textproduct: Topeka

KEY MESSAGES

- Scattered shower and perhaps a thunderstorm could redevelop overnight tonight across northeast and east central Kansas.

- Mainly dry weather is expected Sunday and Monday. Though an isolated shower cannot be ruled out.

- There is good confidence in wet weather for Tue through Fri. Periods of heavy rain could lead to several inches of accumulation with a flooding risk.

DISCUSSION

Issued at 202 PM CDT Sat Sep 26 2026

19Z water vapor imagery showed a shortwave lifting across the forecast area within a broader upper trough over much of the western U.S. Surface obs showed low pressure along the high plains with high pressure to the east of the Great Plains allowing southerly low level flow to continue to bring moisture north.

For the rest of this afternoon, the light rain associated with the shortwave should exit the forecast area as the wave moves northeast of the area. General subsidence behind this wave is forecast to preclude any redevelopment across north central Kansas. However the southerly low level flow is expected to maintain some isentropic lift tonight and the CAMs continue to show scattered showers developing towards midnight. Forecast soundings suggest there will be some modest elevated instability around 500 J/kg. But bulk shear should be weak (around 20KT) and effective shear for an elevated parcel even weaker. The forecast has some chance POPs across northeast and east central Kansas expecting coverage for the most part to be scattered.

Shortwave ridging is progged to develop overhead for Sunday and Monday. Some of the deterministic solutions have isolated QPF progs Sunday afternoon and overnight into Monday morning. Am not sure what is causing this since there isn't much synoptic support nor lift on the isentropic charts. With this in mind have kept POPs less than 20 percent. There should be scattered cloud cover with no strong temp advection for Sunday and Monday. This should allow temps to persist in the upper 70s for highs and lower 60s for lows.

The main focus of the forecast remains on the extended period of wet weather for Tuesday through Friday. Deterministic solutions are converging on a closed upper low slowly trekking from the southwestern U.S. across the plains. And there is a trend in the ensemble solutions to this idea as well. So forecast confidence is improving. Initially the remnants of Polo are progged to be absorbed into the upper trough with a good fetch of tropical moisture advecting into the central plains for Tuesday and Tuesday night. Ensembles continue to show moisture forecast to be in the atmosphere as 2 to 3 standard deviations above normal. And operational solutions show PWs around 2 inches. As this moisture advects into the central plains Tuesday and Tuesday night, this represents first opportunity for heavy rainfall to impact the area. The second opportunity is with cyclogenesis progged to occur Wednesday night and Thursday. The 12Z GFS and ECMWF tend to keep the surface low to the southwest and south of the forecast area through Thursday night placing the forecast area within a favorable synoptic location for good moisture advection and upper level divergence to allow the regeneration of precipitation. By this time the available moisture should have shifted to the east, but soils could be saturated from earlier precipitation. As for rain totals, the NBM has the probability for 1 to 3 inches or rain in the 60 to 75 percent range. Chances for greater than 3 inches sit around 50 percent. Worse case scenarios are pointing to rain totals of 3 to 5 inches which could lead to flooding. Eventually the upper low should get kicked east with dry forecast for Saturday.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 202 PM CDT Sat Sep 26 2026

There is a low chance for some MVFR CIGS moving in Sunday morning, but most guidance keeps VFR conditions in place with an east and southeast wind. Redevelopment overnight of SHRA look to be scattered from the CAMs so have only included a VCSH at TOP and FOE. Think much of the activity will be east of MHK so don't have a mention of precip once this afternoon's rain moves east.

TOP WATCHES/WARNINGS/ADVISORIES

None.