National Hurricane Center's Tropical Weather Discussion

North America - Central America - Gulf of Mexico - Caribbean - Atlantic Ocean

674 AXNT20 KNHC 121759 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1259 PM EST Wed Dec 12 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 1200 UTC surface analysis and satellite imagery through 1745 UTC. ...SPECIAL FEATURES... ...Gulf of Mexico Gale... A cold front is forecast to enter the NW Gulf of Mexico Thu and quickly reach the eastern Gulf late Thu night, then push SE of the basin Fri night. Fresh to Strong to near gale force northerly flow west of the front will increase to gale force on Thu evening over the northwest and west-central gulf waters. Near gale force southerly flow expected east of the front on 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 08N13W to 04N22W. The ITCZ continues from that point to 01N34W to 00N46W near the coast of Brazil 01S46W. Scattered moderate convection is noted along and within the ITCZ and monsoon trough from 07N- 00N between 11W-48W. Scattered moderate isolated strong convection is noted south of the monsoon trough 05N-02S between 09W-07W. GULF OF MEXICO... A 1026 mb high pressure is centered over SW Alabama and the northern panhandle of FL, with a surface ridge extending across most of the Gulf. High, thick cirrus clouds are streaming into the western Gulf from Mexico. Latest observations show no precipitation accumulation has been observed with broken to overcast skies dominating the region. A moderate southeast flow is seen in the latest observations continues across much the northwest portion of the Gulf. Fresh to locally strong southerly return flow will precede a cold front moving off the Texas coast early Thu with the front reaching from the Mississippi Delta to the Bay of Campeche on Thu night, from the Florida Big Bend to the Yucatan Channel on Fri and moving E of area around sunrise on Sat. Strong to near gale force northerly flow west of the front will increase to gale force on Thu evening over the northwest and west-central gulf waters. Near gale force southerly flow expected east of the front on Fri. The pressure gradient will relax on Fri night and Sat with moderate west flow expected on Sat evening with seas subsided to less than 8 ft throughout the gulf by sunrise on Sun. CARIBBEAN SEA... A stationary front extends from eastern Cuba near 20N78W to 19N83W to a dissipating stationary front from that point to near 18N85W. Isolated showers are noted in the vicinity of the front. In the eastern Caribbean, isolated showers are seen near 14N68W just north of the ABC Islands. However, most of the eastern and southwestern Caribbean is relatively dry. Gentle to moderate trades winds are noted. Further west, moderate to fresh northeast winds are observed over the western Caribbean. Fresh to strong trade winds will prevail across the S-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. A frontal trough extending southwest from east Cuba to the Gulf of Honduras will drift west-northwest and gradually dissipate through early Fri. Fresh to locally strong northerly winds will continue west of the front through this evening. A cold front will enter the northwest Caribbean on Fri afternoon, and dissipate over the NW Caribbean during the upcoming weekend. Large north swell will reach the Leewards on Sat, and spread south through the northeast Atlantic passages during the upcoming weekend. ATLANTIC OCEAN... A cold front extends from 31N58W to eastern Bahamas near 21N71W into eastern Cuba near 21N76W. Scattered convection is noted to the south of 31N between 57W-50W associated to the front. A 1026 mb ridge of high pressure extends from the Gulf of Mexico to 27N58W and dominates the western Atlantic. Further east of the cold front, a 1026 mb ridge dominates most of the basin. A weak trough is noted at 25N35W. The cold front is forecast to begin drifting back north on Thu and extend east to west along 25N on Fri. Large seas, primarily due to northwest swell, across the waters north east of the Bahamas will subside from the west through Thu. A surface high near 30N78W will shift east-northeast passing northwest of Bermuda on Thu setting up strong to near gale southerly return flow north of the Bahamas on Thu night and Fri, ahead of another cold front that will sweep east across the northern waters during the upcoming weekend reaching a position from Bermuda to central Cuba on Sun night. For additional information please visit http://www.hurricanes.gov/marine $$ MTorres