000 AXNT20 KNHC 191037 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 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 0600 UTC surface analysis and satellite imagery through 1045 UTC. ...SPECIAL FEATURES... Hurricane Nigel is centered near 29.6N 53.6W at 19/0900 UTC or 600 nm ESE of Bermuda, moving NW at 11 kt. Estimated minimum central pressure is 979 mb. Maximum sustained wind speed is 75 kt with gusts to 90 kt. Seas are peaking to near 34 ft near and just northwest of the center. Satellite imagery shows that Nigel has a rather large eye feature. Numerous moderate to isolated strong convection is seen within 120 nm of the center in the SE quadrant and 90 nm of the center in the NE quadrant. Scattered moderate convection is 90 nm of the center in the NW quadrant, and from 26N to 29N between 49W-52W. Nigel is forecast to turn northward late today, and then accelerate rapidly northeastward through the rest of the week. Nigel is forecast to strengthen some through early Wed, with weakening likely on Thu and Fri. Nigel is forecast to become a strong post-tropical cyclone on Fri. Swells generated by Nigel are expected to reach Bermuda later today. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. 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 far eastern Atlantic tropical wave has its axis along 23W from 04N to 19N. It is moving westward around 10 kt. Scattered moderate convection is within 120 nm west of the wave from 04N to 07N. A central Atlantic tropical wave has its axis along 43W from 02N to 13N. It moving westward at 10-15 kt. Numerous moderate convection is within 180 nm west of the wave from 07N to 10N, and within 120 nm east of the wave from 07N to 10N. ...MONSOON TROUGH/ITCZ... The monsoon trough axis enters the Atlantic near the Gambia- Guinea Bissau border near 13N17W and continues west-southwestward to 09N26W and to 10N34W to 07N48W. The ITCZ extends from 07N48W to 07N54W. Other than the convection described in the TROPICAL WAVES section above, scattered moderate to isolated strong convection is within 240 nm north of the trough between 30W-40W, also within 240 nm south of the trough between 35W-42W, within 120 nm south of the trough and the ITCZ between 46W-49W and south of the trough from 04N to 07N between 26W-30W. Scattered moderate convection is within 60 nm of the ITCZ between 49W-53W. ...GULF OF MEXICO... A stationary front extends from extreme South Florida to near 25N91W. Satellite imagery shows increasing showers and thunderstorms along and near the stationary frontal boundary. A trough is over the far eastern Bay of Campeche. Isolated showers and thunderstorms are near the trough. Moderate northeast winds are north of the stationary boundary, with mainly gentle winds elsewhere. Seas are 2-4 ft north of the boundary and 1-2 ft elsewhere outside of any convection. For the forecast, the stationary front will slowly dissipate through this evening. 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 rather relaxed gradient is present over the area. Fresh northeast to east trade winds and 4-6 ft seas are in the south- central part of the sea. Light to gentle trade winds and seas of 1-3 ft are in the northwest part of the basin. Gentle monsoonal winds with seas at 3 to 4 ft exist offshore from Costa Rica and Panama. Gentle to moderate northeast to east trade winds are over the rest of the basin, except for fresh to strong trades offshore northern Colombia and northwest Venezuela. Seas are 4-6 ft there, and 3-5 ft across the remainder of the waters. Scattered showers and thunderstorms are confined to the southwestern Caribbean. Similar activity is along and near the northeast part of Honduras, also over Haiti and the Windward Passage. 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 on Hurricane Nigel. A stationary front stretches southwestward from 31N72W to South Florida. Scattered showers and thunderstorms are along and within 60 nm northwest of the stationary front. Mainly gentle winds are behind and just north of the front along with seas of 4-6 ft seas. Outside the direct impact of Hurricane Nigel, a broad area of fresh to strong trade winds is present from 20N-27N between the coast of Africa and 41W along with 8-11 ft seas per recent altimeter data. Gentle to moderate trade winds and 5-8 ft seas are found elsewhere north of 10N and east of 45W, with mainly gentle winds and 5-7 ft seas across the remainder of the tropical Atlantic waters. An area of scattered showers and a few thunderstorms moving quickly westward is from 18N to 22N and between 30W-36W. This activity is behind a surface trough that extends from near 20N37W to 15N35W. For the forecast W of 55W, Hurricane Nigel is near 29.6N 53.6W at 5 AM EDT, and is moving northwest at 11 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 31.2N 54.5W this afternoon with maximum sustained winds 85 kt gusts 105 kt, then to north of the forecast waters to near 33.8N 54.8W late tonight with maximum sustained winds 90 kt gusts 110 kt. Nigel will then begin to accelerate northeastward and well away from the area through the rest of the week while weakening. A weak stationary front extending from near 31N72W to South Florida will change little 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. Gale-force northeast to east winds are expected off the southeastern U.S. coast Fri and Fri night. $$ Aguirre