Heavy Snow in Idaho, December 19 to 20, 2016

Area Forecast Discussion
National Weather Service Pocatello ID
226 PM MST Mon Dec 19 2016

.SHORT TERM...Tonight through Wednesday night.

Storm system will approach from the northwest Tonight. This will
bring snow to the Sawtooths and eastern highlands late tonight.
Precipitations will arrive into the Snake Plain and Magic Valley
during the afternoon. Still looking at some warm air in the mid
levels which could lend itself to mixed precipitation from Pocatello
to Burley and south of Shoshone. As the afternoon goes on, the
threat for mixed precipitation will be more confined to the Burley
area as Pocatello will be mainly wet snow. Expect gusty winds to
develop late in the afternoon and evening except at ridgetops where
winds will strengthen tonight. Blowing snow may be a problem. Areas
north of Ketchum will see 6-10 inches with local amounts closer to a
foot. From Rexburg to Island Park and Driggs will see 4-10 inches.
From Pocatello to Idaho Falls, expect 1 to 4 inches. Around Burley,
around an inch but there could be enough freezing rain that might
make travel a little slick there. Expect 2 to 5 inches across the
southeast highlands. Will convert winter storm watches to warnings
and add advisories for the southeast highlands and Snake Plain.
Think these will be the areas with greatest impacts. Expecting
little impacts at this time along I 84, but that could easily change
depending on the precip type. The area from Arco out to Challis will
see a healthy amount of shadowing because of the direction this
system is coming from, so they may not see much snow. This system
should exit the area Tuesday evening with dry weather settling in
for remainder of the short term.

Valle

.LONG TERM...Thursday through Monday night.
European and GFS models coming more together with the potential of a
chance of a holiday storm affecting travel.   Thursday now looks
mainly dry on all models and only kept in some very slight chances
in the central mountains.   A slow moving Pacific storm is likely to
bring in snow Friday and continue into Sunday.   It appears to also
have some mild air entrenched as many of these storms this month
have and there is the potential of a mix or change to rain in the
valleys on Saturday before the cold air moves in.   Being that it is
4 days away the models may undergo many changes but for now be aware
of the potential for dangerous travel especially in the mountains
Friday into Christmas morning.
GK

&&

.AVIATION...All locations have gone VFR with an increase of mid and
high level clouds today.   Brought MVFR To IFR conditions into DIJ
and SUN late tonight through Tuesday morning as the next system
spreads into the region.   Expect the valley sites...BYI, PIH...and
IDA to drop to MVFR or IFR conditions Tuesday afternoon after 18z.
Expect good conditions Wednesday.   Winds will increase Tuesday as
well especially at BYI...PIH and IDA.
GK

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from noon Tuesday to midnight MST
Tuesday night for IDZ020-021.

Winter Weather Advisory from midnight tonight to midnight MST
Tuesday night for IDZ023-025.

Winter Storm Warning from midnight tonight to 6 PM MST Tuesday
for IDZ018-031.

Winter Storm Warning from midnight tonight to midnight MST
Tuesday night for IDZ019.

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