Mesoscale Precipitation Discussion 1234
NWS Weather Prediction Center College Park MD
1057 PM EDT Wed Sep 09 2026

Areas affected...in and near portions of southeast CO & southwest
KS

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

Valid 100256Z - 100856Z

Summary...Showers and thunderstorms are slowly developing across
the area.  Hourly rain amounts to 2" with local totals to 4" could
lead to isolated to widely scattered instances of flash flooding.

Discussion...A substantial shortwave in the Westerlies is moving
through western WY & northwest CO at the present time, enhancing
upper level divergence in the Central High Plains.  Meanwhile,
low-level upslope flow has brought precipitable water values up to
1.5-2", which is quite high for the High Plains.  MU CAPE is ~2000
J/kg.  Effective bulk shear is 25-35 kts.  The mean 850-400 hPa
wind is out of the west at 5-10 kt, nearly antiparallel to the
current east-northeast surface flow.  Thus far, the thunderstorms
that have been occasionally reorganizing and showing minimal
movement just north of a thermal boundary and east of a surface
wave, likely due to the conflicting winds with height.

The expectation is for cells to continue growing in coverage and
track eastward as the 700 hPa winds veer and the upper level
shortwave progresses.  The mass of thunderstorms may drift
somewhat northward as the 700 hPa flow takes on more of a
southerly component.  Given the parameters in place, hourly rain
amounts to 2" with local totals to 4" are possible where cells
backbuild, train, or merge. Given the modest flash flood guidance
values, isolated to widely scattered flash flooding is possible.

Roth

ATTN...WFO...AMA...BOU...DDC...GLD...OUN...PUB...

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

LAT...LON   38640235 38190015 36849988 37170251 37160400
            38330462