textproduct: Huntsville

KEY MESSAGES

Updated at 322 AM CDT Mon Jun 22 2026

- Chances for showers and thunderstorms will begin to increase around daybreak, but will be highest (85-95%) from late Monday morning-early Monday evening.

- Conditions appear favorable for both locally heavy rainfall and flooding and strong-severe storms, with damaging winds and a brief tornado or two. Expect this main threat period for any severe storms and flooding to be between 1 PM and 9 PM. - After a period of drier conditions Tuesday into Wednesday morning, chances for showers and storms increase to 40-60% from Wednesday afternoon into Thursday. A more localized flooding threat may redevelop on Wednesday afternoon into Thursday.

- Rain chances will decrease Friday and Saturday.

NEAR TERM

(Today and Tonight) Issued at 315 AM CDT Mon Jun 22 2026

Good low level convergence (850 mb and lower) continues to setup northwest of the AL/TN border this morning. Stronger shear and forcing aloft is concentrated further north though closer to a weak surface/upper level area of low pressure moving east through central Indiana/Illinois. This should keep stronger thunderstorm activity north of the area in northern Tennessee into areas near Kentucky/southern Indiana this morning.

That being said, there is a weak decaying MCS that is pushing southeast from NE Arkansas towards northern Alabama. Some additional showers and thunderstorms are developing in a north to south line ahead of this in western Tennessee. However, mean flow in most guidance is more ENE to NE through much of the morning hours with the best low level convergence centered more over central/northern Tennessee than further south. Thus, expect most of this convection to continue to develop more so in Tennessee and Kentucky than further south. Likely northern Alabama with see some rainfall this morning along with some scattered storms. However, but given weak shear in place and forecast by models this morning, not expecting any severe thunderstorms to develop. Some storms could produce frequent lighting later this morning and heavy downpours though.

As instability really increases towards 1 PM and into the afternoon hours, a secondary shortwave currently moving east through central Oklahoma will eventually approach the area. Shear increases in model guidance significantly during the late morning hours to our west ahead of this feature. As this feature pushes further east during the afternoon hours before exiting northern Alabama in the evening hours, shear increases over the area. With models showing between 1000 and 2000 J/KG of SBCAPE over the area, strong to severe storms will likely develop, mainly between 1 PM and 9 PM. Damaging winds will be the main threat. There will be just enough helicity that a brief tornado or two cannot be ruled out. A flash flooding threat could develop during this period as well with possible training thunderstorm activity and high PWATS in place (over 2.0 inches). This threat may develop the most later this afternoon.

Most guidance has this secondary shortwave pushing southeast of northern Alabama around 10 PM or very short afterwards. This should push the better shear and convection southeast of the area. However, some lingering rainfall and maybe a few sub-severe storms could hold on just past midnight towards Cullman county.

SHORT TERM

(Tuesday through Wednesday night) Issued at 315 AM CDT Mon Jun 22 2026

Light northeast winds in the wake of the front will advect a drier, but highly modified Canadian airmass southwestward into the region, leading to a temporary period of rain-free conditions for our northeastern forecast zones from Tuesday into Tuesday night. These conditions may very well exist region-wide, but with normal levels of uncertainty regarding precisely where the front will become stationary, we will maintain low-medium POPs in the southwest.

During the timeframe from Wednesday-Wednesday night, models suggest that the front will begin to to lift northeastward once again in response to a northern stream vort max and weak area of surface low pressure over the western Great Lakes. A moist airmass will return to the region as this occurs, with coverage of showers and thunderstorms expected to increase from SW-to-NE during the afternoon and evening hours. Fortunately, deep-layer shear will be much weaker (compared to tomorrow), reducing the threat for organized/severe convection. Regarding temperatures, daytime highs will remain in the l-m 80s with overnight lows in the m-u 60s (l-m 60s on Tuesday night) .

LONG TERM

(Thursday through Sunday) Issued at 1026 PM CDT Sun Jun 21 2026

We continue in a generally wet pattern through the beginning of the long term period, with at least low chances (30%) of showers and thunderstorms daily. With high pressure over the southeastern US and low pressure over the Great Lakes region, the TN Valley will remain wedged between with an upper level shortwave forecast to push eastward into the area by Thursday into Friday. As this occurs, rainfall chances will increase to medium (40-60%) both Thursday and Friday afternoons with the assistance of a lingering frontal boundary south of the area as well as southwesterly flow. There remains some model disagreement in the potential environment based on placement/track of aforementioned upper level shortwave, however, southwesterly flow will likely contribute to a moist environment with PWATs reaching around 1.7-1.8" (just below 90th percentile sounding climatology per BMX). The majority of rainfall/flash flood potential will likely remain to our west in areas where the Weather Prediction Center has already highlighted in a Marginal (risk level 1 of 4) Outlook for Excessive Rainfall. Rain chances will gradually decrease as we head into the weekend as sfc high pressure begins working in from the west. Heat will be a concern towards the end of the week as well as highs are forecast to reach the upper 80s to low 90s with heat index values around 100 degrees by Saturday and Sunday. If you have outdoor interests at the end of the work week, be sure to check back in for updates.

AVIATION

(06Z TAFS) Issued at 1239 AM CDT Mon Jun 22 2026

Overcast stratus based arnd 1500 ft AGL will continue to overspread the HSV/MSL terminals early in the TAF period, as a southwesterly low-level jet strengthens across the region. However, this cloud deck should begin to lift/scatter by 14Z as diurnal mixing begins. Although a few SHRA/TSRA may occur at times, coverage through mid-day will likely be too low to mention in the official forecast. Greater impacts from a reintensifying MCS will likely come during the afternoon hours at both terminals, with PROB30 groups included from 17-21Z/MSL and 19-23Z/HSV, at which point MVFR vsby reductions in hvy rain and AWWs for lightning and strong wind gusts in excess of 35-45 knots can be expected. MVFR-level stratus clouds and light westerly winds will occur in the wake of this activity, and should persist thru the end of the period.

HUN WATCHES/WARNINGS/ADVISORIES

AL...None. TN...None.