textproduct: Topeka

KEY MESSAGES

- Scattered showers and weak thunderstorms will continue today and tonight.

- Periods of heavy rain are forecast for Tuesday - Thursday next week. Widespread several inches of rain with locally higher amounts could lead to a flooding risk.

- Mild temperatures persist. Highs stay near average, lows above average.

DISCUSSION

Issued at 349 AM CDT Sat Sep 26 2026

An amplified upper pattern remains in place this morning. The upper low that was over the Southwest yesterday has weakened into an open wave as it now lifts northeast over the Plains. In association with the broader scale wave, water vapor imagery depicts multiple pockets of ascent, associated with batches of showers and thunderstorms. One of these rounds of weak convection is just exiting the area, while another is beginning to lift northeast from the OK/TX Panhandles. So confidence is increasing that we'll see more scattered showers and thunderstorms throughout the day today, beginning mid to late morning. This should keep widespread clouds around, limiting instability. So potential for any strong to severe storms continues to decrease, and the prior SPC marginal risk has been trimmed well south of the area.

Sunday into Monday still look quieter as upper ridging sets up over the Plains. However can't completely rule out some drizzle or light showers though, as guidance has come into better agreement in keeping some moist easterly flow in place in the lower levels. Have nudged down high temperatures for this period as well, given the potential for increased cloud cover.

Attention then turns to the Tuesday through Thursday timeframe. Guidance remains consistent in a deep upper low developing over the Southwest and shifting slowly east into the Plains. This low looks to interact with and then pick up a recurving Hurricane Polo, absorbing a large plume of tropical moisture. Ensemble mean PWAT is still approaching 2" by Tuesday night, near record values for this time of year. This is very favorable for heavy rain and potential flooding somewhere across the central and southern Plains. However, there is a lot of spread in the exact speed/track of the upper low, as well as the embedded remnants of Polo. This will be the key factor in where the heaviest prolonged rain sets up. LREF 25th-75th percentiles are roughly 2-3" through Friday, which seems reasonable for the most likely rainfall amounts at any one point. Spread out over several days, these values would be less impactful. Looking at the LREF 90th percentile though, values of 5-7" correspond well to deterministic guidance as a reasonable worst case for locally higher pockets. These pockets, with very isolated even higher values, would be more concerning for potential flooding. Pinpointing 4-6 days out where these higher values will be is an exercise in futility, so for now will continue to watch larger scale trends with the overall synoptic setup. Temperatures throughout this period will be dependent on the overall coverage and timing of precipitation, but in general the cloudy and moist airmass should keep diurnal temperature ranges low. Expecting cool daytime highs in the 70s with warm overnight lows in the 60s.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 550 AM CDT Sat Sep 26 2026

Another round of showers and weak thunderstorms moving northeast through south-central KS and should approach the main terminals mid-morning. Another round of showers and storms may develop overnight, but confidence in this was slightly too low to include in TAFs. Otherwise, expecting mainly VFR conditions though some brief scattered MVFR ceilings can't be ruled out this morning. Winds become more southerly this afternoon and increase to around 10 kts, but will once again become more southeasterly and lighter overnight.

TOP WATCHES/WARNINGS/ADVISORIES

None.