000 AXNT20 KNHC 081805 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 105 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 1200 UTC surface analysis and satellite imagery through 1745 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 29N82W where it transitions to a warm front that continues SW to a 1008 mb low near 25N89W. A cold front extends from the low SW to the eastern Bay of Campeche near 18N92W. A strong ridge continue to build in the wake of the front, thus supporting gale force winds N and SW of the front with seas reaching up to 18 ft. Gale conditions in the Gulf are forecast to prevail through Saturday morning. Scattered showers and tstms are within 105 nm ahead of the cold front and within 60 nm either side of the warm front. Please read the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 for more details. ...GALE WARNING IN THE CARIBBEAN... The front over the Gulf of Mexico will make a complete transition to a cold front this evening and is forecast to enter NW Caribbean waters on Saturday morning. Strong to near gale-force winds will will follow the front as it moves SE across Cuba Saturday. Gale force winds are forecast to form 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 06N10W to east Atlantic waters near 04N20W. The Intertropical Convergence Zone extends from that last point to 02N31W to 01N42W. Scattered moderate convection is from 01N to 06N between 03E to 22W. ...DISCUSSION... GULF OF MEXICO... A frontal system is in the Gulf of Mexico extending as a stationary front across northern Florida to 29N82W where it transitions to a warm front that continues SW to a 1008 mb low near 25N89W. A cold front extends from the low SW to the eastern Bay of Campeche near 18N92W. Strong high pressure builds behind the front supporting gale-force winds N and SW of the front. See the special feature section for further details. The front is forecast to fully transition to a cold front this evening and move off the basin to the SW Atlc and the NW Caribbean Saturday morning. CARIBBEAN SEA... A surface trough persists in the SW Caribbean in a deep moisture region and underneath upper level diffluent flow. This scenario allows for the continuation of scattered heavy showers in the SW basin S of 16N between 76W and 83W. Similar convection is over central southern Cuba adjacent waters N of 19N. A center of low pressure will develop near the southern extent of this trough within the next 24 hours allowing for the continuation of showers in that region. Furthermore, a cold front forecast to enter the NW Caribbean waters on Saturday morning will reach the SW basin Sunday increasing the shower activity. Potential heavy rain and gale winds are forecast for portions of Nicaragua, Costa Rica and Panama. See the special features section for further details. Otherwise, the remnants of a dissipating stationary front are analyzed as a surface trough that extends across the NE Caribbean waters along 14N61W to SE Hispaniola adjacent waters near 17N70W. Isolated showers are possible within 60 nm either side of this boundary. ...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 30N78W to NE Florida near 29N81W. A pre-frontal trough extends from 30N77W to 25N79W. Scattered to isolated showers are ahead of the trough to near 72W. To the east, a 1024 mb surface high is centered near 29N58W, which is forecast to move NE and N of surface waters by Saturday morning. Finally, in the NE Atlc, a cold front extends from 29N32W SW to 19N36W where it transitions to a stationary front along 15N44W to 14N52W. A surface trough follows westward towards the northern Windward Islands near 14N61W. Scattered showers are N of 26N between 28W and 39W. A surface ridge prevails east of this front. During the next 24 hours, the frontal boundary over the west Atlantic will push southeast through Saturday. A new low pressure area will develop under the upper-level low in the central Atlantic and will move southwest over our area of discussion enhancing convection. Strong winds will follow this 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 $$ Ramos