textproduct: Kansas City/Pleasant Hill

KEY MESSAGES

- Warming Trend Starts

- Showers and Thunderstorms Start Tuesday Night, Become Widespread Wednesday

- Fluctuating Pattern End of Week

DISCUSSION

Issued at 355 AM CDT Mon Aug 3 2026

Mid and upper-level ridge axis is still present from the Kansas High Plains into Upper Midwest this morning, but upstream we are seeing signs of deamplification as a stronger short-wave trough exits the Pacific Northwest and heads for the Northern Plains and Canadian Prairie Provinces. The stronger dAVA over the lower Missouri River Valley the past few days has shifted toward the Ohio River Valley and Tennessee Valley, and has forced the surface anticyclone center eastward. Multiple short-wave perturbations over the Rockies has provided enough dCVA and lift that has resulted in surface cyclogenesis, with recent objective analysis having this centered over eastern Wyoming this morning. The stronger mid-level support will start to shift northeastward into the Northern Plains, which will limit surface pressure falls for the forecast area, at least for today. However the 594dam H5 high over the desert southwest is also expected to deamplify over the next 24 hours. Expecting short- wave activity to generate cyclonic vorticity into Colorado and the Front Range through the evening, providing another area of surface pressure falls which will extend southward from the cyclone currently deepening over Wyoming. For the lower Missouri River Valley, this sets lower tropospheric flow southwesterly, increasing the strength of WAA this afternoon and will help boost temperatures into the upper 80s across most of the areas, and a few locations may potentially hit the 90F mark this afternoon. Moisture return today will be fairly modest, and without any stronger mid-level lift over the area, should help keep conditions dry for today. Western Missouri and eastern Kansas may see an uptick in winds later in the afternoon, but the stronger pressure gradient remains progged over the Central Plains.

Tuesday, short-wave H5 trough moves a stronger lobe of vorticity across the northern Plains, with mid-level height falls deamplifying the ridge axis across the area. Additional mid-level vorticity generates over the Rockies in Colorado, and this dCVA will help promote surface pressure falls from the Front Range to the Central Plains, while the cyclone over eastern Wyoming moves into the northern Plains along with the primary short-wave trough axis. This movement will also push a cold front into the Central Plains through most of Tuesday afternoon. During this time in the afternoon, most of the forcing remains well west and northwest of the forecast area. However, flow from 850mb to the surface will become more southerly through the afternoon, transporting a higher theta-e airmass into the lower Missouri River Valley. Expecting temperatures to hit the 90s across much of the area, with steadily increasing dewpoints. The afternoon still looks to remain dry for most of the area, but as the cold front moves east-southeast along surface pressure falls spreading across the Plains, convergence will increase eventually bringing providing the lift needed for shower activity. Current ensemble guidance pinpoints the highest probabilities for rain showers in northern Missouri by late Tuesday Night. If there is enough CAPE, a few rumbles of thunder may occur with this activity. The stronger deep layer shear on Tuesday should remain over the central Plains, which will limit the ability for activity to organize on Tuesday in far northern Missouri.

Wednesday, another short-wave trough and enhanced mid-level vort max is currently progged to dig further south, especially in the GFS solution which will provide more lift along with the surface cyclone and cold front moving toward the area. With continued south and southeasterly flow near the surface, theta-e transport will continue, and as the day progresses should see shower activity spread across most of the forecast area. With the stronger mid-level flow on Wednesday afternoon and evening, deep layer shear values increase, with 0-6km bulk shear values potentially hitting near 40kt especially close to thermal boundary. This will provide the support needed to help storm activity organize, and may help produce stronger to marginally severe storms. This morning's SWODY3 outlook places much of the area in a marginal risk (level 1 of 5). The source of uncertainty is how much destabilization will be able to occur Wednesday afternoon and early evening. With a lot of activity expected over the Plains, we may end of with mid and upper-level cloud cover, limiting insolation and the ability for the boundary layer to destabilize. In addition, with deeper moisture transport, model soundings are not showing any kind of EML development, therefore, keeping lapse rates marginal as the forcing move through the area on Wednesday. If stronger updrafts are able to develop, a few severe wind gusts would be the primary threat, along hail around quarter size. In addition to severe concerns, the moist column will also provide support for deep warm cloud processes, and efficient rainfall production. Current PWAT values are progged around 1.75 to 1.80 inches across much of the area, which could present hydro issues especially in developed in areas. Rain shower activity likely continues into Thursday, as more H5 disturbances roll through providing broadscale lift across lower Missouri River Valley. Activity begins to dwindle Thursday evening as the stronger mid- level support then moves into the Great Lakes Region.

For the weekend, the weather pattern still appears to fairly unsettled. Another H5 ridge and strong high attempts to develop over the desert southwest which may force H5 height falls into the Central CONUS, but remains in competition with stronger flow over the Northern Plains and Canadian Prairie Provinces which may try to send forcing further southward into the forecast area. Ensemble guidance is still spread with respect to precipitation potential heading into the weekend, resulting spreading 15 to 20 percent probabilities across nearly the entire weekend. This also maintains uncertainty with the temperatures forecast heading into the weekend, with inner-quartile spread amongst NBM members and other ensembles suites fairly large.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 544 AM CDT Mon Aug 3 2026

Fog has developed in the Missouri River Valley, and in central Missouri from Cooper County northward to the IA-MO state line. Fog is also occurring at STJ in the river valley. The fog will mix out after sunrise. VFR conditions will prevail for the remainder of the afternoon.

EAX WATCHES/WARNINGS/ADVISORIES

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