872
AWUS01 KWNH 150019
FFGMPD
MTZ000-WYZ000-150618-

Mesoscale Precipitation Discussion 0722
NWS Weather Prediction Center College Park MD
818 PM EDT Tue Jul 14 2026

Areas affected...in and near Central MT

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

Valid 150018Z - 150618Z

Summary...Showers and thunderstorms are developing across portions
of central and southern MT.  Hourly rain amounts to 2.5" are
possible, which could lead to flash flooding.

Discussion..CIN has begun to reduce across portions of MT as an
upper level trough edges eastward across the Columbia Basin,
aiding difluence aloft.  Precipitable water values are 1-1.3",
which is quite high for this region/elevation.  Effective bulk
shear is 30-50 kts.  ML CAPE is 1000-3000 J/kg.

With the surface wind flow north of the front being opposed to the
mean 850-400 hPa wind, showers and thunderstorms should be very
efficient from a heavy rainfall perspective.  The guidance
increase in precipitable water values, up to 2" in recent RAP
guidance, is due to a combination of upslope flow and thunderstorm
development and expansion.  Neither the 18z HREF/12z REFS are
picking up on activity presently across central MT nor the
activity moving in from northernmost WY, instead keying in an some
showers/thunderstorms trying to form in southwest MT that then
build upscale and move northeast.  Hourly amounts to 2.5" are
possible where mesocyclones form, cells merge, or cells manage to
train.  This could lead to isolated to widely scattered flash
flooding.

Roth

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

ATTN...WFO...BYZ...GGW...MSO...RIW...TFX...

ATTN...RFC...KRF...PTR...NWC...

LAT...LON   49080791 49070670 48730554 46380668 44890764
            44831032 44861162 45061276 46661216 48211106
            49011013