through Sun. Gale force winds are possible along the coast of Mexico near Tampico Fri night and Sat. CARIBBEAN SEA... A weakening stationary front extends from northern Haiti to the easternmost tip of Jamaica to the SW Caribbean near 11N80W. A wide band of multi-layered clouds with embedded showers is associated with the front. A well defined swirl of low clouds is along the frontal boundary near 13N79W moving southward. This front produced heavy rains over eastern Cuba Sunday through Thuesday. The front will continue to dissipate to a remnant trough tonight. Moisture associated with this trough is forecast to move westward across the western Caribbean Thu and Fri in an easterly wind flow. An earlier scatterometer satellite pass showed moderate to locally fresh northerly winds across the Windward Passage in the wake of the front. Gentle to moderate trades are noted E of the front over the east and central Caribbean, with moderate to fresh winds within about 90 nm of the coast of Colombia. Winds are forecast to increase to 20-25 kt over the south-central Caribbean on Thu night, with gale conditions possible Sat night and Sun night as high pressure builds N of area. A reinforcing and dry cold front has reached western Cuba. This will reinforce the cool and dry airmass over western Cuba. Temperatures could drop below 10 degree Celsius (50F)in some places across the Havana-Matanzas plains overnight tonight. ...HISPANIOLA... Cloudiness has increased over Hispaniola today due to the proximity of a weakening stationary front that currently crosses northern Haiti. Isolated to scattered light to moderate showers are still possible tonight and early Thu. Then, moisture will diminish later on Thu as the frontal boundary continues to weaken and begins to drift westward as a trough. ATLANTIC OCEAN... A reinforning cold front enters the forecast area near 31N63W and continues SW across the central Bahamas into western Cuba. Fresh to strong W-NW winds follow the front but mainly N of 27N based on latest scatterometer data. A weakening stationary front is farther east and stretches from 31N60W to northern Haiti into the Windward Passage and the Caribbean Sea. Fresh to strong S-SW winds are aslo noted ahead of this front N of 27N to about 55W. The reinforcing cold front will continue to move SE while gradually dissipating on Thu. The stationary front will also dissipate on Thu. A ridge will then build along 25N in the wake of the secondary front. Another cold front is forecast to move off the NE Florida coast early Fri, reach from Bermuda to South Florida Sat, then reach from 24N65W to eastern Cuba early Sun. The remainder of the Atlantic Ocean is under the influence of a 1033 mb high pressure located just south of the Azores. This high extends a ridge SW to near the NE Caribbean. For additional information please visit http://www.hurricanes.gov/marine $$ GR