textproduct: Topeka

KEY MESSAGES

- Cool temperatures through the workweek give way to a warming and a mainly dry Memorial Day weekend - highs returning to the upper 70s to near 80.

- Showers with embedded thunderstorm chances Thursday into Saturday morning likely across two separate periods. More areawide for Thursday into early Friday. Friday night into early Saturday mainly south of I-70.

- Another Pacific trough digs into the western CONUS mid to late next week. Could bring another storm system to the Plains by the middle part of next week.

DISCUSSION

Issued at 454 AM CDT Wed May 20 2026

Surface high pressure holds firm across the central Plains through Wednesday as a modified Canadian air mass maintains cool and dry conditions. With quality return flow yet to develop, highs will struggle to reach the upper 60s as the stable air mass keeps temperatures well below normal for late May.

The first precipitation chance comes into Thursday as isentropic ascent develops along the 295-300K surface ahead of a shortwave trough emerging from the Intermountain West. Southerly flow returning through the H850 level supports a deepening moisture profile with precipitable water values near the 75th climatological percentile for this time of year. With a fairly deeply saturated column, generally weaker instability favors efficient stratiform rainfall over organized convection. Peak rainfall rates and best storm chances are expected late Thursday into Friday morning.

A secondary window for rain and storm chances sets up Friday night into Saturday morning as the main trough axis lifts out of the Rockies with more focused ascent just northwest of the area. At least NAM soundings currently indicate that modest elevated instability and marginal shear could overlap mainly across east-central areas. Seems worth monitoring though severe weather potential appears limited at this time.

Heights rise across the central CONUS through the weekend. Expect mainly dry conditions for much of the weekend through Memorial Day with temperatures climbing back above normal. Memorial Day highs reach into the middle 80s across the area.

The next potential storm system arrives mid to late next week as another Pacific trough digs into the western CONUS. Increasing Gulf moisture return and a more dynamic forcing mechanism warrant close attention as the period draws closer, though spread among the ENS, GEFS and GEPS remains wide at this range.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1221 PM CDT Wed May 20 2026

VFR continues this afternoon and evening. A chance (30-40%) of scattered rain showers is then expected tonight, so have included -SHRA for that most likely timeframe with this update. Timing may have to be tweaked if confidence increases with later issuances. Rain will likely not last long, but lingering MVFR CIGS and possibly some light drizzle will remain possible early Thursday morning.

TOP WATCHES/WARNINGS/ADVISORIES

None.