000 AXNT20 KNHC 161103 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 603 AM EST Sat Dec 16 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 0600 UTC surface analysis and satellite imagery through 1100 UTC. ...SPECIAL FEATURES... ...Gale Warning in the Caribbean Sea... Strong high pressure centered south of the Azores extends a ridge axis SW to the SW N Atlc resulting in a tighter pressure gradient in the Caribbean. As a result, gale-force winds are along the northwest portion of the Colombian coast from 11N to 13N between 74W and 77W with seas building to 13 ft. Gale winds will pulse at night during the weekend continuing through Monday. Sea heights will build to 14 feet during that period. Please read the latest NHC 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 07N12W to 06N17W. The ITCZ continues from 06N17W to 04N26W to 06N33W then resumes west of a surface trough from 03N41W to 01N50W. Scattered heavy showers and tstms are from 02N-10N between 10W-34W. ...DISCUSSION... GULF OF MEXICO... The former cold front has stalled along 28N82W to 25N90W to the Bay of Campeche near 18N95W. Fresh to near gale-force northerly winds are occurring south of 24N west of the front with seas up to 12 ft. Broken to overcast skies are north and west of the front with possible isolated showers. A surface trough is ahead of the front in the Bay of Campeche supporting isolated showers. Similar shower activity is in the Yucatan Channel and in the straits of Florida associated with a surface trough moving across the NW Caribbean. Deep layer dry air supports fair weather elsewhere. Looking ahead, the front is forecast to transition to a warm front during the early afternoon hours. Models suggest broad low pressure developing along the boundary in the SW Gulf then move northward into the NW Gulf through tonight with SE-S flow on the eastern side of the low increasing to fresh to strong. The low will then move inland over eastern Texas Sun morning, and linger into early next week. CARIBBEAN SEA... A gale warning prevails for the south-central Caribbean being supported by strong pressure N of the area. These conditions will continue through the weekend and into early Monday. Please refer to the Special Features section above for details. Otherwise, shallow moisture associated with a surface trough in the NW Caribbean supports scattered to isolated showers over Nicaragua, Honduras, the Yucatan peninsula and the Yucatan channel. Fair weather prevails across the remainder of the basin being supported by a broad middle to upper level high and very dry air aloft. Plumes of fresh to strong NE to E winds will develop to the lee of Cuba and through and near the Windward Passage beginning late tonight and diminish some on Tuesday and to 15-20 kt on Wed. ...HISPANIOLA... A broad middle to upper level high covering the Caribbean and very dry air aloft continue to support very stable conditions across the Island. Similar conditions are forecast for the weekend. Plumes of fresh to strong NE to E winds will develop through and near the Windward Passage beginning late tonight and diminish some on Tuesday and to 15-20 kt on Wed. ATLANTIC OCEAN... A cold front extends from 30N74W SW to north of Cape Canaveral, Florida where it transitions to a stationary front into the Gulf of Mexico. Latest scatterometer data indicate fresh W-SW winds N of 29N between 70W and 75W ahead of the cold front. The cold front will brush the northern waters today, followed by strong W-NW winds and seas of 8-10 ft on either side of it. These conditions are expected to be to the N of about 30N and E of 77W. Strong high pressure will build behind this front, with ridging settling along 28N through Tue, ushering in fairly tranquil marine conditions across the entire basin. Otherwise, strong surface high pressure anchored south of the Azores extends a ridge axis into S across the central and eastern Atlc. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos