000 AXNT20 KNHC 182208 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Sun Sep 19 2021 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 2050 UTC. ...SPECIAL FEATURES... Post-Tropical Cyclone Odette is centered near 39.1N 65.1W at 18/2100 UTC or 260 nm ESE of Nantucket Massachusetts moving ENE at 16 kt. Estimated minimum central pressure is 1001 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. The convection is located well east of the given center with scattered moderate to strong noted from 35N to 41N between 55W and 63W. Odette is moving toward the east-northeast and this general motion with an increase in forward speed is expected through Sun. A turn toward the east and east-southeast with a decrease in forward speed is expected on Mon and Tue. On the forecast track, the center of Odette will pass well south of Atlantic Canada tonight through Mon. Strengthening as a post-tropical cyclone is forecast during the next day or two. Please read the latest Atlantic High Seas Forecast issued by the Ocean Prediction Center at https://www.ocean.weather.gov/ and the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT5.shtml and Forecast/Advisory at https://www.nhc.noaa.gov/text/MIATCMAT5.shtml for more details. Please refer to products from the Canadian Hurricane Centre for additional information on potential impacts in Newfoundland at weather.gc.ca/hurricane/ Atlantic Gale Warning: A tropical wave is in the Atlantic Ocean along 51W/52W from 06N to 22N, while a 1008 mb low pressure area is along the tropical wave near 15.5N52W, or about 650 nm E-SE of the northern Leeward Islands, moving west at around 15 kt. Associated winds are currently 20 to 30 kt, and are forecast to increase to 35 kt in the next few hours with a gale warning currently in place. Peak seas are currently 8 to 10 ft. Scattered moderate to strong convection is noted within 300 nm in the east semicircle, 180 nm southwest quadrant, and 480 nm in the northwest quadrant. This low continues to show signs of organization, however satellite-derived wind data from a few hours ago indicated that the system does not yet have a well- defined surface circulation. Only a slight increase in organization of this system would lead to the formation of a tropical depression or tropical storm, which is expected to occur later today or tonight while the low moves toward the west-northwest at about 15 kt. This system is expected to be near the northern Leeward Islands on Mon and Tue, and interests there should monitor its progress. Upper-level winds are likely to become less conducive for development when the system reaches the southwestern Atlantic by the early to middle part of next week. This low has a high chance for tropical cyclone formation in the next 48 hours. Additional information on this system, including gale warnings, can be found in the High Seas Forecasts issued by the National Weather Service at: www.hurricanes.gov/marine and latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details. A tropical wave is in the Atlantic Ocean along 26W/27W from 03N to 19N, while a 1008 mb low pressure area is along the tropical wave near 09N26.5W, over the far eastern Atlantic a few hundred nm south-southwest of the Cabo Verde Islands, moving west at around 5 kt. Associated winds are currently 20 to 30 kt with peak seas of 8 to 10 ft. Scattered moderate to strong convection is noted from 07N to 11N between 25W and 33W. The low continues to show some signs of organization, and environmental conditions appear conducive for further development of this system. A tropical depression could form over the next couple of days while moving toward the northwest at 10 to 15 kt to the west of the Cabo Verde Islands. This system is expected to reach cooler waters and an area of stronger upper- level winds early next week, which could limit its development. This low has a medium chance for tropical cyclone formation in the next 48 hours. Additional information on this system can be found in the Meteo- France High Seas Forecast at: http://weather.gmdss.org/II.html and also refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details. ...TROPICAL WAVES... Refer to the Special Features section above for details on two tropical waves in the Atlantic Ocean. A tropical wave is located near the Yucatan Peninsula and far eastern Bay of Campeche along 91W south of 19N into the eastern Pacific Ocean, moving west at around 10 kt. No deep convection is occurring in association with this tropical wave over water, however showers and thunderstorms are noted over northern Guatemala