699 FXUS64 KHUN 220830 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 330 AM CDT Thu Oct 22 2020 .NEAR TERM...(Today) Issued at 330 AM CDT Thu Oct 22 2020 Latest water vapor imagery shows a mid level trough digging into the Intermountain West, with ridging over the east coast. At the surface, high pressure was centered along the southern Appalachians, with light southeasterly winds across the TN Valley. This has led to fairly mild conditions over the forecast area, as the southerly fetch has kept dewpoints in the upper 50s to lower 60s. This, combined with mostly clear skies has allowed temps to drop within a degree or two of dewpoints, with some patchy fog developing in our river valleys. Some dense fog is possible as we progress through the predawn hours, but fog should remain isolated in nature. Any lingering fog should quickly dissipate after sunrise as temps begin to rise. A rather warm day is expected over the region as southerly flow persists. Under mostly clear skies, highs should warm into the lower to mid 80s .SHORT TERM...(Tonight through Saturday night) Issued at 330 AM CDT Thu Oct 22 2020 Another mild night is expected, with overnight lows falling into the lower 60s. The trough over the west will continue to move eastward and amplify slightly as it makes its way into the Plains. A surface cold front will develop and trail south of its parent low over the Great Lakes region by Friday morning. Most of the precip associated with this front will remain to our north and west during the overnight hours, with isolated showers possible after sunrise. Showers will increase in coverage during the afternoon, with diurnal heating aiding in shower development. However, the front will generally weaken as the mid level trough dampens. Forecast models are in fair agreement that the front will move through the TN Valley Friday night, stalling a bit to our south on Saturday. The highest chance for rain will be during the overnight hours, as the front moves through. Saturday could see showers redeveloping with the front remaining in the vicinity of the area. While isolated thunderstorms are possible, most of the rain will be post frontal, with limited instability. Thus, storms should remain elevated for the most part. Any lingering showers will dissipate and move out of the area by Saturday evening, as the front weakens altogether. Temperatures will be dependent on the timing of the front and its associated precip. On Friday, there will likely be enough sunshine to allow temps to warm into the upper 70s to lower 80s. Temps on Saturday will not see much of a warm up, as lows fall near 60s degrees and highs warm into the lower to mid 70s. .LONG TERM...(Sunday through Wednesday) Issued at 330 AM CDT Thu Oct 22 2020 Flow aloft will be generally zonal on Sunday, with dry conditions expected. The airmass isn't expected to change much, despite the passage of the front, as winds veer to the south during the day. Thus, temps will warm into the upper 70s to lower 80s and dewpoints will rise back into the mid to upper 60s. By Monday, a split flow pattern will develop over the Western CONUS as a northern stream trough digs into Intermountain West and a southern stream trough moves into the Desert Southwest. The southern stream trough will strengthen as it moves eastward, developing a cutoff low as it moves into the Southern Plains. Meanwhile, the northern stream trough will continue to move eastward across the Mid Mississippi Valley and eventually the Great Lakes region by the middle of next week. A cold front will trail south from the parent low to our north, however forecast models differ in the exact timing and how much moisture will be present over the area. Thus, kept precip chances isolated from Monday through Wednesday as uncertainty remains high. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1048 PM CDT Wed Oct 21 2020 VFR TAF conditions are expected to prevail through the TAF period, although some uncertainty exists regarding cloud cover and brief periods of MVFR conditions tomorrow. Have kept scattered high clouds until higher confidence is gained. Some patchy fog is possible tonight and early tomorrow morning, but confidence remains too low to put in TAFs at this point. Amendments may be needed if fog materializes closer to the terminals. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ NEAR TERM...73 SHORT TERM...73 LONG TERM...73 AVIATION...25 For more information please visit our website at weather.gov/huntsville.