textproduct: Topeka

KEY MESSAGES

- Rounds of scattered showers and storms continue through tonight. A few strong to severe storms possible

- Cooler temperatures for most on Sunday, then warming up again with highs in the 90s Monday.

- Cold front stalls somewhere nearby Tuesday into Wednesday. Wetter pattern develops along and behind the front.

DISCUSSION

Issued at 131 PM CDT Sat Sep 12 2026

Complicated short-term forecast setup this evening and tonight, with mesoscale factors likely determining the extent of the thunderstorm and severe weather threat. Weak convection is currently still ongoing across portions of northern and eastern KS, driven by some weak 700 mb WAA. As we head into the late afternoon and evening hours, watching two areas closely for additional and stronger convection. The first area is along the composite frontal and outflow boundary across southern portions of the forecast area (along/south of a line from Morris to Coffey Counties). Convection along this boundary is more conditional, and may stay south of the area, but the environment is favorable for a more discrete supercell. So any storm that does develop could pose a threat for damaging winds 60-70 mph and very large hail up to 2 inches diameter. Farther north towards the Nebraska border, convection should continue to redevelop along the 850 mb front. Here, storms will remain elevated north of the surface boundary. However shear and instability should still be enough for some isolated damaging winds or large hail to around 1 inch. As isentropic ascent continues overnight, storms will likely become more numerous north of the boundary. This should result in a weakening trend but will have to watch for any pockets of training convection. Can't rule out some locally heavy rainfall totals of 2-4" if this occurs.

The overnight convection should reinforce the boundary for Sunday, though there is still some uncertainty in exactly how far south it ends up. But particularly if clouds and showers linger to the north, we could see high temperatures range from the low 70s across far northeast KS to the upper 80s in southern Coffey and Anderson Counties. Confidence remains high that the boundary will lift north of the area Monday as a warm front. Hot and humid conditions will be in place as a result, with temperatures climbing into the 90s with heat indices near or a bit above 100.

Monday night into Tuesday and Wednesday, an upper low moving across the Northern Plains will push a cold front slowly east across the area. Should see several rounds of showers and storms along and behind this front through Tuesday evening. This will keep temperatures behind the front much cooler, in the 70s and even 60s. East of the front, temperatures will warm into the 80s and 90s. Still a fair amount of uncertainty in how far east the front will make it before stalling on Wednesday, so there remains a large spread in forecast temperatures Tuesday into Wednesday and even later on in the week. Regardless, with multiple rounds of rain possible along the front, there is the potential for several inches of rain over the week, especially across northwestern portions of the forecast area. The very dry last 40 days should limit flooding potential, especially spread out over several days, but it's at least something to watch.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1139 AM CDT Sat Sep 12 2026

Main question will be timing of showers and thunderstorms throughout the period. While some isolated storms may linger this afternoon, the best potential through the evening looks to be away from the main TAF sites, with better potential for more widespread convection after midnight. Winds stay light and northeasterly to easterly through the period. Ceilings stay VFR through tonight, though by tomorrow morning some scattered MVFR ceilings may begin to develop.

TOP WATCHES/WARNINGS/ADVISORIES

None.