000 AXNT20 KNHC 172321 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Mon Sep 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 2300 UTC. ...SPECIAL FEATURES... Tropical Storm Nigel is centered near 25.1N 49.5W at 17/2100 UTC or 910 nm ESE of Bermuda, moving NW at 11 kt. Estimated minimum central pressure is 994 mb. Maximum sustained wind speed is 55 kt with gusts to 65 kt. Peak seas range from 21 ft near the center. Scattered moderate to strong convection is noted near from 22N-29N between 46W-54W. Rapid strengthening is forecast during the next 48 hours. Nigel will likely become a hurricane tonight, and is forecast to approach major hurricane intensity in a couple of days. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details. For the latest NHC Forecast/Advisories and Public Advisories on Nigel, please visit www.hurricanes.gov. ...TROPICAL WAVES... An eastern Atlantic tropical wave is near 38W from 12N southward, and moving westward 10 to 15 kt. Scattered showers are noted in the vicinity of the wave. ...MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic through 13N17W to 10N28W. An ITCZ continues from 10N28W to 07N48W. Scattered moderate convection is noted from 05N to 12N between 16W-44W. The eastern end of the East Pacific monsoon trough is triggering scattered showers and thunderstorms across the Caribbean waters south of 12N between 74W-83W. ...GULF OF MEXICO... A cold front extends across the northern Gulf waters from 30N86W to 26N97W. Scattered moderate convection prevails across the Bay of Campeche ahead of the front mainly W of 93W and S of 26N. Gentle to moderate northerly winds and seas of 2 to 3 ft are present near the cold front. Otherwise, weak surface ridging is maintaining light to gentle winds and 1 to 2 ft seas for the rest of the Gulf. For the forecast, the cold front will be followed by a weak reinforcing front Mon. A wind shift along with some isolated to scattered convection will occur with these boundaries. Winds will be moderate or weaker with slight seas through Thu, pulsing to moderate to fresh offshore the W Yucatan in the evenings. Winds may freshen in the NE Gulf by the end of the week due to building high pres N of the area with seas also building. ...CARIBBEAN SEA... Refer to the Monsoon Trough/ITCZ section for weather in the Caribbean Basin. A weak 1019 mb Bermuda High near 36N68W is supporting a modest trade-wind pattern across much of the Caribbean. Moderate to fresh ENE to E winds and seas of 4 to 7 ft are evident at the south-central basin. Gentle NE to E winds and 1 to 3 ft seas are seen at the northwestern basin, including the Gulf of Honduras. Gentle to moderate NE to ESE winds and seas at 3 to 4 ft prevail for the rest of the basin. For the forecast, N-NE swell may impact the Caribbean passages and Tropical N Atlantic through the early part of the week. Moderate to fresh trades will prevail in the central Caribbean, locally strong at times offshore N Colombia, with moderate or weaker winds elsewhere through the week. ...ATLANTIC OCEAN... See the Special Features Section for more details on Tropical Storm Nigel. A surface trough is generating scattered showers and thunderstorms from the northwest Bahamas northward to 27N, west of 74W. To the east, a cold front extends from 27N14W to 31N32W. No convection is present with the front at this time. Refer to the Monsoon Trough/ITCZ and Tropical Waves sections at the beginning for additional weather in the Atlantic Basin. Outside the direct impact of Tropical Storm Nigel, gentle to moderate NNE to SE winds and 5 to 8 ft seas in moderate northerly swell exist north of 20N between the northwest Africa coast and 55W. Farther west, light to gentle E to SE winds and seas at 5 to 7 ft in moderate northerly swell are noted north of 20N between 55W and the Georgia-Florida coast, including the Bahamas Islands. Near the Cabo Verde Islands, fresh to strong NW to NE winds and 4 to 6 ft seas are found from 20N to 30N and E of 34W. Light to gentle southerly winds and seas at 4 to 6 ft in moderate southerly swell prevail for the remainder of the Atlantic Basin. For the forecast W of 55W, Tropical Storm Nigel will strengthen to a hurricane near 26.3N 50.6W Mon morning, move to 27.8N 52.1W Mon afternoon, 29.2N 53.6W Tue morning, 31.0N 55.0W Tue afternoon, then well N of the area to 33.1N 55.4W Wed morning. Otherwise, weak ridging will prevail this evening. A cold front will move off the N Florida coast later tonight, reaching from 31N72W to near Jupiter, Florida Tue morning, then stalling along 28N to 30N through the end of the week. Winds and seas may increase W of the stalled boundary by the end of the week as a tight pressure gradient develops due to a building high inland and a developing coastal trough off the Carolinas. $$ ERA