000 AXNT20 KNHC 111012 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Tue May 11 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 0600 UTC surface analysis and satellite imagery through 1000 UTC. ...Special Features... Caribbean Gale Warning: High pressure located N of the Caribbean Sea combined with the Colombian low will support fresh to strong winds, with frequent gusts to gale force off the coast of Colombia tonight. Then, fresh to strong trade winds will prevail over the south-central Caribbean through Fri. Seas are expected to build to 11-12 ft with the strongest winds late tonight into early Wed morning. Please read the latest NWS High Seas Forecast issued by the National Hurricane Center, at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, for more details. Gale Warning E of 35W: The pressure gradient between the Atlantic ridge and lower pressures over W Africa will support fresh to strong winds N of 20N and within about 150 nm of the coast of W Africa. Meteo-France has issued a Gale Warning for Agadir during the next 24 hours beginning this morning at 11/12Z. The forecast calls for northerly winds Force 8 in the Beaufort Wind Scale with gusts. For more details, refer to the Meteo-France High Seas Forecast listed on their website: www.meteofrance.com/previsions- meteo-marine/bulletin/grandlarge/metarea2. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic Ocean through the coast of Guinea Bissau near 12N16W and continues southwest to 02N25W. The ITCZ continues from 02N25W to 01N40W to 00N50W. Scattered moderate to isolated strong convection can be found from 00N-06N between 10W-15W, from 00N-05N between 23W-34W, and from 00N-05N W of 40W to the coast of Brazil GULF OF MEXICO... Atlantic high pressure extends westward across Florida into the Gulf of Mexico. A surface trough is W of the Yucatan peninsula. Fresh SE winds are noted E of the trough axis. Generally gentle to moderate southeast winds are over the eastern half of the Gulf while moderate to locally fresh southeast to south winds are noted over the western half of the Gulf based on recent scatterometer data. Seas are generally 4-6 ft W of 90W, and 3-4 east of 90W. Scattered moderate to isolated strong convection is observed along the coast of Mexico roughly between Tampico and Jalapa. Multilayered clouds dominate much of the Gulf waters. A ridge will continue to dominate the Gulf waters today producing moderate to locally fresh southerly winds across the western half of the Gulf and gentle to moderate E to SE winds over the eastern half. A surface trough will develop over the Yucatan Peninsula each evening and dissipate over the SW Gulf by morning. Moderate to fresh easterly winds will be associated with this trough. A frontal boundary will linger across the northern Gulf coast through tonight. Building high pressure across the SE CONUS will push a late-season cold front across the Gulf on Wed, and it is expected to extend across the Straits of Florida and the southern Gulf by late Fri. Showers with embedded thunderstorms are expected along the frontal boundary. Fresh to strong northerly winds will follow the front. CARIBBEAN SEA... A Gale Warning for frequent gusts to gale force remains in effect near the coast of Colombia. See the Special Features section for more information. Satellite derived wind data show fresh to strong winds over the south-central Caribbean. Similar wind speeds are in the Gulf of Honduras. Elsewhere, mainly moderate winds are occurring. Seas are 8-11 ft over the south-central Caribbean, 5-8 ft in the Gulf of Honduras and 4-7 ft elsewhere, except 1-3 ft in the lee of Cuba. A diffluent pattern aloft east of an upper-level trough axis continues to support abundant cloudiness and some shower activity over parts of the east and central Caribbean. Plenty of atmospheric moisture will persist in that region today, and combine with the local effects to maintain unsettled weather in the form of scattered showers and isolated thunderstorms over Puerto Rico and Hispaniola and regional waters. Some convective activity is also noted over the SW Caribbean near the base of the above mentioned upper-level trough. As for the forecast: Fresh to strong trade winds will continue over the south-central Caribbean through Fri. Fresh to strong winds are also expected in the Gulf of Honduras tonight and again Wed night. A moisture surge will continue to affect parts of the east and central Caribbean today while gradually diminishing. ATLANTIC OCEAN... A surface trough is analyzed near NE Florida. Scattered showers and thunderstorms are ahead of the trough in a southerly winds flow. E of the Bahamas, a ridge dominates the entire Atlantic forecast waters. Three high pressure centers are N of 30N, with the main center of 1028 mb located near 31N40W. Light to gentle winds are along the ridge axis while moderate to fresh trades are seen over the tropical Atlantic with seas in the 5-7 ft range. W of 65W: A ridge will continue to dominate the forecast waters today. A late-season cold front will move southward across the western Atlantic on Wed. Weak low pressure areas are expected to develop along the frontal boundary allowing the front to move across the northern forecast waters Thu and Fri, reaching the waters S of 27N on Sat. High pressure will follow the front. E of 65W: High pressure will remain in control of the weather pattern across the region over the next several days. A Gale Warning is in effect E of 35W in the area of Agadir. Please, see the Special Features section for more details. $$ GR