000 AXNT20 KNHC 010003 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 805 PM Fri Jul 31 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 2345 UTC. ...SPECIAL FEATURES... Hurricane Isaias is centered near 22.9N 75.9W at 01/00000 UTC or about 150 nm SSE of Nassau, Bahamas and 270 nm SE of Freeport Grand Bahama Island. Isaias is moving NW or 315 degrees at 13 kt. The estimated minimum central pressure is 987 mb. The maximum sustained wind speeds are 70 kt with gusts to 85 kt. GOES-16 satellite imagery shows scattered moderate to strong convection within 120 nm of the center in the northern semicircle and within 60 nm of the center in the SW quadrant. Similar convection is in an outer band within 45 nm of line from 21N74W to 22N73W to 24N73W. Scattered moderate to isolated strong convection is elsewhere from 21N to 25N between 72W-74W. This convection is impacting the southeastern Bahamas and is gradually spreading northwestward to over the lower part of the Central Bahamas. Scatterometer data from this afternoon showed a broad area of 20-30 kt winds covering the area from 19N-26N between 67W-79W. Latest altimeter data passes highlighted seas to 8 ft as far north as 28N between 70W-77W. Maximum sea heights are up to 28 ft near the center of Isaias. Isaias is forecast to continue in a general northwestward motion with some decrease in forward speed for the next day or so, followed by a turn toward the north-northwest by late Sun. On this forecast track, the center of Isaias will be near the central Bahamas tonight, and move near or over the NW Bahamas Sat and near the east coast of the Florida peninsula Sat afternoon through Sun. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website- https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest Isaias NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Tropical Depression Ten in the far eastern Atlantic is centered near 15.9N 20.0W at 01/0000 UTC or about 230 nm east of the Cabo Verde Islands moving N or 355 degrees at 8 kt. The estimated minimum central pressure is 1007 mb. The maximum sustained wind speeds are 30 kt with gusts to 40 kt. GOES-16 satellite imagery shows scattered moderate to isolated strong convection within 120 nm of the center in the NW quadrant. Tropical Depression Ten is forecast to turn toward the northwest tonight, followed by a turn to the west-northwest and west on Sat and Sat night. On the forecast track, the center of the depression is expected to pass north of the northernmost Cabo Verde Islands tonight and Sat. The depression is forecast to strengthen to a short-lived tropical storm late tonight near 17.3N 21.0W, with maximum sustained winds of 35 kt with gusts to 45 kt. Weakening is forecast to begin on Sat and the system is expected to become a remnant low near 19N26W on Sat night. Please read the latest Tropical Depression Ten NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...TROPICAL WAVES... A far eastern Atlantic tropical wave has its axis along 26W, from 02N to 18N, moving westward around 10 kt. Scattered moderate to isolated strong convection is within 120 nm west of the wave from 09N-11N. Scattered showers and isolated thunderstorms are within 120 nm east of the wave from 10N to 13N. A central Atlantic tropical wave has its axis along is along 48W from 02N to 18N, moving westward at 15-20 kt. Scattered moderate convection is within 120 nm west of the northern part of the wave from 15N to 18N. Another central Atlantic tropical wave has its axis along 59W from 06N to 18N, moving westward at 10-15 kt. There is no significant convection associated with this wave at this time as it is being surrounded by a rather dry and stable environment. ...MONSOON TROUGH/ITCZ... The monsoon trough axis passes through the coastal sections of Senegal near 16N16W to just south of newly developed Tropical Depression Ten and continues to 11N130W to 10N40W and to 10N53W, where latest scatterometer data indicates it transitions to the ITCZ to just west of the tropical wave that is along 59W. Scattered moderate convection is within 180 nm south of the trough between 34W-38W and also between 40W-46W. GULF OF MEXICO... Upper-level ridging spans across the Gulf with a weak 1017 mb surface high pressure center analyzed near 27N89W. A surface trough is off the Florida west coast along 84W from 24N to 28N. No shower and thunderstorm activity is noted near this trough. A surface trough is analyzed over the far western