974
FXUS65 KMSO 270739
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
139 AM MDT Mon May 27 2024

.DISCUSSION...A ridge of high pressure will continue to build over
the Northern Rockies today, rounding out the holiday weekend with
dry weather and daytime high temperatures just slightly above
normal. Expect 70s today for the valleys of western Montana, and
80s for the lower Salmon River valley as the ridge axis sits over
western Montana this afternoon.

On Tuesday, the ridge continues to amplify and shift eastward as
a trough of low pressure deepens over the West Coast, putting the
Northern Rockies under moist southwesterly flow. While Tuesday
will be the warmest day of the work week, a lot of factors are
pointing towards good likelihood of afternoon thunderstorms.
North-central Idaho will have the best chances for thunder at
40-50 percent. The Missoula and Bitterroot Valleys and northwest
Montana across Lincoln and western Flathead County will have
about a 30-40 percent chance for thunder. Pacific moisture, along
with good instability and shear, and a dry lower atmosphere, will
fuel storms capable of producing strong, gusty outflow winds,
brief heavy rain, lightning, and small hail in the late afternoon
and evening hours. The chances for storms to become severe (wind
over 58 mph) is about 5 percent.

The low over the west coast arrives in the Northern Rockies on
Wednesday, bringing more widespread stratiform rain to the
region. Impacts under this pattern will be characterized by
temperatures 5-10 degrees below normal, gusty westerly winds
(20-35 mph in valleys), and widespread shower activity.

Model ensemble solutions are leaning towards a return to high
pressure by next weekend, with about 85 percent showing a broad
ridge over the western U.S.



&&

.AVIATION...High pressure today will keep visibility and ceilings
at VFR across the Northern Rockies with light to moderate winds.
The next chance for impactful weather will be on Tuesday as clouds
increase and there will be chances for afternoon thunderstorms
across the Northern Rockies.


&&

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

$$