textproduct: Huntsville

KEY MESSAGES

Updated at 1052 PM CDT Tue Sep 8 2026

- Low chances for showers and thunderstorms will return to the forecast area Thursday night.

- As a moist airmass returns to the region, chances for showers and thunderstorms will increase on Friday, and remain in the 20-50% chance range each day through Tuesday. Lightning and heavy rainfall will be the main impacts from the storms.

- NWS Heat Risk will remain in the Minor to Moderate category throughout the forecast period.

NEAR TERM

(This Evening through Wednesday) Issued at 1052 PM CDT Tue Sep 8 2026

Over the course of the near term period, a strengthening mid- level ridge (initially centered across western parts of the TN Valley) will develop east-southeastward into the Savannah Valley of GA/SC. However, our forecast area will remain under the general influence of the anticyclone, with weak steering currents and subsidence drying aloft maintaining PWAT values in the 1.2-1.4" range. In the low-levels, a surface high (which migrated eastward off the Mid-Atlantic Coast earlier today) will remain nearly stationary overnight, with the resultant pressure gradient expected to sustain a SSE wind of 5-10 MPH.

After a period of clearing skies this evening (in the wake of scattered afternoon showers that dissipated a couple of hours ago across northwest AL), a modest southerly low-level jet of 10-20 knots will foster redevelopment of scattered-broken stratocumulus clouds early Wednesday morning, with an isolated sprinkle of rain or light shower possible, as well. However, with CAMs suggesting a higher likelihood for redevelopment of showers to our north/west, we will only include a 5-10% POP in the forecast. Overnight lows should once again range from the m60s in the east (where gradual westward advection of drier air will be more pronounced) to the u60s-l70s elsewhere. Although patchy mist/fog may develop in wind- sheltered locations (particularly those which experienced wetting rainfall earlier today), low-level mixing should reduce both coverage and density of visibility reductions.

During the day tomorrow, surface winds will weaken and veer to the south as high pressure off the Mid-Atlantic Coast shifts further eastward. With early morning clouds expected to progressively lift/scatter as the mixing layer deepens, stronger insolation will allow afternoon highs to return to the l-m 90s in the valley.

SHORT TERM

(Wednesday night through Friday night) Issued at 1052 PM CDT Tue Sep 8 2026

Throughout the short term period, a strong mid-level ridge (initially centered across the southeastern CONUS) will weaken and translate eastward into the southwestern North Atlantic. As this occurs, a shortwave disturbance will progress southeastward from the northern Plains to the central Appalachians as a weaker trough migrates into the Lower MS Valley, and this will result in a gradual increase in WSW flow aloft (to 10-20 knots) across the TN Valley. Well to our north, a cold front will drift slowly southward Wednesday night, with widespread thunderstorms expected throughout the night in the vicinity of a prefrontal wind shift axis (from eastern KS/OK into the central Appalachians). Although some showers associated with this regime may reach as far south as northwest and northern Middle TN (and a few sprinkles of rain may occur as low-level moisture gradually begins to return northward across our southeastern zones), most locations will remain dry with lows in the m60s-l70s.

Present indications are that the extensive convective regime to our north will decay from W-to-E during the day on Thursday. However, the rain-cooled airmass in its wake will force the wind shift axis to progress southward through the day, with it likely to extend from east-central AR into northern Middle TN/south central KY by 0Z Friday. Any convection related to this feature should remain displaced to our north/west, and it will be another hot day, with highs in the m-u 90s.

Although redevelopment of showers and thunderstorms to the north of the surface boundary may indeed force it further southeastward into our CWFA on Thursday night, this scenario is highly uncertain and the primary reason for a gradual increase in the coverage of showers early Friday morning will be strengthening deep-layer SW flow and moisture advection. However, the boundary to our northwest will likely focus development of thunderstorms across a corridor from northern MS into Middle TN Friday afternoon as temps warm into the l-m 90s and the the increasingly moist airmass destabilizes. This regime should expand eastward into our region with outflow late Friday afternoon and evening, and although shear will be too weak for organized convection, CAPE of 2000-2500 J/kg will support robust updrafts. Due to this (and the combination of slow storm motions and PWAT values approaching or slightly exceeding 2"), flash flooding will become an increasing concern along with frequent lightning.

The wind shift axis is expected to lift northward and lose definition on Friday night as southerly flow strengthens ahead of a cold front dropping southeastward into the Upper MS Valley and a lee cyclone over the OK Panhandle. However, clusters of outflow- driven showers and thunderstorms could persist for much of the night and into early Saturday morning.

LONG TERM

(Saturday through Tuesday) Issued at 1052 PM CDT Tue Sep 8 2026

Global model guidance suggests that light south-southeasterly flow will persist across the TN Valley for much of the extended period, perhaps becoming a bit more pronounced on Sunday and Monday as a low develops across the central High Plains and progresses northeastward into the Great Lakes. This will sustain a very moist airmass (featuring PWAT values in the 2-2.2" range and dewpoints in the u60s-l70s, perhaps rising into the m70s by Monday and Tuesday). Although showers and thunderstorms could occur at any point (day or night), storm coverage during any single specific period remains uncertain due to indications that the Atlantic subtropical ridge will retrograde westward into the southeastern CONUS with time. Weak shear suggests that storms will be unorganized and initiated by low-level warm advection and mesoscale boundary interactions. Regardless, sufficiently high CAPE will exist for frequent lightning and high PWAT values/slow cell motions will support a risk for excessive rainfall and flash flooding. Highs are generally predicted to be in the l-m 90s (but may be lower on days with more extensive clouds and precipitation), with lows in the u60s-l70s. Heat risk will remain in the Minor-Moderate category through the period.

AVIATION

(06Z TAFS) Issued at 1155 PM CDT Tue Sep 8 2026

VFR conditions are forecast through the TAF period.

HUN WATCHES/WARNINGS/ADVISORIES

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