textproduct: Huntsville

KEY MESSAGES

Updated at 927 AM CDT Sat Jun 27 2026

- A medium chance (40-60%) of thunderstorms in southern middle TN and far north and northeast AL today and tonight with a low threat of damaging winds and hail.

- A heat wave builds in on Sunday and continues next week with a Heat Risk value of 3 out of 4 (Major category) for most areas.

NEAR TERM

(Tonight) Issued at 132 PM CDT Sat Jun 27 2026

Convection that flared up over northeast AL has shifted east into north GA. There may be weak subsidence behind this wave of cells over north AL as the cumulus seems to be suppressed at the moment. Just to our north, thunderstorms were developing quickly in middle TN. Meanwhile, the MCV over southeast MO was aiding strong to severe storm development over southern IL into southwest KY. This will be the area to watch in the next several hours. The airmass is very unstable over southern TN into north AL and MS with SB CAPE values of 3-4k J/kg. A majority of the CAMS maintain that the majority of convection this evening and overnight will remain to our immediate north and northeast. However, as mentioned in the previous discussion, shear vectors may favor a more southeast movement later tonight. Also, there are CAMS that suggest a few more storms could develop this evening in the unstable airmass in place over southern TN or far north AL as the low level jet develops. The SPC has upgraded to a Slight Risk that clips our southern TN counties with a marginal just a bit further southwest from that.

SHORT TERM

(Sunday through Monday) Issued at 927 AM CDT Sat Jun 27 2026

There is a low chance of lingering convection in our far northeast AL and southern TN counties early Sunday morning at the tail end of a large MCS advancing through east TN into far northern GA into the Carolinas. This will shift east by midday leaving a boundary through middle TN into central KY which may trigger new development later in the day. However, this appears it should stay to our northeast with deep layer west to northwest flow in middle levels developing as a 5h high develops over the Arklamiss region. Temperatures will reach the lower 90s for valley areas Sunday afternoon, possibly topping out at 95 in the Shoals metro. Heat index values of 100-105F and WBGTs of 85-88F are expected along and west of I-65 with lower values east of I-65. With the upper high building further on Monday, high temperatures will warm into the lower to middle 90s in valley areas (upper 80s to atop the higher Cumberland Plateau). Similar values of heat index (100-105F) and WBGT (85-88F) are expected, but the Heat Risk level will reach level 3 of 4 (Major) for nearly the entire forecast area. We have and will continue to message the heat risk in our social media and web graphics.

LONG TERM

(Tuesday through Friday) Issued at 945 PM CDT Fri Jun 26 2026

The long term forecast will be influenced by a persistent 594dam high aloft, leading to the first real heat wave we have seen this year. This high will be anchored over the OH Valley down through the TN Valley through much of the work week and will likely keep heat related advisories in place over multiple days. The heat threat will come from the combination of temps in the 90s (upper 90s some afternoons) and dewpoints in the low to mid 70s that will bring heat indices to the 100-105 degree range. In addition, overnight lows in the mid to upper 70s will provide very little relief from the warm and humid conditions during the day, keeping us in a Major HeatRisk through the long term period. While the forecast looks relatively dry during this period, low (10-30%) chances for diurnal thunderstorms will exist each afternoon and could keep some locations from reaching the higher heat indices mentioned above. Please keep up with the latest forecast as we head into next week. Those with outdoor plans should prioritize heat safety by staying hydrated, wearing light colored clothing, taking frequent breaks in the shade or A/C, using sunscreen, and never leaving people or pets behind in vehicles.

AVIATION

(00Z TAFS) Issued at 552 PM CDT Sat Jun 27 2026

VFR conditions are forecast through the TAF period with SW winds up to 10-15kts at times. Scattered high clouds will continue overnight with a low chance for a thunderstorm this evening. Confidence was not high enough to include any rain or thunder at either TAF site at this time.

CLIMATE

Issued at 552 PM CDT Sat Jun 27 2026

Moderate Risk for Much Above Normal Temperatures:

The Climate Prediction Center has included the Tennessee Valley in a Moderate Risk for Much Above Normal Temperatures on July 5. This means that there is a medium chance (40-60%) for temperatures to reach or exceed 91-94 degrees with heat indices above 105 degrees 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.