000 AXNT20 KNHC 272345 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 805 PM EDT Fri Oct 27 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... Potential Tropical Cyclone Eighteen was centered near 17.5N 84.5W or about 360 nm south-southwest of Havana Cuba at 2100 UTC, moving north-northwest at 5 kt. Maximum sustained winds are 35 kt with gusts to 45 kt. Minimum sea level pressure is 1006 mb. Numerous moderate isolated strong convection is within 270 nm NE and 120 nm SW of 17.5N 85.4W. The system does not have a well-defined center, with multiple circulations embedded within a broad circulation, and is not classified as a tropical cyclone at this time. Tropical Storm conditions are expected to affect Cuba and the NW Bahamas in the next 24-36 hours. Heavy rain from PTC 18 will spread northward across southern Florida Saturday. A cold front extends across the NW Gulf of Mexico from the Texas Louisiana border to Brownsville Texas. The front will push across the remainder of the Gulf through Sunday, with gale force winds expected to develop south of 26N west of the front later tonight, then continue through Saturday night. Strong northerly winds are expected elsewhere west of the front this weekend. See the latest NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The Intertropical Convergence Zone axis extends from 10N16W to 05N33W to 06N47W. Scattered moderate convection is from 02N-08N between 21W-31W. A surface trough extends from 13N46W to 05N49W, with widely scattered showers within 90 nm of the trough axis. ...DISCUSSION... GULF OF MEXICO... A cold front is moving into the NW Gulf, with gale force winds expected to develop east of southern Mexico by early Saturday. Showers associated with the front are near southern Louisiana. Ahead of the front, a ridge of high pressure extends SW from northern Florida to the Bay of Campeche, supporting mostly fair weather over the remainder of the Gulf. The front will push across the entire basin this weekend, with fresh to strong northerly winds over most of the Gulf waters behind the front. CARIBBEAN SEA... Potential Tropical Cyclone Eighteen is producing widespread convective activity in the NW Caribbean, and is expected to move northward while consolidating into a tropical storm overnight. Convergent low level winds SE of PTC 18 is producing a large area of scattered moderate isolated strong convection in the SW Caribbean south of 15N west of 76W. A surface trough extends S from Puerto Rico to northern Venezuela near 11N68W, with scattered showers from 12N-15N between 64W-67W. Mostly cloudy skies and a few showers prevail across the remainder of the basin. Expect marine conditions to improve in the NW Caribbean Saturday night and Sunday as Potential TC 18 moves north. ...HISPANIOLA... A stationary front in the Atlantic extends across the southern Bahamas to Cuba near 20N76W. A few showers are within 150 nm SE of the front, west of Haiti. A surface trough is over Puerto Rico. The trough will move slowly westward and reach eastern Hispaniola Saturday, increasing showers across the island this weekend. ATLANTIC OCEAN... A cold front over the W Atlantic extends from 32N61W to 24N68W, then becoming stationary SW to eastern Cuba. Scattered showers are north of 24N within 180 nm E of the front. Further E, a surface trough, a remnant of a frontal boundary, is from 24N33W to 21N43W. Scattered showers are within 90 nm of the trough. Expect Potential Tropical Cyclone Eighteen to become a tropical storm, bringing strong winds and widespread inclement weather to Cuba and the Bahamas this weekend. For additional information please visit http://www.hurricanes.gov/marine $$ Mundell