000 AXNT20 KNHC 092328 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 628 PM EST Thu Feb 9 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... ...CARIBBEAN GALE WARNING... A gale warning remains in effect within about 90 nm of the coast of Colombia. The pressure gradient between high pressure north of the region and the Colombian/Panamanian low will continue to support fresh to strong trades over the south-central Caribbean during the next several days. Winds will pulse to gale force within about 90 nm of the coast of Colombia during the overnight and early morning hours through Sunday night. Latest wave guidance shows seas building to 12-13 ft over the region with the strongest winds. Strong to near gale force winds will continue over the south-central Caribbean through Monday. See 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 near the Sierra Leone/Liberia border to 04N20W. The ITCZ continues from 04N20W to the Equator at 29W. Scattered moderate to isolated strong convection is from 02N-04N between 08W-14W. Scattered moderate convection is noted from 02N-04N between 14W-17W, and from 00N-03N between 21W- 26W. ...DISCUSSION... ...GULF OF MEXICO... A cold front is moving across the Gulf of Mexico and extends from SW Florida to 25N90W to 23N96W to near Veracruz Mexico. Tampico Mexico reported gusty winds to 30 kt with the frontal passage. Visible satellite imagery reveals a narrow band of cloudiness with embedded showers in association with this front. Fresh to strong northerly winds and seas of 6-7 ft follow the front. The west part of the front will stall and weaken while the east part will move across the Yucatan Channel and western Cuba by early Friday morning. Winds behind the front are forecast to quickly veer to the NE-E on Friday as high pressure in the wake of the front moves east over the eastern United States. By late Friday, the high pressure will move into the western Atlantic, extending a ridge across the Gulf region. As a result, southerly return flow will set up over the western Gulf. These winds will spread east across the entire Gulf during the upcomimg weekend. Aloft, a long wave trough located over the eastern United States crosses central Florida and the Gulf to near Tampico Mexico. This trough supports the aforementioned cold front. ...CARIBBEAN SEA... A gale warning is in effect for the south-central Caribbean. Please, see Special Feature section for details. Elsewhere, scatterometer data provided observations of moderate to fresh winds across the remainder of the east and central Caribean. Gentle to moderate winds are noted over the NW Caribbean. A fast moving cold front will reach western Cuba and the NW Caribbean by early Friday morning with some shower activity, then the front will move across the remainder of Cuba through late Friday while gradually weaken across the Caribbean Sea. As high pressure, in the wake of the front, moves eastward Friday through Saturday, expect increasing northeasterly winds across Cuba and in the lee of the island, including also the Windward Passage. Friday night into Saturday, the GFS model suggests NE-E winds of 20-25 kt between Las Bahamas and Cuba, south of Cuba, but mainy east of the Isle of Youth (Isla de la Juventud) and across the Windward Passage, where seas are forecast to build to near 8 ft. Shallow moisture embedded in the trade wind flow will continue to move across the region producing isolated to scattered passing showers. Aloft, a westerly flow prevails across most of the basin with moderate to strong upper level subsidence and implied dry air mass. SW winds over northern South America are advecting some mid- upper level moisture into the Caribbean Sea, including the ABC Islands. ...HISPANIOLA... Limited moisture due to the presence of a mid-upper level ridge across the island will support only a few light showers tonight and Friday. By late Friday, an approaching frontal boundary will bring increasing cloudiness with scattered showers ang gusty winds. The front is forecast to stall near the island during the weekend while dissipating. ...ATLANTIC OCEAN... A cold front enters the forecast region near 31N73W and continues SW to across South Florida into the Gulf of Mexico. As previously mentioned, visible satellite imagery reveals a narrow band of cloudiness with embedded showers in association with this front. Gale force winds were noted in the SW flow ahead of the front this morning, but mainly north of 30N. The most recent ASCAT pass provided observations of fresh to strong S-SW winds ahead of the front, mainly north of 28N. Fresh to strong NW-N winds are also expected behind the front, especially tonight into Friday morning. The front will extend from near 31N54W across the SE Bahamas and eastern Cuba by Friday evening, then will be near the coast of Hispaniola by Friday night, and stall there during the weekend. High pressure in the wake of the front will reach a position near 32N76W by Friday evening. At that time, a belt of fresh to strong NE-E winds is expected across much of the Bahamas, the Turks and Caicos Islands, the waters between the Bahamas and Cuba, and across the Straits of Florida. E of the front, a strong high pressure of 1035 mb persists, with the center located west of the Azores near 35N36W. This system dominates the remainder of the forecast area. South of the ridge, fresh to strong trade winds are noted, affecting the tropical Atlantic between the Cabo Verde Islands and the Lesser Antilles. The high pressure is forecast to reamain nearly stationary over the next 24 hours, then will move southward and weaken on Saturday. For additional information please visit http://www.hurricanes.gov/marine $$ GR