textproduct: Omaha/Valley

KEY MESSAGES

- There is a 20-40% chance of showers in portions of eastern Nebraska Wednesday, but expect more dry time than wet.

- Widespread shower and storm chances return Wednesday night and last through Saturday, with chances peaking at 80-90% during the overnight and morning hours each day.

- Cool weather will stick around with the rain chances, followed by a brief warmup and dry period on Sunday.

- Storm chances return early next week. Saturated soil combined with potential for heavy rain may yield a flooding threat.

DISCUSSION

Issued at 1118 PM CDT Tue Sep 22 2026

Water vapor imagery this evening showed a shortwave trough sliding across northeast NE into western IA with an upper level ridge axis just to our west. Said shortwave along with warm air advection and some weak frontogenesis aloft was leading to showers and a few storms across the eastern Sandhills. These will slowly continue eastward, though have shown a diminishing trend as they have done so owing to less instability this way, so not expecting them to amount to much in our area. However, additional development is expected overnight as moisture transport ramps up with latest short term guidance in decent agreement of at least some spotty showers lingering across northeast NE into the afternoon. A few solutions even show those showers extending as far south as the KS border. As it stands, have 30-40% chances in far northeast NE and 20% chances extending south from there, but diminishing as they push east toward Lincoln and Omaha. In general, still expect much more dry time than wet during the day Wednesday as that aforementioned ridge axis pushes east through the area.

On its heels, though, will be a steady stream of shortwave energy out of the Desert Southwest, warm air advection, and moisture transport that will lead to persistent rain chances lasting into Saturday. Chances across most of the area never dip below 40% in that period and generally peak around 80-90% in the overnight/morning hours. With limited instability, not expecting much in the way of thunderstorms, though with precipitable water values in the 1.50-1.75+ inch range (approaching the 99th percentile of climatology for this time of year) there could be some periods of very efficient rain production. Totals through that period look to be in the 1-2" range for most of the area. Temperatures also look to remain on the cooler side, with highs in the 60s to around 70 through Friday. Assuming precip tapers off by Saturday afternoon, we should see some mid to upper 70s return to the area. Upper level ridging will build in on Sunday and lead to a dry and warmer day with a few spots in southeast NE and southwest IA making a run at 80 degrees.

Heading into early next week, there is good agreement that shower and storm chances will return, but there remains quite a bit of spread in timing of those chances. The general idea is that the upper level ridge pushes off to the east with southerly flow allowing a good plume of gulf moisture to push into the area. In addition, some guidance hints that some tropical moisture out of the Pacific on the edges of Hurricane Polo could work its way toward the area. Eventually, a potent shortwave trough pushes straight east out of CA, spinning up a surface low east of the Rockies, with the system eventually moving through the forecast area and giving us widespread shower and storm chances. Again, timing of this wave is still up in the air, but it looks to be sometime Monday or Tuesday, with maybe a slight trend toward being later. Given the potential tropical moisture plume in place with a little instability and the expected rainfall a few days prior further saturating the ground, a flooding threat could develop. In addition, given the strength of the system, there will likely be some decent shear in place, which could yield a severe thunderstorm threat. For what it's worth, machine learning severe weather guidance is starting to suggest at least a 5% chance of severe storms by Monday. Would expect that to increase a bit somewhere in the region as ensemble guidance comes into better agreement on system timing. Overall, still a lot of details to work out, but early next week will be a time period to keep an eye on.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 539 AM CDT Wed Sep 23 2026

The worst conditions of the TAF period are set to occur for the next 2-3 hours, with MVFR to IFR ceilings in place at all three terminals. Scattered showers and storms remain west of KOFK as of the start of the period, with the expectation being that they'll drift east and drop any lightning they had as they pass. Confidence is much lower in those showers affecting KOMA/KLNK, so they did not make the cut for this TAF issuance. Otherwise, southeasterly winds will continue with some gusts this afternoon of over 20 kts at KOFK, with VFR conditions returning this afternoon. Towards the end/just beyond the TAF period, additional showers and storms move in from the southwest Thursday morning.

OAX WATCHES/WARNINGS/ADVISORIES

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