000 AXNT20 KNHC 222301 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 701 PM EDT Mon Jun 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... Subtropical Depression Four is centered near 38.2N 65.7W at 22/2100 UTC or 270 nm SE of Nantucket Massachusetts moving ENE at 8 kt. Estimated minimum central pressure is 1009 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. 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... A central Atlantic tropical wave is near 35W south of 18N, moving W at 15-20 kt. Scattered moderate convection is occurring from 07N to 11N within 120 nm of the wave axis. An eastern Caribbean tropical wave is near 65W south of 18N, moving W at 15-20 kt. A stable air mass associated with a significant Saharan Air Layer outbreak is inhibiting any convection with this wave. A western Caribbean tropical wave is near 84W south of 20N, moving W at 20 kt. Recent satellite imagery indicates that oceanic convection associated with this wave has diminished. ...MONSOON TROUGH/ITCZ... The monsoon trough extends off the coast of Guinea-Bissau near 11N16W to 10N25W. The ITCZ extends from 10N25W to 09N34W, then resumes from 08N36W to the coast of French Guiana near 05N52W. Scattered moderate convection is noted from 05N to 08N between 14W and 18W. GULF OF MEXICO... A mid to upper-level trough that extends across the mid-Mississippi Valley into the NW Gulf is supporting numerous moderate and scattered strong convection over the northern Gulf, generally N of 26N and W of 84W. Stronger thunderstorms are likely producing gusty winds and locally rough seas over portions of the northern offshore waters. Gentle to moderate southerly flow prevails across the Gulf waters W of 90W this evening, although stronger thunderstorms are likely producing gusty winds and locally rough seas over portions of the northern offshore waters. Elsewhere, a weak surface ridge extends into the eastern Gulf, where winds are light and variable based on earlier scatterometer passes. Wave heights range from 3-6 ft in the western Gulf to 3 ft or less in the eastern Gulf. Surface ridging will prevail over the Gulf waters through the forecast period. Moderate to fresh southerly winds are forecast over the western Gulf tonight through Thu night as the pressure gradient tightens between the ridge and lower pressure over Mexico. CARIBBEAN SEA... GOES-16 satellite imagery shows dense Saharan dust covers much of the Caribbean waters E of 80W this evening. This dry, stable air mass is inhibiting convection across the region. At the surface, the pressure gradient associated with strong Bermuda high pressure is producing moderate to fresh trades across the waters S of 18N, with strong to near gale-force winds noted in the south-central Caribbean near the coast of Colombia. Seas in this region peak around 12-13 ft downstream of the strongest winds, with seas 8 ft or greater covering much of the waters from 10N to 16N between 73W and 81W. Fresh to strong trades over the south-central Caribbean will expand to the north-central and southwest basin through the middle of the week as high pressure builds over the western Atlantic. Winds will pulse to near gale force off the coast of Colombia each night through Fri night with seas building to 12 ft and higher during the strongest winds. Fresh to strong winds are expected in the Gulf of Honduras through Fri night. ATLANTIC OCEAN... A surface ridge extends from high pressure centered near 36N51W across the western Atlantic offshore waters towards the Bahamas and the east coast of Florida. A weak surface trough is analyzed from 31N49W to 26N51W to 21N58W, with isolated showers occurring near the trough axis. Strong high pressure dominates north of the region, with earlier scatterometer data showing a large area of fresh to locally strong trades over the waters S of 20N and W of 35W. Combined seas in this region are running 6-9 ft in NE wind waves and SE swell. High pressure extends from the central Atlantic to Florida and will prevail across the offshore waters through the forecast period. Fresh to occasionally strong easterly winds will pulse across the waters north of Hispaniola each night through Fri night. $$ B Reinhart