000 AXNT20 KNHC 222316 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 416 PM PDT Sat Aug 22 2020 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 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 1800 UTC surface analysis and satellite imagery through 2300 UTC. ...SPECIAL FEATURES... Tropical Storm Laura is centered near 18.0N 68.1W at 22/2100 UTC or 90 nm W of Ponce Puerto Rico moving W at 16 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. Laura is moving toward Dominican Republic while continues to produce heavy rain over Puerto Rico. Numerous moderate scattered strong convection is noted from 15N-18N between 65W-68W. Clusters of moderate to strong convection are already affecting parts of Dominican Republic. On the forecast track, the center of Laura will move away from Puerto Rico this evening, near or over Hispaniola tonight, near or over Cuba Sunday and Monday, and into the southeastern Gulf of Mexico Monday night and Tuesday. No significant changes in strength are forecast during the next 48 hours while Laura moves near or over Hispaniola and Cuba. Some strengthening is forecast once Laura moves into the Gulf of Mexico Monday night and Tuesday. Heavy rain across Puerto Rico, Hispaniola and Cuba could lead to life- threatening flash flooding. Swells generated by Laura are affecting portions of the northern Leeward Islands. These swells are expected to spread across the northern coasts of Puerto Rico, Hispaniola, Cuba, much of the Bahamas, and the Florida Keys during the next few days. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT3.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMAT3.shtml for more details. Tropical Storm Marco is centered near 21.9N 85.7W at 22/2100 UTC or 40 nm W of the western tip of Cuba moving NNW at 11 kt. Estimated minimum central pressure is 992 mb. Maximum sustained wind speed is 55 kt with gusts to 65 kt. A band of moderate to scattered strong convection is within about 90 nm E of the center. This convective activity has been affecting western Cuba during the last several hours producing heavy rain. Marco is expected to continue moving toward the north-northwest across the central Gulf of Mexico on Sunday and is forecast to reach the northern Gulf coast on Monday. After moving inland, Marco is expected to slow down and turn toward the northwest and west- northwest Monday night and Tuesday, moving across southern Louisiana into east Texas. Strengthening is forecast during the next day or two, and Marco is expected to become a hurricane tonight or on Sunday. Marco is likely to still be at or near hurricane strength when it reaches the northern Gulf coast on Monday. Weakening is forecast to occur while the center moves farther inland Monday night and Tuesday. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT4.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMAT4.shtml for more details. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is W of the Cabo Verde Islands along 28W from 21N southward, moving W at 10-15 kt. Convection is limited near the wave axis. As a result, tropical cyclone development is no longer expected to occur as environmental conditions are forecast to be unfavorable as the system moves westward over the tropical Atlantic. An eastern Caribbean tropical wave has an axis along 67W from 14N southward, moving W at 10 kt. The wave appears to induce some convective activity over Venezuela. A central Caribbean tropical wave has an axis along 76W from 18N southward, moving W at 15 kt. Isolated moderate convection is within 90 nm either side of the wave axis. A western Caribbean tropical is along 88W from 17N southward, extending from the SW Gulf of Honduras southward to the east Pacific. This tropical wave spawned T.D. Fourteen in the western Caribbean, and now has the potential to help the development of a another tropical cyclone south of the Gulf of Tehuantepec, in the eastern Pacific region early next week. The wave is moving W at 10 kt, and is helping to induce scattered showers and thunderstorms over northern Central America. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Mauritania near 19N16W to 12N28W to 09N45W. The ITCZ continues from 09N45W to 08N58W. Only a cluster of moderate convection is seen from 08N- 11N between 55W-57W. GULF OF MEXICO... Two tropical cyclones are forecast to move across the Gulf of Mexico between now and Wed, and both are expected to reach hurricane strength. Please see the Special Features section above for more details on Tropical Storm Marco and Tropical Storm Laura. Tropical Storm Marco is currently spreading strong winds across the Yucatan Channel and heavy rain over the southern Gulf of Mexico, south of 25N between 82W-87W. Elsewhere in the Gulf currently, mid-level southerly winds are advecting moisture from Tropical Storm Marco toward the NE Gulf of Mexico, where scattered showers and isolated tstorms are seen, between the Florida peninsula and 90W. A recent ASCAT pass shows strong E to SE winds over the southeast Gulf. Gentle winds and drier weather prevail over most of the western Gulf, west of 90W. CARIBBEAN SEA... Please see the Special Features section for details on Tropical Storm Laura and Tropical Storm Marco. Outside of Laura and Marco, some tropical waves are moving across the basin, producing scattered showers. See the Tropical Waves section above for details. ATLANTIC OCEAN... Please see the Special Features section for details on Tropical Storm Laura. A surface ridge dominates the remainder of the Atlantic forecast waters, including the Bahamas and Florida. A pair of 1020 mb centers are noted near 28N55W and near 29N69W. An area of scattered showers related to an upper-level trough is seen from 23N-30N between 51W-58W. A surface trough is analyzed from 26N41W to 16N43W. Mainly low clouds are near the trough axis. $$ GR