Area Forecast Discussion
Issued by NWS Pocatello, ID

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000
FXUS65 KPIH 162120
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
220 PM MST Sat Dec 16 2017

.SHORT TERM...Tonight through Tuesday afternoon. The axis of the low
pressure trough is slowly crossing southeastern Idaho this
afternoon. Meanwhile, the snow associated with the surface
convergence boundary from roughly Idaho Falls, Blackfoot, and Carey
is marching slowly south to Interstate 86, which will take until
about 5 pm. Snow should end at Soda Springs and Bear lake area 7-8
pm. Current radar imagery shows some signs of the band becoming
weaker as it does. The trough is actually digging well to the south,
even Baja California in satellite imagery. The few snow reports we
have are around 2-2.5 inches snow accumulation at Bellevue, Carey,
Pocatello Airport, and Chubbuck. A report was received from Idaho
Falls this morning of 4 inches snow and 3 inches at Irwin. Expect
some partial clearing over night, allowing temperatures to drop into
the single digits and teens, warmest near Burley and Minidoka, and
coldest at Stanley. There is a chance of snow Sunday and Monday,
with activity gradually moving north towards the pan handle of Idaho
by Tuesday afternoon, along with some 5 to 7 degree warming of
temperatures. Snow in the mountains from this will only add up to a
couple inches or so. RS

.LONG TERM...Tuesday night through Saturday. Models offer similar
solutions to medium-range forecast with respect to the approaching
upper low. Surface cold front looks to enter southeast Idaho around
12Z Wednesday and progress fairly quickly, exiting Idaho by around
18Z-00Z Wednesday. Expect snow amounts around 4 to 6 inches in the
Central Mountains and the Island Park area. We will also see some
stronger winds associated with the cold front, but currently
expected to be below advisory criteria. The post-frontal air will
bring temperatures well below normal through the weekend. Expect
single digit lows Thursday night, possibly dipping below zero in the
Upper Snake Plain. A second shortwave will drop out of Canada on
Friday, clipping the Island Park area, so some chance PoPs Friday
night and Saturday. Extended periods look to be cold and dry as a
high-amplitude ridge sets up off the Pacific Coast. Hinsberger

&&

.AVIATION...Much of East Idaho is blanketed in low cloud cover with
some clearing evident on VIS imagery to the west. Snow is expected
to continue through the afternoon across the Snake Plain. One area
of snow appearing on radar over Craters of the Moon is beginning to
shift southward, and may hit KBYI with a couple bursts of snow.
Otherwise, some mid and upper-level clearing will take place
overnight, but fog/stratus is strongly supported by both GFS and NAM
MOS guidance, so morning LIFR/VLIFR conditions may be present across
the terminals in the Snake Plain. Hinsberger

&&

.Air Stagnation...Todays storm system helped disrupt the
inversion conditions and poor air circulation, but may not have
reached all the local valley areas. Inversion conditions will
likely be reinforced late in the week, after the storm system on
Wednesday comes through. RS

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 5 PM MST this afternoon for
IDZ019>021.

Winter Weather Advisory until 8 PM MST this evening for IDZ022-
023-025.

&&

$$



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