textproduct: Kansas City/Pleasant Hill

KEY MESSAGES

- Strong to severe thunderstorms are expected across the region this afternoon. All severe hazards will be possible, but large hail should be the primary threat soon after storm initiation while damaging winds become more probable as storms organize into clusters or lines. Isolated tornadoes cannot be ruled out, especially if storms can remain discrete.

- Flash flooding and river flooding is possible this evening, as storms will be capable of producing torrential rainfall. Additionally, training storms may develop in southern portions of the forecast area, where local rainfall amounts of 2 to 4 inches may occur. A flood watch is in effect late this afternoon through tonight roughly along and south of I-70.

- Much cooler temperatures are expected on Saturday. Temperatures may fall into the low to mid 30s on Saturday night, with areas of frost possible (up to a 50 percent chance north and east of the Missouri River).

SHORT TERM /THROUGH TONIGHT/

Issued at 237 AM CDT Fri Apr 17 2026

Primary concern in the short term remains the severe-weather potential this afternoon and evening across the forecast area. Objective upper-air analysis from this evening indicates a split-flow trough in the western U.S., with notable vorticity maxima near the Montana/Canada border, the Great Basin, and just west of Baja California. All three should eject eastward today, with the northern-most perturbation acquiring a neutral/negative tilt by tonight. The Great Basin vort max will become sheared and elongated north-to-south as it impinges on downstream ridging in the Midwest. Meanwhile, smaller-scale perturbations will eject northeastward from the Baja shortwave trough, which will likely play a substantial role in areas of favored convective initiation this afternoon.

Cyclogenesis downstream of the U.S./Canada border vort max will induce rapid development of an upper jet streak in the Upper Midwest this evening. An antecedent jet streak in the southern Plains will provide support for a region of enhanced upper divergence in the lower Missouri Valley. Substantial large-scale ascent is implied in this pattern, provided by considerable differential cyclonic vorticity advection from the approaching deep trough and warm advection immediately downstream of a southeastward-surging cold front across the northern/central Plains. Strong frontal forcing combined with the aforementioned large-scale ascent should rapidly destabilize the warm sector and provide sufficient lift for convective initiation by early afternoon. Models have been consistent in storm development near and just in advance of the front in the 18-21z time frame, in which the front should be approaching northwest portions of the CWA. Given the strong/widespread lift in play today, numerous storms should develop in a short amount of time. The thermodynamic and kinematic environments today are certainly favorable for severe storms (MLCAPEs >2500 J/kg; effective bulk wind difference (BWD) 30+ kt). Noteworthy here is the relatively modest 0-6 km BWD (25-35 kt during initial stages of convection, potentially a relative minimum in our region given our lack of proximity to the northern stream and southern stream vorticity maxima). However, thermodynamic profiles suggest particularly deep potentially buoyant layers today, implying that a deeper layer than the standard 0-6 km depth may be more indicative of convective wind shear profiles today. That said, low-level helicity may be rather modest during the initial/discrete phase of convection this afternoon, reducing the threat of tornadoes somewhat. With upscale growth expected to be quick, this suggests that large hail early on and damaging winds later on are the primary severe-weather threats today. Of course, isolated tornadoes remain possible, especially if at least semi-discrete storms can be maintained into the early evening, when low-level shear improves via the synoptically- induced low-level jet.

On the north side of the CWA, storm motions will be fast, with convective-system progression mostly downshear-propagating. However, slower progression is anticipated in the southern CWA, in closer proximity to the low-level jet and on the southern periphery of the southwest-to-northeast oriented midlevel jet streak. Convection allowing models (CAMs) are consistently generating a swath of 2-4+" rainfall in a corridor from southeast Kansas into west-central and central Missouri (roughly near and south of U.S. Highway 50), in a setup favoring training convection via upshear propagation effects. With this area relatively vulnerable to flooding via recent heavy rainfall events and in coordination with WFO SGF, hoisted a flood watch for this potential. Additionally, given the unusually high PWs in advance of the cold front (1.3-1.6+") for this time of year, rainfall rates of 1-2 inches per hour are quite likely with the strongest storms. This approaches 1-3 hour FFG in areas near/south of I-70, especially in urban areas and flashy creek/stream basins. Thus, I included the KC metro and areas near/south of the I-70 corridor in the watch as well, especially given (1) the coarser-scale model tendencies to keep the max- QPF swath slightly farther north (though this is a common bias relative to the CAMs), (2) elevated HREF probabilities of FFG being exceeded in the watch area (20-50+ percent during the evening hours), and (3) some indications from a subset of the CAMs (e.g., NAM Nest; RRFS; GEM) of one or more swaths of heavier rainfall immediately north of the strongest signal near/within our far southern forecast area.

Overnight, convection should gradually slide off to the south and east, with the severe threat predominantly done by midnight and the heaviest rainfalls sagging southeastward with time. Precipitation should largely be out of the area by sunrise on Saturday. Strong cold advection on the upstream side of the cold front should allow temperatures to fall to the 40s by Saturday morning, which will be a sharp change from the upper 50s to 60s we have seen of late.

LONG TERM /SATURDAY THROUGH THURSDAY/

Issued at 237 AM CDT Fri Apr 17 2026

Main forecast concern in the long term is the frost/freeze potential on Saturday night.

Breezy northwest winds and dry conditions should be expected on Saturday in the wake of today's system. Highs will only reach the 50s to low 60s (about 20-25 degrees colder than today). If storms weren't likely today, Saturday would be pretty favorable for some fire-weather concerns, with relative humidity likely falling below 30 percent during the afternoon. However, given the recent rainfall (and more expected today) as well as the recent green-up, not especially concerned about fire weather this weekend.

The bigger concern is the drop in temperatures on Saturday night as a surface ridge moves into the region. Winds should rapidly diminish during the evening, and skies will be mostly clear. Fairly ideal radiational cooling conditions will exist, so temperatures should drop readily into the 30s. Expecting some frost to develop, particularly in river valleys and in rural areas of northern Missouri. Some areas could locally reach the freezing mark on Sunday morning. We will monitor for the potential for any frost/freeze headlines.

Following the relative chill of Saturday and Saturday night, a broad upper ridge will move into the central U.S. late this weekend into early next week. This will lead to a quick warm-up across the area, with a nice multi-day stretch of dry conditions. Models/ensembles are hinting at the next western U.S. trough entering the central U.S. late next week, leading perhaps to another active stretch to end the month of April.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 632 AM CDT Fri Apr 17 2026

Main concern for this TAF period remains the strong to severe storms expected this afternoon and early evening at the terminals. Primarily VFR expected through this afternoon (though a few cloud decks near/below minimum VFR thresholds have traversed the area early this morning), with south winds 15 to 20+ kt with gusts 25-30+ kt. A cold front will approach from the northwest this afternoon, initiating storms between 18z and 21z. Storms will move through the KC terminals between 21z and 00z with noteworthy impacts expected, including torrential downpours and sub-VFR CIGs/VSBYs, strong/erratic wind gusts, and possibly some hail. Storms should move well southeast of the terminals after 00z, with any lingering showers ending shortly thereafter. Winds will become northwest 15 to 20+ kt with gusts to 30 kt. Those winds should gradually diminish by sunrise Saturday.

EAX WATCHES/WARNINGS/ADVISORIES

MO...Flood Watch from 4 PM CDT this afternoon through late tonight for MOZ028>031-037>039-043>046-053-054. KS...Flood Watch from 4 PM CDT this afternoon through late tonight for KSZ057-060-103>105.