textproduct: Kansas City/Pleasant Hill

KEY MESSAGES

* Significant threat for severe weather across NW Missouri this evening with destructive hail, damaging winds and tornadoes. This threat will transition to a damaging winds and QLCS tornadoes as scattered storms develop into a line and build southeast.

* Substantial flood threat tonight across the region with rainfall rates expected to exceed 2"/hr. Flood watch in effect tonight into Tuesday morning. Additional rainfall amounts of 1.5-3+" with pockets exceeding 5".

* Cooler and drier conditions develop on Tuesday and continue into Wednesday.

* Rainfall chances return to the region Thursday through the end of the weeekend.

DISCUSSION

Issued at 253 PM CDT Mon May 18 2026

Mature trailing stratiform MCS worked through the area overnight leading to a widespread 1-2 inches of rain across the region. Saw MCS backbuild across central Missouri through the late morning, keeping temperatures quite cool through mid-day. Have seen signs of gravity waves emanating from the tail end of the the MCS, spreading to the north-northwest.

Have started to see some partial-rapid clearing across eastern KS into western Missouri leading to nice warming- roughly west of I-35. Pseudo warm front/outflow boundary is poised just south of the forecast area across central Missouri. This boundary may try to lift north through the late afternoon hours. If that occurs, could see an isolated storms develop south of a line from Butler through Clinton leading to large hail/gusty winds. Expect surface temperatures to continue to warm through the afternoon hours into the upper 70s to 80s, leading to rapidly increasing instability. By late this afternoon, expect moderate to extreme instability with SB CAPE values of 4000-5000 J/kg roughly along and west of the I-35 corridor. Surface low pressure centered near Salina KS is expected to lift northeast this afternoon to southwest Iowa into the evening. Discreet supercells have already begun developing across central into northern KS, building east in time in what is a very volatile environment. 0-6 km shear is in the 40-50 knot range across eastern KS should easily support supercells, with the potential for very large hail and tornadoes. Expect supercells to remain discreet building into Northwest Missouri in the early evening hours, capable of producing very large hail, damaging winds and the potential for strong tornadoes. As the severe weather event evolves, expect the supercells to evolve into a squalline and build southeast in time. Expect severe threat to transition towards damaging winds, but could still see QLCS tornadoes with embedded supercells along the line.

Training storms, along with precipitable water values of nearly two inches and deep warm cloud depths will lead to efficient rainfall. CAMs have been fairly consistent with another 1.5-3+" of rainfall across the region tonight, with pockets of 5+". HREF and REFs probabilities for 2"/hr rainfall rates are approaching 50%. Flash flood guidance across the area is low with the recent rains, generally running from 1-2.5"/6 hour period. Collaborated with WPC and surrounding offices to raise excessive rainfall outlook to moderate across most of the area. Cams suggest storms may linger Tuesday morning as the surface boundary moves slowly through the area. Have extended the flood watch through 18Z south of the Missouri River.

Much cooler conditions are expected midweek behind the front with high in the 60s and lows in the 40s. A developing trough late week across the Northern Plains could bring additional instability showers and storms to the region as early as Thursday.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1210 PM CDT Mon May 18 2026

Scattered showers and thunderstorms have nearly cleared our forecast area moving into central MO. SSE winds will increase with gusts up to 30 knots by early afternoon, continuing through early evening hours. A line of severe thunderstorms will impact STJ between roughly 00z and 03z tonight, moving through the KC metro terminals likely between 02z and 05z tonight. Severe wind gusts will be possible along the leading edge of the severe thunderstorm line, with periods of moderate to heavy rain reducing VIS significantly. Stratiform rain with isolated lightning strikes will linger behind the main convective line into early tomorrow morning. There is a potential (30-50%) terminals will see reduced VIS around 4SM and BR between 10z and 14z.

EAX WATCHES/WARNINGS/ADVISORIES

MO...Flood Watch through Tuesday afternoon for MOZ020>022-028>033- 037>040-043>046-053-054. Flood Watch through Tuesday morning for MOZ001>007-011>016-023- 024. KS...Flood Watch through Tuesday afternoon for KSZ025-057-060- 102>105.