textproduct: Kansas City/Pleasant Hill

KEY MESSAGES

- River levels are gradually receding across far northern MO. Some downstream rivers have yet to crest, but look to lower this weekend*. *Dependent on anticipated rainfall.

- Cool and dry today, widespread rain chances return starting Thursday morning (10-40%); moreso, Thursday evening into Friday morning (40-80%).

- More active weather pattern expected after the Memorial Day holiday with several opportunities for additional rainfall across the area.

DISCUSSION

Issued at 148 PM CDT Wed May 20 2026

Canadian high pressure continues to push into the area. This cool dry air mass has brought with it below normal temperatures and a nice break from the daytime warmth and stormy nights of last several days. High temperatures over the next couple days reside in the mid to upper 60s.

Water vapor imagery shows a two large troughs across the western CONUS. In the Atlantic, a small cyclone has infiltrated the Bermuda high which significantly influenced the weather pattern over the past few weeks. With this low barging in, atmospheric flow has opened up just enough to allow for more transient flow of waves across the CONUS. The western troughs will be the primary catalysts for our weather the next few days. The southern trough has been sitting mostly stationary over the past several days ejecting several shortwave troughs through the area. Thus far, the relatively dry, cool, and stable air of the resident high has prevented any shower development from these passing shortwaves. As the high pressure continues to slide eastward, flow turns back southerly reopening the path of Gulf warm air and moisture advection which quickly builds back into the central CONUS overnight. The enables the shortwaves to take advantage of the influx of moisture developing showers and thunderstorms across the central and southern Plains Thursday and Friday.

Lee cyclogenesis begins tonight off across western KS and OK. This begins a warm frontogenesis process across the central Plains that may bring some showers into the area Thursday morning. This particular wave looks somewhat weak and disorganized as resident dry air aloft inhibits development slightly. A second more substantial wave is expected to develop Thursday morning across Texas which quickly lifts northward during the day pushing more substantial showers and thunderstorms into the region. The good news is that convective variables ahead of this more substantial wave look rather limited keeping expectations to widespread rain showers with some isolated thunderstorms and no severe weather anticipated. However, heavy rainfall looks to once again return to the area. PWAT values around 1-1.5 inches coupled with CVA and isentropic ascent along the warm front do paint a potential for widespread long lasting rainfall starting Thursday night into late Friday. QPF shows 1-2 inches of rainfall, with locally higher amounts possible. Greater overall rain accumulations are more likely south of US-36. Coincidentally, this aligns with several rivers downstream of runoff of the previous week's rainfall which have yet to crest. This will likely lead to at least a delay in the crest to an increase in forecast crest height. Current river forecasts do account for the anticipated rainfall amounts; however, uncertainties in QPF will become more refined as the system draws closer.

Looking at the extended forecast, the pattern becomes more active. As the northern trough passes by, the SW CONUS low gets dislodged and absorbed into the atmospheric flow. This opens up the current across the United States. Multiple small waves are expected to move by the CWA bringing light precipitation chances to the edges of the region early next week. As midweek approaches a large 500mb trough is expected to come on shore in the Pacific NW and dig across the western CONUS. This combined with an anticipated high pressure building across the eastern CONUS results in a compressed corridor of flow across the Central Plains which looks to accelerate warm air and moisture advection into the central part of the county. This also focuses the flow of shortwaves, CVA, and lift contributing to the development of showers and thunderstorms. It is still a little far out to dig into great detail such as the potential strength and severity of storms as there are still many uncertainties and dependencies. Most of these uncertainties are centered on where the axis of this accelerated southerly flow sets up. Regardless, consensus across ensemble model members present a synoptic scale kinematic and dynamic setup which looks conducive for more precipitation opportunities over the coarse of late next week.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 112 PM CDT Wed May 20 2026

VFR conditions are expected for much of the forecast period. North northeast winds continue through the period. Sky coverage closes and CIGs lower ahead of -SHRA which is expected to arrive late overnight toward the end of the period. Spatial coverage of SHRA remains somewhat scattered at this time so kept board PROB30's across the TAFs. VCTS is expected to be limited.

EAX WATCHES/WARNINGS/ADVISORIES

MO...None. KS...None.