000 AXNT20 KNHC 022324 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 805 PM Sun Aug 02 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... Tropical Storm Isaias is centered near 27.8N 79.8W at 02/2100 UTC, or about 55 miles southeast of Cape Canaveral, Florida and about 355 nm south of Myrtle Beach, South Carolina moving NNW or 345 degrees at 8 kt. The estimated minimum central pressure is 994 mb. Maximum sustained winds have increased slightly to 60 kt with gusts to 76 kt. GOES-16 satellite imagery shows a large and rather symmetrical area numerous moderate to strong type convection within 180 nm NE of the center. Similar convection is within 90 NW and 60 nm SE of the center. Scattered moderate to isolated strong convection to the southeast of the center depicts a band within 30 nm either side of a line from 26N77W to 27N78W. Scattered moderate convection is within 30 nm either side of a line from Miami, Florida to 26N78W and to 26N77W. Fresh to strong winds on the periphery of Isaias reach northward to near 30N, eastward to near 75W and westward to near 80W. Peak wave heights with Isaias are up to around 22 ft. Isaias is forecast to continue on a general north to northwest motion through tonight. A turn toward the north and north-northeast along with an increase in forward speed is anticipated on Mon and Tue. On the forecast track, the center of Isaias will pass just to the east of the Florida east coast through tonight. The center of Isaias will then move offshore of the coast of Georgia and southern South Carolina on Mon. It will move inland over eastern North Carolina Mon night and move along the coast of the mid-Atlantic states on Tue. 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. A tropical wave extends along a position from near 20N60W to 15N62W and to inland Venezuela, moving westward at about 15 kt. This wave remains within close proximity to an inverted mid to upper-level trough to its northwest. As a result, scattered moderate convection has been sustained and is increasing with time near and across the northern part of this wave. This activity is evident from 20N to 25N between 58W-63W. Isolated showers and thunderstorms are from 17N to 20N between 58W-61W. This system is forecast to move through environmental conditions that are conducive for additional development during the next few days, and a tropical depression could form by the middle of the week. This system is forecast to move northwestward over the western Atlantic early this week, passing north of the Leeward Islands. It has a medium chance of becoming a tropical cyclone during the next 48 hours. Please refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details. ...TROPICAL WAVES... A far eastern Atlantic tropical wave has its axis from 01N to across the Cabo Verde Islands and to near 19N, moving westward near 15 kt. Scattered moderate to isolated strong convection is within 120 nm west of the wave axis from 06N to 10N and along and within 30 nm east of the wave axis from 08N to 10N. A central Atlantic tropical wave has its axis along 43W from 02N to 16N, moving westward at 15 kt. This wave marks the leading edge of a pool of deep atmospheric moisture. Isolated showers and thunderstorms are within 180 nm east of the wave axis from 04N to 13N. This activity could increase during the overnight hours. A central Caribbean tropical wave has its axis along 75W south of 19N to inland Colombia. It is moving westward at 13 kt. This wave was introduced on the 18Z per updated guidance and past tracking history. Only isolated quick westward moving isolated showers and thunderstorms are noted within 180 nm east of the wave from 14N to 17N and within 120 nm west of the wave from 14N to 18N. Some of this activity is approaching the eastern tip of Jamaica. The northern part of the wave may be assisting to some extent with the development of scattered showers and thunderstorms over most of interior Haiti. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from the coast of Senegal near 14N17W to 11N30W to 10N40W and to 10N50W, where latest scatterometer data indicates that it transitions to the ITCZ and continues to 11N60W. Aside from the convection related to the tropical waves described above, scattered moderate to isolated strong convection is seen from 08N to 14N between 13W-23W. Scattered moderate convection is within 240 nm south of the trough between 29W-32W and within 180 nm south of the trough between 35W-38W. Similar activity is within 60 nm south of the trough between 53W-59W. GULF OF MEXICO... Upper-level anticyclonic flow tied to a small anticyclone that is located just south of the Yucatan Channel covers just about the entire basin, except over in the far northwest part where a mid to upper-level trough is located. At the surface, a 1014 mb high center is analyzed near 27N93W as of 2100 UTC. A trough is over the far southwestern Gulf from near 23N97W to just inland the coast of Mexico at 18N94W. Isolated showers and thunderstorms are south of 25N between 90W-96W. Broken bands of scattered showers and isolated thunderstorms rotating around the western semicircle of Isaias are over the interior sections of the Florida peninsula, with some of this activity having reached the far eastern part of the Gulf mainly south of 29N. The activity over the Gulf waters appears to be diminishing. Winds throughout are in the light to gentle range, except for winds of moderate speeds near the coast of Florida. Seas in the basin are rather low, in the 2-4 ft range. Moderate winds will continue near the west coast of Florida through early Mon as Isaias moves north-northwest near the east coast of Florida. A weak high pressure ridge will persist over the northern Gulf this week, maintaining gentle flow across much of the region with moderate winds expected over the southwestern Gulf. CARIBBEAN SEA... A small upper-level anticyclone is just south of the Yucatan Channel near 21N86W, with associated anticyclonic flow present to the west of 79W. At the surface a trough extends from just south of the western tip of Cuba to a 1011 mb low at 18N87W and to just inland the border between Guatemala and Honduras. Scattered showers and thunderstorms are along and near the trough from 18N to 20N between 84W-86W. Otherwise west of the tropical wave along 75W, isolated showers moving quickly westward are over the central and western Caribbean waters north of about 12N. Similar showers are over the eastern Caribbean north of 14N. Winds are light to moderate across the basin, with seas in the from 3-6 ft. The northern part of the eastern Caribbean sea tropical wave will slightly increase winds and seas over the Tropical N Atlantic waters north of 15N and east of 64W tonight. Fresh trade winds over the central Caribbean waters are expected to strengthen by mid-week following the passage of the above described tropical wave. ATLANTIC OCEAN See the Special Features section above for more details on Tropical Storm Isaias and on a tropical wave near the Leeward Islands with potential for development. High pressure is present across most of the Atlantic, anchored by a 1022 mb high center near 29N47W. A few troughs are analyzed over the eastern and central sections of the area. The first one from near 30N42W to 23N42 with no significant convection associated with it, and the other from 35N31W to 28N36W, also with no significant convection associated with it. A trough left over from former Tropical Depression Ten extends from 23N27N to 16N30W. It has no convection. Another trough is ahead of this one from near 24N32W to 17N36W and it has no convection. The gradient across the area is allowing for light to moderate winds throughout, except for fresh winds near the Canary Islands and fresh to strong winds in the western part of the area on the periphery of Tropical Storm Isaias. Seas range from 5-8 ft, except for much higher seas in the range of 8-12 ft within the area of 20-33 kt winds in the western part of the area outside the tropical storm force winds related to Isaias. Tropical Storm Isaias will move near the east coast of Florida to 29.0N 80.1W Mon morning, 30.9N 79.9W Mon afternoon, then accelerate N-NE away from the forecast waters to near 33.7N 78.8W Tue morning. Large seas associated with Isaias will spread northward across the waters W of 75W through Mon, then gradually subside late Mon night through Tue night. The special features system will approach the southeastern waters tonight, with environmental conditions conducive for development during the next few days. This system is expected to impact winds and seas over these waters. For marine information regarding this system, please read the latest high seas forecasts at website- https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml. $$ Aguirre