000 AXNT20 KNHC 131146 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 646 AM EST Thu Dec 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 0600 UTC surface analysis and satellite imagery through 1130 UTC. ...SPECIAL FEATURES... ...Gulf of Mexico Gale Warning... A cold front is forecast to enter the northwest Gulf of Mexico by early this afternoon. The front will shift across the Gulf waters, moving E of the Gulf Saturday. Gale force winds are expected tonight through Fri morning behind the front over the northwest and west-central Gulf waters, with winds diminishing later Fri. Please read the latest High Seas Forecast under AWIPS/WMO headers HSFAT2/FZNT02 KNHC for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Sierra Leone near 07N12W to 03N21W. The ITCZ continues from that point to 02N25W to 01N37W to the coast of Brazil near 02S44W. Scattered moderate convection is seen from 01N-04W between 40W-52W. Between the W coast of Africa and 40W, isolated to scattered showers are noted within a few degrees of the monsoon trough and ITCZ. GULF OF MEXICO... A surface high pressure ridge continues to retreat away from the eastern Gulf as a 1025 mb surface high is now over the western Atlantic off the SE U.S coast. A 999 mb surface low over the Texas Panhandle has an associated cold front extending into southern New Mexico. In advance of the front, scattered thunderstorms are currently occurring over the NW Gulf W of 93.5W and N of 24.5N, including over the Houston and Beaumont Texas areas. These storms are being enhanced by upper-level diffluence over the western Gulf. Light showers are occurring over the northern Gulf offshore of Alabama and Mississippi and well as the W Florida Panhandle to the SE tip of Louisiana. The cold front that is currently over NW Texas and SE New Mexico will quickly sweep across Texas this morning, reaching the NW Gulf of Mexico this afternoon. The front will shift E across the Gulf waters, moving E of the area Sat. Strong to near gale force northerly flow west of the front will increase to gale force tonight over the northwest and west-central Gulf waters before diminishing Fri afternoon. Near gale force southerly flow is expected east of the front tonight into Fri. Seas of 10-16 ft will cover a large portion of the western and central Gulf by Friday behind the front. In addition, strong thunderstorms are expected ahead of and along with the front beginning today, especially over the northern half of the Gulf, as the front sweeps across the Gulf from west to east. Locally enhanced winds and seas can be expected near the stronger thunderstorms. High pres will build in the wake of the front this weekend and prevail through early next week. CARIBBEAN SEA... A surface trough is present in the NW Caribbean from 21N83W to 16.5N85.5W. Isolated showers are near the trough. Most of the Caribbean is relatively quiet with no significant convection and only some light showers. Fresh to strong trade winds will prevail across the central Caribbean, with nocturnal pulses to near gale force off the northwest coast of Colombia. A cold front will move into the NW Caribbean Fri, where it will dissipate this weekend. Northerly swell will reach the Leewards on Sat, and spread south through the northeast Caribbean passages this weekend. ATLANTIC OCEAN... A cold front extends from 32N50W to 28N55W to 24N65W, then continues as a stationary front from that point to the Windward Passage. Scattered showers are noted along and ahead of the front north of 30N. To the east, a surface trough is analyzed along 41W from 17N-24N with isolated showers. A 1028 mb surface high is centered near 31N28W and extends a ridge across most of the remainder of the basin east of the front. The front from 23N65W to the Windward Passage will begin to drift N today. Southerly return flow will develop later today into Friday ahead of the next cold front forecast to move into the NW waters on Fri night. The front will shift eastward this weekend, reaching a position from Bermuda to central Cuba on Sun night. For additional information please visit http://www.hurricanes.gov/marine $$ Hagen