637
FXUS65 KMSO 181007
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
407 AM MDT Mon Aug 18 2025

.DISCUSSION...


KEY MESSAGES:

-  More thunderstorms capable of gusty outflow winds and brief
   heavy rain with the weather pattern today

-  Above average temperatures through mid week.

-  Weak disturbance on Thursday following by ridge for the
   weekend.

The Northern Rockies continue to be under a very active
southwesterly flow today. Showers and thunderstorms are starting
to move into Idaho county early this morning. These storms will
steadily traverse into west central Montana during the morning
hours. A secondary pulse of showers are just starting to develop
over eastern Washington, these showers will move into northwest
Montana by mid to late morning. Then this afternoon thunderstorms
will once again develop across Lemhi county into southwest
Montana. Stronger storms this afternoon will be capable of gusty
erratic winds up to 40 mph along with heavy rain.

The ridge strengthens over the Northern Rockies on Tuesday which
will allow for warming and drying. The convection development will
be fairly limited, but temperatures will be warming to around 10
degrees above average during by Tuesday afternoon.

A weak disturbance, dry cold front, is still on track to push
across the Northern Rockies Wednesday into Thursday. This front
will bring very little in the way of storms, but gusty westerly
winds are expected by Wednesday afternoon. Temperatures cool to
more seasonal readings by Thursday.

All the models are depicting a ridge of high pressure developing
over the western United States by this weekend. This ridge will
bring warm and dry conditions to the Northern Rockies.


&&

.AVIATION...Multiple pulses of storms are expected to move through
the Northern Rockies for the next 18 hours. The first batch of
convection is currently over central Idaho and will traverse Idaho
county into west central Montana. These storms are anticipated to
be in the vicinity of KSMN, KHRF and KMSO during the morning
hours. A second pulse of showers are starting to develop over
eastern Washington and will move into extreme northwest Montana by
mid morning, but should miss KGPI. Then this afternoon, another
round of convection will develop across Lemhi county into
southwest Montana potentially impacting KSMN, KHRF and KBTM.
Stronger storms will be capable of wind gusts up to 40kts and
heavy rain.


&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&

$$