textproduct: Topeka

KEY MESSAGES

- Favorable environment for severe weather tomorrow but still larger than usual amount of uncertainty for storm timing, coverage, and location.

- Temperatures stay near to slightly below average for the next week.

- Several additional low chances for showers and storms, particularly Wednesday and Friday.

DISCUSSION

Issued at 140 PM CDT Mon Aug 17 2026

Broad west-northwesterly flow is present across the region this afternoon, to the south of a deep upper low up over the Hudson Bay. At the surface, high pressure is centered over the Missouri River Valley, keeping quiet conditions in place over eastern KS. Even with mostly sunny skies, high temperatures are remaining in the 80s, a welcome change from most of last week. The surface high will depart east tonight, allowing southerly winds to return in response to a deepening low over the High Plains. Farther to our northwest, expecting storms to develop this evening along the surface trough across portions of South Dakota and Nebraska. These storms will move southeast into eastern Nebraska by tomorrow morning.

How these storms evolve overnight will play a large role in our thunderstorm potential Tuesday. Some low potential for gusty winds could exist with this first round, but the more interesting potential will be with potential evening storms in their wake. While shear will be plentiful, increasing to around 40 kts by evening, thermodynamics will be dependent on the extent of the morning storms. The more organized and farther west morning storms are, the farther west outflow will extend. This would limit the potential for surface-based storms to redevelop, or at least confine the potential to central KS. On the other hand, if outflow remains weak and better heating (temps rising into the 90s) can develop across the area, there would be a window for surface based supercells with large hail and damaging winds. The former scenario seems a bit more likely at this time, but will need to consistently monitor the mesoscale setup over the next 24 hours. There is better confidence in slightly more elevated storms develop overnight as the main cold front shifts south. These storms would not have as high of a figurative ceiling as any earlier surface-based supercells, but could nonetheless produce some large hail and/or damaging winds.

Cooler temperatures will move in behind the front for Wednesday and Thursday. Highs should stay in the 80s, perhaps even 70s on Wednesday if cloud cover can remain persistent. Some lingering moisture will remain in place behind the cold front, so it's not out of the question we see a few additional thunderstorms Wednesday PM. But the main large scale forcing should stay to our north and west, so think things will generally stay dry. Uncertainty increases by the weekend as the upper flow amplifies. Does seem like we should trend a bit warmer as ridging builds to our west, but with northwest flow overhead we should stay fairly close to average. Precipitation chances will remain tied to low-predictability shortwaves moving through the northwest flow aloft. Slightly better signal for one of these to pass nearby Friday into Saturday, but confidence is low this far out.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1216 PM CDT Mon Aug 17 2026

VFR conditions and light winds will continue through tonight. After sunrise tomorrow, winds increase a bit out of the southeast. Could also see weakening showers and storms approach late in the period, but the best chance should stay to the north.

TOP WATCHES/WARNINGS/ADVISORIES

None.