000 AXNT20 KNHC 012327 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 805 PM Sat Aug 01 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 2315 UTC. ...SPECIAL FEATURES... Recently downgraded Tropical Storm Isaias is centered near 25.1N 78.7W at 01/2100 UTC or about 100 nm southeast of Fort Lauderdale, Florida or 80 nm south of Freeport, Grand Bahama Island. Isaias is moving NW at 9 kt. The estimated minimum central pressure is 993 mb. Maximum sustained winds have diminished to 60 kt with gusts to 75 kt. Recent and current GOES-16 satellite imagery shows that numerous strong convection is rapidly increasing within 120 nm of the center in the NE quadrant. This is occurring after earlier convection had weakened significantly. Scattered moderate to isolated strong conevection trails Isaias from 21N to 25N between 75W-76W and from 25N to 27N between 75W-77W. Maximum wave heights generated by the cyclone are at a peak of 18 ft. Isaias is forecast to continue on a general northwestward motion with some some decrease in forward speed is expected for the next day or so, followed by a north-northwestward motion by late Sun and a turn toward the north and north-northeast on Mon and Tue with an increase in forward speed. On the forecast track, the center of Isaias will approach the southeastern coast of Florida tonight and move near or along the east coast of Florida Sun and Sun night. On Mon and Tue, the center of Isaias will move quickly from offshore of the coast of Georgia into the southern mid-Atlantic states. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT4.shtml, and the Forecast/Advisory at https://www.nhc.noaa.gov/text/MIATCMAT4.shtml, for more details. Tropical Depression Ten is centered near 19.2N 23.5W at 01/2100 UTC or about 195 nm north of the Cabo Verde Islands. Tropical Depression Ten is moving NW or 305 degrees at 11 kt. The estimated minimum central pressure is 1009 mb. Maximum sustained winds are 25 kt with gusts to 35 kt. Satellite imagery shows that the depression is devoid of deep convection. The depression is noted as a poorly defined swirl of broken and mid-level clouds, with possible isolated showers. The cyclone is moving over cool waters and while at the same time is surrounded by a dry atmospheric environment, therefore, deep convection is unlikely to re-develop. It is forecast to turn west-northwestward and become a remnant low tonight and dissipate to the north of the Cabo Verde Islands tonight or on Sun. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT5.shtml, and the Forecast/Advisory at https://www.nhc.noaa.gov/text/MIATCMAT5.shtml, for more details. ...TROPICAL WAVES... A far eastern Atlantic tropical wave has its axis along 33W from 01N to 16N. It is moving westward at 15-20 kt. Scattered moderate to isolated strong convection is within 120 nm west of the wave from 09N to 11N. Scattered moderate convection is behind the wave along the monsoon trough within 30 nm of 09N32W. A central Atlantic tropical wave has its axis along 57W south of 21N moving westward 15-20 knots. Since this wave is within close proximity to an upper-level trough to its northwest, this set-up under divergence aloft east of the upper-level trough is conducive for the development of scattered to numerous showers and thunderstorms along and near the wave. The current observed activity consists of the scattered moderate to isolated strong type intensity from 15N to 22N between the wave and 53W and also from 21N to 24N between 55W-60W. This system is forecast to move through environmental conditions that favor for it to develop within the next couple of days. A tropical depression could form from it early next week. Please monitor the latest Tropical Weather Outlooks for future updates on this system. The earlier tropical wave that was south of the Bay of Campeche has moved further into the eastern Pacific Ocean and is described in the Eastern Pacific Tropical Weather Discussion. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from the coast of Senegal near 13N17W to 10N30W to 07N44W. Latest scatterometer data indicates the ITCZ begins near 09N55W and continues to just inland the coast of Venezuela near 06N54W. Scattered moderate convection from 07N to 12N between 16W-21W. Otherwise, only rather weak isolated showers and thunderstorms are observed along and near the monsoon trough and ITCZ. GULF OF MEXICO... Upper-level ridging prevails across the Gulf with a 1015 mb surface high analyzed near 28N91W. A surface trough is analyzed just inland the Florida coast from near Naples to just of Tampa and to near 30N82W. Isolated showers and thunderstorms are south of 27N and east of 83W. A mid-level trough is pushing eastward across the southern Plains and approaching the Gulf. As a result, scattered showers and thunderstorms are along and just inland the Texas coast and the southwest Louisiana coast. N of 27N between 91W-96W. Light to gentle anticyclonic wind flow is noted across the basin. Observed wave heights throughout the basin remain rather low in the 2-3 ft range. Mainly gentle winds will prevail across the Gulf waters through the middle of next week as weak high pressure over the northern Gulf drifts southward. CARIBBEAN SEA... A surface trough extends across the northwestern Caribbean from near 21N80W to along the coast of the border between Honduras and Nicaragua to 10N83W. Only isolated showers and thunderstorms are noted from 18N to 21N between 78W-81W. The earlier scattered moderate convection in the southwestern Caribbean has dissipated. Otherwise, quick moving showers, in streamer formation, are moving westward across the Lesser Antilles to across the most of the eastern Caribbean and waters. Scattered showers and isolated thunderstorms also moving quickly westward are seen over the waters near and adjacent to Puerto Rico and the U.S. Virgin Islands. Moderate to fresh east-southeast winds are over the eastern Caribbean, with light to gentle winds in the western basin. Wave heights range from 3-6 ft, except higher wave heights of up to 7 ft in the central Caribbean where fresh trades are present. Tropical Storm Isaias is centered near 25.1N 78.7W 993 mb at 5 PM EDT moving NW at 9 kt. Maximum sustained winds 60 kt gusts 75 kt. Isaias will strengthen to a hurricane tonight while moving away from the region toward the east coast of Florida. Fresh trade winds will persist over the central Caribbean waters through the middle of next week. A tropical wave will bring increasing winds and seas to the Tropical N Atlantic waters north of 15N and east of 60W tonight through Sun. ATLANTIC OCEAN See the special features section for information on Tropical Storm Isaias and on Tropical Depression Ten. Upper-level ridging continues across the Atlantic anchored by an upper-level anticyclone situated near 28N49W. At the surface, a 1024 mb high center is analyzed near 29N46W, with a ridge extending west-northwest to near 32N81W. An eastern Atlantic surface trough is along a position from near 31N31W to 25N32W. No significant convection is associated with it. The gradient in place generally supports light to moderate winds across the area, with the exception of fresh to strong winds over the waters south of 27N and west of 70W. Wave heights range 5-8 ft across most of the area, with higher wave heights of 7-12 ft seas in the SW northern Atlantic outside the tropical storm force winds associated with Tropical Storm Isaias. Tropical Storm Isaias is centered near 25.1N 78.7W 993 mb at 5 PM EDT moving NW at 9 kt. Maximum sustained winds 60 kt gusts 75 kt. Isaias will strengthen to a hurricane while it moves near the east coast of the Florida peninsula to 26.1N 79.4W Sun morning and to 27.4N 80.1W Sun afternoon. Isaias will weaken to a tropical storm near 28.8N 80.7W Mon morning, accelerate northward and move to near 30.7N 80.6W Mon afternoon, then pass to the north of the area near 33.4N 79.1W Tue morning. Large seas will remain tonight near and offshore of the Bahamas, then spread northward across the waters west of 75W through Mon. Winds and seas will diminish Tue through Thu as Isaias moves away from the region. $$ Aguirre