490
AWUS01 KWNH 012326
FFGMPD
KSZ000-NEZ000-COZ000-WYZ000-020515-

Mesoscale Precipitation Discussion 0296
NWS Weather Prediction Center College Park MD
724 PM EDT Mon Jun 01 2026

Areas affected...Eastern Colorado...Western Kansas...Southeast
Wyoming...Southwest Nebraska Panhandle

Concerning...Heavy rainfall...Flash flooding possible

Valid 012324Z - 020515Z

SUMMARY...Ongoing discrete supercells are expected to undergo
upscale growth into a couple of Mesoscale Convective System (MCS)
clusters this evening. Rainfall rates will increase as storms
consolidate, leading to localized 2 to 4+ inch totals. Isolated
flash flooding is possible.

DISCUSSION...Real-time radar GOES-W IR satellite imagery across
the central High Plains reveals scattered, discrete supercells
ongoing from southeast Wyoming and the Nebraska Panhandle
southward into eastern Colorado and western Kansas. This initial
convection is being driven by low-amplitude shortwave energy
ejecting eastward out of the Rockies, interacting with a
moderately unstable (MLCAPE 1000-2000 J/kg) and highly sheared
environment.

Regional mesoanalysis indicates a south-to-southeast low-level jet
(LLJ) currently ramping up across the Plains. As this LLJ
strengthens to 30-40+ knots through the evening, it will maximize
low-level moisture convergence along a quasi-stationary front
draped across the region. This coupled with the available
instability pool should sustain the convective threat well into
the night with a gradual process of seeing merging/consolidating
supercells grow into a couple of evolving MCS clusters. This MCS
activity will then advance east out into the Plains with portions
of Nebraska and Kansas seeing the impacts deeper into the night.

Some localized backbuilding and cell-training concerns will exist
with the thunderstorms which will be capable of producing 1 to 2
inch/hour rainfall rates given the moistening low-level
environment and available instability. As the upscale MCS growth
takes place, some 2 to 4+ inch rainfall totals may materialize and
this is supported by an overall consensus of the latest hires
model guidance.

While the soils across the High Plains can generally absorb this
initial rainfall, the expected intense hourly rates and some
persistence of it with the cell-mergers and any cell-training may
locally overwhelm the infiltration capacities. Where the heavier
rainfall totals focus, there will be a concern for isolated areas
of flash flooding which will include some urban impact potential.

Orrison

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...BOU...CYS...DDC...GID...GLD...ICT...LBF...PUB...

ATTN...RFC...KRF...TUA...NWC...

LAT...LON   42110415 42090320 41320212 40330081 39599946
            38729824 37559827 37099907 37040017 37240135
            37720238 38280298 38670378 38980430 39500456
            40260456 41140487 41750481