000 AXNT20 KNHC 162223 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Wed Nov 17 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 2200 UTC. ...MONSOON TROUGH/ITCZ... The monsoon trough remains mainly inland over Africa extending just offshore of the border of Guinea and Sierra Leone near 08N14W. The ITCZ extends from 08N14W to 07N29W, then resumes west of a surface trough from 05N33W to 04N43W. The surface trough extends from 11N31W to 03N31W. Scattered moderate and isolated strong convection is noted from 08N to 13N between 23W and 28W. Isolated convection is noted west of the trough to 35W. GULF OF MEXICO... A 1025 mb high pressure positioned inland near Savannah, Georgia maintains fairly tranquil weather conditions across the Gulf of Mexico. Fresh winds are occurring in the SE Gulf waters, including the Straits of Florida, where seas are 4 to 6 ft. Moderate southerly winds are offshore the Texas and northern Mexico coast, with 2 to 4 ft seas in the area. Gentle winds prevail elsewhere with 1 to 3 ft seas. For the forecast, the high pressure area will move east into the western Atlantic and strengthen tonight into Wed. Fresh to locally strong east winds will develop over the southeastern Gulf and Straits of Florida tonight through Wed night. The next cold front will enter the Gulf region on Thu, and move SE of the area late on Fri. Fresh to strong northerly winds and building seas will follow the front. Scattered showers and isolated thunderstorms are expected ahead of this front. CARIBBEAN SEA... A stationary front extends from Central Cuba near 22N80W to 21N82W. A surface trough continues from 21N82W to 16N85W in the vicinity of the Gulf of Honduras. Another surface trough is located just to the south, offshore of Honduras and Nicaragua, from 17N81W to 11N83W. The monsoon trough extends from the eastern Pacific Ocean across Costa Rica to just north of Panama along 10N. Total precipitable water imagery shows a significant amount of moisture in the western Caribbean. Scattered moderate and isolated strong convection is noted over water from 09N to 22N between 79W and 88W. Moderate to fresh easterly trade winds cover most of the Caribbean Sea, except fresh to strong in the south- central Caribbean. Seas are mainly 4 to 7 ft across the basin, except locally to 8 ft offshore Colombia and eastern Panama. For the forecast, the stationary front will dissipate tonight. Strengthening high pressure over the western Atlantic combined with Colombian low pressure will bring increasing trade winds over the east and central Caribbean, including the Atlantic passages tonight through Thu. A cold front is forecast to approach the Yucatan Channel on Fri. ATLANTIC OCEAN... A cold front stretches from 31N60W to 25N72W, then transitions to a stationary front and continues into central Cuba near 22N80W. Scattered moderate convection is noted within 120 nm ahead of the front, N of 30N. Moderate NE winds are occurring to the north and west of the front, with fresh winds over the Bahamas and the Straits of Florida. A weakening surface trough extends from 28N58W to 22N60W with no significant associated convection. An upper- level low is producing scattered showers and thunderstorms from 10N to 17N between 44W and 47W. The activity in this area are also being enhanced by a surface trough that extends from 16N44W to 11N47W. Farther east, a 1012 mb low pressure is near 29N32W. An associated weakening occluded and cold front stretches ahead of this low from 31N28W to 27N26W to 22N31W, with a surface trough then continuing to 20N42W. Scattered moderate convection is noted north of 28N between 26W and 31W. Strong winds and seas of 9 to 11 ft are likely occurring within 150 nm NW of the low pressure center. Moderate to fresh trade winds and seas of 7-9 ft prevail over the tropical Atlantic from 10N to 22N between 27W-61W. Mainly gentle to moderate winds and 4 to 7 ft seas prevail elsewhere. The Cumbre Vieja volcano, on the island of La Palma in the Canary Islands, has been erupting since 19 September 2021. 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, the cold front will continue to move east, leaving a stationary boundary near 22N through Wed as strong high pressure builds over the western Atlantic. The pressure gradient between the high pressure and the stationary front will lead to increasing east winds and building seas south of about 28N from Wed through late Thu. Looking ahead, a cold front will move offshore NE Florida Fri, then stall from Bermuda to central Cuba over the weekend. This front will be followed by fresh to strong northeast to east winds and building seas north and northeast of the Bahamas. $$ Lewitsky