textproduct: Topeka

KEY MESSAGES

- Mostly dry today and Monday with only a low chance (10-20%) for a pop-up shower.

- Rounds of rain are expected Tuesday through Thursday with the heaviest rain likely late Wednesday into Thursday. Widespread rainfall totals of 1-2.5" with locally higher amounts could lead to flooding.

- Seasonably mild through Wednesday, turning cooler behind a cold front Thursday into next weekend.

DISCUSSION

Issued at 151 PM CDT Sun Sep 27 2026

Satellite imagery shows three main synoptic-scale features this afternoon: a nor'easter along the Mid-Atlantic and northeast US, Hurricane Polo off Baja California, and a longwave trough moving into the western US. The forecast area resides in the middle of these features with weak mid-level energy still meandering around the Mississippi Valley. Shortwave ridging moving overhead favors dry conditions, although some weak ascent could generate isolated showers or a storm through the evening. Similar conditions are expected on Monday; some patchy fog is possible overnight into Monday morning with a low chance for isolated showers through the daytime hours. Highs reach the 70s to near 80s degrees today and Monday.

Attention then turns to the western trough as it advances across the Desert Southwest and into the Plains Tuesday through Friday, picking up remnants of Polo as it does so. Guidance remains consistent in anomalously high PWAT values and a couple rounds of stronger ascent through this timeframe. Still seeing a slower progression and farther northwest trend with the first wave, pushing the heaviest rainfall from southwest Kansas into northeast Nebraska. Portions of central and north central Kansas could still receive an inch or two from this first round through Wednesday morning, although a slower trend could limit rainfall with this round. Better forcing arrives Wednesday through Thursday as the closed upper low and surface cold front move through. Showers and storms become more widespread with this round and lead to the majority of rainfall accumulations. QPF from ensembles has decreased to some degree; ensemble means are now 1.5-2.25". The probability of at least 1" of rain is still 70-90% with a worst-case scenario of 4-5" still possible in isolated spots. The highest chances for flooding comes Wednesday afternoon through Thursday, but there remains uncertainty in overall amounts and location of the heaviest rainfall. Guidance differs in the speed of the front and how quickly precipitation exists the area, but conditions should dry out with cooler temperatures as surface high pressure builds into the area Friday into Saturday.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1228 AM CDT Mon Sep 28 2026

A small area of MVFR to IFR stratus is developing towards KTOP and KFOE, and should push west to KMHK over the next few hours. Still some questions about how widespread it will be, with more confidence in persistent near-IFR ceilings towards KMHK. Regardless, expecting ceilings to rise and scatter out over the morning hours. Winds stay light and easterly.

TOP WATCHES/WARNINGS/ADVISORIES

None.