textproduct: Omaha/Valley

KEY MESSAGES

- Heavy rain and flash flooding will continue to be the main concern overnight. One to two inch rainfall totals expected with isolated totals three to five inches mainly south.

- Another low chance (30%) of showers/storms for northeast Nebraska Sunday afternoon. Not anticipating much of a risk for severe weather with these storms. - Pleasantly mild temperatures for the first full week of summer. High temperatures in the 70s and low temperatures in the 50s are expected. Periodic chances for showers and storms.

DISCUSSION

Issued at 1124 PM CDT Sat Jun 20 2026

Showers have overspread our area across eastern Nebraska and most of southwest Iowa this evening. The instability axis has set up farther southwest than anticipated, driving stronger storms generally south of our area out of central Nebraska at least so far this evening. We still have the nose of the low- level jet forecast to shift eastward into our area closer to midnight tonight. If this occurs, this should lead to additional destabilization in the elevated mixed layer, potentially ramping up more thunderstorm activity across our southern counties. The one element that could hamper this is that storms over northwestern Kansas right now are disrupting the 850-mb jet. If this continues, we would see less of an impact from the LLJ, which would limit any additional convective growth.

A second wave of showers and storms move in from the west overnight, currently active over the Nebraska Panhandle. This will be weakening as it moves into a more stable air mass, but could bring additional rainfall to areas that will have seen a decent amount of rain already. So far our heaviest rainfall amounts have occurred along the convective line through Saline, Jefferson, Gage, and Pawnee Counties. A swath of Jefferson County saw 3.5 to 3.85 inches of rain with the storm that moved through earlier, so we'll be watching this area for any additional heavy rainfall overnight. With this second round, heaviest rainfall amounts will occur along the southern part of that line closer to the nose of the LLJ. This again will greatly depend on the amount of influence we can get from the LLJ coming up out of Kansas. The potential development toward midnight tonight and the second wave closer to 3-5 AM both still bring chances for heavy rain and flash flooding across southeastern portions of our area, so leaving the Flood Watch in place for now.

Rain clears out of our area around 7-8 AM on Sunday with clouds lingering through the day on Sunday. This should keep temperatures cool with highs in northeast Nebraska only in the upper 60s, and low-to-mid 70s across southeast Nebraska and southwest Iowa. Sunday afternoon and evening we see a vorticity lobe move through bringing another chance for showers and storms, mainly to northeast Nebraska. While most hi-res guidance track these storms south into Kansas, the HRRR and FV3 bring storms into northeast Nebraska. If they track into our area, they should be trending weaker with not much of a risk for any severe weather. These should be done by midnight.

Looking back at the broader picture, we have fairly zonal flow across the Central Plains Sunday into Monday with ridging building out west toward midweek. This will lead to a transition to northwesterly flow starting Tuesday with the arrival of a weak trough. This could bring some showers and storms Tuesday morning into the afternoon but weak forcing and dynamic forcing should keep any of this from being too much of a concern.

Weak shortwaves in the northwesterly flow will bring additional periodic chances for rain through the end of the week. Highs mostly stay in the 70s with overnight lows in the 50s. Could see a warming trend going into next weekend as deterministic guidance start to push the ridge eastward into our area as a trough moves out of the Gulf of Alaska into the PacNW. This would lead to enhanced southerly flow advecting hotter, more humid air back into the region over next weekend.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 541 AM CDT Sun Jun 21 2026

IFR to MVFR ceilings are expected to linger through much of the day, but should gradually improve, with VFR conditions expected for most of the area by this evening/overnight. Showers will also gradually exit this morning with perhaps a few brief periods of MVFR visibility under any heavier showers. Winds will generally be easterly to northeasterly with some gusts of 18-22 kts by late morning and through the afternoon. Guidance still hints at a few spotty showers or even an isolated rumble of thunder near OFK and/or LNK this afternoon/evening, but chances remain low (20-30%) so did not include mention at this time.

OAX WATCHES/WARNINGS/ADVISORIES

NE...Flood Watch until 7 AM CDT this morning for NEZ030-042-043-050- 051-065>068-078-088>093. IA...Flood Watch until 7 AM CDT this morning for IAZ090-091.