000 AXNT20 KNHC 261210 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Thu Aug 26 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 0600 UTC surface analysis and satellite imagery through 1000 UTC. ...Updated 810 AM EDT...1210 UTC...for Special Features... ...SPECIAL FEATURES... Shower and thunderstorm activity continues to become better organized in association with a trough of low pressure located less than 170 nm south of Jamaica. Environmental conditions remain conducive for development, and a tropical depression or storm is expected to form later today or tomorrow. This system is forecast to move northwestward over the northwestern Caribbean Sea near the Cayman Islands tonight, near western Cuba and the Yucatan Peninsula of Mexico on Friday, and into the Gulf of Mexico this weekend. Given the recent developmental trends, Tropical Storm Warnings for the Cayman Islands and Tropical Storm Watches for western Cuba could be required later today. Regardless of development, locally heavy rainfall and flooding will be possible over portions of Jamaica and the Cayman Islands today and tonight, and will likely spread across Cuba and the Yucatan Peninsula on Friday. In addition, this system could bring dangerous impacts from storm surge, wind, and heavy rainfall to portions of the coasts of Louisiana and Texas late this weekend and early next week. However, uncertainty remains large since the system has yet to form. Interests in these areas should closely monitor the progress of this system. Refer to the High Seas Forecasts issued by the National Hurricane Center at www.nhc.noaa.gov/text/MIAHSFAT2.shtml for additional information on this system, including gale warnings. Refer to the National Hurricane Center Tropical Weather Outlook at www.hurricanes.gov for details on this disturbance, which has a high chance of developing into a tropical cyclone within the next 48 hr. A broad trough of low pressure is producing disorganized showers and thunderstorms over the central tropical Atlantic about 565 nm east-southeast of Bermuda. Environmental conditions are forecast to be generally conducive for development, and a tropical depression is likely to form late this week or this weekend while the system moves slowly northeastward over the central Atlantic. Please refer to the latest Tropical Weather Outlook for more details. ...TROPICAL WAVES... A tropical wave was added to the 0000 UTC analysis/surface map along 19W. The Hovmoller Diagram indicated the westward propagation of the wave and Dakar was reporting SE winds indicating the passage of the wave. At 0600 UTC, the wave is along 20W, from 19N southward. Scattered moderate convection is ahead of the wave axis from 11N-16N between 20W-23W. This convective activity is reaching the Cabo Verde Islands. The axis of a tropical wave is near 38W, south of 19N, moving W at 10 to 15 kt. A 1008 mb low pressure is along the wave axis near 12N38W. Scattered moderate to isolate strong convection is noted from 10N-13N between 37W-42W. Some development of this system is possible over the next several days while it moves west-northwestward at 10 to 15 mph over the eastern tropical Atlantic. Upper-level winds are forecast to become less conducive for development by early next week. The axis of a tropical wave is near 58W, south of 19N, moving W at 10 to 15 kt. Scattered moderate convection is noted where the wave meets the ITCZ. The tropical wave axis extends into Guyana. The axis of a tropical wave is near 77/78W, south of 20N, moving W at 10 to 15 kt. A 1006 mb low pressure is along the wave axis near 15.1N 77.8W. Numerous moderate and scattered strong convection associated to this disturbance is covering the waters from 15N-19N between 75W-79W, and from 12N-17N between 73W-75W. Please see special features section above for more details on this disturbance. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic Ocean through Senegal near 15N17W and continues to low pres near 12N38W to 07N47W. The ITCZ continues from 07N47W to 10N60W. Aside from convection noted in the tropical waves section, scattered moderate isolated strong convection is observed from 06N-10N between 40W-48W. ...GULF OF MEXICO... A surface trough extends from SE Florida to western Cuba, and is producing scattered showers and thunderstorms. Fresh to strong NE winds are noted ahead of the trough axis affecting the SE Gulf and the Straits of Florida. Elsewhere, mainly gentle to moderate winds prevail. Seas are in the 3-5 ft range over the SE Gulf, and 1-3 ft elsewhere. For the forecast, the surface trough will move into the eastern Gulf this morning reaching the central Gulf by tonight. Otherwise, high pressure pressure will dominate the basin through Fri, producing mainly gentle to moderate E to SE winds. A tropical depression or storm is expected to form later today or tomorrow in the Caribbean Sea. This system is forecast to move into the Gulf of Mexico this weekend. Currently, a Gale Warning has been issued in association with this system located about less than 200 miles south of Jamaica. This system could bring dangerous impacts from storm surge, wind, and heavy rainfall to portions of the coasts of Louisiana, Texas, and the Mexican state of Tamaulipas late this weekend and early next week. However, uncertainty remains large since the system has yet to form. Interests in these areas should closely monitor the progress of this disturbance. Expect a large increase in winds and seas this weekend in association with this system. ...CARIBBEAN SEA... Fresh to strong winds prevail over the central Caribbean associated with a tropical wave and a low pressure along the wave axis. Moderate to fresh winds are over the eastern Caribbean and gentle to moderate winds are over the western Caribbean. For the forecast, a tropical depression or storm is expected to form later today or tomorrow in the Caribbean Sea. For now, a Gale Warning is in effect for the NW Caribbean. Please see the Special Features section above for more on a low pressure along an active tropical wave located over the central Caribbean. ...ATLANTIC OCEAN... Please see special features section above for more on a broad trough of low pressure over the central tropical Atlantic, which has the potential for tropical cyclone development. Elsewhere, a surface trough extends from 29N75W across the NW Bahamas into western Cuba. Scattered moderate and isolated strong convection is ahead of the trough axis affecting SE Florida and the Florida Keys. Similar convection is also noted near the northern end of the trough from 28N-30N W of 75W. Fresh to strong NE winds are west of the surface trough. Fresh to strong winds SE are in the east side of the trough discussed in the Special Features section above. Elsewhere, moderate to fresh winds prevail. Seas are in the 8-9 ft range in the vicinity of the trough over the central tropical Atlantic, and also in the vicinity of the low near 12N38W. Seas of 6-7 ft are NE of the NW Bahamas. Elsewhere seas in the 4-6 ft range prevail. For the forecast W of 65W, A surface trough located over the NW Bahamas will move into the eastern Gulf of Mexico by this morning. Fresh to strong NE winds are expected west of the trough axis, including the Florida Straits. Otherwise, high pressure located just N of the forecast region will dominate the SW N Atlantic through Mon. Fresh to locally strong winds are expected to pulse N of Hispaniola during the evening hours through Sat night. $$ GR/Hagen