000 AXNT20 KNHC 082352 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 652 PM EST Fri Dec 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 2345 UTC. ...SPECIAL FEATURES... ...GALE WARNING IN THE GULF OF MEXICO... A frontal system is in the Gulf of Mexico extending as a stationary front across northern Florida to 29N83W where it transitions to a warm front that continues to a 1008 mb low near 26N89W. A cold front extends from the low to the eastern Bay of Campeche near 19N92W. A strong ridge continues to build in the wake of the front, supporting gale-force winds north and southwest of the front with seas reaching up to 18 ft. These conditions are forecast to prevail through Saturday morning. Scattered moderate convection is observed along the fronts and low covering the area east of 90W. Please read the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 for more details. ...GALE WARNING IN THE CARIBBEAN... The frontal system over the Gulf of Mexico is forecast to enter northwest Caribbean on Saturday morning. Strong to near gale- force winds will will follow the front as it moves across Cuba Saturday. Gale-force winds are forecast to develop off the coast of Nicaragua Sunday morning as the tail of the front reaches Costa Rica. There is a high risk of heavy rains for Costa Rica and western Panama Saturday evening through Monday morning associated with this front. Please read the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 for more details. ...ITCZ/MONSOON TROUGH... The monsoon trough extends across the Africa coast near 06N11W to east Atlantic waters near 05N21W. The Intertropical Convergence Zone extends from that point to 02N41W. Scattered moderate convection is from 01N to 06N between 03E to 22W. ...DISCUSSION... GULF OF MEXICO... The main story of the basin is the frontal system that extends across the central and eastern Gulf. Gale-force winds prevail across the northwestern and southwestern Gulf waters. Please refer to the section above for details. moderate to fresh southwest winds are noted southeast of the low/fronts with isolated showers. This system is forecast move off the basin to the west Atlantic and the northwest Caribbean Saturday morning. CARIBBEAN SEA... A surface trough along 82W persists in the southwest Caribbean in a deep moisture region and underneath upper-level diffluent flow. This scenario allows for the continuation of scattered moderate convection south of 20N between 75W-83W. To the east, a surface trough (remnants of a stationary front) extends along 14N and east of 70W with isolated showers. Scatterometer data depicts moderate to fresh trades across the basin except fresh to strong winds south of 13N between 74W-76W. A center of low pressure will develop near the southern extent of the surface trough within the next 24 hours, allowing for the showers activity in that region to continue. Furthermore, a cold front forecast to enter the west Caribbean waters on Saturday morning increasing the shower activity through the weekend. Potential heavy rain and gale-force winds are forecast for portions of Nicaragua, Costa Rica and Panama. See the Special Features section for further details. ...HISPANIOLA... Fair weather prevails across the island as a surface high centered over the central Atlantic extends through the area. Isolated convection could develop in the afternoon hours through the weekend due to daytime heating. ATLANTIC OCEAN... A stationary front extends across the west Atlantic from a 1010 mb surface low near 31N78W to northeast Florida near 30N81W. Scattered moderate convection is along and behind of the front to near 72W. To the east, a 1025 mb surface high is centered near 30N58W, which is forecast to move northeast Saturday. A stationary front extends from a 1012 mb surface low near 30N39W to 19N37W then becomes weak to 14N53W. A trough continues from that point to 14N61W. Scattered moderate convection is along and east of the front mainly north of 24N between 30W-34W. A surface ridge prevails east of the front. During the next 24 hours, the frontal boundary over the west Atlantic will push southeast through Saturday. The low pressure area in the central Atlantic and will move southwest over our area of discussion enhancing convection. Strong winds will follow its front. Please read the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 for more details. For additional information please visit http://www.hurricanes.gov/marine $$ ERA