000 AXNT20 KNHC 172130 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Wed Oct 18 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 1915 UTC. ...SPECIAL FEATURES... Central Tropical Atlantic (AL94) Gale Warning: Satellite images indicate that a broad area of low pressure located about 1100 nautical miles east of the Windward Islands has become better defined since this morning, and the associated showers and thunderstorms are also showing signs of organization. Current associated winds are 20-30 kt with seas of 8-11 ft. Numerous moderate isolated strong convection is noted from 04N to 16N between 37W and 49W, and from 17N to 19N between 45W and 49W. Environmental conditions are expected to remain conducive for gradual development, and a tropical depression will likely form during the next day or two while the system moves westward to west-northwestward across the central and western tropical Atlantic. Interests in the Lesser Antilles should monitor the progress of this system. Additional information, including gale warnings, can be found in High Seas Forecasts issued by the National Weather Service. Regardless of development, this system has the potential to bring gusty winds, heavy rainfall and flooding to portions of the Lesser Antilles beginning Friday. This disturbance has a high chance of tropical cyclone formation through the next 48 hours. Please refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details. Additional information, regarding the Gale Warning, can be found in High Seas Forecasts issued by the National Weather Service. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic through the coast at the border of Mauritania and Senegal near 16N16W to 05N31W to low pressure (AL94) near 11.5N43.5W to 10N51W. Other than the convection associated with AL94 described in the Special Features section above, scattered moderate isolated strong convection is noted from 03N to 09N between 16W and 20W, and from 00N to 07N between 25W and 37W. ...GULF OF MEXICO... The Gulf of Mexico remains under the influence of a 1021 mb high pressure system extending from the U.S. Great Plains southward to Heroica Veracruz, Mexico, allowing for a dry continental airmass to dominate the basin. Mainly moderate N-NE winds dominate the basin, locally fresh offshore Veracruz, Mexico. Seas are around 5-8 ft in old northerly swell S of 24N, and 2-5 ft N of 24N. For the forecast, high pressure will continue to dominate the Gulf waters the remainder of the work-week. As the high pressure moves toward the SE of the United States, winds will veer to NE and E over the E and central Gulf, and to the SE and S over the western Gulf. Under this pattern, expect mainly gentle to moderate winds and slight to moderate seas. A frontal system will bring moderate to fresh westerly winds for the NE Gulf on Fri. ...CARIBBEAN SEA... A stationary front extends from eastern Cuba to the Gulf of Honduras. Satellite imagery continues to depicts scattered showers and thunderstorms near the frontal boundary within about 60 nm either side of the front, as well as off the coast of Nicaragua, and between Jamaica and eastern Cuba. Scattered showers and thunderstorms are also seen from 10N to 18N between 75W and 80W in association to deep layer trough. To the northwest of the stationary front, moderate to locally fresh north winds are occurring, along with seas 5-7 ft, locally 8 ft near the Yucatan Channel. Moderate to locally fresh easterly trade winds are evident in the south-central Caribbean along with 3-5 ft seas, with similar winds nearshore Nicaragua due to a locally tight pressure gradient somewhat associated with the stationary front. Seas are 1-3 ft elsewhere SE of the stationary front. Light to gentle winds prevail across the remainder of the waters. For the forecast, the front should remain in place through Wed before dissipating Wed night. Fresh NE winds and moderate seas will persist over the northwest Caribbean through Wed as high pressure builds over the area. Looking ahead, a broad area of low pressure (AL94) located about 1100 nautical miles east of the Windward Islands has become better defined since this morning, and the associated showers and thunderstorms are also showing signs of organization. Now, it has a high chance of tropical cyclone formation trough 48 hours. Interests in the Lesser Antilles should monitor the progress of this system. ...ATLANTIC OCEAN... Please see the SPECIAL FEATURES section above for more details on Invest 94L. A stationary front extends from 31N64W to across the SE Bahamas to eastern Cuba. A clusters of scattered thunderstorms are noted along and within 150 nm SE of the front. Moderate to fresh winds and seas 6-9 ft are occurring from 27N to 31N between 55W and 75W. Winds are mainly gentle farther south, to the north of eastern Cuba, Hispaniola and Puerto Rico. Farther east, an 1011 mb low associated with the remnants of Sean and is located near 19.5N59W along a NE to SW surface trough from 25N56W to 16N60W. Associated scattered showers and isolated thunderstorms are noted from 19N to 25N within 180 nm W of the trough where winds are moderate to fresh with seas of 5-7 ft. A surface ridge extends from 30N25W to 1019 mb high pressure near 27N42W to 24N69W. Light to gentle winds and 5-7 ft seas are near the ridge axis. In the far NE part of the area, north of 29N and east of 27W, large swell of 7-10 ft is subsiding, due to a departing storm system far to the north. Gentle to moderate winds and 4-7 ft seas prevail across the remainder of the open waters. For the forecast W of 55W, the front will remain in place before dissipating Wed night or Thu. Expect fresh winds over waters north of 25N through this morning, on both sides of the front. Winds and seas will diminish tonight as high pressure builds over the area in the wake of the front. Looking ahead, the next frontal system will move offshore the southeastern United States Fri night. Fresh to strong winds and rough seas are forecast north of 27N Fri night through Sat night with this system. A broad area of low pressure (AL94) located about 1100 miles east of the Windward Islands has become better defined since this morning, and the associated showers and thunderstorms are also showing signs of organization. Now, it has a high chance of tropical cyclone formation trough 48 hours. Interests in the Lesser Antilles should monitor the progress of this system. $$ Lewitsky