textproduct: Omaha/Valley

KEY MESSAGES

- A Flood Watch is in effect until this 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 strong storms could potentially occur Friday night with the primary hazards being damaging winds, large hail, and flash flooding.

DISCUSSION

Issued at 1143 PM CDT Tue Sep 15 2026

Today and Tomorrow

Water vapor imagery this evening features broad southwesterly flow across the majority of the CONUS, lobbed eastward by a digging trough pushing inland from the Pacific Coast. Zooming in locally, we find ourselves to the north of a cold front draped from western Oklahoma towards central Illinois, with broad warm air advection and isentropic lift overrunning that boundary to extend shower development northward. Working with those broader lift mechanisms are localized pockets of low-level frontogenesis that have allowed some of the elevated storms reach their full potential across northern Missouri. Along and north of the frontal boundary, precipitable water values are at their peak of 2+ inches to go with long/skinny instability profiles that are supportive of warm rain processes. This environment will expand into southeastern Nebraska and southwest Iowa, with MCVs developed by the convection and subtle zones of frontogenesis being the things to track for heavy rainfall monitoring. Healthy rainfall amounts are expected out of established storms, with wetter soils making flooding an increased risk through noon tomorrow when shower and storm activity slows. River basins so far have behaved aside from some minor flooding along the East Nishnabotna River near Red Oak, but focused rain in across the southeastern forecast area would give us more hydro-related headaches in the short-term. As of now, the main rainfall is forecast from 1 AM to 6 AM with lingering showers that decrease in intensity and coverage through 1 PM.

Aside from the rainfall to start out tomorrow, dreary conditions will stick around and stymie our high temperature potential as values in the upper 60s to mid 70s are forecast.

Thursday and Beyond:

Southwesterly flow aloft is set to continue through the remainder of the week and upcoming weekend, with a cooler lean to forecast highs than what is usually on deck for the time of year (80 for Omaha). Another nighttime swath of showers and storms is on deck to develop during the early hours of Thursday morning as the LLJ noses into north-central Kansas/southern Nebraska, trekking over the same areas that have gotten recent rainfall. This environment has lower potential in terms of rainfall rates, making flood chances lower but still possible. During the day Thursday, we'll see a widespread mass response to the east of a deepening surface low over eastern Colorado that will help push temperatures aback into the upper 70s, only to be improved further Friday for our one day of above-average high temperatures.

That surface low is expected to eject off to the northeast Friday, developing a focused area of precipitation to its eastern and northeastern flanks (both of which are forecast to be largely north of the forecast area). What will move through our area will be a morning warm front that shoots north, with a dryline/surface trough that will stretch from the surface low over eastern SD towards western KS. This could have enough convergence along it to create some very high-base storms that would carry wind potential during the afternoon/early evening hours, with development much farther east towards the increasingly moist airmass looking unlikely. Over the course of the evening and heading into early Saturday, the main cold front will push into the area from the northwest, timing out poorly for severe weather watchers across the area. Nevertheless, another shot at moisture for wet areas could lead to some localized flooding threat with other hazards looking unlikely.

The winds of change brought in by the cold front should take temperatures in a refreshing direction, with highs in the 70s Saturday falling further to near 70 Sunday and slightly cooler still Monday. Another shot at rainfall will arrive during this period as a shortwave trough traverses the northern two tiers of CONUS states while dragging forcing through the forecast area to create additional shots at rainfall. This again does not appear to be particularly potent rainfall at face value, but wet soils brings in a low end chance for hydro issues. At the moment the middle of the upcoming week is looking a bit drier, but rainfall won't be too far away as we transition from southwesterly flow to zonal flow aloft.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 532 AM CDT Wed Sep 16 2026

Low ceilings are gradually lifting north through the area this morning. Scattered showers near OMA are beginning to dissipate with new thunderstorms developing near LNK. These thunderstorms will gradually become more showery through the remainder of this morning as they slowly lift northeast. Showers should largely end by afternoon. Additionally, a continued reduction through MVFR and eventually IFR ceilings is expected across the area. Areawide IFR ceilings is forecast by this afternoon with patchy fog possible for southeast Nebraska and southwest Iowa due to recent rainfall. MVFR visibility is likely in fog. Fog may linger into tonight, though additional showers may also develop. Showers may briefly cause visibility to improve, but IFR ceilings remain. Light winds will continue through the period. Northeast to east winds gradually become southeasterly.

OAX WATCHES/WARNINGS/ADVISORIES

NE...Flood Watch until 1 PM CDT this afternoon for NEZ052-053- 066>068-089>093. IA...Flood Watch until 1 PM CDT this afternoon for IAZ069-079-080- 090-091.