textproduct: Huntsville

KEY MESSAGES

Updated at 955 AM CDT Sun Jun 21 2026

- A Slight Risk for strong to severe storms exists tomorrow with the primary threats being damaging winds and heavy rainfall.

- Low to medium chances of general showers and thunderstorms remain in the forecast through Wednesday with frequent lightning and heavy rainfall being the primary threats.

NEAR TERM

(Tonight) Issued at 240 PM CDT Sun Jun 21 2026

Under partly cloudy skies temps have heated into the low to mid 80s. Showers and storms can be seen lifting north along a boundary in central AL and MS. This convection is largely forecast to remain to our south, keeping the CWA dry through the remainder of the weekend. Through the early morning hours on Monday, low clouds and gusty SW winds will build in ahead of a decaying MCS that looks to enter our area just after sunrise. The morning storm threat is discussed below, just make sure to bring a rain coat when heading out the door tomorrow.

SHORT TERM

(Monday through Wednesday) Issued at 955 AM CDT Sun Jun 21 2026

2:30 PM UPDATE: SPC has upgraded the eastern half of the area to a Slight risk for severe storms tomorrow. Models have started to show redevelopment along a lingering boundary tomorrow afternoon prompting another round of strong to severe storms from about 2-8 PM. Likewise, SPC has introduced a low tornado threat due to the presence of some favorable low level shear. While a tornado or two may occur, we feel the overall tornado threat remains low for both rounds of storms.

Previous Discussion:

Through the short term we will be in zonal flow aloft that will allow several embedded shortwaves to pass through the TN Valley, the first of which arrives on Monday. Early Monday morning an MCS will be ongoing to our NW associated with a weak surface cyclone. Through the morning this feature will push SE and move through the TN Valley. While a stray shower or storm may develop during the early morning hours, the main MCS looks to enter NW AL just after sunrise and move from NW to SE through the morning. Models indicate a decent amount of surface instability (+1000 J/KG) will be present. Paired with an okay amount of bulk shear (25-35 KTS), a few strong to severe storms certainly look possible with damaging winds being the main severe threat. This is supported by SPC with the whole area being under a Marginal Risk (1/5). Unfortunately our tropical airmass will still be in place with high dew points and PWATS, making heavy rainfall again a concern. Low corfidi up shear values raise concerns for training convection and potential flash flooding. As such, WPC has place most of the area in a Slight Risk (2/4) for Excessive Rainfall.

The MCS looks to weaken as it pushes south but model guidance does push it all the way through our area by early afternoon. Brief clearing may occur, yet without much change in the airmass, low to medium (20-40%) chances for general showers and thunderstorms will remain in the forecast late Monday afternoon through Wednesday afternoon. While no severe weather is forecast, all storms will remain capable of efficient rainfall production through midweek, making heavy rainfall and localized flooding the main concern. With an active weather pattern for the entire short term forecast, make sure to remain weather aware and have multiple ways to get warnings.

LONG TERM

(Tuesday night through Saturday) Issued at 958 PM CDT Sat Jun 20 2026

For the first couple of days of the extended period (Wednesday/Thursday), our forecast area will remain beneath a light (10-20 knot) NW flow aloft between a strong subtropical high centered across southern AZ/southern NM/northern Mexico and an amplifying northern stream shortwave trough digging southeastward into the Great Lakes. In the low-levels, high pressure (initially across the central Appalachians) will shift quickly eastward off the Mid- Atlantic Coast as a slow-moving area of low pressure drifts southeastward across the Upper MS Valley/Great Lakes. This will yield light SSW return flow across our region (perhaps as early as Wednesday, but more likely by Wednesday night) which will contribute to an increase in the coverage of showers/thunderstorms once again. Present indications are that storm coverage will remain fairly high on Thursday to the south of a weak cold front trailing southwestward off the low to our north, but deep-layer flow and shear appear too weak to warrant concern for organized convection. Nevertheless, a moist/unstable airmass featuring PWAT values of 1.6-1.8" and CAPE of 1500-2500 J/kg could result in a risk for strong downburst winds.

During the timeframe from Friday-Saturday, global models suggest that the mid-level high over the southwestern deserts will begin to weaken as the central North Atlantic subtropical ridge strengthens and retrogrades westward across the FL Peninsula and into the eastern Gulf. With our region likely to become increasingly influenced by minor height rises aloft and drying profiles, we expect the coverage of showers and thunderstorms to gradually decrease from Friday into Saturday (although with a lingering front/convergence axis likely to lie somewhere in the vicinity of the TN Valley, rain chances will certainly be non-zero). Highs will progressively warm from the l-m 80s into the m-u 80s by Saturday, as overnight lows rise from the m-u 60s into the u60s-l70s.

AVIATION

(00Z TAFS) Issued at 728 PM CDT Sun Jun 21 2026

VFR conditions will continue at the HSV/MSL terminals this evening, as a bkn-ovc layer of convective debris clouds spreads northeastward. Although a 5-10 kt SW wind in the low-levels will keep the boundary layer well-mixed (and reduce concern for BR/FG development), a southwesterly low-level jet will progressively strengthen throughout the night as a sfc low tracks eastward across IL/IN/OH. This will result in formation of an initially scattered layer of stratocu by 6Z, which should transition into a broken layer of MVFR stratus by 10Z (that will largely remain intact thru the end of the TAF period). Chances for SHRA/TSRA will begin to increase shortly after Midnight, as the low-level strengthens ahead of an approaching MCS. However, this activity should remain sufficiently scattered and we will not mention in the forecast attm. Greater impacts from the MCS will likely come from 10-16Z, 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. As the morning MCS spreads southeastward and out of the region by early-mid aftn, convection may redevelop across parts of NW AL/southern Middle TN late in the TAF period and additional PROB30 groups will be included in the next issuance of the TAFs.

HUN WATCHES/WARNINGS/ADVISORIES

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