textproduct: Huntsville

KEY MESSAGES

Updated at 301 AM CDT Tue Aug 11 2026

- There is now a Marginal Risk (Level 1 of 5) for strong to severe storms on Wednesday. Primary threats will be gusty to damaging winds and heavy rainfall.

- High chances of meeting Heat Advisory Criteria (105F) or higher across much, if not all, of the area later this week, and into next week. Heat Products will be needed.

NEAR TERM

(Today) Issued at 301 AM CDT Tue Aug 11 2026

Nighttime RGB Microphysics is already highlighting fog developing in the valleys and near bodies of water with sfc obs showing a slight reduction in visibilities there. Patchy fog can develop elsewhere this morning, so use caution during your morning commute to work or school.

Ridge of high pressure anchored in the eastern Gulf will expand westward today and include more of the Southeast. Diurnal pulse convection expected again today. There will be a fair amount of instability, but very little shear. Storms could create gusty winds and with weak steering flow and PWATS still holding on close to 2", heavy rainfall could create local nuisance flooding concerns. Main concern for the day though is the heat. Sadly, today will be the "coolest" day of the week as the heat ramps up quickly after today. Highs will be in the lower 90s but the heat index values will make it feel more like it is in the upper 90s to 106 degrees. There is not enough coverage to warrant a Heat Advisory today, however regardless of that, heat safety is going to be important today and for the next week or two. More on that below.

SHORT TERM

(Tuesday night through Thursday) Issued at 1010 PM CDT Mon Aug 10 2026

The models were showing upper level ridging becoming more established over the SE CONUS as we go into the mid week. Thus, the heat (and humidity) will continue. Similar conditions with slight warmer temperatures are forecast on Wed. Slight drier air in the lower levels, along with more heating aloft will help suppress shower development on Thu. With showers not expected, highs into the mid 90s are expected.

Area coverage of values of 105 and higher are forecast Wed/Thu, which more likely will warrant a Heat Advisory. Some of the heat index values Thu could require an Extreme Heat Warning if a larger trend of 110 or hotter readings are realized.

LONG TERM

(Thursday night through Monday) Issued at 1010 PM CDT Mon Aug 10 2026

Models really strengthen the upper ridge over the Deep South Thursday night into Friday. Model guidance hints at a very strong 597 or 598 decameter high pressure center with this feature. This upper ridge will produce very strong subsidence over the area and should keep any moderate to high shower/storm chances well to our north and east of the area. 925 mb temperatures climb to between 28 and 30 degrees in most guidance by Friday afternoon. This will likely push high temperatures into the 95 to 99 degree range at least with good insolation through the day. A high or two of 100 degrees is not out of the question. It does look like some mixing of drier air below 800 mb will occur with the strong subsidence. This will likely lower afternoon dewpoints, maybe more than currently lowered in straight NBM guidance. For now, lowered dewpoints only conservatively for now from NBM (75% NBM/25% CONSRAW). Still, heat index values above 105 degrees look like a good bet (though some uncertainty exists if 108 or above heat index values will be met in many locations). However, if NBM guidance is correct and less mixing occurs, these values may be more widespread and extreme heat products may be needed for some areas.

Either way a heat wave will continue into the weekend, as the upper ridge either remain as strong or strengthens a bit more. Some guidance on Saturday and Sunday push 925 mb temperatures into the 29 to 32 degree range (likely values closer to 32 degrees in NW AL). This could push afternoon highs with strong low level subsidence continuing over the century mark at more locations. With the highs possibly being a few degrees higher over the weekend, even if mixing occurs, extreme heat looks most likely to occur then.

A few models (GFS in particular) try to extend a front into the southeast Sunday afternoon. However, given the strength of the upper ridge, this looks very dubious. If that does happen, then highs will likely be a bit less hot and remain in the mid/upper 90s versus upper 90s to over 100 degrees. The bigger impact would be a focusing of lower level moisture/higher dewpoints over the area Sunday afternoon, which would drive heat index values higher despite lower high temperatures. Whichever solution is correct, heat index values look to still climb to between 105 and 108 degrees at least on Sunday afternoon.

By early next week, models do seem to convergence on a solution that slides the center of the upper ridge WNW over Texas and puts the Tennessee Valley region in a more NW flow aloft. This should bring some increase in afternoon shower/storm activity and likely more afternoon cloud cover to the area. 925 mb temperatures will still climb into the 23 to 27 degree though, so highs in the mid 90s at least will likely still continue. However, this drop in highs, may make the oppressive heat less widespread.

AVIATION

(06Z TAFS) Issued at 1241 AM CDT Tue Aug 11 2026

Scattered showers and thunderstorms along a weak boundary across central AL should remain south of the TN Valley for the overnight, with VFR conditions expected. Residual moisture from recent rain that impacted KMSL could result in late night fog formation from before daybreak. Otherwise strong daytime heating and resultant instability could produce isolated to scattered afternoon showers and storms. With low confidence, stayed with a PROB30 from 18-24Z, along with MVFR VSBY reductions from showers. Convection that forms should dissipate after sunset Tue evening. Light winds overnight should become light from the south after daybreak, then SW 4-7kt in the late morning/afternoon, then become light/variable Tue night.

CLIMATE

Issued at 301 AM CDT Tue Aug 11 2026

The Climate Prediction Center has included the whole area in a Moderate to a High Risk for Much Above Normal Temperatures for August 18th through August 22nd. The High Risk includes locations south of a line from Lexington, to Athens, New Hope and Fort Payne. The Moderate Risk include locations north of that line. Therefore, there is a 40-60% chance in the Moderate Risk locations and a 60-80% chance for those in the High Risk areas for temperatures above 95-97 degrees F during this period.

More information on the CPC U.S. Hazards Outlook can be found at: https://www.cpc.ncep.noaa.gov/products/predictions/threats/threats.php

HUN WATCHES/WARNINGS/ADVISORIES

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