textproduct: Omaha/Valley

KEY MESSAGES

- Widely scattered thunderstorms are expected overnight. A few strong to severe storms will be possible, with isolated pocket of small hail and damaging wind gusts the primary hazards.

- Repeated rounds of heavy rainfall may lead to localized flash flooding overnight, with pockets of 2-3+ inches possible.

- Periodic chances for showers and thunderstorms will continue into the weekend, with a few storms potentially becoming strong to severe.

DISCUSSION

Issued at 929 PM CDT Thu Aug 13 2026

Tonight and Friday...

Water vapor imagery and objective analysis this evening depicts a mid-level ridge centered over the Mid-South, with the local area positioned along the northern periphery of the ridge. This will continue to allow a series of shortwave disturbances to round the ridge and bring periodic precipitation chances to the region. Another round of thunderstorms is expected tonight as a shortwave impulse moves from the Front Range towards the mid-MO Valley. Increasing forcing for ascent, combined with a strengthening LLJ nosing into eastern Nebraska, should support the development of west- to-east oriented cluster of widely scattered thunderstorms along a theta-e gradient around midnight. Meanwhile, thunderstorms have also developed across northeast KS along a northeastward-advancing surface low and associated front, and some of this activity may progress into southeast NE and southwest IA overnight.

A few strong to severe storms will be possible, with a corridor of 1750-2500 J/kg of MLCAPE extending across eastern NE into western IA and decreasing northward. Deep-layer shear will be a limiting factor, with only 20-25 kts of bulk shear in place. Even so, this may be sufficient for a few stronger pulses capable of producing isolated pockets of hail (up to 1-1.25") and damaging wind gusts (up to 60 mph). Attention will then turn toward the heavy-rainfall and flash-flooding potential, as training thunderstorms will encounter PWATs of 2-2.25 inches and warm-cloud depth of 4-4.5 km, supporting efficient rainfall production. CAM guidance continues to suggest localized totals of 2.5-3.5 inches within a relatively narrow east- to-west corridor, with the primary uncertainty remaining the latitudinal placement of this band. Recent guidance has trended the heaviest rainfall corridor southward from northeast Nebraska toward areas along and just north of the Platte River Valley. This would shift the greatest rainfall amounts from some locations that received the heaviest totals Wednesday night. However, this narrow axis will need to be monitored near the saturated soils.

Storm intensity and coverage will gradually decrease overnight, thought scattered showers may linger into Friday morning as an MCV drifts in from the west. By Friday afternoon, a surface boundary will lift northward into the area, returning southerly low-level flow and allowing temperatures and moisture to increase. Highs should reach the low to mid 90s across southeast NE and southwest IA, while more persistent cloud cover and northerly low-level flow north of the front hold temperatures in the mid 70s across northeast NE.

Additional thunderstorm development will be possible Friday afternoon and evening across southeast NE and southwest IA as we remain in a WAA regime, the MCV meanders across the area, and modest instability redevelops. Deep-layer shear will again be somewhat limited at around 25 kts, though a strong to severe storm cannot be ruled out. Initial development will likely be fairly isolated, with coverage increasing into the evening as the LLJ strengthens. The bulk of this later activity should remain south of Interstate-80 where the better instability and area of convergence resides.

Saturday and Beyond...

High temperatures Saturday will again range from the low 90s across southeast NE and southwest IA to the lower 80s towards northeast NE. Additional precipitation chances are expected as the stalled boundary remains draped across the southern portion of the area. An initial round of showers and thunderstorms may move through during the morning as a remnant MCV passes nearby, supporting 20-30% PoPs. Chances increase again Saturday evening as another shortwave disturbance approaches the region, with PoPs increasing to 50-75%. Questions remain regarding the extent of lingering cloud cover and subsequent destabilization, though another round of strong to severe storms will be possible, primarily south of Interstate-80.

Cooler conditions are expected Sunday and Monday as the stalled boundary is finally pushed south of the area, allowing more persistent northerly flow and a brief period of CAA to settle in. Highs will generally range from the upper 70s to mid 80s. Temperatures through the remainder of the work week are expected to hang around the upper 70s to upper 80s. Periodic precipitation chances around 15-30% will continue as disturbances traverse the area, with improved chances (30-60%) Tuesday evening.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 534 PM CDT Thu Aug 13 2026

VFR conditions are favored this evening, with patchy MVFR conditions as a scattered to broken cloud deck moves in at FL025-035. An east- west oriented line of thunderstorms is expected to develop across east- central into northeast Nebraska around 14/04-07Z. The highest confidence in impacts is at KOFK and KOMA, with lower chances for thunderstorms at KLNK. Isolated pockets of gusty winds (up to 40 kts) and small hail will be possible under initial thunderstorms.

As showers increase in coverage, expect decreasing ceilings at all terminals with MVFR and patchy IFR/LIFR conditions through much of the overnight period. Showers will taper off from west to east Friday morning, with ceilings then gradually breaking up and improving back to VFR.

OAX WATCHES/WARNINGS/ADVISORIES

NE...None. IA...None.