textproduct: Omaha/Valley

KEY MESSAGES

- Showers and storms this afternoon continuing overnight. A few strong storms will be possible with hail, damaging winds, and heavy rain/flash flooding being the main hazards.

- Cooler weather returns Wednesday and Thursday, with highs in the upper 70s to mid 80s.

- Next front arrives late Friday bringing another chance for severe weather late Friday into the overnight hours. Shower and storm chances continue through early next week.

DISCUSSION

Issued at 1249 PM CDT Tue Sep 8 2026

Showers continue across northeast Nebraska into west-central Iowa this morning. A cool front is slowly pushing south into our area which will provide forcing for thunderstorm development this afternoon. The environment will be ready. The 850mb jet continues to bring in a stream of moisture from the Gulf. PWAT this afternoon will start around record territory for this time of year (1.8-1.9in) and only go up over 2 inches as we see moisture pooling along the front advancing south into the evening and overnight. Moisture and daytime heating will only enhance environmental instability with generally around 2000-2500 J/kg of SB- and MLCAPE along the surface front. As far as shear, the more deep-layer shear will be well behind the front, but we do see enhancement of the low-level shear (0-1km bulk shear and helicity) around 7pm as we see winds increase on the nose of the LLJ.

We're predicting two bands of storms to develop this evening, the first will initiate along the surface front around 05-06PM. There is some uncertainty in where this band will exactly set up, but somewhere along or just south of I-80, southeast into Saline county seems likely. The second band will set up north of the surface front along a corridor from Boone and Platte Counties through Thurston, Burt, and Monona. Storms should initially struggle to strengthen with weaker environmental shear. As we see shear increase around and after 7PM, there will be a window along the southern line where we could see enough low-level shear for a tornado or two before this line weakens and the northern line becomes more dominant. Once the northern line takes over, expect more typical elevated thunderstorm threats, mainly being damaging winds and large hail.

We are also very concerned with how much rain these storms will produce, especially as we go into the overnight hours. With PWATs above climatological record territory for this time of year, these storms will be VERY efficient rain producers. Going into the overnight hours, we see the frontal boundary stall west to east across our area with signals indicating likely training of storms north of this boundary (the northern line mentioned above). Hi-res ensemble guidance indicate a west-east band of 2-4 inches of rain likely to set up somewhere across our area anywhere from Norfolk to Lincoln. Flash flooding will be a concern for this area overnight with the band of rain dropping south around 7am and clearing later Wednesday morning.

Once storms wrap up Wednesday morning, the forecast becomes quieter for a couple days as a surface high out of Canada shifts south over our area brining in pleasant, seasonable temperatures for this time of year. Highs Wednesday and Thursday will only be warming into the upper 70s to low 80s across our area with dew points dropping into the upper 50s to near 60 Thursday afternoon. The upper-level pattern shows the stubborn ridge that has been keeping our temperatures Hot will be pushed off to the east and northwesterly flow will be reinforcing the CAA into the Central Plains behind the front.

A more zonal flow regime sets up for the second half of this week as ridging over the Desert Southwest fights against an active series of troughs moving into the PacNW out of the Gulf of Alaska. The first stronger of these troughs will bring a cold front into the Northern Plains, leading to an increase in southerly flow across the Missouri River Valley late Thursday into Friday. With this we'll see temperature warm back up on Friday with highs up into the upper 80s to low 90s. Could be breezy in northeast Nebraska closer to the front where gusts 35 to 40 mph will be possible. The cold front advances south across our area Friday night into early Saturday bringing our next chance for thunderstorms, potentially severe. SPC has us highlighted under a 15% outlook for Day 4 which usually lines up with at least a coming slight or enhanced risk. What may help our situation is that we'll be a bit south of the main wave and surface low, with the greater potential more likely to our north over eastern SD into central MN. Certainly a time period to monitor.

The forecast details get fuzzier over the weekend with another strong through over the Inter-Mountain West putting us into more of a southwesterly flow regime with shortwaves bringing a series of chances for showers and storms through the weekend into early next week. While it likely won't be continuous rain through the period, uncertainty in timing of these waves keeps precip chances throughout the rest of the forecast period. Temperatures will be cooler with highs mostly in the 70s peaking around 80 south through the weekend into early next week.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1249 PM CDT Tue Sep 8 2026

Showers and storms are moving in along a cold front currently located near KOFK. Expect this to gradually shift south with another line of development near KLNK late this afternoon. A line of storms will linger through the evening overnight, finally shifting off to the south Wednesday morning. Could potentially see longer periods of storms impacting KOMA and KLNK, but limited windows to 2 hours with the best chance for storms. Winds will be shifting to northerly behind the front and stay out of the north, weakening and potentially going VRB for a few hours toward daybreak Wednesday morning. If KOFK see some clearing, fog will be possible around 10-15Z, but confidence is low in how well we will clear north of the front until later Wednesday morning. Expect clearing skies Wednesday morning once storms clear south with winds holding out of the north into the afternoon.

OAX WATCHES/WARNINGS/ADVISORIES

NE...Heat Advisory until 7 PM CDT this evening for NEZ066>068-078- 088>093. IA...Heat Advisory until 7 PM CDT this evening for IAZ079-080-090- 091.