Area Forecast Discussion
Issued by NWS Huntsville, AL
Issued by NWS Huntsville, AL
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757 FXUS64 KHUN 211116 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 616 AM CDT Fri Aug 21 2026 ...New AVIATION... .KEY MESSAGES... Updated at 409 AM CDT Fri Aug 21 2026 - Areal flooding will continue to impact the eastern half of north AL through the early morning hours. - A slightly cooler/drier airmass will spread across the region later today. However, this will be short-lived with additional showers and thunderstorms possible beginning Saturday evening and continuing through much of next week. && .NEAR TERM... (Today) Issued at 409 AM CDT Fri Aug 21 2026 Severe thunderstorms (which impacted much of the region with damaging winds, hail, excessive lightning and flooding rainfall yesterday evening) have largely dissipated to the south/east of the forecast area. However, another loosely organized complex of convection (which initiated along the same frontal confluence axis) is currently spreading southeastward across northern MS. Most high-resolution model data suggests that this activity will bypass our region to the southwest before decaying across west- central AL by 12Z, but due to lingering runoff and residual flooding from the widespread 2-4" rainfall event, Areal Flood Warnings will remain in effect for the eastern half of north AL through 5 AM CDT. Although environmental conditions currently support development of patchy, locally dense fog as early morning temps remain steady in the l70s, there have thus far been no indications of widespread fog formation. Over the course of the day, light northerly flow at the surface (coupled with strengthening NW flow aloft) will advect a slightly drier airmass into the local forecast area, with dewpoints by late afternoon expected to range from the m60s in the north to the u60s-l70s in the south. A few afternoon showers (and perhaps a thunderstorm or two) may develop in the vicinity of the Cumberland Plateau, but it appears as if more robust convection (related to the southward sagging cold front and boundary layer moisture gradient) will be focused across central AL and points southward. Thus, we will retain only a low 15-25% POP for much of the forecast area. With the combination of falling dewpoints and a broken layer of postfrontal stratocu expected to result in much lower CAPE (compared to yesterday), any thunderstorm activity that may materialize in our region will remain well below severe thresholds. Afternoon high temps will be several degrees cooler, ranging from the m80s in elevated terrain to the u80s-l90s elsewhere. && .SHORT TERM... (Saturday through Sunday Night) Issued at 741 PM CDT Thu Aug 20 2026 Any remaining MCS clusters will shift south of the TN valley by Friday morning. There is a very low chance of a shower or thunderstorm along the cold front that will slip southeast into the TN valley on Friday, but the chance is less than 15%. Dry weather should last through Saturday. But then another northwest flow shortwave and cold front arrives Saturday night which may generate showers and thunderstorms in the eastern OH valley into eastern TN. It is unclear if thunderstorms will be able to develop southwest into the TN Valley Saturday evening or overnight. We will monitor model trends, but for now most areas will remain dry in the forecast. Dew points should drop into the 60s by Sunday behind this front which will be a welcome relief from the higher dew points we have experienced lately. && .LONG TERM... (Monday through Thursday) Issued at 741 PM CDT Thu Aug 20 2026 A mean trough axis will remain in place over the eastern CONUS with a strong ridge over the southern Rockies into the southern Plains. This will keep a fairly active northwest flow regime over the central Plains and upper Midwest through the OH and TN valleys. This will keep at least low chances of showers and thunderstorms in play, with the big question begin details of MCS timing and intensity. It`s far too early to discern this with much confidence, so will side with the NBM in this forecast. High temperatures will remain near normal in the upper 80s to lower 90s with lows in the 60s to around 70. && .AVIATION... (12Z TAFS) Issued at 616 AM CDT Fri Aug 21 2026 Although the remnants of evening TSRA continue to dissipate well to our southeast early this morning, another small but weakening complex of storms will track southeastward (safely to the S/W of both HSV and MSL) early in the TAF period. With only a few afternoon convective cells possible along the Cumberland Plateau (and frontal convection expected to initiate across central AL), we will keep the forecast dry at this point. Thus, VFR conds will exist, with development of a sct-bkn stratocu field by 15Z (followed by rapid clearing around 0Z). Sfc winds will remain from 360-020 at sustained speeds of 5-10 kts. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...70/DD SHORT TERM...17 LONG TERM...17 AVIATION...70/DD