Wind Advisory 30, NWS Pocatello, ID

Area Forecast Discussion
National Weather Service Pocatello ID
311 AM MDT Thu Nov 3 2022

.SHORT TERM...Today through Saturday night.

High pressure will produce dry weather but below normal temperatures
today with most areas seeing highs in the 30s to low 40s. Our next
storm arrives on Friday in the form of an atmospheric river event
from the northwest. We will see moisture pour into the central
mountains Friday morning, then into the eastern Idaho Friday
afternoon. The Snake Plain and eastern Magic Valley will see
considerable shadowing effects off the central mountains. This will
cut into rainfall amounts considerably here. Liquid precipitation
will range from just a few hundredths near Arco to up to 0.25 inches
near Rexburg and Idaho Falls to up to 0.50 inches from Pocatello to
Burley. However, the high country in this event will see much much
more. Liquid totals are 0.50 inches to 1.50 inches with
upslope/downslope effects dictating amounts. Some upslope favored
areas in the Sawtooth and western Smoky mountains could see up to 3
inches liquid from this event. Snow levels start at valley floors
Friday afternoon but climb to 6500 feet Friday night for the Snake
Plain westward. Snow levels will not begin to rise on the valley
floors until late morning Saturday or possible Saturday afternoon.
Then, snow levels will hold at 6500 feet until the cold front moves
through the region Saturday night, bringing precipitation to an end
across the region. The more impressive snow amounts areawide will be
found above 6500 feet where winter storm watches will be issued. 8
to 14 inches is possible in the watch area. Some locations across
the central mountains, especially in the Sawtooths and western
Smokys could exceed 20 inches. Snow amounts fall off very quickly
below 6500 feet across the central amounts to only a couple inches.
The eastern highlands are a slightly different story where locations
between 5500 feet and 6500 feet may see 5 to 10 inches of snow
potentially resulting in advisories issued for later shifts. The
Snake Plain and eastern Magic Valley does not do well for snow,
generally less than an inch. Low lying eastern highland communities,
such as Malad and Preston, might do a little better, perhaps a
couple inches. There's a good chance that this could be a windy
event as well with models showing 50kts at 700mb punching into the
region Friday night and Saturday. So blowing and drifting snow may
be a problem as well in this event.

13

.LONG TERM...Sunday through next Thursday. Sunday morning will see
some lingering snow tapering off in the higher elevations of the
southern hills and eastern highlands. Winds will still be breezy
Sunday morning with gusts across the Arco Desert and Snake Plain
between 20-30kts still. Winds are expected to decrease a bit through
the day, but stay gusting up to 20kts at times. However, winds will
pick up on Monday afternoon again with gusts generally up to 20-
25kts, but higher wind gusts of 30-35kts in the southern hills and
eastern highlands. These winds will be increasing as our next system
brings impacts to our area. Both the ECMWF and GFS show a closed low
sitting off the coast of the Pacific Northwest on Monday and
Tuesday. This low will help funnel atmospheric river moisture into
eastern Idaho on Monday and Tuesday. As the low begins to make its
move eastward late Tuesday, it looks to take a northeasterly track
Wednesday, Thursday, and Friday through eastern Oregon, central
Idaho, and through Montana. The GFS and ECMWF show some disagreement
in the exact track and timing of the low, but they are in consensus
on more moisture throughout Wednesday and into part of Thursday. The
ECMWF wants to keep more wrap around moisture for us even Thursday
into early Friday. With highs in the 40s for many on Monday, we
likely see a rain to snow mix in the valleys with mostly snow on
Tuesday as highs fall into the 30s and we keep highs in the 30s
through Thursday. At this time, the NBM 4.0 WSUP viewer is showing a
50-70% chance for at least an inch of snow through the eastern Magic
Valley and Snake Plain from Monday to Wednesday evening. Of course,
it's still too early to fine tune the track of the low or forecast
any concrete snow totals at this time, so we will continue to watch
this evolve over the next several days. AMM

&&

.AVIATION...12Z Thursday to 12Z Friday. Watch for IFR conditions from
low CIGs developing at BYI from 12Z to 18Z. Otherwise expect VFR to
MVFR conditions from some low CIGs throughout the day at SUN, PIH,
IDA, and DIJ. Winds will pick up at BYI and PIH during the
afternoon, too, with gusts up to 20-25kts and continue overnight
into Friday morning. The wind starts to pick up at IDA and DIJ
overnight. Gusts early Friday will be 20-30kts at all sites except
for SUN where winds will be lighter. Rain and snow will arrive at
TAF sites on Friday, though likely beginning around or just after
12Z. AMM

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from Friday evening through Saturday evening
for IDZ060-063-064.

Winter Storm Watch from Friday evening through Saturday
afternoon for IDZ071>073.

&&