000 AXNT20 KNHC 190535 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Tue Sep 19 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 0000 UTC surface analysis and satellite imagery through 0545 UTC. ...SPECIAL FEATURES... Hurricane Nigel is centered near 28.6N 52.7W at 19/0300 UTC or 660 nm ESE of Bermuda, moving NW at 10 kt. Estimated minimum central pressure is 979 mb. Maximum sustained wind speed is 75 kt with gusts to 90 kt. Seas are peaking near 31 ft near and just northwest of the center. Numerous moderate to isolated strong convection is found near and up to 150 nm in the SE semicircle and 90 nm in the NW semicircle. Nigel is forecast to turn northward late Tuesday, and then accelerate northeastward through the rest of the week. Additional strengthening is forecast during the next day or so. Gradual weakening is expected to begin by late Wednesday. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest Nigel NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...TROPICAL WAVES... A tropical wave is off the Africa coast near 21W from 18N southward, and moving west around 5 to 10 kt. Scattered moderate convection is found from 03N to 07N between 19W and 29W. A central Atlantic tropical wave was relocated based on wave diagnostics and satellite imagery and it is now near 42W from 12N southward. Widely scattered moderate convection is noted from 05N to 12N between 33W and 46W. ...MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic near the Gambia-Guinea Bissau border near 13N17W then extends west-southwestward across 08N24W to 07N46W. The ITCZ continues from 07N46W to 07N53W. Other than the convection described in the TROPICAL WAVES section above, scattered moderate isolated strong convection is evident from 06N to 10N between 46W and 53W. The eastern end of the East Pacific monsoon trough is producing scattered showers and thunderstorms across the Caribbean waters north of Costa Rica, Panama and northwestern Colombia. ...GULF OF MEXICO... A cold front reaches west-southwestward from South Florida to 25N86W. Then a surface trough turns west-southwestward to 23N92W. Scattered showers and thunderstorms are depicted near the frontal boundary and the trough. Another surface trough is depicted over the Yucatan Peninsula producing scattered showers and thunderstorms in the eastern and central Bay of Campeche. Moderate NE winds are occurring N of the boundary with mainly gentle winds elsewhere. Seas are 2 to 4 ft north of the boundary and 1 to 2 ft elsewhere outside of any convection. For the forecast, a weak cold front extends from extreme South Florida to near 25N85W and to 22N93W. The front will become stationary overnight tonight and dissipate Tue. 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 pressure north of the area with seas also building. ...CARIBBEAN SEA... An upper-level trough runs from west of the Lesser Antilles throughout the Greater Antilles and into the Gulf of Honduras. This trough is producing scattered showers and thunderstorms across the northwestern and north-central basin. Please refer to the MONSOON TROUGH/ITCZ section for additional weather in the Caribbean Basin. A modest trade-wind pattern continues for much of the basin. Fresh NE to E winds and 4 to 6 ft seas are present at the south- central basin. Light to gentle winds and seas of 1 to 3 ft are noted at the northwestern basin. Gentle monsoonal winds with seas at 3 to 4 ft exist offshore from Costa Rica and Panama. Gentle to moderate NE to E winds prevail for the rest of the basin, except fresh to strong offshore N Colombia and NW Venezuela. Seas are 4 to 6 ft there and 3 to 5 ft across the remainder of the waters. For the forecast, long period north to northeast swell will impact the Caribbean passages and Tropical N Atlantic through early Wed. Moderate to fresh trades will prevail in the central Caribbean, locally strong at times offshore northern Colombia and northwest Venezuela, with moderate or weaker winds elsewhere through the week. ...ATLANTIC OCEAN... Please read the SPECIAL FEATURES section for details about Hurricane Nigel. A cold front runs southwestward from 31N73W to near South Florida. Scattered showers and thunderstorms are found south of 31N and west of 73W. Mainly gentle winds are behind and just N of the front along with 4 to 6 ft seas. Please refer to the MONSOON TROUGH/ITCZ and TROPICAL WAVES sections above for additional convection in the Atlantic Basin. Outside the direct impact of Hurricane Nigel, a broad area of fresh to strong trades is noted from 20N to 29N between the coast of Africa and 41W along with 8 to 11 ft seas. Gentle to moderate trades and 5 to 8 ft seas are found elsewhere north of 10N and E of 45W, with mainly gentle winds and 5 to 7 ft seas across the remainder of the tropical Atlantic waters. For the forecast W of 55W, Hurricane Nigel is near 28.6N 52.7W at 11 PM EDT, and is moving northwest at 10 kt. Maximum sustained winds are 75 kt with gusts to 90 kt, and the minimum central pressure is 979 mb. Nigel will continue to strengthen as it moves to near 29.9N 53.8W Tue morning with maximum sustained winds 85 kt gusts 105 kt, to just north of the area near 32.1N 54.5W Tue evening, then begin to accelerate northeastward well away from the area through the rest of the week while weakening. A weak cold front extending from near 31N73W to extreme South Florida will reach from near 31N72W to near West Palm Beach, Florida early Tue, then stall over the northern forecast waters through Thu. The boundary should begin to slowly lift northward on Fri as low pressure develops along it to the east of northern Florida. Winds and seas will likely increase in that area by the end of the week as a tight pressure gradient develops between the developing low pressure off the Carolinas and high pressure inland over the U.S. $$ KRV