textproduct: Omaha/Valley

KEY MESSAGES

- Regular chances of thunderstorms continue each day through the forecast. Late Wednesday night and late Thursday night bring the best chances (40-70%).

- Hot conditions linger across southeast Nebraska into Iowa, with afternoon heat indices of 100 or more lingering into Monday.

- Strong to severe storms are possible tomorrow late afternoon into the overnight hours. The primary hazards are damaging winds and hail.

DISCUSSION

Issued at 200 PM CDT Sun Aug 9 2026

Today and Tomorrow:

Water vapor imagery this afternoon continues to feature slight ridging over the western half of the CONUS that terminates to the east with a shortwave-powered MCS that is currently moving through the Great Lakes Region. Zooming in locally, a somewhat messy pattern is in place with a swath of leftover stratus creating a differential heating boundary while just to the west, an area of scattered clouds with greater vertical extent push eastward towards it. Observations have been coming in rather soup-ey across far southeast Nebraska into southwest Iowa, where dewpoints in the low-to-mid 70s alongside quickly-climbing temperatures have led to heat indices in the upper 80s and 90s already. Lower dewpoints are being advected in from the southwest and could curb how high apparent temperatures reach, especially for southern Nebraska. A Heat Advisory is in place for Pawnee/Richardson/Nemaha Counties through 8 PM, where the highest temperatures are expected to occur. There is some chance that an expansion is needed to the north, particularly into southwest Iowa.

Other than the heat, we'll be on the lookout for some very minor rain chances as forcing for ascent intersects a boundary laid across southern Nebraska this evening into the overnight hours.Chances increase along the southern two tiers of counties in Nebraska around midnight, carrying into the early morning hours. Fog formation becomes possible once again over northeast Nebraska where limited mixing keeps dewpoints higher. Efficient cooling may be somewhat limited by cloud debris being wafted in from the west. With both of those factors in mind, it seems prudent to keep patchy fog forecasted, but widespread fog would seem somewhat difficult to develop. Primary time for its development would be 5 AM, lasting until 9 AM.

Another warm day is forecast for Monday, with early morning fog/lingering low clouds limiting potential for that heat and any thunderstorms that may develop as well. Heat indices are not forecasted to be as high (95-102) as extra mid- and upper-level clouds continue to waft overhead. Showers and storms have a better shot at getting off the starting line tomorrow afternoon as strong heating and modest convergence occurs in western Nebraska and South Dakota. Stronger flow aloft will help increase shear values and give storms a better shot at holding together, but that will all depend on them forming in the first place (20-25% chance). Better chances for the region develop with the LLJ ramping up after sunset but as of now, it overshoots the are to ignite storms in South Dakota instead.

Tuesday and Beyond:

Pushing into the work week, we are set to have one more warm day on Tuesday before we see temps tumble heading into the latter part of the week. The mid/upper pattern will transition from the semi- persistent but weak ridge into a more zonal pattern with the main jet stream shifting south to be just north of the area. This will allow for greater access to increased shear, forcing for ascent via embedded shortwaves, and cooler temperatures. We'll see comfortable temperatures in the lower 80s and even 70s at times with nearly daily rain/storm chances, with timing/intensity tough to nail down at this point.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1138 AM CDT Sun Aug 9 2026

Lingering MVFR ceilings continue near KOFK and the surrounding area, while KOMA and KLNK continue to stay east of it before it dissolves this afternoon. Winds will remain light, and will gradually turn through the next 24 hours as a wind shift hangs out in the area. Speeds should remain at less than 15 kts. There are signals for some fog formation overnight, though high clouds may make it hard for any to form (most likely place would be KOFK). Shower and storm chances remain low at this time, but a swath of clouds from central Nebraska could spark a few close to 00z near KLNK (10-15% chance).

OAX WATCHES/WARNINGS/ADVISORIES

NE...Heat Advisory until 8 PM CDT this evening for NEZ091>093. IA...None.