textproduct: Omaha/Valley

KEY MESSAGES

- A cluster or thunderstorms is expected to push southward across the area into the afternoon. The strongest storms may pose a risk for isolated damaging wind gusts and hail.

- Fog development is expected overnight, with patchy dense fog Thursday morning.

- Near-daily storm chances persist through the week, with additional strong to severe storms possible. However, dry periods are expected to outnumber wet ones.

DISCUSSION

Issued at 725 AM CDT Wed Aug 19 2026

Today and Tomorrow...

Water vapor imagery and objective analysis this morning depict an amplifying ridge over the western CONUS, bringing northwesterly flow aloft to much of the area. A train of shortwave disturbances passing through the flow will bring near daily storm chances, the first of which is passing through this morning/afternoon.

Storm development has trended later than initial CAM guidance this morning, allowing for additional (though still not overly impressive) instability, with pockets of 1500-2000 J/kg of MUCAPE in place. An additional delayed trend will bring more instability to work with. A cluster of thunderstorms is expected to develop across southeast SD/northeast NE later this morning before pushing southward across eastern NE/far western IA through the remainder of the morning and early afternoon. Sufficient bulk shear (40-50 kts) will be in place with model hodographs being long and generally straight. However, 0-3 km shear remains weaker (~15 kts), bringing the potential for an initial hail threat before storms gust out and transition to more of a damaging wind threat with pockets of 60-70 mph gusts possible.

The cluster of thunderstorms is expected to exit to the south by mid- afternoon. CAM guidance indicates some potential for storms to redevelop across eastern Nebraska during the late afternoon and early evening, though this potential will hinder on the amount of destabilization that is able to occur behind the initial cluster of thunderstorms.

Cloud cover will break up and improve through the evening, setting the stage for fog development overnight. Model soundings indicate calm winds and a saturated surface layer, though somewhat shallow, it should allow for fairly widespread fog with patchy areas of dense fog Thursday morning before gradually burning up after sunrise. High temperatures on Thursday will be near seasonal norms, peaking in the mid 80s.

Later Thursday, surface low pressure will develop over Minnesota, draping a cold front southwestward into northeast Nebraska. Destabilization through the afternoon will bring a corridor of ample instability (MLCAPE > 2500 J/kg) ahead of the front in northeast NE. Coupled with sufficient bulk shear, strong to severe storm development will be possible along the front during the late afternoon and evening. The primary question will be how widespread development along the front is, with the better forcing for ascent to the northeast and a weak cap in place. If storms are able to initiate in the area, model soundings indicate steep lapse rates and a favorable environment for isolated pockets of large hail and strong wind gusts. For the time being, PoPs are capped at 20% given the lower confidence in convective initiation and likely more isolated nature of development.

Friday and Beyond...

Friday into early next week, the large scale pattern will remain generally unchanged, with ridging centered over the Four Corners region and a stream of shortwave disturbances embedded in the northwesterly flow aloft bringing periodic precipitation chances. High temperatures on Friday are expected in the mid to upper 80s before storm chances return again during the evening. An unstable airmass will develop through the afternoon before an incoming shortwave disturbance and surface trough initiate a round of strong to severe storms over western Nebraska, gradually pushing into the area through the evening and early overnight period. Questions remain regarding storm coverage, with PoPs of 30-45% in place.

High temperatures through the weekend and early next week will oscillate from the upper 70s to the mid 80s as daily precipitation chances and cloud cover occasionally hinder daytime heating. Near- daily PoPs of 15-30% are in place, with additional strong to severe storms possible.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 531 AM CDT Wed Aug 19 2026

Showers and storms will continue to push southeast through the area this morning with potential re-development this afternoon, depending how long morning storms last. A few storms could be strong with 40-50+ kt gusts and hail, but still questions on the exact track of the strongest storms. Latest guidance suggests OMA and LNK are most likely sites to see strong storms, but ongoing storms northwest of OFK have strengthened. In addition, patchy fog will linger this morning, but with increased cloud cover over the TAF sites, impacts there seem unlikely. Outside of storms expect light winds, with northeasterly to easterly favored at OMA and LNK and OFK becoming southerly this evening. Daytime clouds around 5000 ft will scatter out this evening and set the stage for fog development late in the period.

OAX WATCHES/WARNINGS/ADVISORIES

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