000 AXNT20 KNHC 140005 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 705 PM EST Sat Jan 13 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... ...Gale Warning within 60 nm of the coast of Nicaragua... A cold front extends from central Cuba to NW coastal Honduras. The front will move slowly southeastward and become stationary from eastern Cuba to Costa Rica tonight. Fresh to locally strong N winds are expected behind the front through tonight. Wind speeds are forecast to increase even more behind the front on Sunday morning as strong high pressure builds across the NW Caribbean Sea and in northern Central America. The increase in wind speeds will allow strong to minimal gale-force northerly winds to blow behind the front, and within 60 nm of the coast of Nicaragua, with building seas of 8-11 feet. Please read the latest NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...THE MONSOON TROUGH/THE ITCZ... The monsoon trough extends from the coast of Africa near 06N10W to 04N15W to 02N22W. The ITCZ continues from 02N22W to 02N40W, to the Equator at along 45W, and along the Equator at 50W at the coast of Brazil. Precipitation: Isolated moderate to locally strong rainshowers are within 360 nm to the N of the ITCZ between 30W and 52W. ...DISCUSSION... ...THE GULF OF MEXICO... A surface ridge passes through central Texas, to a 1034 mb high pressure center that is near 22N98W in the coastal plains of Mexico, to the Isthmus of Tehuantepec of southern Mexico, to central Guatemala. High pressure centers of 1042 mb and 1043 mb are in the northern Plains of the U.S.A. Cold air stratocumulus clouds cover much of the Gulf of Mexico, with the advection of cold air over relatively warm waters. Reinforcing cold air will move through the eastern Gulf for the rest of today, behind a secondary cold front that currently is moving through north- central Florida. The second front is forecast to reach south Florida tonight, bringing another round of cold temperatures. High pressure will continue to prevail across the area through early on Monday. The high pressure will slide eastward on Tuesday night as the next cold front moves over the NW gulf waters. Fresh northerly winds will persist across the eastern Gulf tonight and Sunday, with gentle to moderate NE-E winds elsewhere. ...THE CARIBBEAN SEA... A cold front extends from central Cuba to NW coastal Honduras. Please read the SPECIAL FEATURES section for more details about the winds and the sea heights that are and will be associated with the cold front. A surface trough is along 77W/78W from 13N, crossing the western part of Jamaica, to southern sections of SE Cuba. Precipitation: isolated moderate rainshowers are within 520 nm to the E and SE of the front, including in parts of Hispaniola, and elsewhere in the Caribbean Sea. Rainshowers are possible elsewhere in the Caribbean Sea, from 72W eastward, in areas of broken low level clouds in surface tradewind flow. ...HISPANIOLA... Isolated to scattered passing showers are expected across the island today under the influence of a ridge. Moisture will continue to be limited on Sunday. ...THE ATLANTIC OCEAN... A cold front passes through 32N72W, across the northern half of the Bahamas, beyond central Cuba, and into the Caribbean Sea. Precipitation: widely scattered moderate to isolated strong rainshowers are within 180 nm to the E and SE of the colf front. A second cold front passes through 32N75W beyond central Florida. A surface trough is along 23N50W to 18N52W. Precipitation: widely scattered moderate to isolated strong rainshowers are from 18N to 26N between 49W and 58W. A second surface trough is along 15N53W to 10N55W. Precipitation: isolated moderate to locally strong rainshowers are from 10N to 14N between 53W and 60W. Fresh to strong SW-W winds are blowing between fronts. The main front will become stationary from 31N73W to the central Bahamas and to eastern Cuba on Sunday, while the secondary front will merge with the main front tonight. For additional information please visit http://www.hurricanes.gov/marine $$ mt