textproduct: Omaha/Valley

KEY MESSAGES

- A few showers and storms are possible across far northeast Nebraska overnight into early Saturday (20-40% chance), with the best chance for a severe storm occurring between 5 AM and 8 AM.

- Oppressive heat will continue into next week, with warm lows in the 70s will providing little relief.

- There will be periodic shower and storm chances (20-40%), especially during the overnight and early morning hours. Severe weather chances remain low (generally 5% or less), but a few storms could produce gusty winds and hail in northeast Nebraska Saturday morning.

DISCUSSION

Issued at 1056 PM CDT Fri Sep 4 2026

Tonight through Saturday:

Water vapor imagery this evening shows the stalwart cutoff upper low spinning over the Pacific Northwest, propping up southwesterly flow over the Intermountain West that terminates in a ridge axis over the central CONUS. With another day of heat in the books, the attention in the near future now shifts to overnight/morning storm chances over parts of the NE/SD/IA vicinity, where already a swath of scattered cloud cover marks where forcing for ascent along the periphery of the LLJ is occurring. These clouds span from northwest Kansas into southeast South Dakota, the later of which is where a best overlap of instability, dry lower levels with increase DCAPE, and forcing for ascent will exist. Sufficient instability will be in place for a few strong updrafts, but the maintenance of them could be difficult with minimal effective shear for them to avoid cold pool dominance. Recent runs of the CAMs have been a bit more tepid on how widespread the showers and storms will be, with several favoring the cluster across north-central SD to creep southward towards greater instability before falling apart near the state line. Whether the develop in that area or drift in from the north, a 20-24% chance for storms exists for far northeast Nebraska, with only a 5% chance that a storm or two can reach strong to severe levels, maxing out between 5-8 AM.

Once those storm chances simmer down we'll see soupy conditions manifest once again across the area, with widespread dewpoints remaining in the 70s while temperatures climb well into the 90s during the afternoon hours. This does appear to the warmest day of the forecast period, but with poor timing as many will be trying to enjoy outdoor gatherings on the front end of the holiday weekend. Heat indices are set to climb back into the 100-107 degree range at their peak, with the highest values forecast over southwest Iowa and for the local metro areas. The tail end of a Heat Advisory carries through 7 PM tomorrow evening, with only slightly cooler temperatures expected going forward, so don't break out the fall sweaters just yet.

A few scattered showers could cling to the nearby boundary set out by the morning convection across SD/northeast NE, with additional storms developing out west that drift towards us after 10 PM. Shower activity will likely increase overnight as convergence along the LLJ and leftover forcing from the decaying MCS to the west combine for rain chances covering eastern Nebraska. Once again, a low-end chance for severe storms exists for this activity (level 1 out of 5 risk for wind and hail), with the better chances focused west of the area.

Sunday and Beyond:

Lingering showers from the overnight activity drifting in from the west will combine with additional activity from the north to make for a stormy morning and early afternoon, as several CAMs depict a more vigorous swath of storms moving across far eastern SD, into MN and western IA during the afternoon hours. Extended runs of the CAMs have featured strong wind gusts in their surface fields around 4 PM, which will likely necessitate an upgrade to the severe risk for Sunday. Mentioning these storms occur during the afternoon hours does bring the hope of a cooler evening as widespread convection interrupts our stagnant airmass while hopefully bringing some much- needed moisture to the recently dry area.

Monday through the rest of the week will start out with mid/upper heights falling slightly as the upper low out to the west begins its departure across far southern Canada, dragging a frontal boundary through the area Tuesday through Wednesday. The exact timing and speed of the passage will dictate shower and storm potential, with an afternoon passage spelling higher strong to severe storm potential as storms try to take full advantage of surface instability. By Thursday, global deterministic solutions suggest that this front will have pushed just to the south of the area into KS/MO, with a more uncertain fate for the boundary. Solutions have converged away from the GFS in depicting another slight ridge, while much of the other guidance suggests a more zonal (and therefore cooler!) pattern that grows with uncertainty towards the weekend.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 542 AM CDT Sat Sep 5 2026

Thunderstorms have moved into northeast Nebraska and are expected to remain north of KOFK (75%) but could impact the aerodrome through about 8am... but they have not been added to the forecast due to low probability.

There has been patchy fog observed along the Missouri River and could temporarily impact KOMA this morning. Chance of that is under 30%. Otherwise, expect to see VFR conditions persist.

OAX WATCHES/WARNINGS/ADVISORIES

NE...Heat Advisory until 7 PM CDT this evening for NEZ044-045- 050>053-065>068-078-088>093. IA...Heat Advisory until 7 PM CDT this evening for IAZ055-056-069- 079-080-090-091.