textproduct: Kansas City/Pleasant Hill

KEY MESSAGES

- Heavy rainfall leading to flooding is the primary concern with multiple rounds of showers and storms expected this week. Flood risk appears to be greatest north of the Missouri River.

- Slight Risk (Level 2 of 5) for severe weather for extreme northwestern portions of Missouri on Monday evening. There is a brief window where all hazards may be possible, but this is low probability. Showers/storms to increase in coverage over time with a diminishing severe risk overnight.

- Marginal Risk (Level 1 of 5) for severe weather for much of the forecast area on Tuesday. Damaging wind gusts are the main concern.

DISCUSSION

Issued at 251 PM CDT Sun Sep 13 2026

Weak, quasi-zonal flow continues today with the surface boundary having slid to the south of the forecast area. Overnight showers and storms had mostly waned by sunrise, though some renewed development was observed in eastern Kansas earlier this morning. A cursory mesoanalysis investigation yielded the discovery of small area of low- level frontogenesis that helped promote this resurgence on the edge of a weakening low-level jet. Showers and storms continued to work their way into our southeastern Kansas counties this afternoon. With cloud tops warming substantially over the course of the day, only a couple of light showers remain with most remaining dry.

As we proceed into the late evening and overnight period, our rain chances will increase once again as the low-level jet ramps up over the Plains and kicks off elevated showers and storms. PWATs are forecast to rise to around 1.8" with the moisture surge. With elevated instability and shear, there may be a brief period overnight where we could see some small hail and gustier winds, but even these more organized storms should remain sub-severe. The main concern would be heavy rainfall, particularly within a corridor south of US-36 and between I-35 and US-65. It is just to the northwest of this corridor where development is expected to occur on the nose of the intensifying low-level jet roughly around midnight. Northwesterly steering flow will guide storms to the southeast along a strong 310K isentropic gradient as the night progresses, further fueling efficient warm rain processes. WPC has highlighted the northwestern and western portions of the forecast area in a Slight Risk (Level 2 of 4) of excessive rainfall for reasons such as these.

Warmer conditions are expected on Monday as a warm front approaches from the southwest. The question of how warm it will be depends heavily on the speed of the boundary with cloud cover clearing in its wake. Currently, maximum temperatures in our far south are forecast to top out in the mid 90s, but this is assuming we clear out rapidly after sunrise. Dewpoints in the low/mid 70s will keep heat index values mostly in the upper 90s but some locations that are able to heat up quickly may be able to approach 105. The warm front is not expected to make it through northeast Missouri by sunset, so temperatures may only top out in the low/mid 80s in those areas.

Behind the warm front and ahead of an approaching cold front, isolated storms may be possible across northwestern Missouri late Monday afternoon and evening. By this time, moderate instability will have built in across the region with around 35-40 kts of deep- layer shear. There is a non-zero chance of some sort of discrete development in the warm sector, but this potential seems to be highest further north in eastern Nebraska and southern Iowa. Currently, it seems the more likely scenario for far northwest Missouri is that it gets clipped by upscale growth along the cold front later Monday night. SPC has highlighted a sliver of northwest Missouri in a Slight Risk (Level 2 of 5) for severe weather tomorrow night for which all hazards could be possible. The severe threat would likely peak between 6 PM and 9 PM before gradually lessening through the overnight period.

The cold front will continue moving to the southeast over the course of the day on Tuesday, bringing widespread rain and storm chances to the region (best chances remain north of I-70 but still have 40-50% PoPs further south). Much of the forecast area is encompassed in an SPC Marginal Risk (Level 1 of 5) that day, but the greatest threat remains the heavy rainfall with PWATs in excess of 2.0" and very strong isentropic ascent parallel to the boundary and on the nose of the low-level jet. Except for a few of our southeast counties, WPC has enshrouded the area in another Slight Risk (Level 2 of 4) of excessive rainfall on Tuesday. By Wednesday morning, the cold front will have effectively stalled out along our southern CWA border, only to ever so slightly drift back northward over the course of the day. Though the setup is not quite as concerning from a rainfall production standpoint, any additional rain on top of what had fallen on Tuesday could exacerbate any existing flooding and flash flooding concerns. That is, by Wednesday, it doesn't appear that it will take much cause flooding problems, and for this, WPC has included areas generally north of I-70 in yet another Slight Risk (Level 2 of 4) for excessive rainfall. Additional rainfall is possible Thursday and beyond but these forecasts are lower confidence at this stage. Regardless, between now and Friday night, we could see a large swath of 3"+ total rain accumulations across northwestern Missouri and northeastern Kansas, with isolated spots potentially exceeding 5". Along and south of I-70, the cumulative rainfall accumulation forecast is lower, ranging from 0.5" in our far southern tier of counties up to around 2-2.5" in the vicinity of I-70. It is very likely that a Flood Watch will be necessary for at least part of the forecast area by this time tomorrow.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 133 PM CDT Sun Sep 13 2026

VFR conditions and easterly winds sustained near 10KT will prevail through the TAF period, but scattered thunderstorms move into the forecast area between 07-09z. Have maintained PROB30 for thunderstorms at all terminals between 08-12z, as this is when confidence is highest in the coverage of storms. Coverage of thunderstorms will decrease by 13z, and winds shift to southerly and increase to around 15KT gusting to 25KT near the end of the forecast period.

EAX WATCHES/WARNINGS/ADVISORIES

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