000 AXNT20 KNHC 282311 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Mon Nov 29 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 1800 UTC surface analysis and satellite imagery through 2300 UTC. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Africa near 08N13W to 05N20W. The ITCZ continues from 05N20W to 01N50W. Scattered moderate convection is noted from 03N to 13N between 21W and 40W. GULF OF MEXICO... A stationary front extends from the SE Gulf near 25N83W to a 1015 mb surface low centered off the Texas coast near 27N92W. A cold front stretches from the low center to near 22N97W. Surface observations along with a recent scatterometer satellite pass indicate strong NE winds of 30 kt to the N of the low, with 20-25 kt NW winds in the wake of the front with 4 to 7 ft seas. Weak high pressure dominates the pattern elsewhere across the basin, supporting light to gentle winds and slight seas. For the forecast, the low pressure will move across the central Gulf through Mon then dissipate across the southeast Gulf along with the front. A reinforcing cold front is expected to enter the northeast Gulf early Mon and move across the eastern Gulf through Tue night, allowing high pressure to build over the northern Gulf through Thu. CARIBBEAN SEA... Weak high pressure located N of the Caribbean is supporting fresh to locally strong trade winds near the coast of Colombia and just S of Hispaniola, with 4 to 6 ft seas. Fresh northerly winds are off the Atlantic coastline of Nicaragua. Light to gentle winds persist elsewhere with 2 to 4 ft seas, except a little higher near Atlantic passages where N swell persists. Scattered showers and thunderstorms are noted north of Panama, and also near the Nicaragua/Costa Rica border. A diffluent pattern aloft is helping to induce this convective activity. Elsewhere, shallow moisture embedded in the trade wind flow will continue to move across the region producing isolated to scattered passing showers. A surface trough crosses the US/UK Virgin Islands and extends into the eastern Caribbean to near 13N66W. Some shower activity is noted near the northern end of the trough axis affecting the Atlantic waters of Puerto Rico. For the forecast, moderate to fresh NE to E winds will persist over all but the NW Caribbean through Mon before a cold front sinks slowly southward across the northwest Caribbean Mon night, then stalls along 20N and dissipates Wed. High pressure north of the front will induce strong trade winds across the south central Caribbean Tue night through Fri night. Moderate N to NE swell will continue across the Atlantic waters east of 70W and through the NE Caribbean passages through Mon tonight. ATLANTIC OCEAN... A cold front enters the Atlantic forecast area near 31N65W and continues SW to the NW Bahamas. Mainly light winds are noted near the frontal boundary based on scatterometer data with the exception of gentle to moderate NW winds just off NE Florida. Weak high pressure of 1019 mb follows the front. Large northerly swell has been moving across the Atlantic waters east of 60W over the past couple of days, but this is starting to subside from west to east. Another set of long period NE swell will propagate across the waters E of the Bahamas tonight building seas to 4-7 ft, highest E f 70W. For the forecast west of 65W, the reinforcing cold front is moving southeastward across the waters off northeast Florida this afternoon, and will reach from Bermuda to the Florida Keys by Mon evening, then weaken and stall from 27N65W to central Cuba Tue through Wed. Meanwhile, a mix of northerly swell will continue to move through the waters east of the Bahamas into early next week, then subside Mon night through Tue. High pressure will settle across the northern waters along 30N Wed through Thu. Farther east, latest scatterometer pass captured the presence of a 1015 mb low pressure centered near 28N54W. Fresh to strong winds are within about 90 nm on the southern semicircle of the low center. A surface trough extends from 29N54W to the low to near 21N59W. The same scatterometer pass indicates the wind shift related to this trough. Seas of 9-11 ft in NE swell are noted per an altimeter pass on the E side of the low and trough. Convection is displaced to the NE of the low center affecting mainly the waters just N of area between 44W-52W. A strong ridge dominates the eastern Atlantic anchored by 1037 mb high pressure located just N of the Azores. Divergence aloft east of a mid/upper trough along 40W is supporting some shower activity north of 20N and E of 38W. Scatterometer data depicts fresh to strong winds along the southern periphery of the above mentioned high pressure, and northeast of line roughly from the Cabo Verde Islands to 31N42W. Seas are 8 to 13 ft northeast of this line as well. Gentle to moderate trade winds and 5 to 8 ft seas are noted elsewhere. The Cumbre Vieja volcano, on the island of La Palma in the Canary Islands, has been erupting since 19 September 2021. Low to medium ash concentration is noted in the vicinity of the volcano drifting towards the SW. 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/. $$ ERA