070 AXNT20 KNHC 271741 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 141 PM EDT Mon Aug 27 2018 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 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 1200 UTC surface analysis and satellite imagery through 1730 UTC. ...TROPICAL WAVES... A far eastern Atlantic tropical is just west of the African coast with its axis along 21W from 04N-20N, moving westward at 10-15 kt. The wave is embedded within the broad monsoonal trough region of W Africa. Satellite imagery shows scattered moderate convection in the wave's vicinity between 14W-23W. A central Atlantic tropical wave has its axis along 51W from 04N to 20N, moving westward at 10-15 kt. This wave is surrounded by a rather stable and dry environment. Isolated showers are noted along the wave's axis from 08N-14N. A tropical wave is moving across the eastern Caribbean, with axis along 62W between 05N-20N, moving west at 10-15 kt. This wave is well depicted by model guidance and surface observations. Scattered showers are noted within this wave mainly south of 10N affecting eastern Venezuela. A western Caribbean tropical wave has its axis along 83W and south of 20N, moving westward at about 15 kt. The upper-level cyclonic flow prevails across the western Caribbean west of 77W enhancing convection in this area. Scattered moderate convection prevails south of 14N between 79W-86W affecting Central America and adjacent waters. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Africa near 17N17W to 10N26W to 09N49W. Aside from convective activity associated with the far eastern Atlantic tropical wave, scattered moderate convection is within 75 nm on either side of the monsoon trough between 25W-31W. ...DISCUSSION... GULF OF MEXICO... An upper-level trough extends from northeastern Florida to 23N83W, At the surface, a ridge prevails across the basin anchored by a 1023 mb high centered over northern Georgia. Very moist and unstable atmosphere is noted across the basin enhancing scattered showers. The strongest activity prevails north of 25N between 86W-92W. An upper-level low is centered over central Cuba enhancing convection across the Florida Peninsula and Keys mainly east of 82W. A surface trough will develop during the evening hours over the Yucatan Peninsula, before pushing offshore into the SW corner of the Gulf of Mexico each night. This trough, in combination with Sunday's daytime heating acting on ample instability in place, will trigger off scattered moderate convection over much of the Peninsula and the eastern Bay of Campeche. A surge of moderate to fresh northeast to east winds will accompany this trough. A weak surface ridge will continue over the rest of basin, with its associated gradient supporting a mainly gentle to moderate wind flow regime. CARIBBEAN SEA... Tow tropical waves are moving across the basin. Refer to the section above for details. An upper-level low is centered over central Cuba near 20N81W. This feature, along with abundant tropical moisture, is inducing scattered showers currently affecting the island and the southeast Gulf of Mexico. The activity will gradually shift from east to west as the upper low tracks further away to the W. The eastern segment of the eastern Pacific monsoon trough stretches eastward into the far southwestern Caribbean to the northwestern coast of Colombia. This, combined with a tropical wave along 83W, are supporting scattered showers and thunderstorms are south of 14N between 79W-86W. Fresh to strong winds, and building seas to 10 feet, will continue in the south central Caribbean Sea through mid-week. The tropical wave near the Lesser Antilles will continue moving across the basin accompanied by fresh easterly winds and wave heights expected to max out around 8 ft. Another wave will enter the eastern Caribbean early on Wed, increasing the likelihood of scattered showers and thunderstorms over much of the Lesser Antilles. ATLANTIC OCEAN... Two tropical waves are moving across the basin. Refer to the section above for details. An upper level low is centered over the northwestern Caribbean enhancing scattered moderate convection across the west Atlantic mainly west of 77W. A surface trough was noted in current observations extending over the northern Bahamas from 29N77W to 25N79W. To the east, another trough was noted in scatterometer data, extending from 27N67W to 23N69W. Moderate winds are noted with this trough between 67W-69W. A weak cyclonic surface rotation is noted between 40W-50W and north of 28N with scattered showers. A surface trough was analyzed in this area. The remainder of the basin is under the influence of a broad surface ridge, anchored by a three surface highs aligned along 32N. For additional information please visit http://www.hurricanes.gov/marine $$ ERA