textproduct: Topeka

KEY MESSAGES

- Above average temperatures continue through the end of this week.

- Showers and storms look increasingly likely (60-80% chance) Saturday late afternoon through Sunday, followed by cooler temperatures next week.

DISCUSSION

Issued at 357 AM CDT Thu Sep 17 2026

An upper low remains stationary over northern CA early this morning while a ridge holds over the southeastern US and is starting to retreat back west. Mid-level moisture is noted streaming north through the meridional flow over the Four Corners region. At the surface, a warm front has a slight southwest-northeast orientation from roughly Minneapolis through Hiawatha. Dense fog has been observed north of that boundary via satellite, observations, and webcams, and expect that to remain the case through mid to late morning as soundings show the fog mixing out around 15-16z. Areas just to the south of the front may still see some patchy fog given light winds, clear skies, and residual low-level moisture from recent rainfall. A few light showers from isentropic ascent have developed across part of north central KS, mainly the far northwest corner of the CWA, which should move into Nebraska further into the morning as the warm front lifts north. This leaves us with another warm day in store as highs reach the 90s for most. Locations north of I-70 may stay in the mid to upper 80s with early fog lifting to stratus before that eventually moves north as well, leaving less time for insolation.

Heading into Friday, the upper ridge continues to retrograde over the Southern Plains while the low starts to move east ever so slowly. A lead shortwave ejecting out of the High Plains ahead of that system results in a deepening sfc low in western KS. An early look at short-term guidance indicates that the associated cold front probably won't make it far enough east for precip to develop in our north central KS counties during the late afternoon or early evening. There is a low chance for storms that develop ahead of the front in southern Nebraska to graze northern KS overnight, which could bring strong winds if they make it into our area. The highest rain chances are focused on the frontal passage Saturday. There are still varying ideas on the speed of the front with the NAM being the fastest solution, GFS being on the slower side, and Euro somewhere in between. The location of the front by late afternoon will then determine where thunderstorms have the best chance of initiating. In any case, modest shear and instability would support a few marginally severe storms along the front. As long as the front is progressive enough, that should limit flooding concerns. However, it should be noted that Pwat values around 1.6-2", while not nearly as high as this last rain event, are still on the high end of climatology so would support efficient rainfall and could result in higher QPF if the system moves slower. The upper low looks to fill as it moves out of the Rockies and across the Northern Plains the rest of the weekend. PVA from that system keeps rain chances around through Sunday before dry conditions return Monday.

CAA behind the front as well as clouds and rain bring cooler temperatures starting Sunday with highs in the 70s and even a few upper 60s. The cooler air mass remains in place through mid-week, which would be more fall-like if it wasn't for the dew points staying in the 60s and 70s. The pattern looks to stay fairly active with low-amplitude ridging keeping dry conditions in place through Tuesday, followed by another shortwave bringing slight chances for rain Wednesday.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1200 PM CDT Thu Sep 17 2026

VFR conditions prevail. Winds initially from the west-southwest become southeasterly this afternoon, then increase from the south-southwest after sunrise Friday.

TOP WATCHES/WARNINGS/ADVISORIES

None.