000 AXNT20 KNHC 200532 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Wed Sep 20 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 33.2N 54.7W at 20/0300 UTC or 510 nm E of Bermuda, moving N at 13 kt. Estimated minimum central pressure is 971 mb. Maximum sustained wind speed is 85 kt with gusts to 105 kt. Seas are peaking near 35 ft just NE of the center. The eye of Nigel is surrounded by intense deep convection from 31N to 33N between 54W and 56W. Hurricane Nigel, currently a Category Two on the Saffir-Simpson Hurricane Wind Scale. Nigel is forecast to turn toward the northeast with an increase in forward speed is expected on Wednesday. Some additional strengthening is possible through early Wednesday. Weakening is expected on Thursday and Friday. Nigel is forecast to become a strong post-tropical cyclone by Friday. Swells generated by Nigel will affect Bermuda during the next couple of days. 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. Atlantic Gale Warning: The pressure gradient between low pressure that is expected to develop along a stationary front over the northwest part of the SW N Atlantic and high pressure over the southeastern U.S. is expected to result in gale force north to northeast winds of 30-35 kt for the waters north of 29N between 77W-79W on Thursday night. Seas with these winds are forecast to be 9 to 13 ft. Please see the latest NWS High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2 for further details. ...TROPICAL WAVES... An eastern Atlantic tropical wave has its axis near 28W, south of 18.5N, moving westward at 10 to 15 kt. Scattered moderate convection is depicted from 05N to 11.5N and between 28W and 33W. A western Atlantic tropical wave has its axis near 48W, south of 14N, moving westward at 10 to 15 kt. Scattered moderate convection is depicted from 07N to 11N and between 46W and 50W. ...MONSOON TROUGH/ITCZ... The monsoon trough reaches the Atlantic through the coast of Senegal near 15N17W and continues southwestward to 09N28W and then westward to 10.5N46.5W. The ITCZ extends from 10N49W to 11N58.5W. Other than the convection described in the TROPICAL WAVES section above, scattered moderate to isolated strong convection is depicted from 11N to 114N, E of 20.5W. Scattered moderate convection is present from 06N to 13N and between 32W and 45W and from 10N to 12N between 51W and 56W. ...GULF OF MEXICO... A stationary front extends from near Fort Myers, Florida, westward to near 25N89W. Scattered moderate convection is noted within 90 nm of the boundary. Outside of convection, gentle to moderate east to southeast winds and seas of 2 to 4 ft are evident north of the front. Light to gentle winds and seas of 1 to 3 ft are found south of the boundary. For the forecast, the aforementioned stationary front will gradually dissipate through early Wed. Otherwise, high pressure will be in control of the weather regime allowing for generally gentle to moderate east to southeast winds along with slight seas, pulsing to moderate to fresh offshore the western Yucatan Peninsula in the evenings. Developing low pressure east of Florida will tight the pressure gradient over the NE Gulf bringing fresh NE winds Thu night into Fri. ...CARIBBEAN SEA... Divergent flow associated with an upper level trough located in the NW Caribbean Sea and abundant tropical moisture continue to support scattered moderate convection in the NW Caribbean. A weak pressure gradient sustains mainly moderate to fresh easterly trade winds in the central Caribbean. However, strong winds are occurring just off the NW Venezuelan coasts. Seas in the central Caribbean are 4 to 7 ft. Elsewhere, light to gentle winds and seas of 2 to 4 ft prevail. 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 and the ATLANTIC GALE WARNING. In addition read the TROPICAL WAVES and MONSOON TROUGH/ITCZ sections for convection in the tropical Atlantic. A stationary front extending from near 31N70W to Stuart, Florida is producing scattered moderate to isolated strong convection within west of 76.5W. Moderate or weaker winds and 2 to 4 ft seas are found behind the frontal boundary. The remainder of the Atlantic is dominated by a broad subtropical ridge positioned near the Azores. The pressure gradient between the aforementioned 1023 mb high pressure system and lower pressures in the deep tropics support fresh to strong easterly winds east of 50W and north of 16N. Seas in these waters are 6 to 9 ft. Elsewhere, moderate or weaker winds and moderate seas prevail. For the forecast W of 55W, Hurricane Nigel is north of the area near 33.2N 54.7W at 11 PM EDT, and is moving north at 13 kt. Maximum sustained winds are 85 kt with gusts to 105 kt, and the minimum central pressure is 971 mb. Nigel is forecast to accelerate northeastward on Wed as IT pulls farther away from the area. Strong winds and rough seas associated with Nigel will continue to affect the forecast waters through Wed. A stationary front extending from near 31N70W to Stuart, Florida will change little through Thu. The frontal boundary should begin to slowly lift northward on Fri as low pressure develops along it to the east of northern Florida where gale conditions and rough seas are possible Thu night into Fri. This non-tropical area of low pressure could acquire some subtropical characteristics this weekend while it moves generally northward. $$ KRV