000 AXNT20 KNHC 062334 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 634 PM EST Sat Jan 6 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 2315 UTC. ...SPECIAL FEATURES... ...Atlantic Gale Warning... Strong high pressure of 1040 mb building SE toward the U.S. Atlantic coast will support strong to minimal gale force NE winds through the Windward Passage and just W of stationary front currently extending from 31N56W to the easternmost tip of Cuba. The strongest winds are expected W of front to the S of the Turks and Caicos Islands, and in the approach to the Windward Passage Sun through Sun evening. Seas are forecast to build to 11-12 ft within the area of gale force winds. Fresh to strong NE winds are expected to also affect the remainder of the waters between the Bahamas and Cuba, and the Straits of Florida. Conditions across the region will improve Mon night through Tue as the high shifts E and weakens. See the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...Caribbean Gale Warning... The aforementioned high pressure will also bring strong to minimal gale force NE winds in the lee of east-central Cuba, including the Cayman Islands tonight through Sunday morning. Seas are forecast to build to 10-12 ft near the Cayman Islands by Sun morning. See the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The monsoon trough enters the Atlantic Ocean through Liberia, Africa and continues to 01N24W. The Intertropical Convergence Zone extends from 01N24W to the Equator at 30N to NE Brazil near 02N51W. Scattered moderate convection is noted from 03N-05N between 34W-38W. Convection is limited elsewhere. ...DISCUSSION... GULF OF MEXICO... A ridge dominates the entire Gulf region anchored by a strong high pressure of 1040 mb located over the Ohio Valley. A surface trough has developed across the central Gulf. The most recent scatterometer passes showed moderate to fresh easterly winds E of the trough, and gentle to moderate winds W of the trough. Patches of low level clouds are noted near the trough axis, and across the western Gulf and the eastern slopes of the Sierra Madre Mountains. The pressure gradient between the trough and the strong high pressure will produce fresh to strong NE-E winds across the Straits of Florida and SE Gulf tonight through late Sun. The high pressure will then shift E into the W Atlc late Sun and Mon to bring fresh to strong return flow across the central Gulf early Sun through Monday. The next cold front is forecast to emerge off the Texas and Louisiana coasts on Monday followed by mainly fresh northerly winds and building seas of 5-6 ft. CARIBBEAN SEA... A stationary front extends from the easternmost tip of Cuba across Jamaica to W Panama near 09N79.5W. Clusters of moderate convection are noted along the the frontal boundary, particularly from 10N to 15N between 78W and the front. Abundant cloudiness with embedded showers are noted across much of Cuba, Jamaica and the Cayman Islands in association with this front. Patches of low level moisture with embedded showers are noted over the eastern Caribbean where a surface trough is analyzed along 65W. Latest scatterometer data indicated fresh to strong winds across the Windward Passage, and across the south-central Caribbean near the coast of Colombia. The stationary front will slowly weaken and drift W to the S of 16N during the next few days. Strong high pres building SE toward the U.S. Atlantic coast will support gales between Jamaica and lee of Cuba tonight through Sun morning. Please, see Special Features section for more details. ...HISPANIOLA... Moisture associated with a frontal boundary now located over eastern Cuba will continue to support some shower activity across the island tonight and Sunday. A patch of low-level moisture currently over the eastern Caribbean will also reach the island on Sunday, keeping the likelihood of showers. Strong high pres building SE toward the U.S. Atlantic coast will support strong to minimal gale force winds through the Windward Passage on Sunday. Please, see Special Features section for more details. ATLANTIC OCEAN... As of 1800 UTC, a stationary front extends from 31N56W to the easternmost tip of Cuba into the Caribbean Sea. A wide band of cloudiness with showers and likely isolated tstms is associated with the front, affecting much of the Bahamas and Cuba. West of the front, a ridge dominates the SW N Atlantic, including Florida and the Bahamas. Strong NE winds are noted W of the front across the Bahamas, and the Old Bahama Channel. These winds will expand in coverage through tonight as strong high pres builds SE toward the eastern U.S. coast. Gale force winds are expected NW of front to the S of the Turks and Caicos and in the approach to the Windward Passage Sun through Sun evening. Please, see Special Features section for more details. The remainder of the central and eastern Atlantic is under the influence of a surface ridge anchored by a 1030 mb high centered SW of the Azores near 32N37W. Mainly fresh to locally strong trades are seen along the southern periphery of the ridge between the coast of Africa and the Lesser Antilles based on scatterometer data and buoy observations. A recent ASCAT pass indicates the presence of gale force winds NE and within about 150 nm of the Madeira Islands in association with a low pressure system near the coast of Morocco. For additional information please visit http://www.hurricanes.gov/marine $$ GR