955
FXUS65 KMSO 291933
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
133 PM MDT Tue Jul 29 2025

.DISCUSSION...

KEY MESSAGES:

-  The KMSO Radar (Missoula, MT local weather radar) will remain
   offline due to scheduled maintenance through the first week
   of August.

-  Showers and thunderstorms expected each day through the
   weekend.

-  Flash Flood Watch for this afternoon/evening for slow moving
   storms producing moderate to heavy rainfall across Lemhi county
   into west central Montana.

Cumulus clouds are beginning to pop up on the terrain with scattered
showers and thunderstorms by mid afternoon continuing through
late evening as outflows push development northward. The focus for
storms will be mainly south and east of Missoula with locally
heavy rain a concern as storms will be slow moving. Burn scars and
flood prone areas will be susceptible to runoff issues. Initial
outflow wind gusts of 30-40 mph will also be common. Wednesday
looks quite similar with perhaps slightly less thunderstorm
coverage overall.

Thursday will see an uptick in both thunderstorm coverage and
intensity. A disturbance currently off the Northern CA coast will
approach the region with anomalously high moisture levels and
improved instability. Locally heavy rain with flash flooding
potential on burn scars and flood prone areas is again a concern
during the afternoon and evening hours. Pattern recognition is
backed by machine learning models supporting a threat for a few
strong to severe thunderstorms as well with strong outflow winds
and hail. One potential fly in the ointment is cloud cover during
the morning hours but currently most models allow for abundant
sunshine and sufficient afternoon instability. On Friday, the
focus for stronger storms and locally heavy rain shifts into
Northwest Montana.

There are considerable uncertainties with how the pattern will
evolve Saturday through early next week varying from continued
southwest flow to an upper level trough overhead. Regardless,
common themes are below normal temperatures and an active
shower/thunderstorm pattern.

&&

.AVIATION...Disorganized convection will affect the Northern
Rockies this afternoon with outflow helping to develop convection
from south to north. Thunderstorms outflow gusts of 30-40 mph may
be an initial concern followed by moderate to locally heavy
rainfall. The best chances for showers and thunderstorms will be
in the vicinity of KSMN, KBTM, and KHRF. Activity at other
terminals is low probability but cannot be ruled out. Any shower
or thunderstorm will be capable of briefly (30-45 minutes)
degrading visibility to 4SM. Convective activity will diminish by
late evening. Wednesday looks quite similar with perhaps slightly
less thunderstorm coverage overall.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Flood Watch until 9 PM MDT this evening for Bitterroot/Sapphire
     Mountains...Butte/Blackfoot Region...Lower Clark Fork
     Region...Missoula/Bitterroot Valleys...Potomac/Seeley Lake
     Region.

ID...Flood Watch until 9 PM MDT this evening for Eastern Lemhi
     County...Western Lemhi County.

&&

$$