Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 081726

Area Forecast Discussion
National Weather Service Boise ID
1026 AM MST Thu Dec 8 2016

.DISCUSSION...Snow associated with a warm front moving through
from Southwest to Northeast is currently falling in most of the
Oregon zones, and is just now coming over the Owyhee mountains as
of 10 am MST. Cold air trapped in valleys, including the Snake
River Valley will set up a scenario for snow to continue at valley
floors through the day today and into at least the late evening
hours. A Winter Weather advisory continues to be in effect for
this snowfall across the entire area, with the evening commute
being of concern in the Treasure Valley. This advisory highlights
the various snow amounts expected around the CWA. Some minor
changes have been made to the forecast for this afternoon to
better reflect current temperatures trends and snowfall amounts.


.AVIATION...An area of light snow detected by radar and
observed at surface reporting locations in southeastern Oregon was
moving towards the northeast.  The leading edge of the snow will
reach a KBKE-KBOI-KTWF line around 18Z.  The area of snow will
continue moving north and east and reach a KMYL-KSNT line by 22Z.
The snow will be associated with IFR ceilings and mountain
obscurations. Some improvement to MVFR is expected after 04Z this
evening as snow tapers off across the southern portion of the
forecast area...though snow and IFR conditions will continue in the
mountains overnight.


SHORT TERM...Today through Friday...A warm front associated with a
weather system over northern California continues to push north
toward our CWA. Snow will cross the Nevada border into southern
portions of southeast Oregon, and Owyhee County in Idaho, by about 5
am mst, reaching Baker County and the Snake River Valley by 11 am
mst, and spreading into the central Idaho mountains this afternoon.
By early Friday morning temperatures will warm enough for
precipitation to change to rain below 5000 feet as far north as
Burns, Ontario, and the Snake River Valley, but snow is expected to
continue in Baker County and the central Idaho mountains. A Winter
Weather Advisory for snow remains in effect for southeast Oregon and
southwest Idaho. Latest model runs continue to support timing,
duration, and snow amounts, so no updates are needed at this time.

LONG TERM...Friday Night through Thursday. Rain and snow
continues in moist westerly flow Friday night. Lower valleys will
see a cold rain with snow levels around 3k feet in east-central
Oregon to 5k feet along the ID/NV border. Lower valleys and areas
toward the NV border start to see some drying by late Saturday which
will continue into Sunday. Northwest flow around a deep low over
southern Canada will keep snow showers over Baker county and the
west-central and Boise mountains through the weekend. Model
differences remain for early next week with regard to displacement
of cold air over southern Canada. Latest GFS solution is further
west which would bring a much colder air mass to southeast Oregon
and southwest Idaho for Tue/Wed. For now have stayed closer to the
warmer ECMWF which remains consistent in displacing the cold air
further east. By Thursday, models are back in agreement with a
strong Pacific jet pushing a mild air mass and more rain/snow into
the region.


ID...Winter Weather Advisory until 5 AM MST Saturday IDZ011-013.
     Winter Weather Advisory until 10 PM MST this evening IDZ015-029.
     Winter Weather Advisory until 10 PM MST this evening
     Winter Weather Advisory until 5 AM MST Friday IDZ016-028-030.
OR...Winter Weather Advisory until 10 PM MST /9 PM PST/ this evening
     Winter Weather Advisory until 10 PM MST this evening ORZ064.
     Winter Weather Advisory until 4 AM PST Saturday ORZ062.



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