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

(Rest of Today and Tonight) Issued at 927 AM CDT Sat Jun 27 2026

A west-southwest low level jet of 20-25kt was helping to generate showers and a couple of thunderstorms this morning in middle TN into northwest AL. These will likely weaken or dissipate through midday before additional diurnally driven thunderstorms redevelop this afternoon during peak heating. These will be more "random" in nature. Afternoon highs will be in the upper 80s to around 90. With westerly 5h flow of 25-35kt today, another MCV in southern MO will be transported eastward into the OH and lower TN valleys late this afternoon into the evening hours igniting clusters of thunderstorms along and just south of a frontal boundary situated from central MO into IN and OH, and along an outflow boundary located over KY resulting from the current thunderstorm activity. Deep layer shear vectors will veer more to a northwest-north direction tonight which will steer the convection southeast into middle and eastern TN and perhaps clipping southern middle TN and far northeast AL late tonight feeding off another low level jet of 25-30kt. Most of the CAMs suggest this activity will remain just northeast of our area, but any shift to the southwest will put our TN counties and far northeast AL counties at risk for strong to severe storms and heavy rainfall.

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

(12Z TAFS) Issued at 543 AM CDT Sat Jun 27 2026

VFR conditions persist through this morning before a low chance of MVFR conditions move in this afternoon dependent on thunderstorm formation. This has been accounted for as a PROB30 group at both KMSL and KHSV. VFR conditions are forecast to persist tonight into Sunday morning.

CLIMATE

Issued at 325 AM CDT Sat Jun 27 2026

Moderate to High Risk for Much Above Normal Temperatures:

The Climate Prediction Center has included the Tennessee Valley in a High Risk for Much Above Normal Temperatures for July 4. Therefore, there is a 60-80% chance for temperatures above above the mid 90s and Heat Index values above 105 degrees F during this period.

The Climate Prediction Center has included the Tennessee Valley in a Moderate Risk for Much Above Normal Temperatures for July 5. Therefore, there is a 40-60% chance for temperatures above above the mid 90s and Heat Index values above 105 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.