000 AXNT20 KNHC 110541 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 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 0000 UTC surface analysis and satellite imagery through 0500 UTC. ...TROPICAL WAVES... A eastern Atlantic tropical wave has its axis along 23W from 02N to 15N. It is moving westward at 10-15 kt. Isolated showers are ahead of this wave within 30 nm of 11N24W. A western Atlantic tropical wave, with a very noticeable signature on satellite imagery, has its axis extending from 19N52W to inland Suriname. This wave is moving westward at about 20 kt. Scattered moderate convection is seen from 14N to 18N between 49W-59W. Resent scatterometer data shows fresh easterly trade winds. Seas of 6-9 ft are occurring in the vicinity of the tropical wave, mainly north of 13N. A western Caribbean Sea tropical wave has its axis along 80W, south of 20N. It is moving westward at 10-15 kt. This wave extends from central Cuba to Panama. Scattered 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 Guinea/Bissau near 18N16W and extends south-southwestward to to 13N22W. The ITCZ begins at 11N24W and continues to 07N33W and northwestward to 10N53W. It resumes at 13N55W to 13N61W. Aside from convection that is associated to tropical waves, numerous moderate isolated strong convection is occurring from 05N to 09N between 29W-36W and within 60 nm south of the ITCZ between 38W-44W. GULF OF MEXICO... The combination of divergence aloft associated to broad troughing with a surface cold front and pre-frontal boundary that is just inland the southern United States has resulted in the development of scattered showers and thunderstorms north of 26N and east of 91W. Scattered showers and thunderstorms are seen west of Cuba moving westward as it dissipates. Another area of scattered showers and thunderstorm is noted in the Bay of Campeche is association with a surface trough. Stronger winds and higher seas may occur near the strongest convection. 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. Elsewhere, light to gentle 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... Please see the Tropical Wave section above for convection associated with waves in the Carribbean Sea. The rest of the basin is under a generally dry weather pattern that is suppressing the development of showers and thunderstorms, thanks to the presence of Saharan Dust. The pressure gradient between the 1025 mb high pressure in the Central Atlantic 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 scatterometer pass over that part of the basin. 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, light to moderate winds and 2-4 ft seas prevail. 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. Strong to 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 E Caribbean and tropical Atlantic waters through Sat night. One of the aforementioned tropical wave 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 NE winds are expected in the Windward Passage ahead of the wave axis by Wed night. ATLANTIC OCEAN... Please see the Tropical Wave and Monsoon Trough/ITCZ sections above for convection in the Tropical Atlantic. The central Atlantic is dominated by an expansive subtropical ridge located in the area. The basin is mostly devoid of deep convection aside from scattered showers and thunderstorms found off the coast of central Florida. 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. Light to moderate 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 will come off the SE CONUS Tue and move E over the waters N of 30N through late Wed. The pressure gradient between these two features will support moderate to fresh SW winds north of 27N through Tue. A developing low pressure N of the forecast region could bring increasing winds over the NE 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. $$ KRV