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000
FXUS65 KMSO 121935
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
135 PM MDT Fri Apr 12 2024

.DISCUSSION...The Northern Rockies will be transitioning to zonal
(westerly) flow this week as a large low pressure system digs
southward along the Pacific coast and moves inland over
California. This large system will send some moisture and pulse of
weak energy into the Northern Rockies the next couple of days.
The first disturbance is expected tonight across north central
Idaho into west central Montana causing scattered rain showers and
maybe even a few lightning strikes. Instability on Saturday
afternoon should allow for a few storms to develop across Lemhi
county into southwest Montana. The models are depicting another
pulse of energy for Sunday which will increase the coverage and
intensity of storms during the afternoon and evening hours.

A low pressure system will begin to move southward into British
Columbia on Monday. The surface pressure gradient will tighten
over the Northern Rockies, especially northwest Montana, during
the day on Monday creating gusty westerly winds. The winds will be
strong enough to create choppy conditions on area lakes,
particularly Flathead lake.

The models are still diverging on how that low pressure system
will be moving through the Northern Rockies Tuesday into
Wednesday. Around 51% of the models indicate that the low will
pass southward through Northern Rockies, bringing colder and
snowier conditions to the region. While the remainder of the
models have the system sliding along the Canadian border then
dropping southward into eastern Montana and the Dakotas. This
solutions will bring cooler conditions, but snow will be fairly
limited.

The majority of the models, ~60%, are showing a ridge of high
pressure building back over the western United States by the end
of the week into the weekend causing a warming and drying trend of
the Northern Rockies.


&&

.AVIATION...A few weak pulses of energy will be moving through the
Northern Rockies tonight causing clusters of showers and
thunderstorms. The first pulse appears to move into Clearwater and
Idaho counties this evening then track across western Montana,
impacting KMSO. A slightly weaker clusters of storms will develop
over Lemhi county and the southern Bitterroot this evening
potentially causing convection near KHRF and KSMN then move
towards KBTM. KGPI does not appear to be impacted by any storms
during the overnight hours. The convection will be moving off to
the east during the early morning hours decreasing the potential
of convection at the terminals.


&&

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

$$