869
AWUS01 KWNH 301604
FFGMPD
COZ000-WYZ000-UTZ000-302000-

Mesoscale Precipitation Discussion 1150
NWS Weather Prediction Center College Park MD
1203 PM EDT Sun Aug 30 2026

Areas affected...Northern Utah, Northwestern Colorado, & Southern
Wyoming

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

Valid 301603Z - 302000Z

SUMMARY...Training thunderstorms over Utah may cause localized
areas of flash flooding into early this afternoon.

DISCUSSION... A strong upper level shortwave trough centered
across Montana will provide the forcing needed to allow already
ongoing showers and storms across northwestern Colorado to break
the cap. Inflow into the right entrance region of a weak jet
streak will also provide additional lift into this afternoon.
Moisture values are over 1 inch across eastern Utah, which is 2
sigma above normal. Despite the abundant cloud cover, instability
is building, mostly over Utah, with values over 1,000 J/kg in some
areas. While instability hasn`t yet built across Colorado, RAP
forecasts for the next few hours suggest instability will build to
over 1,500 J/kg into parts of northwestern Colorado over the next
few hours. Time will tell if the cloud cover present over that
area will allow this.

HRRR and a few other HiRes guidances suggest more widely scattered
storms form across this region over the next few hours, most
likely towards 20Z. Considering some of these areas have seen rain
for much of the morning, as well as much of this area seeing rain
over the past couple days, it appears probable that additional
flash flooding will occur from these storms into the early
afternoon.

This area will continue to be evaluated with a likely update for
this area this afternoon, depending on how well instability builds
and how plentiful storm coverage is near the end of this
discussion period.

Wegman

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

ATTN...WFO...BOU...CYS...GJT...RIW...SLC...

ATTN...RFC...KRF...STR...NWC...

LAT...LON   41620755 41400624 40680583 39870589 39590633
            39250757 38850903 38731042 38521184 38271249
            38211264 38081311 38921304 40171200 41201069
            41530933