000 AXNT20 KNHC 292310 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Sun Jul 30 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 2310 UTC. ...TROPICAL WAVES... A tropical wave is being analyzed in the eastern Atlantic extending along 20W from the equator to 19N, moving westward at an uncertain 10-15 kt. Scattered moderate convection is observed from 10N to 17N east of 18W, enhanced by the monsoon trough. A central Atlantic tropical wave extends along 20N47W to 04N54W in French Guiana, moving westward at 15-20 kts. Strong E winds are in the vicinity of the northern terminus of the wave axis with seas of 8-9 ft. While this feature is only producing disorganized cloudiness and showers, environmental conditions are expected to be favorable for gradual development during the next few days, and a tropical depression is likely to form early next week. The disturbance is forecast to move west- northwestward to northwestward at about 15 kt during the next day or so, and then turn north-northwestward to northward over the central subtropical Atlantic Monday and Tuesday. This feature has a low chance of tropical cyclone development through 48 hours and a high chance over the next seven days. The tropical wave is expected to continue westward after the disturbance moves northwest and breaks away. A Caribbean tropical wave extends along 69W from the Mona Passage to Venezuela, moving west at 10-15 kt. Outside of some showers and tstorms impacting Puerto Rico and Hispaniola, no other convection is noted at this time. The far northern extent of a tropical wave is over the Bay of Campeche, SE Mexico, and central America along 92W south of 20N, moving west at 15 kt. Scattered moderate convection is in the Bay of Campeche south of 22N east of 92W, including inland over the Yucatan Peninsula. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Africa near 15N17W to 07N28W to 18N45W to 12N57W. In addition to the convection in the eastern Atlantic described in the tropical wave section, scattered moderate convection is observed from 12N to 16N between 55W and 60W. The eastern extent of the Pacific monsoon trough is supporting scattered showers and thunderstorms in the SW Caribbean along the coast of Panama and Costa Rica. GULF OF MEXICO... Please refer to the TROPICAL WAVES section above for information about the Bay of Campeche tropical wave. 1020 mb high pressure is centered near south-central Louisiana. Scattered moderate convection is in the SW Gulf of Mexico from 18N to 23N west of 95W. Easterly winds are light to gentle across the majority of the basin, increasing to moderate speeds in the Bay of Campeche. Seas are 1-3 ft in the northern Gulf and 2-4 ft in the southern Gulf. For the forecast, a weak surface ridge will remain the dominant feature across the basin through early next week. This will support gentle to moderate winds, except over the eastern Bay of Campeche, where winds will be enhanced by a thermal trough that will emerge off the Yucatan Peninsula each night. A weak surface trough currently extending from northern Florida to western Florida Keys will meander across the eastern Gulf tonight and remain the focus for scattered showers and isolated thunderstorms. Weak high pressure will shift SE into the east central Gulf Tue and Wed and allow for moderate return flow to develop across the W Gulf. CARIBBEAN SEA... Please refer to the TROPICAL WAVES and MONSOON TROUGH/ITCZ section above for convection in the Caribbean Sea. The gradient between the expansive subtropical high and lower pressure over Colombia is supporting enhanced easterly trades winds across the basin. Trades are strong in the south-central Caribbean with 8-10 ft seas, and fresh in the remainder of the central basin with 7-8 ft seas, and moderate to fresh in the eastern and NW Caribbean with 5-7 ft seas. Isolated showers and tstorms are noted in the lee of Cuba. For the forecast, the pressure gradient between the Bermuda High and lower pressure over Colombia will induce pulsing fresh to strong trades across the entire central Caribbean through the weekend, then become confined to the south central Caribbean through early next week. A strong tropical wave over Central America will continue to produce scattered showers and thunderstorms across the SW Caribbean tonight and Sun. A strong tropical wave is expected to move across the Tropical Atlantic and reach 55W by late Sun. A broad area of low pressure has developed in the vicinity of the wave and is expected to move NW into the open Atlantic through Wed. ATLANTIC OCEAN... The weather pattern is dominated by a subtropical high pressure ridge with its axis oriented E-W along 32N. In the western Atlantic winds are gentle to moderate from the S-SE with 4-6 ft seas. In the central Atlantic, winds are gentle to moderate from the E. Seas are generally 4-6 ft in the central Atlantic. Higher winds and seas are near the tropical disturbance. In the eastern Atlantic, the gradient between the subtropical high pressure and lower pressure over Africa is supporting moderate to fresh NE winds and 6-8 ft seas. An area of Saharan Air is observed east of 40W and north of 12N. Lower visibility and hazy skies may be possible within this area. For the forecast west of 55W, high pressure centered over the central Atlantic will gradually shift eastward through Tue, and will maintain moderate to locally fresh trade winds S of 23N through early Mon. Fresh trades will pulse each late afternoon through evening N of Hispaniola and over the Windward Passage. Developing surface low pressure across the central Atlantic near 17.5N45.5W will move NW then N across the NE offshore zones Mon through early Wed before exiting the region to the N. $$ Mahoney