Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Fri Aug 22 2025 21:56:17

AWUS01 KWNH 222156
FFGMPD
COZ000-230355-

Mesoscale Precipitation Discussion 0977
NWS Weather Prediction Center College Park MD
555 PM EDT Fri Aug 22 2025

Areas affected...Eastern CO

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

Valid 222155Z - 230355Z

SUMMARY...Showers and thunderstorms should gradually expand in
coverage this evening. Some cell-merger and cell-training concerns
may cause some isolated areas of flash flooding.

DISCUSSION...The latest GOES-E IR satellite imagery shows cooling
convective tops near the Front Range and Palmer Divide which are
expected to gradually grow upscale a bit this evening with some
gradual consolidation into some loosely organized MCS activity
over eastern CO this evening. The convection is forming in close
proximity to a stationary front with the additional aid of
orographic ascent/forcing within a moderately unstable environment.

Much of the instability pool is along and just north of the front
in this case with MLCAPE values across north-central to northeast
CO as high as 1500 J/kg. This is mainly due to the fact that
surface dew points (locally 55 to 60+) just north of the front are
quite a bit higher than they are to the south out ahead of it.
Weak shortwave energy rounding the top of a mid-level ridge near
the Four Corners region will eject down across eastern CO this
evening and interact with this instability axis and the
aforementioned frontal zone to support the upscale growth of
convection.

A consensus of the latest 12Z HREF/REFS guidance suggests some
spotty areas of 2 to 4 inch rainfall totals will be possible where
some localized cell-merger and cell-training activity occurs. Both
the HREF and REFS depict some low to moderate probabilities
(generally 30 to 50 percent) of seeing the 3-hour FFG values
exceeded this evening as this shower and thunderstorm activity
continues to grow in coverage and intensity. As a result, some
isolated areas of flash flooding will be possible.

Orrison

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!681kSBXyaO26XX5rMnmZmakGChP-LhLm_c90fIFh-sXfDp-iV-DoBI83gR2vw9ltl-a2=
6C4esbBRDCgavWH6nVFlFtU$  for graphic product...

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

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

LAT...LON   40310271 39540211 38850248 38240349 37880472=20
            38070552 38580579 39360560 40030443=20

=3D =3D =3D
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