and portions of eastern Mexico. ...MONSOON TROUGH/ITCZ... The monsoon trough extends across the coast the Mauritania at 18N16W through 1008 mb low pressure near 09N26.5W to 05N35W to 06N38W. The ITCZ continues from 06N38W to 12N48W. Other than the convection described above, scattered moderate and isolated strong convection is noted from 05N to 08N between 33W and 37W. Scattered moderate convection is noted within 180 nm south of the monsoon trough and ITCZ between 30W and 46W. ...GULF OF MEXICO... A surface trough continues to linger over the north-central and central Gulf from the coast of Louisiana near 29N90W to 24N95W to 22N97W. Scattered moderate and isolated strong convection is noted within 240 nm southeast of the trough. Another surface trough is analyzed from 21N95W to 18N94W in the Bay of Campeche. Otherwise, a broad ridge extends into the eastern Gulf of Mexico. Gentle to moderate SE-S return flow is noted south of 25N and east of 93W, with light and variable winds elsewhere. Seas are in the 2 to 4 ft range across the central and eastern Gulf, and 3 ft or less across the western Gulf. For the forecast, weak high pressure will extend across the eastern and central Gulf of Mexico through early next week. This pattern will support continued gentle to moderate winds and mostly slight seas across the Gulf through the next several days. Looking ahead, a weak cold front may move into the northwest and north-central Gulf by mid week. ...CARIBBEAN SEA... The eastern extension of the east Pacific Ocean monsoon trough enters the SW Caribbean Sea near the Costa Rica and Panama border and continues to northern Colombia. Scattered moderate to strong convection is noted south of 11N. Afternoon and early evening isolated thunderstorms are noted over portions of Hispaniola, Jamaica and Cuba, as well as portions of Central America. Otherwise, the rest of the basin is dominated by generally dry weather conditions, suppressing the development of showers and thunderstorms. Moderate to fresh trades are noted north of 10N and west of 80W, with gentle to moderate trades east of 70W. Seas are 6 to 9 ft in the SW Caribbean, 4 to 6 ft elsewhere west of 70W, and 3 to 5 ft east of 70W. For the forecast, the Atlantic ridge will shift westward through Sun. This will support fresh to strong winds over the south- central Caribbean and Gulf of Honduras into early Sun. The ridge will weaken starting Sun night as a tropical wave and area of low pressure currently across the central Atlantic along 52W move to the northeast of the Leeward Islands early Mon, then begin to move more northwest. There is a high chance this low pressure will form into a tropical cyclone over the next several days. Regardless of further development, expect increase winds, seas and thunderstorms north through east of the Leewards early next week. ...ATLANTIC OCEAN... Refer to the Special Features section above for details on two disturbances in the tropical Atlantic with a chance of tropical cyclone formation over the next few days. Otherwise, a broad 1027 mb subtropical ridge anchored near the Azores extends southwestward to the Bahamas and Florida. A weak surface trough is analyzed from 30N51W to 23N54W with scattered moderate convection noted from 23N to 25N between 52W and 56W. A few showers and thunderstorms are also noted off the northeast coast of Florida in association with convection spilling from the Gulf of Mexico. The rest of the basin enjoys fairly tranquil weather conditions. Fresh to locally strong NE winds are observed off the coast of northern Africa and the waters surrounding the Canary Islands. Moderate to fresh trades are noted north of the convergence zone and east of 40W, with gentle to moderate winds elsewhere. Seas in the tropical Atlantic east of 55W are in the 4 to 7 ft range, and 3 to 5 ft west of 55W. For the forecast west of 55W, weak ridging through the northern Bahamas will support mostly light breezes and slight seas north of 22N through early next week, and moderate to fresh trade winds and moderate seas south of 22N through Sun. Meanwhile, an area of low pressure currently over the central tropical Atlantic along 52W will approach the waters northeast of the Leeward Islands Sun and Mon then begin to move more northwest over open Atlantic waters. There is a high chance this low pressure will form into a tropical cyclone over the next several days. Regardless of further development, expect increase winds, seas and thunderstorms north through east of the Leewards Islands and northeast of Puerto Rico early next week. $$ Lewitsky