000 AXNT20 KNHC 270508 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Wed Oct 27 2021 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 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...SPECIAL FEATURES... Gulf of Mexico Gale Warning: Strong to near gale force winds will follow a cold front expected to move through the Gulf of Mexico Wed through Thu. Water temperatures are still relatively warm over the Gulf of Mexico. The cooler air following the front will move over the warmer waters and allow gale force winds in the lower levels of the atmosphere to mix to the surface over the north- central and northeast Gulf. Therefore a gale warning for frequent gusts to gale force has been issued for these area valid from Wed night through Fri. Seas will build as high as 14 ft in the wake of the front over the northern Gulf. A squall line containing strong to severe thunderstorms with very strong wind gusts is expected to accompany the cold front as it moves from west to east Wed afternoon through Thu morning. The strongest thunderstorms should occur over the northwest and north-central Gulf with the line, Wed afternoon through Wed night. ...TROPICAL WAVES... An Atlantic tropical wave is along 28W from 18N southward, moving W at 10-15 kt. Scattered moderate to isolated strong convection is evident from 05N to 07N between 25W and 30W. A recent ship observation showing NE winds between Colombia and Jamaica indicated there may be a surface trough along 74W/75W, but extending no farther north than 15N/16N into the ridge axis farther north. A deep layer trough moving through the Bahamas toward the Windward Passage is providing support for the surface trough. A few showers and thunderstorms are active along this feature off the coast of Colombia near Barranquilla and Cartagena. This feature will move little over the next couple of days, and gradually become absorbed into a broader area of low pressure centered over the southwest Caribbean. ...MONSOON TROUGH/ITCZ... The monsoon trough extends off the coast of Senegal near 13N17W to 11N28W. The ITCZ extends from 07N30W to 07N40W to 04N50W. In addition to the convection described in the Tropical Waves section, scattered moderate to isolated strong convection is occurring on either side of the ITCZ, from 06N to 08N between 30W and 40W. GULF OF MEXICO... A cold front extends from west central Florida near Sarasota to 28N87W, where it becomes stationary to southwest Louisiana. Light to gentle breezes follow the front, and it may be starting to weaken and stall over the eastern Gulf. Gentle to moderate SE winds and 3 to 5 ft seas are noted off Texas and northern Tamaulipas, with light to gentle SE winds and 1 to 3 ft elsewhere. A few showers are noted north of the front over the northeast Gulf, but no significant shower or thunderstorm activity is noted elsewhere. For the forecast, fresh to strong southerly winds will develop across the NW Gulf tonight into Wed ahead of the cold front expected to push off the Texas coast on Wed morning. The front will move across the Gulf region through Thu night. Fresh to strong winds are expected ahead and behind the front, with building seas to 12-14 ft in the wake of the front by Thu. Frequent gusts to gale force are forecast over the north-central and NE Gulf Wed night through Fri before quickly diminishing early Sat. CARIBBEAN SEA... The Atlantic ridge extends from northeast of the region across Hispaniola and Cuba. A 1014 mb high was analyzed off southwest Haiti along the ridge axis. The ridge was displaced southward ahead of a deep layer trough and associated cold front currently north of the region moving through the Bahamas. Recent observations and data from a scatterometer satellite pass from 0140 UTC showed moderate to fresh winds trade winds south of 15N, with fresh to strong E winds over the Gulf of Venezuela. The same pass along with observations from Roatan indicated fresh winds off Honduras through the Bay Islands. Gentle to moderate E to SE winds are noted elsewhere. Seas are 4 to 6 ft in most areas. For the forecast, the position of the surface ridge will continue to support moderate to fresh trades across the south-central Caribbean, including the Gulf of Venezuela through early Thu. Gentle to moderate SE to S winds will prevail over the NW Caribbean through Thu night ahead of a cold front forecast to reach western Cuba and the NW Caribbean. The front will extend from western Cuba to the Gulf of Honduras by midday Fri, and from central Cuba to NE Honduras on Sat. ATLANTIC OCEAN... A recent scatterometer satellite pass showed fresh to strong W to NW winds following a cold front reaching from 31N73W to central Florida. This front follows another boundary reaching from near Bermuda to the northern Bahamas. Divergence aloft ahead of deep layer trough supporting both these features is responsible for clusters of moderate to strong convection east of the fronts from 25N to 27N between 62W and 65W, and north of 30N between 65W and 67W. Elsewhere, a surface ridge extends from 1026 mb high pressure near the Azores southwestward to Hispaniola. Seas are 6 to 9 ft in the area of fresh to strong winds north of 26N between 50W and 75W, and 4 to 6 ft elsewhere over open waters. Moderate trades are noted south of the ridge, except for moderate to fresh NE winds off northwest Africa, and light to gentle breezes elsewhere. The Cumbre Vieja volcano, on the island of La Palma in the Canary Islands, has been erupting since 19 September 2021. Ash cloud slowly drifting SW. Higher concentration over volcano and western vicinity. Marine and aviation interests should monitor this ongoing situation by reading the Volcanic Ash Advisory issued by Meteo-France, at http://vaac.meteo.fr/volcanoes/la-palma/. For the forecast west of 65W, the cold front extending from 31N73W to central Florida will reach from 31N67W to the Straits of Florida on Wed, and from 31N65W to the central Bahamas by Wed night. The front will dissipate over the SE waters on Thu. The next cold front is expected to sweep across the region Thu night through Fri night, then stall from 31N68W to eastern Cuba during the upcoming weekend. Fresh to strong winds and building seas are expected on either side of these fronts. $$ Christensen