312
FXUS65 KMSO 260753
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
153 AM MDT Sun May 26 2024

.DISCUSSION...Satellite imagery early this morning shows a weak
circulation moving through southwest Montana. As this system
moves east, high pressure will build in its wake and strengthen
through the remainder of the Memorial Day weekend. Expect
decreasing clouds and fair weather across the Northern Rockies
into Tuesday morning as the ridge amplifies over the northwestern
U.S. As the ridge strengthens, daytime high temperatures will
increase through Tuesday. Model ensembles show daytime highs
exceeding 80 degrees (greater than 90 percent chance) for the
valleys of west-central Montana and the lower valleys in north-
central Idaho.

An increase in moisture will accompany warm temperatures on
Tuesday under southwest flow aloft. A less stable atmosphere,
along with ample shear, will create a good environment for
thunderstorms capable of producing strong outflow winds, brief
heavy rain, and small hail. The geographic focus for convection
will be across Idaho and northern Lemhi Counties in Idaho and
western Montana south of about I-90.

Forecast confidence decreases Wednesday into Thursday next week.
Guidance is struggling with the amplitude and track of the
aforementioned Pacific trough as it moves eastward. Roughly 40% of
solutions suggest the trough will deepen into a closed low, with
widespread precipitation and another round of snow across
southwest MT and the higher elevations in ID, while the other
members portray a weaker trough with higher snow levels and less
precipitation.

&&

.AVIATION...Precipitation will come to an end this morning across
the Northern Rockies airspace. Today, westerly winds will be
increasing by late morning or early afternoon. Expect gusts of
about 20 to 30 knots, especially at KBTM and KMSO, to last until
about 27/0300Z.


&&

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

$$