000 AXNT20 KNHC 082347 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 647 PM EST Wed Feb 8 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. ...CARIBBEAN GALE WARNING... A gale warning is 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. Model guidance shows seas building to 8 to 12 ft over the region with the strongest winds. 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 through the coast of Liberia near 06N10W to 05N13W. The ITCZ continues from 05N13W to 05N22W to 01N30W to the Equator at 40W. Scattered moderate isolated strong convection is over SE Liberia and coastal waters, and from 02.5N-04N between 09N-13N. Similar convection is from 01N-02N between 17W-19W. Scattered moderate convection can be found within abouth 60 nm SE of a line from 06n14W to 05N17W to 02N21W. Scattered moderate convection is also from the Equator to 03N between 25W and 31W. ...DISCUSSION... ...GULF OF MEXICO... A ridge dominates the entire Gulf region. Under the influence of this system, mostly fair weather prevails. Latest observations indicate the development of patches of fog over the coastal waters W of 87W due to a moist and warm air spreading over relatively cooler waters. Gentle to moderate southwesterly winds are noted over the north Gulf north of the ridge axis while SE-S winds are seen elsewhere south of the ridge axis. The ridge will weaken tonight as a cold front moves across the NW waters. Currently, Doppler Radar shows a band of showers, with embedded thunderstorms over the Florida Panhandle ahead of the front. This system will move quickly across the Gulf, reaching from central Florida to northeast Mexico Thursday morning, and pushing through south Florida during the afternoon hours. Fresh to strong northerly winds are expected in the wake of the front, with seas building to 6-8 ft. Winds are forecast to quickly veer to the NE-E by Thursday night as the high pressure behind 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. Aloft, mainly a NW flow is noted across the Gulf. ...CARIBBEAN SEA... A gale warning is in effect for the south-central Caribbean. Please, see Special Feature section for details. Scatterometer data provided observations of moderate to fresh winds across the remainder of the east and central Caribean. Lighter winds are noted over the NW Caribbean. A fast moving cold front will reach western Cuba and the NW Caribbean by Thursday evening with some shower and thunderstorm activity, then the front will move across the remainder of Cuba on 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. Shallow moisture embedded in the trade wind flow will move across the region producing isolated to scattered passing showers. Aloft, a westerly flow prevails across the basin with strong upper level subsidence and implied dry air mass. ...HISPANIOLA... Moisture associated with an exiting trough north of Hispaniola will support a few light showers across the island. By late Friday, an approaching frontal boundary will increase the likelihood of showers. ...ATLANTIC OCEAN... High pressure centered near 36N42W extends a ridge across the majority of the forecast area. Winds have increase to 20-30 kt just E of NE Florida due to the pressure gradient between the ridge and a low pressure located near Cape Hatteras. South of the ridge, mainly fresh trade winds are noted across the central Atlantic, particularly south of 20N, and E of the Lesser Antilles. These winds are expected to persist on Thursday, affecting mainly the tropical Atlantic between the Cabo Verde Islands and 55W as the high pressure shifts eastward to a postion near 36N35W. A band of moderate convection is ahead of trough extending from 31N71W to 27N73W. This trough is a reflection of mid-level trough moving eastward across the ocean north of Hispaniola, causing the ridge to retreat eastward. A frontal trough stretches from 31N34W to 26N51W with low-topped showers. A stronger cold front will move rapidly across the western Atlantic on Thursday, and reach from 31N61W to the SE Bahamas and eastern Cuba by Fri morning. For additional information please visit http://www.hurricanes.gov/marine $$ GR