textproduct: Omaha/Valley

KEY MESSAGES

- A Flood Watch is in effect until Wednesday afternoon. The flash flood threat is highest for areas that have already received several inches of rain.

- A wet pattern continues through the week into next weekend with daily shower and storm chances. This may lead to rises on local rivers and streams.

- Next chance for severe weather could potentially occur Friday night with primary hazards being damaging wind large hail, and flash flooding.

DISCUSSION

Issued at 1215 PM CDT Tue Sep 15 2026

Showers with a few embedded storms continue through this afternoon and evening. The upper-level pattern shows a broad ridge over the Southeast with troughing over the PacNW. This puts the Central Plains under a strong southwesterly flow regime, with shortwaves continuing to trigger showers and storms along and just north of a frontal boundary currently over far southeast Nebraska and southwest Iowa. As we go through the day today, showers and storms will gradually shift south with the frontal boundary with skies becoming partly to mostly sunny over far northeast Nebraska. Temperature will stay on the cooler side today with highs in the upper 60s to low 70s.

A developing low pressure system on the lee side of the Rockies in eastern Colorado will bring an upper-level warm front back north through our area on Wednesday leading to more chances for showers and storms Wednesday morning tapering off Wednesday afternoon from west to east. While this will bring back southerly flow, cloud cover will limit temperatures with highs staying in the low-to-mid 70s Wednesday afternoon.

Repeated rounds of locally heavy rainfall will only increase the potential for flooding through Wednesday. A Flood Watch continues until Wednesday afternoon as conditions remain favorable for locally heavy rainfall and flash flooding.

Thursday into Thursday night the low pressure system tracks northeast across west-central Nebraska, pulling the surface front north across our area. Additional showers and storms will be possible as this front moves through with temperatures warming into the low-to-mid 80s south of the front, and mid 70s north where the front doesn't arrive until later in the day. Shear is really weak along this frontal boundary, meaning little-to-no severe weather threat with more disorganized scattered convection.

A strong southwesterly low-level jet develops Thursday night into early Friday advecting in drier air from west Texas. This will bring down rain chances during the day on Friday and could limit shower and storm coverage across our western counties Friday night into early Saturday as another shortwave interacts with the dry line draped across our area. Best chances will be Omaha-Nebraska City eastward (60-70%) while farther west rain chances will be more 30- 45%. This may be our next chance for some stronger storms as NSSL Machine Learning guidance highlights this time period. NAM, GFS, and ECWMF struggle to line up storms with the better 0-1km and 0-3km shear, but if these come into alignment we could see stronger storms, mainly with large hail and damaging winds as hazards Friday evening.

We remain in this active southwesterly flow pattern going into the weekend, with details becoming more uncertain as fine details become more difficult for our longer-range models to pick out. Temperatures may cool back down through the weekend with additional periodic chances for showers and storms, nothing looking particularly severe at this time. Guidance diverges more significantly going into next week with potential for us to break out of this persistent southwesterly flow regime. This could mean drier, seasonably cooler weather to start next week.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 627 PM CDT Tue Sep 15 2026

Messy flight conditions are forecast to settle in later this evening, with VFR conditions kicking off the period as scattered shower and isolated storm activity continues across the area. Expect storms to develop later this evening, becoming increasingly widespread and moving northward alongside worsening flight conditions in a stair-stepped fashion from VFR to MVFR, then to IFR tomorrow morning. We've targeted a certain window for thunderstorm activity, with additional showers expected to linger longer after the scattered band passes through, with some mist developing later in the period towards KLNK and potentially KOMA. Towards 00z tomorrow, ceilings will try and start improving but until then, expect winds to be increasingly easterly while staying near 10 kts in speed with widespread cloud cover.

OAX WATCHES/WARNINGS/ADVISORIES

NE...Flood Watch through Wednesday afternoon for NEZ052-053-066>068- 089>093. IA...Flood Watch through Wednesday afternoon for IAZ069-079-080-090- 091.