textproduct: Omaha/Valley

KEY MESSAGES

- Low to moderate chances (30-60%) of non-severe thunderstorms across portions of northeast Nebraska tonight.

- Periodic chances of showers and thunderstorms Tuesday through next weekend. A marginal risk of severe storms (5-14%) exists for Tuesday afternoon into early Wednesday. The best chance of severe weather returns next weekend.

- Temperatures will remain 5 to 10 degrees below normal through the Friday, with high temperatures in the 70s and lows from the middle 50s to lower 60s.

DISCUSSION

Issued at 153 PM CDT Sun Jun 21 2026

Quasi-zonal short-wave flow will remain across the central part of the country through the week, though the forecast area generally will remain under the influence of the cyclonic shear side of a semi-persistent large scale trough across the eastern U.S. An active polar jet will at times be amplified by sub- tropical jet to produce periodic chances of showers and thunderstorms. The aforementioned large scale trough will keep overall heights lower than normal through the week, allowing for cooler than normal (5-10 degrees F) temperatures.

Tonight...Stratus will remain semi-persistent across the forecast area tonight as a stream of lower tropospheric moisture remains across the region along with east-northeast low level flow. Where clouds scattered tonight, upslope flow could produce fog, but left out of forecast for now. A shortwave moving out of Wyoming will help to activate storms across the high plains, which will advect into the northeast Nebraska by mid- evening. The CAMS and synoptic models are consistent in moving the storms eastward thus used a HREF/NBM blend for PoPs. Currently these storms are not expected to be severe due to limited instability.

Monday...Sensible weather will overall be pleasant with high surface pressure encroaching from the northeast. Skies will become partly cloudy, allowing for slightly warmer temperatures, with high temperatures in the lower to middle 70s.

Tuesday and Wednesday...A more potent shortwave dropping southeast out of Alberta will induce lee side cyclogenesis and moves a cold front through the central plains Tuesday into Wednesday. Strengthening southerly flow will draw deeper moisture into the region and increase instability. Coupled with bulk shear values 45-55kts, better chances of severe storms will return, with SPC currently highlighting a marginal risk for the area. Given recent heavy rains, WPC also is highlighting a marginal risk of flooding/flash flooding due to excessive rainfall.

Thursday through Friday...The convection will move the aforementioned cold front into the southern plains and lower Mississippi Valley, but then becomes quasi-stationary as the shortwave flow again becomes more zonal. EC ENS are more aggressive in pushing the boundary further south than the GFS, which will play a role in whether southern portions of the forecast area will experience persistent low chance (15-30%) chance of showers and storms Thursday-Friday.

Saturday into Sunday...A deeper long wave trough dives into the Pacific Northwest Saturday into Sunday. The net effect will be increasing low level, moist and warm flow and better chances for more widespread strong to severe thunderstorms next weekend.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 642 PM CDT Sun Jun 21 2026

We've seeing cigs gradually lift to 3500-4000ft over the last few hours and become broken in a few spots. Winds are generally out of the east or ENE. A line of showers is moving into KOFK around 00Z with some potential (30%) for another round later around 06-08Z. Not anticipating any lightning with any of these showers. There is a good chance MVFR cigs move back into KOFK around 05-07Z (80% chance), while only a 40% chance at KLNK and 10% chance at KOMA. Any low clouds should break up by 15Z Monday with VFR conditions through the remainder of the day.

OAX WATCHES/WARNINGS/ADVISORIES

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