textproduct: Huntsville

KEY MESSAGES

Updated at 148 AM CDT Mon Jun 30 2026

- A heat wave will occur this week with a HeatRisk value of 3 out of 4 (Major category) to 4 out of 4 (Extreme category). Afternoon highs in the mid to upper 90s will be common, with peak heat index values between 105 to 110 degrees

- A Heat Advisory is currently in effect through 7 PM Thursday for the entire Tennessee Valley.

- Potential exists on Wednesday for a few thunderstorms capable of producing strong wind gusts

NEAR TERM

(Today) Issued at 148 AM CDT Tue Jun 30 2026

A strong mid/upper-level ridge will remain centered directly over the Tennessee Valley, resulting in another hot/humid day across the region. The combination of ample sunshine and light southerly flow will allow daytime highs to reach the mid to upper 90s. These hot temperatures combined with dewpoints in the low to mid 70s will create maximum heat index values between 105-110 degrees in most locations by this afternoon. A Major (level 3 out 4) Heat Risk was noted across the entire region today, with Extreme values (level 4 out 4) forecast for much of the region Wednesday and Thursday. Thus, a Heat Advisory remains in effect for the entire Tennessee Valley through 7 PM Thursday. Please practice heat safety today -- stay hydrated, take frequent breaks from the heat, and never leave people or pets in vehicles!

One small caveat to watch will be the potential for a few showers and storms to develop just to the south and east of area due to a weak impulses over Georgia and south Alabama. Have kept a 10% PoP for our northeast Alabama counties in case one or two showers/storms is able to briefly drift northward into area late this afternoon.

SHORT TERM

(Tuesday night through Thursday) Issued at 1040 PM CDT Mon Jun 29 2026

As we progress into Wed/Thu, the ridge will tend to become more elongated along an W-E axis, while moving gradually into the central Appalachian region. This will result in a deeper easterly flow developing across the region. The broad suite of global and regional/hi-res guidance indicates a coherent shortwave will ride south and then westward along the eastern periphery of the broad upr ridge on Wed. This will bring the feature into the Srn Appalachian region, further inciting vertical coupling with the development of lower-level vorticity, and producing shower/storm activity. The coverage of any ensuing activity is uncertain at this time, with a rather wide range in the guidance suite. However, given the robust state of moisture/instability expected on Wed, strong wind gusts could occur from any stronger cells. Steep low and mid level lapse rates, along with high mixing ratios and very high max/min theta-e differences between low/mid levels also suggest a potential for downbursts. The timing of this activity remains a bit uncertain, but appears most plausible during the afternoon. With that said, if the activity holds off long enough on Wed, Heat Advisory criteria would still be met, with the potential for even higher HeatRisk (widespread Level 4) than on Tues, and heat indices perhaps reaching or breaking 110 F.

Thursday may end up being a near carbon-copy of Wed, with the prospects for yet another vort max to move into the region near peak heating. From an instability standpoint, the overall parameter space may be a little less robust on Thu, but could again be supportive of some strong updrafts/downdrafts in the afternoon. Either way, both days will bear some watching. In similar fashion to Wed, outside of shower/storm activity, heat may surge once again during the day on Thursday in the moisture-rich humid air mass. Due to uncertainty with the coverage of clouds and showers/storms, the Heat Advisory will continue to be advertised through Thursday.

LONG TERM

(Thursday night through Monday) Issued at 1040 PM CDT Mon Jun 29 2026

The apex of the upper level ridge will shift over the eastern seaboard by Friday and also start to flatten as ripples of shortwaves progress over the Midwest, Great Lakes, and upper Ohio Valley regions. Some global guidance suggests that a few of these shortwaves will dig towards the Southeast late in the weekend and into early next week. Meanwhile, surface high pressure will persist over the Appalachians down through the ArkLaMiss region through Sunday; however, a cold front may approach the Tennessee Valley by early next week, pushing the high pressure to the southeast.

Overall, expect a diurnal pattern to set up by late week, with daily chances of showers and storms (generally 20-40%) in the afternoon and evening. With the continued warm and humid conditions, along with DCAPE values near or just over 1000 J/kg, we'll be keeping an eye on downburst potential during this time as well. By Sunday, and especially Monday, shower and storm chances then increase as the aforementioned cold front approaches the region. While there looks to be more than enough instability for storms, bulk shear values are fairly weak (10 knots or less). Therefore, severe weather is not anticipated Sunday or Monday at this time.

As for temperatures, Friday and Saturday will continue to be very warm with highs in the lower to upper 90s along with heat index values in the 98-106 degree range. NWS HeatRisk looks to mainly be in the Major category (Level 3 of 4) by late week, but WBGTs remain in the upper 80s to around 90. Therefore, heat products may need to be extended into the first part of the weekend to account for the lingering heat. Make sure to take precautions for the dangerous heat! Wear light-colored, loose-fitting clothing, stay hydrated, and take frequent breaks in the shade if you work outside or have outdoor activities! Look before you lock - never leave people or pets in vehicles! By Sunday and Monday, the increased precipitation chances will result in an ever so slight cooldown, with highs topping out in the lower to mid 90s on Sunday and in the upper 80s to lower 90s on Monday.

AVIATION

(06Z TAFS) Issued at 1222 AM CDT Tue Jun 30 2026

VFR conditions will prevail through the period, with light winds and mostly clear sky.

HUN WATCHES/WARNINGS/ADVISORIES

AL...Heat Advisory until 7 PM CDT Thursday for ALZ001>010-016.

TN...Heat Advisory until 7 PM CDT Thursday for TNZ076-096-097.