000 AXNT20 KNHC 121721 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1221 PM EST Fri Jan 12 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 1200 UTC surface analysis and satellite imagery through 1715 UTC. ...SPECIAL FEATURES... A cold front extends across the Gulf of Mexico from 30N87W to 24N90W to 18N94W. A strong pressure gradient has developed between the front and a surface ridge that extends from the north-central CONUS to eastern Mexico. These conditions support strong to gale-force northwesterly winds over the western Gulf waters behind the front. These winds will prevail through this afternoon. See 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 06N10W to 01N33W. The ITCZ continues from 01N33W to 00N50W. Scattered showers are noted along these boundaries between 30W-51W. ...DISCUSSION... GULF OF MEXICO... Moderate to locally fresh return flow prevails over the eastern half of the Gulf ahead of a cold front that extends across the central Gulf waters. Gale-force northwesterly winds are behind the cold front over the western Gulf. These conditions will continue through this afternoon. Please refer to the section above for more details about the Gale Warning. To the east of the front, a surface trough extends from 30N86W to 22N88W with scattered showers. Expect for a reinforcing front to move across the northern portion of the basin tonight and across Florida on Saturday. Strong northerly winds in the wake of the front will diminish by then. CARIBBEAN SEA... Deep-layer dry air over the west Caribbean supports fair weather west of 80W. To the east, southwesterly flow aloft continues to advect moisture from the EPAC and northern South America into the central Caribbean supporting cloudiness with scattered showers affecting Jamaica, Hispaniola and Puerto Rico. Shallow moisture in the tradewind flow supports isolated showers over the Lesser Antilles. Latest scatterometer data shows moderate to fresh winds in the eastern half of the basin while light to gentle easterly flow prevails over the western half. A cold front will enter the northwest Caribbean waters tonight with fresh to strong winds. The front will then stall from eastern Cuba to northeast Nicaragua adjacent waters by Saturday evening. A strong pressure gradient will develop over northern Central America supporting near gale-force winds behind the front continuing through the weekend. ...HISPANIOLA... Southwesterly flow aloft supports cloudiness and scattered showers across the island and southern adjacent waters. This activity is forecast to continue through the next 24 hours. ATLANTIC OCEAN... Diffluent flow generated by a short-wave trough over the Bahamas and a ridge to the east of it continues to support scattered showers from 22N-28N between 70W-75W. Farther east, a broad middle to upper level trough support a stationary front that enters the north-central Atlantic waters near 30N27W to 24N49W. Scattered showers are within 120 nm on either side of the boundary. Elsewhere, surface ridging dominates the remaining of the area anchored by a 1040 mb high centered near 38N53W. The next cold front is expected to move offshore tonight, reaching the west Atlantic waters with convection and fresh to strong winds. A reinforcing cold front will follow the leading front and move across Florida early this weekend then merge with the leading front over the west Atlantic waters. For additional information please visit http://www.hurricanes.gov/marine $$ ERA