National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS65 KMSO 210818
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
218 AM MDT Sun Apr 21 2024

.DISCUSSION...The weather pattern for the next week will be very
Spring like with the weather changing from day to day in an active
pattern. There`ll be some very nice days mixed in with some
cooler, showery, windier days.

Today, an upper level low moves across southern Canada quickly and
compresses the ridge over the region south. This sets up a
stronger pressure gradient and more wind, with the potential for a
Lake Wind advisory for Flathead Lake on Sunday. The trailing
surface cold front with this system will cause some more showers
and a cool down to about 5 degrees below average. There isn`t much
moisture to work with, so the showers are expected to be pretty
light.

Tomorrow through mid-week another ridge builds in with the ridge
axis over central Montana. That sets up southwest flow into
central Idaho and western Montana. That will bring a warmer,
moister air mass to the region with temperatures running 5 to 10
degrees above average through Thursday. Wednesday and Thursday
will also have some shower potential, but with the warmer
temperatures these will mostly be rain showers.

For the end of the week, models disagree with timing of the next
system potentially coming in as early as Thursday afternoon or as
late as Friday morning. So far models are showing this as a much
wetter system than we`ve seen recently. Recently we`ve had some
systems bring isolated heavy showers, but this system looks like a
closed off low that will be wetter over a much broader area. With
the drought across the region, a typical wet system like we
normally would get in the late Spring is a welcome sight in the
models.

&&

.AVIATION...A cold front passing through this morning will cause
some showers, especially over the mountains. The main impact of
the front will be increased westerly winds today with gusts over
30 kts at frontal passage. Frontal passage is expected this
morning and should be through all terminals including KSMN and
KBTM by 21/18Z.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Lake Wind Advisory from 7 AM this morning to 8 PM MDT this
     evening for Flathead/Mission Valleys.

ID...None.
&&

$$