textproduct: Omaha/Valley

KEY MESSAGES

- Widespread rainfall amounts of 2 to 4 inches are expected through Thursday, with a narrow band of over 5 inches in some locations. A Flood Watch has been issued for Tuesday evening through Thursday. - If we get any clearing on Wednesday, a few strong to severe thunderstorms will be possible during the afternoon and evening, mainly in southeast Nebraska. - Rain will end Thursday night, with cooler, dry conditions expected through the weekend.

DISCUSSION

Issued at 233 PM CDT Mon Sep 28 2026

Early afternoon analysis showed an upper level ridge axis passing through with low level clouds slowly but surely eroding from south to north. Temperatures as of 1 PM were in the mid 60s to lower 70s.

The main focus in the forecast will be widespread rainfall expected Tuesday through Thursday. A strong upper level trough currently over the Desert Southwest remains on track to ingest tropical moisture from Hurricane Polo and edge eastward on Tuesday with a surface low spinning up ahead of the trough and eventually pushing northeast toward the area on Wednesday. In addition, we'll have a decent stream of moisture coming in from the gulf which, when combined with the tropical moisture from the southwest, will lead to precipitable water values exceeding 2 inches per NAEFS and EPS guidance, exceeding the climatological maximum for this time of year. As warm air advection and moisture transport ramp up ahead of this system, showers and storms will develop to our west and push into northeast NE by early Tuesday morning. Precip will gradually overspread the area, lingering through Thursday before a cold front slides through and pushes the precip out.

With the aforementioned moisture availability/origin, moisture transport pointing into the area, and warm cloud depths exceeding 4 km, all the ingredients appear to be there for some very efficient rain producing showers and storms. Add in the fact that most of the area has received 2 to 5 inches of rain in the last couple weeks leading to saturated soils and slightly elevated river levels, we're primed for flooding impacts. The big question is where the heaviest band of rain will fall. Model consensus paints a broad band of 2-4" across much of the forecast area through Thursday with individual models highlighting potential for a narrow (~30 mile wide) band of 5-7 inches somewhere in there. Unfortunately, there remains quite a bit of spread in that band, with solutions ranging from it falling across central into far northeast NE to north-central KS into far southeast NE/far southwest IA. For what it's worth, highest probabilities for those 5+ inch amounts (20-30% chance) stretch from Butler County, east through the Omaha metro area and northeast into Harrison/Shelby Counties. Obviously, where that falls will significantly impact which rivers will see the highest potential for flooding, but at this point, at least the Missouri, Platte, Elkhorn, Big Blue, and Nishnabotna Rivers all have at least some potential for flooding. As such, a Flood Watch has been issued for much of the area from Tuesday evening through Thursday. Keep a close eye on the forecast, especially if you have interests near rivers.

If the flooding potential wasn't enough, there is at least some small concern for severe thunderstorms, especially on Wednesday as the surface low pushes closer to the area. While most guidance suggests we'll be cloudy and rainy much of that time, a few "extended" CAMs (e.g. 28.12Z NAMNest) hint at a little instability building across far southeast NE with very curvy low-level hodographs immediately northeast of the low. If this pans out, would need to keep an eye on severe storms potential, particularly tornadoes. Very low confidence that this pans out, but worth monitoring with such a dynamic system on the way.

As mentioned above, a cold front will pass through sometime late Thursday and bring an end to the precip with surface high pressure building in. A few weak shortwave troughs look to pass by just to our north Friday and Saturday, but consensus generally keeps associated precip out of our area, giving us only a 5-10% chance High temperatures will be in the upper 60s to mid 70s through Wednesday, with lower to mid 60s through the weekend.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1246 PM CDT Mon Sep 28 2026

Mostly MVFR ceilings will linger early in the period, but guidance continues to suggest they'll eventually scatter out, with clouds bases around 4000-6000 ft thereafter, though confidence in exact timing isn't particularly high (it may end up being later). Attention then turns to incoming shower and storm chances Tuesday. Latest guidance suggests at least showers will move through OFK by 18Z, but hold off at OMA and LNK until after the period. Otherwise, winds will stay steadily out of the south to southeast around 10 kts, with a few gusts approaching 18-20 kts on Tuesday.

OAX WATCHES/WARNINGS/ADVISORIES

NE...Flood Watch from Tuesday evening through Thursday evening for NEZ015-018-030>034-042>045-050>053-065>068-078-088>093. IA...Flood Watch from Tuesday evening through Thursday evening for IAZ043-055-056-069-079-080-090-091.