611 AXNT20 KNHC 110005 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Tue Jul 11 2023 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 2315 UTC. ...TROPICAL WAVES... A far eastern Atlantic tropical wave has its axis along 22W from 02N to 17N. It is moving westward at 10-15 kt. Isolated showers are ahead of this wave within 30 nm of 11N24W. A central Atlantic tropical wave, with a very noticeable signature on satellite imagery, has its axis extending from 20N51W to 05N55W. This wave is moving westward at about 20 kt. Scattered moderate convection is seen from 14N to 17N between 49W-59W. Fresh to strong easterly trade winds and seas of 6-9 ft are occurring in the vicinity of the tropical wave, mainly north of 13N. An eastern Caribbean Sea tropical wave has its axis along 69W south of 19N. It is moving westward at around 15 kt. Scattered showers and thunderstorms are east of the wave to 62W and from 12N to 15N. A central Caribbean Sea tropical wave has its axis along 79W, south of 21N. It is moving westward at 13 kt. This wave extends from eastern Cuba to Panama. Isolated moderate convection is present near the northern portion of the wave axis. ...MONSOON TROUGH/ITCZ... The monsoon trough axis reaches the Atlantic through the coast of northern Senegal near 16N17W and extends south-southwestward to 07N24W and to 07N29W, where it transitions to the ITCZ and continues to 06N38W and northwestward to 15N50W. It resumes at 14N54W to 11N61W. Aside from convection that is associated to tropical waves, numerous moderate isolated strong convection is occurring from 05N to 08N between 27W-32W and within 60 nm south of the ITCZ between 32W-37W. GULF OF MEXICO... The combination of divergence aloft associated to broad troughing with a surface cold front and pre-frontal that is just inland the southern United States has resulted in the development of scattered showers and thunderstorms north of 27N and east of 91W. The remainder of the Gulf of Mexico is in the southwestern periphery of the broad subtropical ridge positioned over the central Atlantic. This pattern is suppressing the development of deep convection, especially in the southeastern part of the Gulf, where a batch of dry Saharan dust is noted. Moderate to locally fresh anticyclonic winds are found in the NE Gulf and Bay of Campeche, along with seas of 3-4 ft. Stronger winds and higher seas may occur near the strongest convection. Elsewhere, moderate or weaker winds and 1-3 ft prevail. For the forecast, a ridge will continue to dominate the Gulf waters while a trough will develop over the Yucatan Peninsula each evening and move offshore. Under this weather pattern, moderate to fresh winds will pulse north and west of the Yucatan peninsula during the late afternoon and evening hours. Elsewhere, gentle to moderate anticyclonic flow and slight seas will prevail. CARIBBEAN SEA... The combination of low-level convergence and plenty of moisture is supporting numerous moderate to isolated strong convection in the southwestern Caribbean Sea, especially within 120 nm of the coasts of Nicaragua, Costa Rica and Panama. The rest of the basin is under a generally dry weather pattern that is suppressing the development of showers and thunderstorms, with the exception of the shower and thunderstorm activity that is east of the tropical wave in the eastern part of the sea as described above. The pressure gradient between the 1024 mb high pressure near the Azores and lower pressure in NW South America sustain strong to locally near gale-force easterly trade winds in the south- central Caribbean. This was confirmed by the latest ASCAT data pass over that part of the sea. These winds also support seas of 8-10 ft in the area described. Fresh to strong easterly trade winds and seas of 5-8 ft are found in the north- central Caribbean. Moderate to fresh easterly breezes are occurring in the eastern Caribbean and Gulf of Honduras, along with seas of 3-6 ft. Elsewhere, moderate or weaker winds and 2-4 ft seas are present. For the forecast, fresh to strong winds and rough seas will continue over the central Caribbean through the weekend as two tropical waves moves across the region. Locally near gale force winds are likely off Colombia. Fresh winds will reach strong speeds at night in the Gulf of Honduras through Tue, and resume Sat night. Moderate to fresh trade winds will prevail over the eastern Caribbean and tropical Atlantic waters through Sat night. One of the aforementioned tropical waves is forecast to bring an increase in winds and seas across the waters E of the Leeward Islands on Tue, and over the NE Caribbean on Wed. Fresh to strong northeast winds are expected in the Windward Passage ahead of the wave axis by Wed night. ATLANTIC OCEAN... The tropical Atlantic is dominated by an expansive subtropical ridge positioned near the Azores. The basin is mostly devoid of deep convection aside from isolated showers found north of the NW Bahamas. The pressure gradient between the ridge and a frontal system off the eastern United States is sustaining moderate to fresh southwest winds north of 28N and west of 55W. Moderate easterly trade winds are noted south of 24N and west of 55W. Seas in the waters described are 4-7 ft. Elsewhere W of 55W, light to gentle anticyclonic winds and seas of 3-5 ft prevail. Satellite imagery reveals that another outbreak of Saharan dust is occurring off the coast of Africa and will be propagating westward over the next several days. Moderate to locally strong northerly winds are present in the eastern Atlantic, especially south of 29N and east of 35W. Seas over these waters are 5-8 ft. Moderate or weaker winds and moderate seas are prevalent over the remainder of the basin. For the forecast W of 55W, a ridge will remain in place across the SW N Atlantic while a weak frontal boundary emerges off the southeastern United States, and shifts eastward across the waters north of 30N through late Wed. The pressure gradient between these two features will support moderate to fresh southwest winds north of 27N through Tue. Developing low pressure north of the forecast region could bring increasing winds over the northeast waters Tue night into Wed. The northern end of a tropical wave is forecast to impact the waters north of the Leeward Islands and Puerto Rico on Wed, and north of Hispaniola, including approaches to the Windward Passage by Wed night. Light to gentle winds will persist elsewhere along the ridge axis. $$ Aguirre