textproduct: Huntsville

KEY MESSAGES

Updated at 1121 PM CDT Wed Jul 1 2026

- An Extreme Heat Warning remains in effect through 7 PM Thursday due to a combination of afternoon temperatures in the mid- upper 90s and heat indices of 108-112F. A Heat Advisory will remain in effect from 7 PM Thursday-7 PM Friday.

- Strong-severe thunderstorms will impact portions of the region once again on Thursday and Friday (mainly from late afternoon into the evening). These will feature a risk for locally damaging downburst winds, small hail and excessive lightning.

- The coverage of afternoon/evening showers and thunderstorms will begin to increase this weekend and will remain in the 40-60% range through the middle of next week.

NEAR TERM

(This Evening through Thursday) Issued at 1121 PM CDT Wed Jul 1 2026

A strong 500-mb high will remain positioned across the central Appalachians for the duration of the near term period, maintaining light SE flow aloft of 10-20 knots across the TN Valley. In the lower-levels, our region will remain along the southwestern flank of a high over the northwestern Atlantic, which will ensure a continuation of light/variable flow at the surface. With lingering light rain from showers/thunderstorms earlier today now over, we expect dry conditions to prevail through the early morning hours on Thursday. However, a low probability for redevelopment of a few showers and thunderstorms will exist from northeastern MS across northwest AL and into southern Middle TN shortly before sunrise as a remnant MCV (from previous convection) begins to lift northwestward around the periphery of the anticyclone aloft. Overnight lows will be a few degrees cooler (compared to last night) and in the l-m 70s due in part to rain- cooled air across the region. Areas of locally dense fog may also develop (particularly in locations that experienced wetting rainfall earlier today).

If showers and thunderstorms begin to redevelop shortly before sunrise (as indicated in some model guidance), this activity would likely expand in coverage through the late morning hours and spread north-northwestward across western TN. However, of more concern for our CWFA will be development of new thunderstorms early tomorrow afternoon as intense heating occurs across the Cumberland Plateau and Smoky Mountains/southern Appalachians. With a lighter and more westerly steering flow indicated in forecast soundings, this activity will begin to spread into eastern portions of our forecast area late tomorrow afternoon and may continue a bit longer into the evening hours if multiple cold pools can materialize. A similar thermodynamic profile will exist tomorrow, with MLCAPE of 2500-3500 J/kg, DCAPE of 1000-1500 J/kg and steep 0-3km lapse rates to support a risk for locally damaging downbursts, small hail and excessive lightning. With strong insolation anticipated for much of the day, highs will once again reach the m-u 90s, with dewpoints perhaps a few degrees higher due to recent rainfall. Thus, we will continue the Extreme Heat Warning for afternoon HI in the 108-112F range in many locations.

SHORT TERM

(Thursday night through Saturday night) Issued at 1121 PM CDT Wed Jul 1 2026

During the period from Thursday night-Friday night, a strong subtropical high (initially across the central Appalachians) will begin to weaken and shift eastward into VA/NC as a northern stream trough digs southeastward across Ontario/Quebec. This will occur as the axis of a low-level ridge shifts southward into the Gulf, and for this reason, steering currents will become progressively weaker as we move forward through the short term period. A small complex of thunderstorms will likely be in progress across the region early tomorrow evening, but should dissipate between 2-4Z, leaving another warm/muggy night featuring lows in the l-m 70s Friday morning and patchy fog in locations that experience late afternoon/evening rainfall. Redevelopment of thunderstorms is anticipated once again early Friday afternoon across the higher terrain to our north/east, with some of this activity likely to be propelled westward into our CWFA later in the afternoon. However, due to weaker deep-layer flow, coverage may be confined to a smaller portion of northeast AL/southern Middle TN before dissipation occurs Friday evening. With a similar thermodynamic environment (compared to previous days) this activity should once again carry a risk for locally damaging downburst winds, small hail and excessive lightning.

By Saturday and Saturday night, the subtropical ridge will continue to weaken off the coast of NC, and with less impacts from subsidence aloft, the local environment will become more conducive for a greater spatial coverage of showers and thunderstorms. This activity may also begin earlier in the day on Saturday (perhaps aided by ascent from a more defined easterly wave that will approach the southeastern Atlantic Coast tomorrow and lift northwestward into AL/MS this weekend) and could also extend further into Saturday night as outflow-driven convection from storms across MO/IL/IN may spread southeastward into the TN Valley during the evening. Fortunately, mid-level lapse rates will weaken with time as light southwesterly flow becomes established to the west of the 500-mb ridge and to the east of a weak shortwave trough across the southern Plains, and this will lessen the risk for strong-severe downbursts. However, gusty winds, locally heavy rainfall and lightning will still be a concern. With afternoon highs gradually falling back into the l-m 90s by Saturday, we will not make any changes to the expiration time of the Heat Advisory.

LONG TERM

(Sunday through Wednesday) Issued at 1121 PM CDT Wed Jul 1 2026

Global models are in general agreement that a subtropical high in the mid-levels (located off the southeastern Atlantic Coast) will begin to slowly strengthen once again early next week before eventually retrograding westward into the northeastern Gulf. This configuration will maintain light to moderate deep-layer SW to WSW flow, providing abundant moisture for development of showers and thunderstorms as a series of smaller scale waves travel along the edge of the ridge. Although a gradual increase in subsidence aloft may keep overall coverage of showers and thunderstorms a bit lower at our latitude, we will advertise a 40-60% POP (mainly focused during the afternoon/early evening) each day from Sunday- Wednesday. The anticipated combination of shear and instability suggests that convection will be unorganized and sub-severe, with lightning and heavy downpours the primary impacts. Due to clouds and precipitation, afternoon highs will fall back into the u80s-l90s by Wednesday, with Heat Risk diminishing as we move toward the middle of next week.

AVIATION

(06Z TAFS) Issued at 1210 AM CDT Thu Jul 2 2026

Patchy fog may develop early this morning due to moist boundary layer conditions from previous rainfall, prompting IFR conditions between 09-13z and potentially localized LIFR conditions from locally dense fog (have handled this with a TEMPO for now for the same timeframe). Thereafter, a return to VFR conditions will occur, but we will have to watch for afternoon TSRA develop which could result in MVFR conditions and AWWs/amendments. Have handled this with a PROB30 between 18-00z for now.

HUN WATCHES/WARNINGS/ADVISORIES

AL...Extreme Heat Warning until 7 PM CDT this evening for ALZ001>010- 016.

Heat Advisory from 7 PM this evening to 7 PM CDT Friday for ALZ001>010-016.

TN...Extreme Heat Warning until 7 PM CDT this evening for TNZ076-096- 097.

Heat Advisory from 7 PM this evening to 7 PM CDT Friday for TNZ076-096-097.