000 AXNT20 KNHC 130551 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1251 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 0000 UTC surface analysis and satellite imagery through 0515 UTC. ...SPECIAL FEATURES... ...Gulf of Mexico Gale Warning... A cold front is forecast to enter the northwest Gulf of Mexico by early this afternoon and extend from the Mississippi Delta to Tamiahua Mexico tonight, from the Florida Big Bend to the Yucatan Peninsula Fri morning and move E of area before sunrise on Sat. Gale force winds are expected tonight through Friday afternoon behind the front over the northwest and west-central Gulf waters. 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 02N24W. The ITCZ continues from that point to 01N30W to 01N40W to the coast of Brazil near 01S48W. Scattered moderate convection is seen from 02N-04W between 39W-51W. Between the W coast of Africa and 39W, isolated showers are noted near and within 180 nm S of the monsoon trough and ITCZ. GULF OF MEXICO... A 1025 mb surface high is centered near the Florida/Georgia border near 31N82W. The high extends a surface ridge across the eastern portion of the Gulf. Scatterometer data depicts moderate anticyclonic flow across the eastern Gulf. Little in the way of any shower activity is noted over the eastern Gulf. However, in the far western Gulf, SE to S winds have increased to fresh to strong. Satellite imagery shows higher moisture content and increasing mid to high clouds over the western Gulf. Scattered showers are seen west of 95W from 24N-28N. Fresh to locally strong southerly return flow will increase early this morning ahead of a cold front, which will move off the Texas coast by early afternoon today. 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. Near gale force southerly flow is expected east of the front Thu night into Fri. Strong to near gale force winds will cover the Bay of Campeche on Fri. Seas of 12-16 ft will cover a large portion of the Gulf by Friday behind the front. In addition, thunderstorms will accompany the front, especially over the northern half of the Gulf. The pressure gradient will relax on Sat resulting in moderate to fresh west winds with seas subsiding to less than 8 ft Sat night. CARIBBEAN SEA... A weakening stationary front extends from the Windward Passage to 19N80W to 16N85W. Isolated showers are noted along the front. Scatterometer data from Wednesday evening indicate that a surface trough is present in the NW Caribbean from 21N82W to 17N85W. Isolated showers are near the trough south of 20N. In the eastern Caribbean, radar and satellite imagery show isolated showers from 13N-15N between 67W-71W. Fresh to strong trade winds will prevail across the south central Caribbean with nocturnal pulses to near gale force off the northwest coast of Colombia. These strong trades will expand north across the entire central Caribbean on Fri and Fri night. The weak frontal boundary across the west Caribbean will dissipate early today. The surface trough over the NW Caribbean will move to the Yucatan Peninsula later this morning. A cold front will enter the northwest Caribbean on Friday afternoon, and dissipate over the NW Caribbean during the upcoming weekend. Fresh to strong winds are expected west of the front on Sat. Large north swell will reach the Leewards on Sat, and spread south through the northeast Caribbean passages during the weekend. ATLANTIC OCEAN... A cold front extends from 32N53W to 27N59W to 23N65W, 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 40W from 17N-24N with isolated showers. A 1029 mb surface high is centered near 30N28W and extends a ridge across most of the remainder of the basin. The front is forecast to drift back north today and extend east to west along 25N on Fri. Fresh to strong winds will develop along this boundary as strong high pressure moves east across the northern waters ahead of the next cold front to enter the NW waters on Fri night. A strong pressure gradient between this front and the high pressure will support strong to near gale southerly return flow north of the Bahamas on Thu night and Fri. The front is expected to reach from 30N67W to the central Bahamas on Sun evening and from 30N63W to the southern Bahamas on Mon night. For additional information please visit http://www.hurricanes.gov/marine $$ Hagen