textproduct: Huntsville

KEY MESSAGES

Updated at 403 AM CDT Wed Jul 23 2026

- Flood Watch in effect for areas east of I-65 through 7 PM Friday.

- Low to medium chances of showers and storms today; will increase to medium to high chances by Friday and Saturday.

- Through the end of the week, locally heavy rainfall and a low- medium flash flooding threat may evolve due to several days of showers and thunderstorms and an extremely moist, tropical-like air mass.

NEAR TERM

(Today) Issued at 403 AM CDT Thu Jul 23 2026

Based on area observations and radar trends, the frontal boundary currently stretches from near Columbus, MS ENE through our southern middle Tennessee counties into southeastern Tennessee at this hour. Fairly widespread light to moderate rainfall has developed near and south of it over areas north of the Tennessee River and into southern middle Tennessee. A few heavier downpours also are likely embedded, but these pockets of heavier downpours look to be very isolated at this time and showers are moving ENE fairly quickly.

Expect these areas of rain to shift slowly southward and expand in coverage during the day today. Expect some thunderstorms to develop producing heavier amounts of rainfall given PWATS of 2.0 to 2.2 inches forecast. Some areas of flash flooding (especially east of the I-65 corridor) could develop as the focusing mechanism (frontal boundary) slowly moves south through the afternoon hours. Expect highs to struggle to reach the 80 to 85 degree range in many locations near and north of the Tennessee River. Some locations further south should be a tad warmer with highs climbing into the mid/upper 80s.

SHORT TERM

(Thursday night through Saturday) Issued at 923 PM CDT Wed Jul 22 2026

The short term pattern will be largely dominated by an upper level ridge and subsequent sfc high in the southern Plains/Deep South- keeping the Tennessee Valley in a NW flow pattern. Additionally, remnants from Tropical Storm Bertha will be shifting northward into the area to meet a stalled frontal boundary, which should provide enough forcing/moisture for a prolonged period of intermittent heavy rainfall. The gradient in rainfall amounts will likely be sharp, with greater rainfall amounts along and east of I-65, where a Flash Flood Watch is in effect through 7 PM Friday. The Weather Prediction Center has continued a Slight risk (level 2 of 4) for flash flooding through most of the area on Friday and a Marginal risk (level 1 of 4) for flash flooding on Saturday as the front begins to retreat out of our area. The flash flood threat is supported by PWATs in the 2-2.25" range, which is above the 90th percentile per BMX sounding climatology. Areas along and east of I-65 will likely receive at least 1-2 inches of rain with isolated higher amounts (up to 4-5") in areas where stronger storms occur. Heavy rainfall will likely cause ponding of water on roadways and in areas of poor drainage as well as rises on rivers/creeks in the area. A low to medium risk of flash flooding exists through the weekend. Be sure to pay attention to the latest forecast and have multiple ways to get warnings, especially if you have outdoor plans. Otherwise, temperatures will be capped in the mid to upper 80s under cloud cover through the area. However, a warm up is on the way next week (more on this in the long term below).

LONG TERM

(Saturday night through Wednesday) Issued at 923 PM CDT Wed Jul 22 2026

A ridge dominated upper level pattern will prevail across much of the Lower-48 as we head into next week. Forecasts of 500mb heights late Sat indicated strong upper ridging sprawled from the Desert SW, southern Rockies, and the High Plains from Wyoming to the Big Bend. A deep upper low over the Hudson Bay was producing troughing which extended southward along the East Coast. This firmly places the greater Tennessee Valley in a NW flow aloft, which appears will continue into the middle of next week. A number of passing upper level disturbance within this stream will help contribute to convection impacting the area early in the period. Exact timing and placement of them is rather difficult, so am depending upon ensemble and blend guidance versus deterministic output.

At the surface, a frontal boundary now moving in a NW-SE manner across the area should return as a warm front late Fri into Sat. This will bring additional lower level moisture from the Gulf of America further inland. Output from the NBM has precipitable water amounts of over 2" across the forecast from Sat evening into Sun morning. With passing upper level support, there will be good chances for numerous showers and thunderstorms to impact the Tennessee Valley. Some of the storms could become strong. Of greater worry is rainfall output in such a humid environment. Excessive rainfall and a potential of flooding cannot be ruled out; which will be dependent upon how much rainfall occurs beforehand. The frontal boundary per DESI and NBM guidance should move southward again late Sun into Mon, with shower activity ending for the start of a new work week.

Daily temperatures into the middle of next week appear will be on the rise, in part thanks to the strong upper ridge just to our west. As shower activity ends on Sun, the heat will return. Highs to start a new week should range from the mid/upper 80s to the lower 90s west. Even warmer conditions are expected for the Mon-Wed timeframe, with highs all three days mainly in the low/mid 90s, and lows in the low/mid 70s. Heat index values on Sun should range from the mid/upper 90s east to 107 in the more urbanized spots. Another need for Heat Advisories maybe needed Sun, but appear more likely next Mon/Tue, with values ranging from the upper 90s to 109 in the hottest spots. They could be some relief by the midweek, as another frontal boundary moves across the area from the north. This boundary will also bring lower end rain chances back to parts of the Valley.

HUN WATCHES/WARNINGS/ADVISORIES

AL...Flood Watch through Friday evening for ALZ006>010-016.

TN...Flood Watch through Friday evening for TNZ076-096-097.