Winter Storm Warning 5, NWS Pocatello, ID

Area Forecast Discussion
National Weather Service Pocatello ID
151 PM MDT Sun Apr 10 2022

.SHORT TERM...Today and Monday. Looking at satellite imagery,
there is an upper level low just off the southern British Columbia
coast. Models continue to show moisture and a cold front from this
upper level low moving through us tonight into tomorrow. There is
breezy to moderate winds ahead of this system today. Expect winds
of 15 to 25 mph with gusts of around 35 mph especially for the
Snake Plain and ridgetops. We have a lake wind advisory in effect
today for the American Falls reservoir. Expect moisture from a
warm front to move through the area this evening, mainly impacting
the central mountains with 1 to 3 inches of snow. Southerly flow
ahead of this system will bring moderate to heavy snow amounts to
the Central mountains especially for the Pioneers and the Sun
Valley Region. Expect 5 to 10 inches with locally higher amounts
favoring southerly upslope areas starting Monday in the morning,
a winter weather advisory and winter storm warnings are in place.
The cold front starts moving through in early to mid afternoon for
our western areas. The challenge will be snow levels in southerly
flow. Expect 5000 to 5500 (possibly higher) feet snow levels.
However, this frontal boundary is convective and along the front,
any rain will quickly turn to snow. Some areas like the Shoshone,
Richfield, and Carey zone we have low confidence in snow amounts.
The southern part of this zone could see 1 inch of snow with the
northern part of the zone having the potential to have 5 to 7
inches. It depends on snow levels and how quickly rain turns to
snow. This will be true especially for the Eastern Magic Valley
and the Snake Plain. The front will come through around 3 to 5 pm
for the Eastern Magic Valley and 5 to 7 pm for the Lower Snake
Plain and 7 to 9 pm for the Upper Snake Plain. Expect 1/2 to 2
inches for the Eastern Magic Valley and Lower Snake Plain and 1 to
3 inches of the Upper Snake Plain. For our Eastern areas, snow
starts around noon with heavier amounts in the evening. Look for 4
to 10 inches with locally higher amounts, especially for higher
elevations. Again winter weather advisories are in place. Went
with a winter storm warning for the Wasatch mountains. Left out
the Teton Valley from the winter weather advisory 2 to 3 inches of
snow is expected. Higher amounts may be possible for the Teton
Valley especially near the Wyoming line. Also left out the Raft
River and Oneida regions out of this advisory, however 1 to 3
inches of snow is possible with up to around 4 to 5 in the
mountains. Winds will be around 20 to 30 mph with gusts near 40
mph. With frontal passage there will likely be gust of 50 to 60
mph. This frontal boundary will be convective bringing the
possibility of thunderstorms. However, there is a greater chance
of a snow squall along the frontal boundary with strong winds and
extremely low visibility from blowing snow. For much of the area
this will happen late afternoon into early evening during evening
commute. Cold front goes through our eastern Wyoming border mostly
by midnight.
Wyatt

.LONG TERM...Tuesday through Sunday. The long term periods continue
under a broad upper trough interrupted on Wednesday night/early
Thursday by a transitory ridge. Operational models start Tuesday off
with a closed low over central Idaho. A couple of shortwaves
embedded in the low will rotate through the region. Models are
depicting a surface trough oriented from the Caribou Range to the
Stanley Basin along which we're seeing some enhanced QPF, though it
seems the snow amounts are less than the previous forecast. We'll be
seeing some instability along the Caribou Range to the Wyoming
border that may help initiate some thunderstorms Tuesday afternoon.
Winds will continue to be strong through the day Tuesday.

As mentioned before, we'll see some ridging build in briefly
Wednesday night and Thursday, while another trough amplifies off the
coast, which models are showing in generally good agreement.
Ensemble clusters are generally in good agreement through Thursday,
but show increasing uncertainty in the depth of the trough beyond
that. Operational models show a trend toward drier weather going
into Sunday.
Hinsberger

&&

.AVIATION...Terminals should be VFR until late tonight.
Precipitation should intensify and surge northward from the Utah
border ahead of a warm front between 09Z and 12Z. HREF flight
category probabilities favor MVFR conditions at BYI and SUN
starting around 10Z, though SUN will likely deteriorate to LIFR
between 12Z and 15Z as snow intensifies across the Central Mountains
ahead of an advancing cold front. PIH and IDA could see a drying
downslope flow, and may avoid going below VFR, but HREF is showing
some fairly equal chances of dropping to MVFR or even IFR. Winds are
expected to remain strong through the day and evening across the
Snake Plain, and even at KSUN. Expect to see a transition to a
southerly flow around 09Z to 12Z as the warm front surges northward.
Hinsberger

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 6 AM Monday to 6 AM MDT Tuesday for
IDZ052-056-068-069-072>075.

Lake Wind Advisory until 9 PM MDT this evening for IDZ054.

Winter Weather Advisory from noon Monday to noon MDT Tuesday for
IDZ060-062>064-066-067.

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