part of the SW Gulf along a position from 24N98W to just inland the coast of Mexico at 19N95W. Weakening scattered showers and a few thunderstorms are seen from 20N to 24N between 92W-97W. Scattered moderate convection is over the northern Yucatan Peninsula to along that coast. Some of this activity is weakening with time. Otherwise, the weak 1017 mb is allowing for generally light to gentle anticyclonic winds across the basin and rather low seas, in the range of 2-3 ft are present. Hurricane Isaias is east of the Gulf basin over the SE Bahamas near 22.9N 75.9W at 8 PM or about 150 nm SSE of Nassau, Bahamas and 270 nm SE of Freeport Grand Bahama Island. Isaias is moving NW or 315 degrees at 13 kt. The estimated minimum central pressure is 987 mb. The maximum sustained wind speeds are 70 kt with gusts to 85 kt. Hurricane Isaias will is forecast to be near the central Bahamas tonight, and move near or over the NW Sat and near the east coast of the Florida peninsula Sat afternoon through Sun. Otherwise, mainly gentle winds will continue across the Gulf waters through early next week as weak high pressure remains situated over the northern Gulf waters. CARIBBEAN SEA... A 1009 mb low is analyzed in the west-central Caribbean near 16N78W with a trough extending northeastward from the low to eastern Cuba near 20N76W and southwestward from the low to near 11N82W. A mid to upper-level inverted trough stretches from just west of Jamaica to near 15N81W and to near 11N82W. Isolated showers and thunderstorms are noted from 15N to 19N between 77W-84W. Scattered moderate to isolated strong convection aided by low pressure over northwestern Colombia is noted along and to within 60 nm of the Colombia coast between 75W-77W. Moderate to fresh east-southeast winds are occurring over the northeastern Caribbean as a result of a tighter gradient there that between Hurricane Isaias and high pressure that is over the central and western Atlantic. Otherwise, light to gentle winds are over the western Caribbean. Observed seas range from 3 to 6 ft with higher seas, up to 8 ft from 15N to 18N between 64W-80W. Hurricane Isaias is centered near 22.9N 75.9W at 8 PM or about 150 nm SSE of Nassau, Bahamas and 270 nm SE of Freeport Grand Bahama Island. Isaias is moving NW or 315 degrees at 13 kt. The estimated minimum central pressure is 987 mb. The maximum sustained wind speeds are 70 kt with gusts to 85 kt. Isaias will continue to pull away from eastern Cuba through tonight and Sat as it moves across the central Bahamas tonight and the NW Bahamas Sat. Fresh to strong flow will be south of Hispaniola tonight, then diminish on Sat. A low pressure trough will bring increasing winds and seas to the waters north of 15N and east of 60W late Sat night and Sun. ATLANTIC OCEAN... See the Special Features section for more information on Hurricane Isaias and recently formed Tropical Depression Ten. A trough is analyzed in the central Atlantic along a position from near 30N54W to 27N57W and to 23N58W. This trough is supported by a small upper-level low at 29N56W. Isolated showers are seen within about 90 nm either side of the trough. High pressure dominates the basin, with high center of 1022 mb near 32N41W and 29N42W and a 1021 mb high center at 32N53W. Outside Isaias, the gradient supports generally light to moderate winds, except for fresh to strong winds south of 26N between 69W-76W. Seas are in the 5-7 ft range, except for 8-12 ft seas south of 26N and between 69W-76W. Hurricane Isaias is centered near 22.9N 75.9W at 8 PM or about 150 nm SSE of Nassau, Bahamas and 270 nm SE of Freeport Grand Bahama Island. Isaias is moving NW or 315 degrees at 13 kt. The estimated minimum central pressure is 987 mb. The maximum sustained wind speeds are 70 kt with gusts to 85 kt. Isaias will move toward the NW Bahamas near 23.9N 77.2W Sat morning, then move near the east coast of the Florida peninsula to 25.4N 78.8W Sat afternoon, 26.8N 79.9W Sun morning, 28.3N 80.4W Sun afternoon, and weaken to a tropical storm near 30.0N 80.4W Mon morning. Isaias will then accelerate north of the area to near 32.5N 79.4W by Mon afternoon. Very large seas attributed to southeast swell are expected over a large portion of the SW North Atlantic waters near and offshore of the Bahamas tonight into Sat. Swell associated with Isaias will spread northward across the waters west of 75W Sat night through Sun night, then move north of the region early next week. $$ Aguirre