textproduct: Topeka

KEY MESSAGES

- Hot and humid again today with thunderstorm chances increasing by the mid to late afternoon.

- A few storms this afternoon and evening could be strong to severe with damaging winds (60-65 mph) and large hail (up to 1-1.25") as the main hazards.

- Rain chances linger into Sunday with much cooler air filtering in for the remainder of the week. Expect highs in the 60/70s and lows bottoming out in the 50s/60s.

DISCUSSION

Issued at 228 AM CDT Sat Sep 19 2026

Water vapor imagery this morning shows a large ridge of high pressure still dominating the synoptic pattern across much of the eastern US as a trough approaching from the PNW looks to bring change to the central US. The first influences from the trough - now situated near the WY/ID border - are noted with scattered showers and storms across much of the northern Plains as ample PVA streams in within the southwesterly flow. Through the day today, a shortwave just ahead of the main trough axis will push out into the central Plains. A deepened lee trough axis will follow suit as a weak boundary extending from southwestern Kansas to eastern Nebraska moves east into eastern Kansas by the early afternoon. Given warm sector parameters of 1500-2500 J/kg of MLCAPE, 25-35 knots of effective shear and steep 0-3km lapse rates, storms - some strong to severe - will be expected to develop along the frontal boundary and trough axis around peak heating as inhibition reaches a diurnal minimum. Initial storm hazards should initially be hail up to 1.25" and wind gusts of 60-65 mph while storms stay mostly isolated. CAMs depict storm interactions later in the afternoon and evening to congeal convection. This would in turn evolve storm threats to more of a wind threat with some isolated small hail embedded in stronger cores. In addition to the hail and wind threat, PWATs near the 99th percentile for this time of year may lead to torrential rainfall and isolated flooding. HREF guidance depicts this in latest runs with pockets of 1.5-3" of rainfall in the course of 3 hours. The severe threat should end by the mid to late evening tonight as storms move east into Missouri and the effective surface boundary slides south of the area.

Scattered storm and rain chances will persist into Sunday as the main trough axis ejects off the Rockies and moves across Nebraska. This will come with a push of cool air from the north and will pave the way for a nice week of more seasonable weather. Expect temperatures for much of the upcoming work week to top out in the 60s/70s with morning lows in the 50s/60s. Dry weather should persist until Wednesday night/Thursday when low-level flow returns back towards the south and surges moisture back into the area. Luckily, long range guidance keeps a fairly active jet stream pattern across much of the US that should keep temperatures on the cooler side for the remainder of the month.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/

Issued at 1200 AM CDT Sat Sep 19 2026

First half of the period should remain fairly quiet with the TAF driven by winds. Pilots may experience some marginal low-level wind shear through the lowest 2kft, mainly around sunrise, but opted to keep out mention as winds through this layer remain fairly unidirectional and sfc winds expected to stay around 10 mph overnight.

Added mention of convection at KTOP and KFOE Saturday afternoon. Kept all sites at VCTS as overall coverage of storms at this time is still a bit uncertain. High-res guidance does show good chances that thunderstorms along a weak front will develop near the terminals.

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.