textproduct: Omaha/Valley

KEY MESSAGES

- Strong to severe thunderstorms are expected Monday evening/night with hail, damaging winds, heavy rain, and a few isolated tornadoes possible.

- Strong to severe thunderstorms are expected Tuesday afternoon and evening. Damaging winds, large hail, a few isolated tornadoes, and flash flooding will be possible with any storms that develop.

- Cooler temperatures return to the forecast Wednesday, with a gradual warming trend expected heading into the weekend. Periodic chances for showers/storms are expected Wednesday through Friday.

DISCUSSION

Issued at 1130 PM CDT Sun Aug 16 2026

The forecast period begins with a mid-level ridge over the Rockies and northwest flow over the Great Plains. Clouds have cleared out over most of eastern Nebraska/western Iowa this evening. With calm to fairly light winds and cooling temperatures, fog development will be possible, particularly for areas along the Missouri River and the Iowa/Missouri border. A few models have been trying to bring some fog as far west as Lancaster and Gage counties for a few hours Monday morning. A few areas may have visibility reductions to 1 mile or less for a few hours around sunrise.

A few isolated thunderstorms are expected to develop across southern South Dakota overnight, dropping into eastern Nebraska by sunrise Monday morning. A few areas may wake up to some showers or weak storms moving through. High temperatures will reach the upper 70s to upper 80s across the region. A shortwave trough will move into the region Monday afternoon, bringing some chances for showers and storms. Moving into a decent environment, this first potential wave of storms will have the potential of becoming strong to severe. The main hazards with any storms that are able to strengthen would be large hail, strong winds, and heavy rainfall which may result in localized flash flooding, particularly for areas that have already had decent rainfall over the past few days. An isolated tornado risk cannot be entirely ruled out. A second wave of thunderstorm activity will be possible after midnight Monday night/Tuesday morning. With the earlier convection and a more stable environment, the possibility for severe weather will go down some with this later wave of storms.

Surface low pressure develops over the Central High Plains on Tuesday and a slow moving cold front arrives in northern Nebraska and Iowa. Expect some slightly cooler temperatures near the NE/SD border, ranging from the mid-70s to low 80s for highs. Areas further south will top out in the low to mid-80s. Moisture will be moving into the region and destabilization is expected over southeastern Nebraska/southwestern Iowa during the afternoon. Strong to severe thunderstorms are expected Tuesday afternoon and evening across the entire Omaha CWA, with large hail, damaging winds, and a few isolated tornadoes all possible. Precipitable water values of 1.5- 2.0" are expected as well. Heavy rainfall with any storms may result in some localized flash flooding. Several areas across the region have already received quite a bit of rainfall over the past few days and may therefore be more prone to flooding with any additional heavy rainfall.

An amplifying ridge over the western CONUS will send a series of weak shortwaves through the Great Plains Wednesday through Friday. This will bring periodic chances (30-60% Wednesday; 20-30% Thursday and Friday) for showers and storms to the region. Wednesday high temperatures will be fairly nice for August standards, reaching the mid-70s to low 80s. Typical highs for eastern Nebraska/western Iowa are in the mid-80s. Expect a gradual warming through Friday with highs returning to the low to mid-80s.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1221 AM CDT Mon Aug 17 2026

Could see some patchy fog development overnight, especially across southwest Iowa, but confidence in anything reaching the TAF sites is low. For the rest of the day, expect SCT clouds around 5000-7000 ft. Winds will remain light and westerly to northwesterly overnight before becoming southwesterly in the morning, but still mostly staying under 10 kts. Shower and storm development is expected by late afternoon with latest guidance suggesting OFK could be impacted by 01Z. Still some questions on how far south and east storms will extend by 06Z, so didn't include mention at LNK and OMA for now.

OAX WATCHES/WARNINGS/ADVISORIES

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