000 AXNT20 KNHC 281805 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Mon Jun 28 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 1200 UTC surface analysis and satellite imagery through 1630 UTC. ...SPECIAL FEATURES... Newly formed Tropical Depression (TD) Four is centered near 32N78W, about 180 nm ESE of Charleston, South Carolina. Disorganized scattered moderate to isolated strong convection is displaced W of the center due to strong upper level wind shear. Fresh to strong E to SE winds and seas of 7 to 9 ft are seen N of 30N from 73W to the coast of south and north Carolinas. TD Four is forecast to move quickly WNW near 16 mph and make landfall along the coast of South Carolina later this evening. Aided by the warm waters of the Gulf Stream, TD Four is expected to intensify into a weak tropical storm before making landfall, and bring tropical storm conditions to portions of the South Carolina coast. A Tropical Storm Warning is in effect for portions of the South Carolina coast. Locally heavy rainfall is also expected along the coastal areas and adjacent waters of South Carolina and Georgia. 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 tropical wave is along 23W from 15N southward and moving W at 15 to 20 kt. Scattered moderate to isolated strong convection is noted from 02N to 09N between 17W and 24W. Another Atlantic tropical wave is near 40W from 16N southward and moving W at 15 to 20 kt. A 1009 mb low pressure system is embedded within this wave near 12N41W. Scattered showers are seen from 10N to 16N between 38W and 43W. Fresh to locally strong NE to E winds and seas of 6 to 8 ft are found from 12N to 16N between 37W and 45W. Some slow development is possible through the end of the week. It is anticipated to reach the Lesser Antilles by Wed night. Please read the latest Tropical Weather Outlook at www.hurricanes.gov for more information. A third Atlantic tropical wave is along 58W from 17N south- southwestward near the Lesser Antilles. It is moving W at 10 to 15 kt. Scattered showers and isolated thunderstorms are noted off the coast of northern Venezuela and the NE corner of Venezuela. A Caribbean tropical wave is along 76W from Jamaica southward and moving W near 15 kt. Scattered moderate to isolated strong convection is occurring over part of the western Caribbean, near the coasts of Honduras and Nicaragua from 10N to 18N between 79W and 83W. Scattered moderate convection is evident between Cuba and Jamaica, and also over the coast of eastern Panama. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal plains of Guinea-Bissau near 11N15W to 08N24W to 07N38W. An ITCZ then continues from 06N41W to near Suriname at 04N52W. Scattered moderate convection is present from 03N to 10N between 27W to 37W. GULF OF MEXICO... An upper-level trough extending from a low near the Mexico/Texas border to another low near the Yucatan Peninsular is coupling with convergent E to SE winds to trigger numerous moderate to isolated strong convection across the western Gulf. Scattered moderate to isolated strong convection is seen from near the Louisiana coast, southeastward across the central Gulf to just W of the Keys. Moderate to locally fresh winds and seas of 3 to 5 ft are found near this convection. Gentle to moderate winds and seas of 2 to 3 ft are found elsewhere. For the forecast, a ridge will dominate the Gulf waters over the next several days producing mainly moderate E to SE winds. Expect E to SE fresh winds at night near the western Yucatan Peninsula through Fri night due to local effects induced by a thermal trough. CARIBBEAN SEA... Aside from convection associated with the tropical waves described above, no significant convection is occurring. Moderate to fresh trades and seas of 6 to 8 ft are across the central Caribbean. Gentle to moderate trades and seas of 3 to 5 ft prevail across the rest of the basin. For the forecast, a tropical wave currently moving across Jamaica will move west across the Western Caribbean tonight into Tue. Increasing winds and seas are expected behind the wave axis as high pressure builds westward N of the Caribbean Sea. A broad area of low pressure is associated with another tropical located over the central tropical Atlantic Ocean along 41W S of 16N. Some slow development is possible through the end of the week while this system moves quickly westward to west-northwestward near 15 mph, likely reaching the Lesser Antilles Wednesday night. ATLANTIC OCEAN... Please see the Special Features section above for details on Tropical Depression Four. A slow-moving cold front extends westward from a 1020 mb low pressure system at 29N49W to 28N55W, then curves northwestward to 31N58W. Scattered showers are found from 27N to 31N between 41W and 57W. An upper-level trough stretches southeastward from N Florida through a low north of the Bahamas at 28N73W to another low north of Puerto Rico at 24N65W. Scattered moderate to isolated strong convection is flaring up from the Keys westward to just W of the Bahamas, and farther E from 23N to 27N between 63W and 72W. A broad area of Saharan dust is indicated on satellite generally S of 25N and E of 40W. Light to gentle winds and seas of 3 to 5 ft prevail N of 20N W of 27W. Moderate to fresh trades and seas of 5 to 7 ft dominate from 08N to 20N between from 28W to the Lesser Antilles, and also near the Canary Islands from 20N to 29N E of 30W. For the forecast W of 65W, Tropical Depression Four is located just N of the forecast region near 31.9N 78.3W 1013 mb at 11 AM EDT moving WNW at 14 kt. Maximum sustained winds are 30 kt gusts 40 kt. This tropical cyclone will remain N of the forecast area and should make landfall along coast of South Carolina later this evening. The Atlantic ridge will build westward and dominate the forecast waters the remainder of the week. Fresh winds are expected just N of Hispaniola at night beginning Wed night. A tropical wave may approach areas south and east of the Bahamas late in the week. $$ PC