textproduct: Omaha/Valley

KEY MESSAGES

- Strong to severe thunderstorm potential will continue through afternoon and evening (15% chance of severe for any given storm), with the greatest risk between 2 PM and 8 PM.

- Dry conditions behind the front are driving extreme fire danger for areas of northeast Nebraska, with a Red Flag Warning in effect.

- Cooler temperatures this weekend with additional chances for showers and thunderstorms on Saturday (30-60%) and Sunday (60-90%).

- Near normal temperatures into next week with on and off shower and thunderstorm chances.

DISCUSSION

Issued at 1137 AM CDT Thu Apr 23 2026

Today:

Water vapor imagery this afternoon features a broad mid/upper trough pushing to the south and east with forcing for ascent apparent already over eastern Nebraska and western Iowa. Recent surface observations show the front draped from south-central Nebraska into northeast Nebraska and northwest Iowa with a slow move to the east set through the afternoon. This system has brought with it strong winds throughout the vertical column, helping to increase shear while lapse rates to work along with steep lapse rates to provide a favorable environment for severe storms. Even now, increasing vertical development is occurring over northeast Nebraska, where updrafts aided by mid/upper height falls and frontal convergence.

Just to keep things organized, I'll set out the main expectations for the day and get further into the hazard. Initial showers and storms are ongoing across northeast Nebraska, as updrafts fight weak capping at 850-700 mb. These showers and storms are expected to be strong to marginally severe, with only a handful of storms being able to make it past the inhibition to reach a stronger level. This area will generally be limited to areas north of a line from Columbus to Wahoo through 1 PM. Between 1 and 3 PM, stronger storm development will become likely. Strong to severe storms will begin to initiate, and be more isolated at first as weaker updrafts fail fail to break through. Those cells will be more likely the farther north you move along the front, and this semi-isolated storm regime will continue until 5 PM. Those cells will initiate generally east of a line From there, further erosion of any capping inversion will occur and the largely in-line component of deeper-shear vectors will help dive upscale growth, and transition storm mode into a liner/QLCS character as it pushes east and out of the forecast area by 8 PM.

Getting into hazards, the more isolated storms will hold the greatest threat for hail, as they will be able to maintain rotating mid/level mesocyclones and tap into the steep lapse rates. Hail analogs up and down the line show plenty potential for 2+ inch hail, with some curvature in the lower hodograph to support an isolated tornado threat. As storms grow upscale, hail would become less favored, transitioning to wind, QLCS tornado, and marginal hail as the hazards. The best tornado potential will be associated with storms that can bend back a bit to be northwest, or where remnants of any supercells remain embedded in the line. This QLCS regime will then push eastward, limiting the training that could occur and limit the overall flood threat.

Not to be forgotten, very dry conditions will fall into place behind the front with RH values between 10-25% and winds increasing to 20- 30 mph. A wind shift will push through late this evening and increase to 40 mph gusts, but with increasing RH at that point. Those factors are pushing fire danger into the extreme category for northeast Nebraska, and a Red Flag Warning is in effect through 8 PM for the threat.

Friday and Beyond:

A generally busy pattern is on tap entering the weekend into next week. Numerous chances for rainfall will move through the area, driven first by the leftover low spinning over southern Canada before it gets kicked out by a deepening shortwave that pushes east from the Pacific Coast later next week. The main period to watch for will be Sunday into early Monday, where widespread rainfall is set to move into the area, and potentially some strong storms as well based on latest machine-learning output. The timing of that system will entirely dictate if severe weather occurs; a late arrival that delays most of the rainfall until nighttime would greatly hamper severe potential. Nevertheless, we should do some good work to make back some much-needed rainfall to the area as temperatures in the 50s and 60s continue.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1230 PM CDT Thu Apr 23 2026

VFR conditions are forecast through the period at KOFK, while KOMA and KLNK deal with strong to severe storms shortly. A line of storms is building to the west of these locations, set to arrive 1930-2000z lasting for 1-2 hours. As the move through, potentially strong winds will be possible (greater than 35 kts) along with hail, and possibly a tornado. Ceilings will dip into MVFR territory, with visibilities following suit or staying just above at 6 miles. Once it passes through, winds will become somewhat variable and then turn northwesterly once the larger wind shift arrives. There will likely be some increase in gusts as it arrives for a few hours, before dissipating overnight while staying out of the north.

OAX WATCHES/WARNINGS/ADVISORIES

NE...Red Flag Warning until 8 PM CDT this evening for NEZ011-012- 016-017-030-031-042. IA...None.