textproduct: Kansas City/Pleasant Hill

KEY MESSAGES

- Heat will build into the region through early next week. Widespread highs in the 90s with heat indices in the 100s are expected Sunday through at least Tuesday. An extreme heat watch is in effect for areas south of U.S. Highway 50 for Sunday through Wednesday because of the extended nature of the heat.

- There are slight chances for storms (generally less than 30 percent) this evening and tonight. An isolated severe storm is not out of the question, with damaging winds the main threat.

- The pattern will change late next week, with cooler weather moving back into the area and frequent chances for storms.

SHORT TERM /THROUGH MONDAY NIGHT/

Issued at 221 AM CDT Sat Aug 8 2026

The forecast remains rather challenging during the short term, with building heat the primary concern. However, there are subtle chances for storms through Sunday morning, and questions remain regarding any potential impacts on temperatures/heat on Sunday.

The western U.S. ridge has amplified somewhat during the past couple of days, with northwest flow downstream in the northern Plains. This pattern will deamplify somewhat this weekend as the ridge axis drifts eastward slightly. After a couple of perturbations move through the northern/central U.S. today and tonight, the slowly approaching ridge will lead to warming temperatures Sunday and Monday. Forecast heat indices, in the absence of convective interference (see below), will approach/exceed heat advisory criteria Sunday and Monday (105+ degrees) in much of the forecast area. With the semi-persistent ridging in the western U.S. through the next week, this heat should continue for a lengthy period (through Tuesday in most of the area and Wednesday for areas south of I-70/U.S. 50). With confidence reasonably high that heat indices will meet/exceed advisory criteria for several days in these areas, have hoisted an extreme heat watch for the Sunday through Wednesday time period. For the KC metro, northeast Kansas, and northern Missouri, confidence is a little lower on the front end and the back end of the heat event. Initially, storm chances through Sunday morning may keep temperatures slightly at bay on Sunday, especially in north-central and northeast Missouri. Meanwhile, for Wednesday, a cold front will approach/move into the region from the north, likely bringing cooler temperatures and increased chances for storms. Thus, these areas will likely require heat advisories some time during the Sunday through Tuesday time window, but the duration of heat will not sufficiently meet extreme heat warning criteria.

Subtle perturbations in the northwest flow in the northern U.S. are expected to initiate storms/convective systems at times through the weekend. Unfortunately, CAMs have continued to exhibit poor run-to-run continuity and model-to-model agreement on convective scenarios/evolutions. These discrepancies appear right away, with the HRRR/RRFS/NAM Nest waxing and waning on a forecast convective system moving southeastward from South Dakota and Nebraska today. Some simulations keep such a system fairly vigorous right through the evening hours as it would move into the CWA. Others dissipate the convective system during the day, well before reaching the CWA, or develop no such convective system at all. Thus, the forecast is quite uncertain today. Currently, PoPs are below mentionable levels through early evening for the area. However, do have some slight-chance PoPs tonight in northern Missouri, when CAMs have a more consistent tendency to initiate storms as a perturbation moves through the central Plains and the nocturnal low-level jet strengthens. Even then, stronger ascent/forcing will be north of the forecast area, so storms tonight are much more probable in Iowa than northern Missouri.

The pattern may repeat itself Sunday afternoon through Monday, with storms mostly confined to the faster northwest flow to the north of the area. Ridging will also be stronger in the region on Sunday and Monday, so storm chances seem even lower than on Saturday. The highest chances are in far north and east parts of the region during the nighttime hours, when forcing for ascent attendant to shortwave troughs glances the region, aided by the nocturnally enhanced boundary-layer wind maximum.

LONG TERM /TUESDAY THROUGH FRIDAY/

Issued at 221 AM CDT Sat Aug 8 2026

As the new week progresses, the repeated passage of northwest- flow perturbations to the north of the forecast area will eventually re-amplify the western-ridge/eastern-trough pattern. Stronger vorticity maxima will dig southeastward Tuesday night and Wednesday night through the central U.S. Eventually, these shortwave troughs will enable a synoptic cold front to sag southward into the forecast area. This will lead to a stout cooling trend for the middle and latter portions of next week. Additionally, the faster upper-level flow will sink southward into the central Plains, leading to round after round of vorticity maxima passing over the region. As a result, storm chances will greatly increase Wednesday through at least Friday across the CWA.

This pattern change is favorable for a swath of heavy rainfall. Coarser physical/AI models show such swaths of heavier QPF (2-4+ inches) in a northwest-to-southeast swath near the storm track that sets up. Of course, given the extended time range, these swaths have considerable spatial variability given the lower predictability. However, the general area of these swaths is somewhere between central Iowa (ECMWF) to central Missouri (AIGFS/CMC) or areas in between (GFS/EC-AIFS). The key here is that this will be a period to watch for flooding potential, and portions of our forecast area may be at heightened risk later next week.

Of course, another question mark will be how quickly the heat of the early week period dwindles with time. Uncertainty increases considerably Wednesday and Thursday, with models tending to be a little too conservative with the southward push of cooler air. This will be largely dependent on the extent and evolution of several convective systems in the early-to-mid week period. As a result, substantial temperature and PoP forecast adjustments may be required for the mid-week period.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 646 AM CDT Sat Aug 8 2026

A somewhat uncertain TAF period ahead, as models are continuing to struggle with development and evolution of storms upstream in the northern/central Plains this morning. Current expectations are that storms in Nebraska this morning will weaken as they approach the area late this afternoon and evening. However, there is at least a slight chance (10-20 percent) that storms remain and potentially even intensify late this afternoon in vicinity of northern Missouri. However, this potential still seems rather low at this time...too low for mention in the TAFs. As a result, VFR with light/variable winds becoming southeast around 10 kt this afternoon is expected. Assuming storms do not occur this afternoon/evening, VFR should continue through tonight, with potential for some southwesterly LLWS as a strong low-level jet develops. Winds will become southerly around 10 to 15 kt overnight.

EAX WATCHES/WARNINGS/ADVISORIES

MO...Extreme Heat Watch from Sunday afternoon through Wednesday evening for MOZ039-040-043>046-053-054. KS...Extreme Heat Watch from Sunday afternoon through Wednesday evening for KSZ057-060.