Monroe Lake, Idaho Weather Forecast Discussion

627
FXUS65 KMSO 060817
AFDMSO
Area Forecast Discussion
National Weather Service Missoula MT
217 AM MDT Sat Sep 6 2025
.DISCUSSION...
KEY MESSAGES:
- Thunderstorms today primarily for north-central Idaho, spreading
  into all of western Montana and north-central Idaho by Sunday
- Pattern change to cooler and wetter weather early next week
A ridge of high pressure will become centered over the Northern
Rockies this morning. Light surface winds will keep degraded air
quality across much of western Montana and north central Idaho
into Sunday morning. The ridge will shift eastward this evening,
putting the Northern Rockies under southwesterly flow aloft. This
pattern will bring increasing moisture and chances for
thunderstorms this evening focused on north-central Idaho. While
storms will likely have some rainfall associated with them, the
bigger threat will be lightning and gusty outflow winds. The one
limiting factor could be the smoke, which may limit low level
heating, suppressing instability and inhibiting convective
activity.
By Sunday, the ridge axis will be east of the Continental Divide.
A fast-moving shortwave embedded in southwesterly flow aloft will
bring chances for rain to north-central Idaho and west-central
Montana on Sunday morning. Thunderstorms will be possible across
all of western Montana and north central Idaho in the afternoon
and evening. Atmospheric moisture will have increased enough that
storms will be capable of locally heavy rainfall in addition to
lightning and gusty outflow winds.
Confidence in a pattern change by Tuesday continues to increase,
with nearly all forecast models bringing a trough of low pressure
into the Pacific Northwest on Monday night. There is still some
discrepancy in how much precipitation will occur, but wetting
rains (0.10" or more) look likely by Thursday with a generally 60
to 90 percent chance. A more significant rainfall event (0.50" or
more) is less likely, but probabilities for those amounts continue
to increase, particularly through north central Idaho and
northwest Montana. This pattern change towards cooler and wetter
weather should also help improve air quality by the middle to end
of next week.
&&
.AVIATION... Smoke from area wildfires will continue to limit
visibility across the Northern Rockies airspace today. The thicker
smoke will be focused over north-central Idaho. Otherwise, expect
generally clear skies today. Showers and thunderstorms will be
possible this afternoon across north-central Idaho and the
southern Bitterroot Valley, possibly impacting KSMN and, less
likely, KHRF. The main threats with storms will be gusty outflow
winds and lightning.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&
$$

NWS MSO Office Area Forecast Discussion