000 AXNT20 KNHC 201016 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Sat Jul 20 2024 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 1100 UTC. ...TROPICAL WAVES... An eastern Atlantic tropical wave is along 28W/29W, south of 20N, moving westward at 10 to 15 kt. A few showers are seen near the trough axis. A tropical wave is moving westward across the central Caribbean at 20 to 25 kt. Its axis is along 74W/75W extending from the Windward Passage to northern Colombia. The wave is helping to induce scattered to numerous showers with embedded thunderstorms over Hispaniola and regional waters as well as across the Windward Passage and the waters between eastern Cuba and Jamaica. These storms may produce heavy downpours, lightning and gusty winds. A tropical wave is over the Yucatan Peninsula and Guatemala extending southward into the EPAC region moving westward at 20 kt. The wave, combined with an upper-level low over the south- central Gulf of Mexico, is supporting scattered to numerous showers and thunderstorms over parts of Belize and Guatemala. Gusty winds are possible near the stronger storms. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic through the coast of Senegal near 15N16W and continues westward to 10N30W and to 07N55W. A large area of Saharan dust extends across the Atlantic, and is suppressing any significant convection at this time. ...GULF OF MEXICO... Scattered showers and thunderstorms are noted over portions of the Gulf region associated with an upper-level cyclonic circulation located over the south-central Gulf. At the surface, the Atlantic ridge extends westward into the central Gulf, supporting gentle to moderate winds S of 25N, and light to gentle winds N of 25N. Seas are in the 1 to 3 ft range. For the forecast, a ridge will remain in place across the Gulf waters over the next several days. It will support gentle to locally moderate E to SE winds and slight seas. Pulsing moderate to fresh winds are expected near and to the NW of the Yucatan Peninsula during the evening and night hours due to local effects. ...CARIBBEAN SEA... A tropical wave is moving westward across the central Caribbean Sea. Please, see the Tropical Waves section above for more details. Recent satellite derived wind data indicate moderate to fresh trade winds with seas of 4 to 6 ft over the east and central Caribbean. Gentle to moderate winds and seas of 3 to 5 ft are evident over the NW Caribbean while light and variable winds are noted offshore Costa Rica and Panama due to the presence of the EPAC monsoon trough. Seas there are 2 to 3 ft. A band-like of showers and thunderstorms extends from the Gulf of Honduras across NE Honduras and northern Nicaragua into the SW Caribbean. Low-topped trade wind showers are seen elsewhere outside the influence of the tropical wave. For the forecast, as previously mentioned, a tropical wave is moving across the central Caribbean. Expect increasing winds and building seas in the wake of the wave axis today through Mon. The forecast calls for fresh to strong winds and seas of 8 to 10 ft. The trade winds and associated seas will diminish slightly on Tue, then increase again across the east and central Caribbean Tue night into Wed as the Atlantic high pressure strengthens some. ...ATLANTIC OCEAN... An area of showers and thunderstorms is just N of Hispaniola to about 24N. This convective active is related to the northern end of a tropical wave moving across the central Caribbean. The pressure gradient between the Atlantic high pressure and the northern end of the wave is resulting in an area of fresh to locally strong E winds offshore Puerto Rico and Hispaniola, particularly from 20N to 22N between 67W and 74W, including approaches to the Windward Passage. Scattered showers and thunderstorms are also noted across the Florida coastal waters. As it is normal for this time of the year, Saharan dust dominates most of the Atlantic waters E of 62W/63W, including the Lesser Antilles. Of note, SAL activity usually ramps up in mid-June, peaks from late June to mid-August, and begins to rapidly subside after mid- August. During peak period, individual SAL outbreaks reach father to the west (as far west as Florida, Central America and even Texas) and cover a vast areas of the Atlantic. A 1028 mb high pressure located ENE of Bermuda near 33N56W dominates the Atlantic forecast waters. Under the influence of this system, mainly moderate to fresh winds and 5 to 7 ft seas prevail S of 26N with gentle to moderate winds and seas of 3 to 5 ft N of 26N. Winds increase to fresh to strong speeds between the Canary Islands and off the northwest coast of Africa. A surface trough runs from 30N35W to 20N46W. Mostly low level clouds with possible showers are near the trough axis. For the forecast west of 55W, the Bermuda-Azores high will continue to dominate the Atlantic forecast waters. The associated ridge will slowly lift N to near 30N Mon through midweek. The related pressure gradient will support moderate to fresh easterly winds south of 26N, with winds pulsing to strong during the late afternoons and evenings off the northern coast of Hispaniola into next week. The northern portion of a tropical wave will move through the waters south of 24N through Mon accompanied by scattered to numerous showers and thunderstorms, some of which may produce strong gusty winds and rough seas. Tropical cyclone formation is not expected during the next 7 days. Please, see the latest NHC Tropical Weather Outlook at www.hurricane.gov for more details. $$ GR