Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 282008
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
208 PM MDT Thu Mar 28 2024

.DISCUSSION...Unstable conditions behind the passage of our most
recent cold front has lead to convective showers, with the
occasional clap of thunder mixed in where conditions are most
unstable (north central ID). Showers will be prevalent across
much of western Montana and north central Idaho today into Friday,
with snow expected above 4000 feet. Below 4000 feet, graupel
(soft, small, hail- shaped pellets) showers will occur and may mix
with rain or snow through Friday. Light snow accumulations of an
inch or two will be possible over most area mountain pass highways
tonight through Friday morning.

The large scale weather pattern will involve a low pressure
system off the PacNW coast digging southward towards the
California coast as it moves inland. With this southerly
trajectory of the low, the bulk of the precipitation associated
with it will also move southward, but that will not relieve the
Northern Rockies region of all shower potential. Both Saturday and
Sunday show between a 40% and 65% probability of elevations above
4500 feet receiving measurable precipitation (in the form of
snow), while lower elevations show a much lower probability
(<25%). With this in mind, there are still some forecast models in
agreement that the low to our south will actually move into the
Yellowstone region Sunday into Monday. Should this scenario pan
out, locations across southwest Montana and central Idaho, such as
Lemhi County, would experience snowy conditions. Forecast
confidence remains low at this time, but we’ll continue to monitor
if the probability increases in the coming days.

There is higher forecast confidence in a ridge of high pressure
building to the west, which will make its way into Idaho and
western Montana by Monday and last through Tuesday. Temperatures
during this time frame will rise into the upper 50s to upper 60s,
with the exception being the Camas Prairie in Idaho, where daytime
high temperatures will exceed 70 degrees. This will be our driest
period during the next week, as a troughing pattern returns mid-
week, with cooler temperatures and wetter conditions also
returning.


&&

.AVIATION...Snow lingering in the KBTM area and nearby regions has
been slow to dissipate. Recent radar trends indicate a shift from
persistent snow causing reduced visibility to scattered showers
with intermittent visibility reductions. These showers are
increasing in coverage, with reports of a thunderstorm occurring
in north-central Idaho. Radar projections suggest the possibility
of isolated thunderstorms, valley rain, and mountain snow
persisting into the evening, followed by a decrease in shower
coverage overnight. Expect another round of showers on Friday
afternoon. Forecast soundings indicate sufficient instability for
isolated thunderstorms to develop.


&&

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

$$


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