000 AXNT20 KNHC 180423 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Wed Sep 18 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 0000 UTC surface analysis and satellite imagery through 0355 UTC. ...SPECIAL FEATURES... Central Atlantic Ocean Significant Swell Event: A 1007 mb non- tropical low pressure center is near 28N51W. A cold front extends from the low center to 23N55W, followed by a stationary front to 31N64W. A warm front extends form the low center to 27N46W, followed by a stationary front to 31N37W. Strong to near gale NE to E winds and seas of 12 ft and greater are occurring within 180 NM to the west and north of the center. Peak seas are around 16 ft. Numerous moderate and scattered strong convection is noted north of 26N and east of the center to 42W. The system will gradually weaken as it moves slowly toward the southwest Wed and Thu. Winds will diminish below strong force and seas below 12 ft by Thu night. Please see the latest NWS High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for further details. ...TROPICAL WAVES... An eastern Atlantic tropical wave is along 29W, south of 20N, moving westward at 5 kt. A few showers are found near the trough axis. A central Caribbean tropical wave is along 79W, south of 20N, moving westward at 5-10 kt. A few showers and isolated thunderstorms are seen near the trough axis, especially along the northern portion. ...MONSOON TROUGH/ITCZ... The monsoon trough reaches the Atlantic near 15N17W through the coast of Senegal and continues west-southwestward to 12N29W and then to 15N43W. Isolated to scattered moderate convection is present from 05N to 15N and east of 31W. ...GULF OF MEXICO... Generally dry conditions are prevalent over much of the Gulf of Mexico. A few showers and isolated thunderstorms are evident in the eastern Bay of Campeche as storms that formed over western Yucatan earlier tonight move westward. A persistent weak pressure gradient across the Gulf supports moderate or weaker winds and slight seas. For the forecast, weak surface ridging over the Gulf waters will support generally light to gentle winds and slight seas through Thu. Moderate to locally fresh winds may pulse in the Bay of Campeche nightly through Fri. A cold front moving through the NE Gulf will lead to moderate NE winds across the basin on Fri, and building high pressure this weekend will support a gentle to moderate anticyclonic flow. ...CARIBBEAN SEA... A sharp upper level trough over the SE United States continues to enhance the development of showers and isolated thunderstorms over the NW Caribbean, with the strongest activity affecting Cuba and surrounding waters. A few showers are also seen in the eastern Caribbean. A broad ridge to the north of the islands forces moderate to fresh easterly winds and seas of 4-7 ft across the central Caribbean and Gulf of Honduras. Elsewhere, moderate or weaker winds and slight to moderate seas prevail. For the forecast, the pressure gradient between high pressure centered near 26N68W and the Colombian low will continue to support moderate to fresh trades and moderate seas across the central Caribbean through Wed. Locally strong winds and rough seas will be possible off the coast of Venezuela and Colombia. For Thu through the weekend, moderate trades and slight seas will occur across the central Caribbean, with light to gentle winds occurring across northwest and southwest portions of the basin. Moderate to locally fresh winds may pulse in the Gulf of Honduras nightly through Fri. ...ATLANTIC OCEAN... Please read the Special Features section for details about the Central Atlantic Ocean Significant Swell Event. A sharp upper level trough over the SE United States and abundant moisture continues to support scattered showers and isolated thunderstorms west of 68W and north of 24N. Similar convection is also noted between Cuba and the central Bahamas. The rest of the SW North Atlantic, west of 55W, is under the influence of a broad subtropical ridge located in the NW Atlantic. This ridge forces fresh to strong easterly trade winds south of 22N and between 69W and 73W. This was confirmed by a recent scatterometer satellite pass. Seas in these waters are 4-6 ft. Elsewhere west of 55W outside of the influence of the low pres near 28N51W, moderate or weaker winds and moderate seas prevail. A broad area of low pressure centered near 20N49W, the remnants of Gordon, is producing disorganized showers and thunderstorms, mainly south of the center. A surface trough extends from the low center to the Windward Islands and scattered showers are observed near this boundary. Moderate to locally fresh southerly winds and seas of 5-7 ft are occurring from 15N to 24N and between 44W and 50W. The broad subtropical ridge dominates the remainder of the tropical Atlantic, sustaining moderate or weaker winds and moderate seas. For the forecast, a non-tropical low pressure system located near 28N51W will lead to strong to near gale force winds north and west of the center of the low pressure, generally north of 27N and east of 58W through Thu. Rough seas are expected east of 60W and north of 23W, with peak seas of 8 to 12 ft in NE swell. These marine conditions will gradually diminish on Fri. Expect pulsing fresh trades off the coast of Hispaniola through Thu. Otherwise, gentle to moderate winds and slight to moderate seas will prevail across the rest of the basin. $$ Delgado