Area Forecast Discussion

KEY MESSAGES

- Showers and thunderstorms likely (30-50%) areawide tonight and tomorrow morning, with highest likelihood (60-75%) across eastern KS/western MO. Primary hazards include heavy rainfall, hail, and severe winds.

- Lingering probabilities (30-50%) for showers/storms tomorrow afternoon and evening; higher potential exists further south and east.

- Temperatures cool into next week.

DISCUSSION

Issued at 344 PM CDT Sat Sep 19 2026

Areawide, temperatures have climbed into the low/mid 90s amidst daytime heating and ample warm/moist transport from the southwest on the back edge of a low-level ridge. Presently, a weak band of showers/storms have begun to pop up along the slowly advancing cold front situated right at the intersection of the IA/NE/MO state lines. This cold front, along with a slowly encroaching shortwave situated over central Kansas, will be the main story for the short term forecast period.

As the cold front continues slowly pushing southeastward, it will encounter an airmass with ample instability (2000-2500 J/kg MUCAPE) and increasing shear (30-35 kts). With ascent along the cold front exacerbated by the oncoming shortwave and its associated vorticity advection/height falls, the potential for thunderstorm development across eastern Kansas and western Missouri this evening continues to look likely (60-75%). Looking to specific hazards with these thunderstorms, the signal continues to trend towards severe wind/hail, with steepening mid-level lapse rates out ahead of the cold front and elevated DCAPE ~1000 J/kg. However, the greater opportunity for larger hail resides further towards the southwest of the forecast area, as storms initiate along the boundary amidst higher CAPE and effective bulk shear. The larger focus for severe threats going into the evening will be towards severe wind as storms congeal and become more elevated/cold pool dominant as they push east/northeast. There continues to be an additional risk for heavy rainfall creating localized hydro concerns, but overnight activity looks to remain progressive enough that even 6 hourly accumulations look to remain below flash flood guidance across the area. However, the environment still remains favorable for efficient rainfall in the strongest storms (PWATs ~2"), and any training thunderstorms could increase hydro concerns with continued rainfall accumulations, especially if the cold front slows/stalls over time.

Speaking of the front potentially slowing/stalling... Recent model guidance has trended towards slowing down the forward progression of the cold front overnight into tomorrow morning, with storms lingering through at least the late morning. Severe potential decreases through the overnight period, but stronger storms could still pose a wind/hail risk with elevated CAPE and continued steepening lapse rates with the front. Potential activity tomorrow afternoon/evening will depend on the location of the cold frontal boundary in relation to further shortwave perturbations in the atmospheric flow, as there looks to be some lingering instability in the atmosphere that could be invigorated with synoptic ascent and organized by sufficient shear. Recent CAM guidance has not been incredibly helpful in agreeing on one particular solution over the other, with scenarios ranging from quiet weather to a complex of thunderstorms pushing through the forecast area by the late afternoon/early evening depending on the placement of the synoptic- scale features. With continued uncertainty in the exact position of these mechanisms, have elected to once again lower and broaden PoPs across the area tomorrow afternoon/evening, with the potential existing for scattered showers/storms but uncertainty remaining higher in exact timing/location.

Any remnant activity from Sunday will gradually phase out by Monday evening as the cold front continues to push towards the southeast out of the forecast area. At the synoptic scale, predominantly northerly flow on the backside of a retreating upper trough will introduce much cooler and drier conditions through the early half of next week, with daytime highs and overnight lows cooling down to the 60s and 50s, respectively. By the later half of next week, ridging looks to build back across the southern half of the CONUS, with guidance progressively indicating warmer and wetter conditions with the intrusion of shortwave perturbations in the upper-level flow off the Rockies.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1244 PM CDT Sat Sep 19 2026

Presently VFR at all terminals. Currently seeing gusts of 20-25 kts starting to spread northward from enhanced daytime mixing, so have included prevailing lines for those gusts to persist through sundown (2-3z) at downtown terminals. Primary concern is TSRA impacting terminals this evening, with FROPA shifting winds out of the north and lowering cloud ceilings. Have a general timing of 1-10z for -SHRA, with narrower timing of 1-5z for TSRA impacts across western terminals. Activity is projected to spread eastward through the overnight, with lower certainty in continued weather generally north of KIXD tomorrow. However, with FROPA fully realized by 10z, guidance has indicated degrading ceilings from north to south. Have included mentions of these lowering cloud ceilings to low MVFR at the end of the forecast period, with high IFR possible.

EAX WATCHES / WARNINGS / ADVISORIES

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