000 AXNT20 KNHC 181056 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Fri Jun 18 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 1030 UTC. ...SPECIAL FEATURES... Potential Tropical Cyclone Three is centered near 25.2N 91.5W at 18/0900 UTC or 270 nm S of Morgan City Louisiana moving N at 12 kt. Estimated minimum central pressure is 1007 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. At this time, scattered to moderate moderate convection prevails from 23N to 29N between 86W to 91W. On the forecast track, the system will approach the north-central Gulf Coast tonight or early Saturday. A slow northeastward motion across the southeastern United States is likely after landfall through the weekend. Some strengthening is forecast, and a subtropical or tropical storm is likely to form over the west-central or northwestern Gulf of Mexico later today. 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 WAVES... An Atlantic tropical wave axis is analyzed along 29W from 18N southward, and is moving west at 10 to 15 kt. Scattered moderate convection is noted south of 09N between 26W and 33W. Another Atlantic tropical wave axis is along 49W from 19N southward, moving west at 10 to 15 kt. Scattered showers are noted from 11N to 17N between 46W and 52W. A Caribbean tropical wave axis is analyzed near 69W from 21N southward into Venezuela, and is moving W at around 15 to 20 kt. Scattered moderate convection is present from 17N to 21N between 67W and 71W. Another Caribbean tropical wave axis is analyzed along 84W from 19N southward over Honduras southward into Costa Rica, and is moving west at 5 to 10 kt. Isolated thunderstorms are noted within 60 nm of the axis in the Gulf of Honduras. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coast of Africa near 11N15W to 10N18W. Segments of the ITCZ continue westward from 10N18W to 07N22W, then resumes west of a tropical wave near 05N32W to 04N46W. A small piece of ITCZ is near the South American coast from 04N50W to 04N52W. Aside from the convection described with the tropical waves in the section above, scattered moderate convection is noted along the ITCZ from 00N to 09N between 32W to 39W. GULF OF MEXICO... Refer to the Special Features section above for details on Potential Tropical Cyclone Three. A surface trough extends along the Potential Tropical Cyclone Three from 27N89W to 22N93W. Fresh to strong winds were detected by the latest scatterometer passes north of the Yucatan Peninsula near 21N to 27N and east of 90W. Aided by upper-level divergent flow, scattered showers are occurring from the Yucatan Channel north to the Florida Gulf coast from 22N to 28N between 83W and 88W. Scattered moderate convection is noted in the SW Bay of Campeche from 18N to 23N between 91W to 97W. A stationary front stretches westward across the northeastern Gulf to the Texas coast. Scattered showers are possible along the boundary. Gentle to moderate E winds are noted in the northern Gulf north of 26N. In the Bay of Campeche, winds shift cyclonically to S around the broad low pressure. Seas are mainly in the 3-5 ft range, except 4-6 ft in the south-central Gulf and southeast Gulf. For the forecast, Potential Tropical Cyclone Three near 25.2N 91.5W 1007 mb at 4 AM CDT moving N at 12 kt. Maximum sustained winds 30 kt gusts 40 kt. Three will move northward and become better organized today, and expected to become a tropical storm this afternoon near 27.0N 91.5W, reach near 29.2N 91.2W Fri night, then move inland near 31.0N 89.5W Sat afternoon before accelerating off to the NE. The majority of strongest winds and frequent squalls and tstms are expected to occur north and east of Three through tonight. High pressure is forecast to build in across the basin in the wake of Three Sat night into early next week. CARIBBEAN SEA... Two tropical waves are moving across the basin. Refer to the Tropical Waves section above for details. The eastern Pacific monsoon trough extends from SE Panama to northern Colombia. Scattered moderate to strong convection is noted along the monsoon trough south of 13N between 74W to 83W. Fresh to strong tradewinds were detected by the latest scatterometer pass in the south central Caribbean. The strongest winds extend from the coast of Colombia north to 14N between 70W and 77W. Mainly moderate to fresh trades prevail elsewhere in the basin. Seas of 4-6 ft throughout the basin, except 6-9 ft near the area of strong winds off in the south central Caribbean. For the forecast, high pressure extends from the E central Atlantic W-SW to central Florida and will weaken north of the area through early Sat before building back Sun through Tue. This ridge will combine with lower pressure over Venezuela and Colombia to support pulsing fresh to strong trades over the S central Caribbean and Gulf of Honduras during the weekend through Tue. Fresh to strong trades, scattered tstms and squalls will follow a tropical wave along 70W tonight as it moves W across the Caribbean through Sun. ATLANTIC OCEAN... A pair of tropical waves are moving across the basin. Refer to the Tropical Waves section above for details. Diffluent flow aloft continues to support scattered moderate convection over the western Atlantic mainly north of 24N and west of 59W. To the east, a surface ridge dominates the entire Atlantic forecast area anchored by the Bermuda-Azores High located north of the area. Fresh SW winds are occurring in the W Atlantic north of 28N between 68W and 75W. Moderate to fresh trades dominate south of 22N west of 45W. Gentle to moderate trades prevail elsewhere, except from 18N to 24N between the west coast of Africa and 24W where fresh N-NE winds persist due to a locally tight pressure gradient. Seas are 7 to 10 ft in this area of fresh winds. In the Bahamas, seas are 2-4 ft. Outside of these areas, seas of 5 to 8 ft prevail across the waters south of 22N, with mainly 4 to 7 ft seas north of 22N. For the forecast west of 65W, high pressure extends from the E central Atlc W-SW to central Florida will weaken W of 70W through early Sat. This will allow a trough to sweep eastward across the northern forecast waters through Fri night. High pressure will then build back into N Florida over the weekend into early next week. Fresh to strong winds are expected to pulse at night over Hispaniola adjacent waters during the forecast period. $$ AReinhart/MTorres