682 FXUS64 KHUN 190432 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 1132 PM CDT Wed Aug 18 2021 .UPDATE... For 06Z TAFS. && .NEAR TERM...(Rest of tonight) Issued at 1000 PM CDT Wed Aug 18 2021 A rather busy time this evening across parts of the Tennessee Valley, with a few strong to severe thunderstorms and locally heavy rainfall. The storms that produced wind damage and a possible tornado in the Athens area have moved further to the east, from west of Chattanooga to across Scottsboro and Albertville. Additional convection was moving WSW-ENE from the Quad Cities to the Bankhead Natl forest. Yet other convection was moving this direction from central Mississippi. Given the showers headed this direction, will keep at least isolated rain chances in for the overnight, with higher rain chances for Thu morning, as the convection from Mississippi nears. Places that had heavy rainfall could be impacted by fog in the overnight. Some of the fog could become locally dense with visibilities reduced to 1/4 of a mile or less in spots. The rest of the forecast looks fine at this time. .SHORT TERM...(Thursday through Friday night) Issued at 1255 PM CDT Wed Aug 18 2021 Clusters of showers and thunderstorms will continue Thursday as the shortwave drops southeast. The weak front will also edge southeast as well. Plenty of debris clouds will keep instability down, so thunderstorm chances may lessen somewhat during the middle part of the day, with the main axis shifting southeast. Thus, PoPs are in the likely range, but there remains some uncertainty through the entire day. Some clearing may yield heating and redevelopment of a few thunderstorms in the afternoon in middle TN and north MS that also drop southeast during the afternoon and evening. Temperatures as a result will stay in the 80s for highs. Northwest flow aloft at 5h and a ridge at 8h and a very moist and at least slight to moderately buoyant airmass will keep chances of showers and thunderstorms at times through Friday. A weak westerly LLJ at 8h may help aid nocturnal thunderstorms Friday night as well. Heavy rainfall (possibly excessive in a few spots) will continue to be the main issue through Friday. Highs will again be in the 80s on Friday. .LONG TERM...(Saturday through Tuesday) Issued at 1255 PM CDT Wed Aug 18 2021 Multiple MCS clusters will be draped from the eastern corn belt and lower OH valley south through AL to the Gulf Coast on Saturday. These will be aided by a either MCVs or weak shortwave impulses dropping over the upper ridge in the Plains and south- southeast into the southeast region. It remains difficult to say if a more dominant singular MCS will drive southeast through the area, or multiple smaller clusters. In either case, the main hazards will be gusty outflow winds with any larger scale cold pools that can develop on Saturday, along with locally heavy rainfall. The ridge may build a bit further east by Saturday night into Sunday, lowering chances of showers and thunderstorms. As the ridge builds east through early next week, a return to more seasonably hot and humid conditions with isolated diurnally driven thunderstorms. Highs will likely reach the lower 90s with lows still in the upper 60s to lower 70s. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1132 PM CDT Wed Aug 18 2021 Unsettled weather is expected for the TAF. A SW mid/upper level flow will bring a few upper level systems across the Tennessee Valley. Those systems will help bring periods of scattered to numerous convection to the area. The best timing for showers is in the morning around sunrise Thu, and again in the afternoon. VSBY/CIG reductions to MVFR, possibly lower are possible in the heavier showers as well as erratic gusty winds. Shower activity should wane Thu evening. Light winds overnight should become SE-S in the late morning and afternoon, before becoming light and variable Thu evening. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ NEAR TERM...RSB SHORT TERM...17 LONG TERM...17 AVIATION...RSB For more information please visit our website at weather.gov/huntsville.