textproduct: Kansas City/Pleasant Hill

KEY MESSAGES

- Scattered showers and thunderstorms this afternoon, though most areas will stay dry. Localized brief downpours and gusty winds are possible with the strongest storms.

- Heat and humidity continue for the next several days. Temperatures and heat indices elevate through the weekend, with Sunday and Monday expected to be the warmest days.

- Relief from the heat arrives for Wednesday and Thursday, with lesser humidity and highs in the 80s.

DISCUSSION

Issued at 245 AM CDT Sat Jul 18 2026

Current Conditions and Synoptic Overview: Ridging aloft still dominates the upper-air pattern over the central CONUS. 00z upper air analysis indicated a trough pushing across the Great Lakes region along the eastern periphery of the ridge, with mid-level high pressures over the central Gulf Coast and the northern High Plains. An upper-level low and troughing is also pushing into the Pacific Northwest. At the surface, high pressure is building in North Dakota and slowly expanding southward, nudging a frontal boundary south along the southern periphery of the high. Northwest Missouri and northeast Kansas are caught in the middle of the deformation zone of these features, with early morning water vapor satellite imagery showing a corridor of dry mid- level air ahead of the front.

Today: With a similar setup to Friday, similar conditions are expected to yesterday. High temps in the 90s with dew points in the low 70s, partly cloudy skies, and 5-10mph southwesterly winds will allow heat indices to creep up into the upper 90s to low 100s this afternoon. Lows tonight in the low to mid-70s.

Isolated to scattered pop-up showers and thunderstorms will be possible (15-40% chance) again this afternoon in the deformation zone. Convective temperatures of 92-95 degrees will allow for differential heating to produce some isolated, short- lived cells across the forecast area this afternoon. The best and most organized shower and thunderstorm chances will be across northern Missouri after 3PM, as the front sags south to near the Missouri/Iowa state line and acts as a stronger source of lift to initiate convection. Instability will be best just south of the front (2000-3000 J/kg SBCAPE by 00Z), and the better lift will also allow for slightly more longevity of storms that develop, potentially lasting into the evening hours and moving southward with the front into Saturday night.

While the upper-levels will be quite moist, with PWATs remaining near 2" throughout the area, the low-levels will be infiltrated with the layer of prefrontal dry air visible on the early morning water vapor imagery. This corridor of dry air will bisect the forecast area by this afternoon, with moisture pooling along the frontal boundary in northern Missouri as well as converging along the northern periphery of the Gulf high pressure in the far southern portion of the area.

This dry air infiltration could act to suppress free convection some, so while 15-20% chances are widespread this afternoon, the highest 20-40% chances are moreso confined to far north- central Missouri as well as areas south of Highway 50. While the dry air could allow for some dry microburst wind action, it would require a deep updraft and local enhancement of otherwise weak shear profiles to produce damaging winds or enough heavy rainfall to result in even localized flash flooding concerns, so any low-end severe chances would likely remain confined to areas along the front during a brief window of time late this afternoon.

Sunday: Surface high pressure shifts east towards the Great Lakes into Sunday, and the cold front remains focused along the southern periphery of the associated anticyclonic flow. Therefore, the cold front will linger across portions of northern Missouri into Sunday, and act as a focal point for additional showers and thunderstorms on Sunday afternoon. Best chances (20-35%) are generally confined to areas south of Highway 36 and east of Highway 65 where the front is expected to be.

Heat Continues Into Next Week: Southerly flow will continue to advect warm air into the region under the upper ridge into Monday and Tuesday of next week, increasing temperatures into the mid- to upper 90s Monday and Tuesday. NBM temperature spreads are much smaller on Monday compared to Tuesday, indicating a much higher confidence in temperatures Monday than Tuesday. NBM suggests heat indices near or above 105 degrees on Monday with dew points in the mid-70s, but forecast soundings suggest that mixing will reduce afternoon dew points, likely keeping widespread heat indices below 105 degrees.

LREF guidance also indicates high confidence in heat indices just below Heat Advisory criteria for Monday. Probability of >100 degree heat index is 75-90% areawide, while probability of heat index >105 is at most 20-30% and these probabilities are confined to more localized pockets of the area. Would not be surprised to see some localized areas south of I-70, especially low-lying areas, reach a heat index of 105 on Monday, but confidence in widespread heat indices >105 degrees is not high enough to issue an Advisory at this time.

Pattern Change After Tuesday: The upper-level low currently pushing into the Pacific Northwest will start to flatten the northern extent of the upper-level ridging over the western US by Tuesday, with the next synoptic wave looking to push through the Northern Plains into Tuesday. This wave could bring some low precip chances to far north- central Missouri, but more importantly, will also bring a stronger cold front through the area.

While overall confidence in details are low for Tuesday and beyond due to questions about timing of the arrival of cooler, drier air, it does look like a cooler and drier air mass will be in place by Wednesday. Highs will decrease into the 80s for Wednesday and Thursday, with dew points dropping into the 50s and 60s. The breakdown of the ridging over the Northern Plains is likely to result in the return of shortwaves moving through the Midwest by the end of next week, and associated thunderstorm chances with each wave, but overall predictability remains low at this time.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 613 AM CDT Sat Jul 18 2026

VFR conditions expected through the TAF period. Southwesterly winds 5-10 kts this afternoon, with some BKN low-level clouds with bases around 7kft to start the period. These clouds should dissipate by late morning, giving way to a SCT cumulus deck by early afternoon. Some cumulus clouds may become agitated enough this afternoon to develop into scattered showers and storms, but best chances remain east of the TAF sites, so no mention in the TAFs themselves at this time.

EAX WATCHES/WARNINGS/ADVISORIES

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