textproduct: Omaha/Valley

KEY MESSAGES

- Showers and storms return late this evening into the overnight hours, with potential for a few strong to severe in central Nebraska and near the NE/KS border.

- Additional showers and a storm or two are possible Wednesday morning into the overnight hours, with low-end potential (5-10% chance) for one to be severe.

- A warming trend begins on Thursday with temperatures gradually increasing into the 80s. Periodic rain chances (15-25% chance) remain in the forecast.

DISCUSSION

Issued at 157 PM CDT Tue Aug 18 2026

Today and Tomorrow:

Water vapor imagery this afternoon features ridging beginning to build over the western CONUS/Intermountain West, with west- northwesterly flow pouring in across the eastern two thirds. Taking a look at the surface, a cold front is currently place just south of the NE/SD border region into northern Iowa while isolated to scattered showers linger across southeast Nebraska, where modest surface pressure rises continue. A swath of shallow cumulus is in place over northeast Nebraska into Iowa, with little capping overhead. Wind/thermodynamic profiles in this environment show potential for wind/hail with a storm mode that would grow upscale quickly. Though there is no inhibition, we are relying on modest subsidence and limited convergence along the frontal boundary to keep the lid on any storm chances in this area this afternoon/early evening. Otherwise, Temperatures have recovered well despite initial cloudiness today, with highs expected to push a bit further to into the upper 70s to low 80s across the area, with increasing shower and storm potential this evening and overnight hours continuing to the main concern of the short-term forecast.

A surface low is currently located over northeast Kansas with a strengthening boundary extending southeast, with that boundary forecast to shift into northeast Kansas over the course of the afternoon and evening hours. Additional lift across the High Plains is to lead to shower and storm development, shifting eastward later this evening/overnight hours and decaying while it does so. Convective remnants from it alongside new storm initiation represent the late evening/overnight shower and storm chances locally, with the Kansas action holding the highest potential for severe activity that could glance our area. As we push into the evening, the LLJ will nose just to the north of the surface boundary, helping the storms initiate and sustain themselves. Currently the best convergence looks to be just south of the NE/KS border but is close enough to keep an eye on. The remaining showers wafting in from the northwest meanwhile favor central Nebraska as they walk down the main theta-e gradient. All in all, the morning convection has limited our chances to only being along the periphery of our area of responsibility, but it'll be close on the south and west sides.

Additional storms will attempt to develop during the morning hours in central Nebraska, spurred on by leftover lift from farther displaced High Plains convection, though timing has been shifting based on how overnight showers transpire. Those chances will likely linger into the early afternoon, though their ceiling will be limited by decreasing instability due to the timing diurnally with marginally-severe wind and hail being the primary hazards before diminish by the evening hours.

Thursday and Beyond:

Thursday takes a step towards the quieter side of the pattern with increasing influence of the ridge to the west taking over. We'll see increasing temperatures that peak Friday (mid-to-upper 80s), wavering a bit into early next week. Minor rain chances continue to dot the extended forecast, with no particular day being a home run for rain chances locally.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 606 PM CDT Tue Aug 18 2026

VFR conditions and light winds, mainly from the northeast, start the period. Showers and thunderstorms are anticipated this evening and early tonight, mainly along the Nebraska/Kansas border. Local aviation impacts are not expected with this. With light winds and plentiful moisture, patchy fog is forecast to form between 11-14Z over much of the area. MVFR visibility reductions will be possible with any fog that develops. Additional showers and thunderstorms are expected to form over north-central Nebraska after 06Z. This complex of storms will spread southeast. The strongest of these thunderstorms should remain west of the area, but weaker showers and thunderstorms are likely to impact OFK and LNK during the morning hours (10-16Z). Other areas may see impacts, but confidence is low due to the thunderstorm complex potentially limiting additional development. Thunderstorm chances begin to decrease Wednesday afternoon as a cold front pushes south through the area.

OAX WATCHES/WARNINGS/ADVISORIES

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