Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Missoula Montana
249 PM MDT Monday Jul 27 2015
Discussion...a very unstable and moist air mass has triggered
numerous showers and isolated thunderstorms across much of
central Idaho into much of western Montana. These are in response
to an upper low pressure system in northern Idaho which will move
through western Montana through the overnight hours. Expect
locally heavy rain and some pea sized hail with storms through the
mid evening hours. Expect mainly stratiform rain along the
Continental Divide the rest of this afternoon.
This low will exit the region by morning. Expect some morning fog
in the valleys and low stratus clouds hugging the mountains late
tonight through mid morning Tuesday.
Clearing skies, a drier air mass and a pretty chilly Tuesday night
may be conducive for patchy frost in some lower valleys such as
the vicinity of Kalispell and Polebridge. Higher elevation valleys
such as Butte and Dixie may also receive patchy frost.
Wednesday through the weekend will be dry with temperatures
warming quite a bit under a high pressure ridge. Expect near
normal temps in the upper 80s Wednesday then a return to lower to
mid 90s Thursday through Sunday.
Aviation...persistent light to moderate rainfall will impact
kbtm through 28/0100 then turn more convective with scattered
showers and isolated thunderstorms through midnight. An unstable
atmosphere will produce scattered thunderstorms through 28/0200z
at kmso, kgpi and ksmn. Showers will gradually diminish through
after sunset and through the overnight hours. Expect patchy fog at
kmso and kgpi from 28/1000z through 28/1500z.