textproduct: Kansas City/Pleasant Hill

KEY MESSAGES

* Strong to severe storms possible (50-70%) late this afternoon and evening, primarily across northern Missouri. All hazards are possible, but the greatest threats are damaging winds and heavy rainfall.

* Warm and windy conditions Sunday before another chance of storms later in the evening/overnight, mainly across northern Missouri again. The primary hazard would be hail.

* Greatest chance for severe weather arrives Monday evening into the overnight hours. All severe hazards will be possible.

DISCUSSION

Issued at 342 PM CDT Sat May 16 2026

Earlier this morning, scattered showers and storms driven by the low- level jet spread across the southern half of the CWA. A residual outflow boundary from overnight convection lifting north caused additional storms to form near the US-36 corridor. These storms persisted for a couple of hours before decaying in tandem with the low-level jet. CAMs were unable to latch onto the morning convection, thus limiting trust in guidance for the remainder of the immediate forecast period and leading to several questions about how the evening will unfold.

In the wake of morning precipitation and storms, clear sky conditions largely took hold along and west of US-63. This, along with southerly surface flow, led to destabilization across the CWA. Mesoanalysis indicates around 1000-1500 J/kg of SBCAPE was ushered into the region between 15Z and 18Z. As of 20Z, SBCAPE across Missouri has increased to 3000-4000 J/kg. ACARS soundings have shown this trend, most recently with SBCAPE ~3000 J/kg and falling CIN. With increased instability, sporadic cumulus development was noted across the region early this afternoon. The latest analysis of surface observations indicate that a stalled boundary continues to roughly bisect Iowa in a northwest/southeast manner. This boundary will be the primary lifting mechanism as we head into the late afternoon and early evening. Importantly, there has been a southward trend in the boundary's trajectory this evening, ultimately increasing the likelihood of convection for the northern portions of Missouri as well as northeast Kansas. Satellite imagery remains indicative of some sort of mesoscale boundary within the US-36 corridor that could allow for convection to light up as a weak shortwave trough propagates eastward and ahead of the larger, synoptic scale boundary currently sitting in Iowa. As such, isolated discrete storms could form as early as late this afternoon. With CAPE >1000 J/kg in the hail growth zone, hail is a reasonable expectation for storms that are able to develop in the late afternoon hours. LCLs are anticipated to sit roughly around 1500ft, and 19Z mesoanalysis suggests the presence of 100-150 m2/s2 0-1km SRH east of I-35 with >150 m2/s2 0-3km SRH surrounding the US-36 corridor in Missouri. The tornado threat is expected to be largely confined to the late afternoon/early evening with any supercellular structures that are able to develop. As the northern boundary sags south later in the evening, rapid upscale growth is anticipated, after which point the primary threat would become damaging winds and excessive rainfall, but a tornado cannot be entirely ruled out due to potential boundary interactions and cell mergers. With several models suggesting PWATs > 1.8", confidence in heavy rainfall between the US-36 corridor and the Missouri-Iowa border is high, leading to WPC upgrading to a slight risk of excessive rainfall through 12Z tomorrow.

Storms are expected to retreat northward with the synoptic boundary after midnight, though the southward portion of a QLCS coming out of western Kansas and Nebraska could lead to brief periods of rain and thunder in our far northern Missouri counties through sunrise. Southerly flow will prevail on Sunday, allowing for another day of temperatures in the mid/upper 80s. Breezy conditions will also be widespread with sustained winds up to 15-20 MPH and gusts up to 35- 40 MPH. Much of the area is outlooked in a marginal risk for strong to severe storms tomorrow evening, though assessment of forecast soundings suggests the cap will be rather difficult to overcome. Upper-level support also looks considerably better further north and west of the CWA. Some broad and weak QG frontogenic forcing overnight could produce or sustain some elevated showers and storms from other portions of the Plains, but CAMs don't seem particularly eager on anything severe tomorrow night.

Looking ahead to Monday, an upper/mid-level trough axis is progged to sit overhead of the Four Corners region. Throughout the course of the day, a mid-level jet is expected to intensify, primarily into Kansas, Nebraska, and Iowa where southwesterly flow around 80 knots is predicted to be present. Closer to home, only about half the magnitude of the mid-level jet is realized. A surface low pressure center near the IA/NE/MN border with an attendant cold front will continue to move eastward, with the cold front pushing into Kansas and Missouri sometime Monday evening. Guidance suggests that a high to extremely unstable airmass will spread across much of the Central Plains. Deep layer shear is anticipated to strengthen to 40-45 kts ahead of the cold front. High CAPE in the HGZ, DCAPE, SRH, PWATs and low LCLs are all indicative of a robust convective environment. Questions remain regarding the timing of the front and whether we will see discrete convection initiate in the open warm sector. However, confidence is high in a line of thunderstorms along the front sometime Monday evening and/or overnight into early Tuesday morning.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1214 PM CDT Sat May 16 2026

Breezy southerly/southeasterly winds are expected at all four terminals for much of the TAF period. Saturday, sustained winds between 10-15 kts with occasional gusts up to 25 kts will persist through sunset. After sunset, winds should lighten with limited gust potential. After sunrise Sunday, however, winds will again pick up out of the south, this time sustained between 15-20 kts with gusts around 30 kts. Scattered thunderstorms are possible between 22Z Saturday and 09Z Sunday across northern Missouri. PROB30 for -TSRA has been included from 00Z through 03Z Sunday for KSTJ given the uncertainty surrounding the southern extent of storm development/coverage.

EAX WATCHES/WARNINGS/ADVISORIES

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