005
AWUS01 KWNH 210214
FFGMPD
KSZ000-COZ000-210800-

Mesoscale Precipitation Discussion 1345
NWS Weather Prediction Center College Park MD
1013 PM EDT Sun Sep 20 2026

Areas affected...eastern CO into western KS

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

Valid 210213Z - 210800Z

SUMMARY...Increasing thunderstorm coverage across eastern CO into
western KS may result in a couple of areas of flash flooding over
the next 4-6 hours. Areas of short term training are expected to
result in hourly rainfall totals of 1-2 inches.

DISCUSSION...Through 02Z, infrared satellite and area radar
imagery showed the early stages of increasing
showers/thunderstorms over portions of eastern CO, located within
a low level easterly wind regime, to the south of a closed
mid-level low over the WY/SD/NE border. A reinforcing surface
boundary (effective cold front) had been analyzed via KPUX radar
imagery and surface observations to be slowly sinking south from
near PUB to LAA, with a notable surge in low level ENE winds noted
on the KPUX VAD wind display, along with increasing surface
dewpoints across the Front Range. The increase in low level
moisture has resulted in a 3-hour increase in MLCAPE of 200 to
600+ J/kg, centered about 30-40 miles east of Pueblo according to
the 02Z SPC mesoanalysis. 02Z SPC mesoanalysis data also showed
MLCAPE values of 500 to 1500+ J/kg over eastern CO (highest over
southeastern CO).

Subtle mid-level height falls, easterly upslope flow and
sufficient instability/shear profiles are expected to allow for
thunderstorms to increase over eastern CO over the next 1-3 hours
with movement of cells off toward the east and southeast. While
the details vary from run to run, this setup has been consistently
advertised by recent HRRR/RRFS cycles going back several hours.
The potential for enhanced rainfall efficiency with mesocyclones
and multiple cells/mergers/brief training should allow for hourly
rainfall to reach 1 to 2 inches. Storm total rainfall of 1 to 2
inches (isolated amounts up to 3 inches) through 08Z may result in
a couple of areas of flash flooding, although the coverage of any
flash flooding is expected to remain fairly localized.

Otto

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

ATTN...WFO...BOU...DDC...GLD...PUB...

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

LAT...LON   39940455 39880375 39470172 38610080 37970084
            37600107 37310159 37200248 37320322 37500390
            37860451 38680505 39630504