textproduct: Omaha/Valley

KEY MESSAGES

- There is a 50 to 80% chance of storms in northeast Nebraska and west-central Iowa through 8 AM Thursday, with lower chances farther south. Some of these storms could be strong to severe, with damaging winds over 70 mph being the primary threat.

- Widespread showers and storms arrive late Wednesday (60-80% chance) into Thursday. Some storms could be severe with strong winds, hail, and heavy rain.

- Periodic shower and storm chances continue through the weekend into early next week. Cooler temperatures arrive by Sunday and Monday.

DISCUSSION

Issued at 1142 PM CDT Tue Aug 11 2026

Main story in the short term is severe storm potential overnight into early Wednesday morning. As of 11 PM, ongoing storms over southwest SD were pushing southeast and producing 70+ mph wind gusts in some locations. Looking at the environment ahead of said storms, there is plenty of instability in place (4000+ J/kg of MUCAPE per SPS objective mesoanalysis) along with plenty of effective and deep layer shear to remain organized. 0-3 km shear does taper off farther southeast, so assuming storms get here, they could become a little more outflow dominant. That said, guidance does suggest 0-3 km shear strengthens, or at least maintains as we go through the overnight hours. Things working against the storms maintaining are a little bit of dry air aloft and the primary forcing sliding by just to our north. However, with low level moisture transport pointing into our area, an already unstable airmass in place, and latest short-term guidance being in fairly good agreement that they make it to and through the area, think we will have a severe weather threat starting around 3-4 AM. The primary threat will be pockets of 50 to isolated 70+ mph gusts and perhaps some hail. In addition, precipitable water values around 1.75" and warm cloud depths over 4 km suggest they'll be efficient rain producers and could lead to some localized flooding, but guidance does suggest they should be somewhat progressive. The big questions will be how far south the wind threat extends and just how strong the winds will be. Some guidance suggests areas as far south as I-80 could see damaging winds, while other solutions favor the threat remaining mainly in northeast NE and west-central IA. Finally, one thing to watch is how ongoing weaker storms in north-central NE evolve. For now, they seem weak enough that they won't put much of a dent in the instability in place. However, if they strengthen, they could work the environment over just enough that the incoming storms from SD end up sub-severe.

Whatever storms do move through should exit to the southeast by 8-9 AM with perhaps a few lingering showers in southeast NE and far southwest IA along the the surface boundary and any remnant outflow. With the boundary to the south, we'll be a bit "cooler," but still warm and muggy, with highs in the upper 80s to lower 90s and dewpoints in the 70s. By late afternoon/evening, we should start to see storms develop across western NE as shortwave energy currently over the Desert Southwest rounds the ridge and pushes into the area. In the low levels, a low will push east out of CO and into KS, helping to induce a strengthening low level jet/moisture transport that runs over the surface boundary near the NE/KS border and points into the area. Expect storm development on the nose of this moisture transport, with latest CAMs suggesting they'll be mostly north of I- 80. That said, it may be worth watching for development a little farther south/closer to the surface boundary where 900 mb moisture transport points into very strong frontogenesis. Model soundings suggest there will be a little CIN to overcome for parcels originating at that level, but given the forcing, think it's possible for that CIN to be overcome. Regardless of where storms develop, deep layer shear looks favorable for storm organization with plenty of instability to work with for a damaging wind and hail threat. In addition, guidance hints at precipitable water values of 1.75 to 2+ inches with warm cloud depths of 4+ km, suggesting potential for heavy rain. With CAMs indicating potential for storms training from west to east, a flooding threat could develop into early Thursday morning.

Precip should taper off through the morning hours with lingering cloud cover across much of the area limiting temperatures to the mid 70s to mid 80s, except for near the NE/KS/IA/MO border area, where a few lower 90s will be possible. Rinse, repeat with evening shower and storm chances once again as shortwave energy slides through and we see more warm air advection, while the surface boundary remains in/near the area. While there will be slightly less instability and shear, there could be just enough of both to yield at least some stronger storms. This pattern with nightly (strong/severe?) storm chances continues into the weekend before ensemble consensus shows surface high pressure building in on Sunday with the surface boundary finally pushing well south of our area. However, any break we get looks short-lived as guidance hints that the train of shortwaves returns into next week with more on and off precip chances. Otherwise, temperatures remain steady through Saturday, before cooler high pressure pushes in and leads to highs in the mid 70s to lower/mid 80s Sunday and Monday. Temperatures should warm slightly through the rest of the week, though will depend on timing of those precip chances.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 627 AM CDT Wed Aug 12 2026

A line of showers and thunderstorms is exiting far eastern Nebraska early this morning. While the line is largely sub-severe at this time, expect to see some west northwesterly gusts of 30 to 40 kts at KOMA and KLNK for the next hour or so. Thereafter, should see winds lower to less than 12 kts from the east northeast for the rest of the TAF cycle with VFR conditions.

Another round of showers and storms will develop after 06z and track to the east impacting TAF sites. Have introduced -TSRA and -SHRA mentions with this issuance, but will likely need to refine timing in forthcoming issuances. These storms could be severe with damaging wind gusts of 50 kts, large hail, and heavy rain reducing visibilities to MVFR/IFR. Ceilings lower to MVFR late in the period after 12z.

OAX WATCHES/WARNINGS/ADVISORIES

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