000 AXNT20 KNHC 051006 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 606 AM EDT Wed Aug 5 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... The center of Post-Tropical Cyclone ISAIAS, is near 47.5N 71.8W at 0900 UTC. This position is about 55 mi/90 km to the NNW of Quebec City, Canada. ISAIAS is moving NNE, or 015 degrees at 40 mph. The estimated minimum central pressure is 1000 mb. Maximum sustained wind speeds are 40 mph with higher gusts. This general motion with a decrease in forward speed is expected today. Continued weakening is expected, with wind speeds expected to decrease to less than tropical storm-force this morning. The post-tropical cyclone is expected to dissipate over southeastern Canada on Thursday. 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 WAVES... An Atlantic Ocean tropical wave is along 28W, from 17N southward, moving W 10 to 15 knots. Associated scattered convection is located along and south of the monsoon trough in that area. An Atlantic Ocean tropical wave is along 40W, from 19N southward, moving westward 15 knots. Scattered moderate isolated strong convection is seen from 03N to 10.5N between 34W and 44W. An Atlantic Ocean tropical wave is along 52W-53W, from 17N southward, moving westward 15 to 20 knots. Scattered moderate convection is see from 10N to 14N between 50W and 54W. A Caribbean Sea tropical wave is along 83W, from 20N southward, moving W 15-20 knots. An upper level cyclonic circulation center over the central Caribbean south of Jamaica is masking the wave signature in satellite imagery. Scattered moderate convection is seen from 14N to 22N between 77W and 85W. ...MONSOON TROUGH/ITCZ... The monsoon trough passes the coastal sections of Mauritania near 17N16W to 11N28W to 08N39W. The ITCZ is along 08N/09N between 40W and 52W, and from 09N54W to 11N62W. Scattered moderate isolated strong convection is seen within 270 nm southeast of the monsoon trough from 34W to the African coast. GULF OF MEXICO... Upper level cyclonic wind flow covers the Gulf of Mexico, as an upper level low continues to sink slowly SSE offshore of Louisiana. An associated frontal trough is stationary from northern Georgia to east Texas. Scattered strong convection is shifting westward across the central Bay of Campeche south of 20N, while widely scattered moderate convection dots the Florida Bay and adjacent coastal waters. A 1017 mb high pressure center is near 27N93W. Broad surface anticyclonic wind flow spans the entire area. Light to gentle variable wind will dominate the Gulf N of 22N through most of the period as a weak surface ridge prevails. Otherwise, moderate to fresh NE to E winds are expected at night in the eastern half of the Bay of Campeche and along the Yucatan peninsula associated with a surface trough. CARIBBEAN SEA... An upper level cyclonic circulation center is to the south of Jamaica and is enhancing scattered moderate to strong convection along the monsoon trough across southwest portions from 08.5N to 12N between 75W and 83W. Stable sinking air dominates the middle and upper levels of the eastern Caribbean due to the presence of an upper level low east of the Leeward Islands. The western periphery of a central Atlantic ridge extends W-SW to near 60W this morning. The associated pressure gradient between this high and low pressure across Colombia and the monsoon trough is supporting fresh to strong tradewinds across the central Caribbean between 70W and 77W, where seas are running 6-8 ft. Elsewhere light to moderate trade prevail across western portions while moderate trades are seen across eastern portions and the Tropical Atlantic waters east of the Lesser Antilles. The pressure gradient between the Bermuda High across the W Atlantic and the eastward extension of the NE Pacific monsoon trough to Colombia will support fresh to strong trades across the central basin through Wed, then will expand to the SW Caribbean Wed night and continuing through the weekend. Moderate to fresh winds are expected in the Gulf of Honduras during this period as well as the eastern Caribbean. Strong tradewinds are expected across the central Caribbean from Colombia to Hispaniola this weekend with the passage of a tropical wave. ATLANTIC OCEAN... Scattered moderate convection is seen across the NW waters between 78W and 80W from the NW Bahamas to beyond 31N. This is being supported by the broad upper low dominating the Gulf of Mexico. A stationary front extends from the central Atlantic southwestward and across the central waters along 28N between 55W and 65W. A 1022 mb surface high is north of this trough across the western Atlantic near 36N61W and extends to offshore of NE Florida. A weak and narrow ridge extends from the NE Atlantic W-SW to near 60W, passing south of the surface trough. This pattern is producing moderate SE to S winds from the N coast of Hispaniola to offshore of NE Florida, and moderate to locally fresh tradewinds across the Tropical Atlantic south of 18N. The high pressure across the W Atlantic Ocean will promote moderate to locally fresh E-SE winds across the Great Bahama Bank and N of Hispaniola through the weekend, while fresh to strong winds are expected N of Hispaniola at night. A broad and weak low pressure will develop over the NE offshore waters tonight and shift to the north-central waters by Fri before dissipating over the weekend. $$ Stripling