Area Forecast Discussion

KEY MESSAGES

-Scattered strong to severe storms are expected to develop along a front late this afternoon/early this evening.

-Shower/storm chances linger through the night, but the severe threat should largely diminish after dark.

-A dramatic temperature swing occurs between today and early in the upcoming workweek. Below average temperatures stick around through the week.

DISCUSSION

Issued at 206 PM CDT Sat Sep 19 2026

The main focus in the short-term is on thunderstorm chances from this afternoon into tonight, and whether storms will reach severe thresholds. At 18Z, a cold front was moving into north central KS. A few agitated cu had grown tall enough to produce isolated, small showers ahead of the boundary. SBCAPE has increased to 2000-3000 J/kg ahead of the boundary and DCAPE is over 1000 J/kg, but deep layer shear is less impressive at around 25 kts. This environment is developing as expected and continues to indicate downburst wind potential with any storms that form today. CAMs still do not show a lot of agreement on timing and location of the more robust convection, but thinking is that coverage of storms will increase after 23Z with initiation likely occurring along a line extending from near Sabetha to Manhattan to Herington. Initial updrafts could congeal into clusters as the entire system progresses eastward across the area this evening. Severe potential should begin to diminish in the hours after sunset in far eastern KS as CIN increases. Most CAMs then show another cluster of showers and storms moving into central KS overnight in response to a shortwave ahead of a main wave aloft. Models show those storms producing some gusty winds in central KS and weakening with eastward extent.

Rain showers may linger into the early morning hours of Sunday with chances decreasing after sunrise. The cold front should be south of the area by midday tomorrow, so with low clouds and north winds, temperatures will be noticeably cooler (following a six day stretch of 90+ highs). Will maintain at least slight chance POPs in east- central areas through the afternoon with rain possibly clipping the area from the south near the stalled H85 boundary.

A cooler air mass fully settles into the area with a surface ridge early next week. NBM has high temperatures ranging from the mid 60s in far northern KS to the mid 70s near I-35 Monday afternoon in part due to limited insolation from lingering cloud cover. Tuesday could be the coolest day of the period with highs in the 60s nearly area- wide (this is cooler than recent nighttime lows). Temperatures slowly creep back up, but stay on the cool side of average through the workweek. POPs return later in the week when longer range models show the next shortwave aloft possibly impacting the region. Confidence is not currently high on that possible round of wet weather.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1237 PM CDT Sat Sep 19 2026

The main challenge this period is on thunderstorm chances and timing. Storms look to develop near a cold front this evening, likely around 23Z/00Z near KMHK. However, there remains some level of uncertainty with a lack of good agreement between high resolution models. Once storms develop they will progress eastward and impact the Topeka terminals late this evening. Storms could produce damaging wind gusts and hail. Additional showers could develop later in the night, which is also when MVFR CIGS become likely. Rain chances decrease Sunday morning, but low stratus could linger into midday.

CLIMATE

Issued at 229 AM CDT Sat Sep 19 2026

Saturday 9/19:

Forecast High Record High (year)

Topeka: 96 99 (set in 2022)

TOP WATCHES / WARNINGS / ADVISORIES

None.