000 AXNT20 KNHC 071752 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1252 PM EST Thu Dec 7 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 1530 UTC. ...SPECIAL FEATURES... ...GALE-FORCE WINDS IN THE GULF OF MEXICO... A cold front extends from the Tampa Bay area of Florida to 27N87W then transitions to a stationary front that extends through a 1014 mb low centered near 25N93W to 18N95W. Strong high pressure building NW of the frontal system over the Gulf of Mexico supports gale force winds over the NW Gulf today. The gale force winds will spread to the SW Gulf this afternoon, with peak winds of 40 kt expected this evening and then again on Fri morning as a reinforcing push of cooler and drier air moves into the region. Wave heights will peak near 16 ft today, and 19 ft on Monday. 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 09N14W and extends to the E Atlantic near 07N20W. The Intertropical Convergence Zone axis extends from 07N20W to 04N25W to 04N40W to 03N46W. A surface trough extends from 08N37W to the ITCZ axis near 05N41W. Scattered moderate convection is from 02N to 06N between the Prime Meridian and 33W, and from 05N to 11N between 36W and 43W. ...DISCUSSION... GULF OF MEXICO... A cold front extends from the Tampa Bay area of Florida to 27N87W then transitions to a stationary front that extends through a 1014 mb low centered near 25N93W to 18N95W. Strong high pressure building NW of the frontal system supports gale force winds over the NW Gulf today. Please refer to the special features section for more details on this gale. Strong to near gale force winds are elsewhere NW of the front. Scattered showers are within 60 nm of either side of the front. The combination of low to mid level moisture and the subtropical jetstream is supporting numerous showers over the NW and N central Gulf. Mainly gentle to moderate winds are south of the front. Over the next 24 hours the low and front will move very slowly to the SE. Thereafter, the upper trough supporting the frontal system will dig farther south, and allow the low to accelerate NE and bring the cold front across the remainder of the Gulf basin Friday afternoon and Friday night. CARIBBEAN SEA... Deep moisture over the SW Caribbean is interacting with diffluent flow aloft and a surface trough from 16N83W to 10N82W to support scattered moderate convection from 11N to 20N W of 81W. The tail end of a dissipating cold front extends from the central Atlantic to the Lesser Antilles near 16N61W to 16N67W, supporting scattered showers and isolated thunderstorms within 90 nm of the frontal boundary. Generally fair weather covers the remainder of the Caribbean. Atlantic high pressure supports strong winds S of 18N between 68W and 80W over the central Caribbean. Mainly moderate to fresh NE to E trades are over the remainder of the basin. The strong winds over the central Caribbean will diminish through the weekend as the high pressure north of the region shifts NE, while a frontal system crosses the Gulf of Mexico. This cold front will reach the NW Caribbean early Saturday and cross the NW Caribbean through Saturday night with strong to near gale force winds behind the front. Gale force winds will then be possible along the coast of Nicaragua Sunday and Sunday night as the front surges southward across the area. ...HISPANIOLA... Isolated thunderstorms are expected over the higher terrain this afternoon and evening due to daytime heating. This activity will weaken overnight. This afternoon thunderstorm pattern is expected to repeat again Friday. ATLANTIC OCEAN... A cold front has exited the Florida coast and extends from 31N78W to 29N81W. A pre-frontal trough extends from 31N75W to 28N79W. Fresh to strong northerly winds and scattered showers are confined NW of the front. Elsewhere over the SW N Atlantic, a 1023 mb high is centered near 29N61W supporting generally fair weather. Farther east, a cold front enters the area of discussion near 31N34W and extends to 22N40W to 16N50W. A pair of surface troughs surround the northern portion of this front. The westernmost trough is the reflection of an upper low and extends from 31N40W to 25N42W. The easternmost trough is a pre-frontal trough that extends from 29N32W to 21N37W. Scattered moderate convection with numerous thunderstorms are within 210 nm east of the cold front N of 23N. Scattered thunderstorms are between the western trough and the cold front N of 26N. Scattered showers and thunderstorms are also within 90 nm of either side of the cold front W of 55W. Over the next 24 hours the cold front will stall off of Florida, before accelerating SE on Saturday. A new surface low pressure area will develop under the upper low over the central Atlantic and will move SW over our area of discussion this weekend. For additional information please visit http://www.hurricanes.gov/marine $$ Latto