000 AXNT20 KNHC 281721 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Thu Oct 28 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 1200 UTC surface analysis and satellite imagery through 1630 UTC. ...SPECIAL FEATURES... Gulf of Mexico Gale Warning: Satellite derived wind data this morning confirm minimal gale force winds over the NW Gulf behind a strong cold front moving across the eastern Gulf today. The front currently extends from the central Florida Panhandle to near Veracruz, Mexico. Very active convection is along the front, and is also occurring within 60-120 nm ahead of it in a squall line, where frequent lightning and strong gusty winds prevail. Fresh to strong southerly winds will continue ahead of the front today as it moves into the Gulf coast of Florida. Winds and seas are expected to peak tonight. At this time, W to NW winds of 30-35 kt and seas in the 10-15 ft range are expected. These dangerous marine conditions will begin to gradually diminish from W to E late Fri into Sat. Please, see the latest NWS High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for further details. ...TROPICAL WAVES... An Atlantic tropical wave has been repositioned along 27W from 19N southward moving W at 10 to 15 kt. Long term satellite imagery animations as well as precipitable water animation suggest that some low level moisture has continued moving westward ahead of the wave, to along 32W, where a 1011 mb surface low is along the monsoon trough near 10.5N32W. However the main wave energy appears to be consolidating further to the east along 27W. Very active convection continues to the south and east of the wave, where satellite imagery shows scattered moderate to convection from 04N to 08N between 23W and 30W, and from 04N to 15N between 19W and 24W. Scattered moderate convection is noted within 90 nm across the SW quadrant of the low along 10.5N32W. ...MONSOON TROUGH/ITCZ... The monsoon trough exits the Guinea coast near 11N15.5W and meanders westward to 09.5N18.5W to 11.5N26W to 1011 mb low pres near 10.5N32W to 08N37W. A segment of the ITCZ extends from 05N43W to the coast of French Guiana near 05N52W. Numerous moderate to strong convection is seen from 03N to 09N between 10W and 19W. Scattered moderate convection is noted from 02.5N to 06.5N between 30W and 40W. ...GULF OF MEXICO... A strong cold front extends from the central Florida Panhandle to the coast of Mexico near Veracruz, and is racing quickly SE across the basin today. Strong tstorms and squalls are occurring along and within 120 nm ahead of the front. Gale force W to NW winds and large seas to 14 ft are occurring behind the front and N of 26N, while strong NW to N winds are elsewhere behind it. Scatterometer winds from this morning also depicted strong SW winds to 30 kt ahead of the front moving into the Florida Big Bend, where seas of 8-10 ft prevail. Please see the Special Features section for more details. The front is supported by a large area of low pressure shifting eastward across the eastern United States, producing a strong pressure gradient over the northern Gulf. This will support the strong to gale force winds across the northern Gulf waters behind the front through Fri. ...CARIBBEAN SEA... Generally fair and stable atmospheric conditions prevail across all but the SE Caribbean today. Morning scatterometer data showed moderate to fresh trade winds across the south central Gulf between 65W and 74W, where peak seas were to 8 ft. Scatterometer data also showed fresh southerly winds opening up across the NW Caribbean and flowing through the Yucatan Channel and into the SE Gulf of Mexico, ahead of the cold front. Wind and seas are generally more tranquil across the remainder of the Caribbean today. Active convection across the SW Caribbean has diminished somewhat this morning. Scattered moderate isolated strong convection is seen within 90 nm of the NW coast of Colombia, and S of 15N to the W of 81W. A weak ridge over the northern Caribbean Sea will continue to support mainly gentle to moderate trade winds across the basin, with locally fresh winds possible in the Gulf of Honduras and off the coast of Venezuela. A cold front will enter the basin through the Yucatan Channel tonight. This front will move through the NW Caribbean into the weekend, before stalling from the Windward Passage to northern Nicaragua by Sun. Moderate to fresh NW winds and seas to 8 ft can be expected behind the cold front. ...ATLANTIC OCEAN... A cold front enters the discussion area near 31N60W to 27N66W where it becomes stationary to the northern Bahamas near 25N77W. Active convection continues along and within 90 nm southeast of both of these boundaries. South Florida. Fresh to strong westerly winds are occurring behind the front, to the N of 29N and E of 70W, while fresh SW winds prevail southeast of the front and N of 24N to 60W. Seas are 6-11 ft in NW swell behind the front and 6-10 ft ahead of it. The remainder of the Atlantic is under the influence of a 1023 mb high pressure located near 30WN27W. This system extends a ridge SW across the Greater Antilles. Light and variable winds are along the ridge axis while a belt of gentle to moderate trades is along the southern periphery of the ridge. The Cumbre Vieja volcano, on the island of La Palma in the Canary Islands, has been erupting since 19 September 2021. Ash cloud is slowly drifting SW. High volcanic ash concentration remains in the vicinity of the volcano. 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/. A aforementioned cold front will move east and weaken N of 27N, while the remaining stationary portion will drift northward and gradually dissipate through Fri. The next cold front will move off the SE U.S. coast tonight, then gradually reach from Bermuda to the Windward Passage over the weekend. Strong winds with seas in excess of 8 ft are expected to develop on both sides of the front this afternoon through Sat night, mainly N of 26N. Moderate to large NE swell will dominate the waters W of 65W through the weekend. $$ Stripling