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Area forecast discussion 
National Weather Service Boise Idaho
831 PM MST Sat Dec 27 2014

Discussion...Winter Weather Advisory working out well so far as snow
has overspread most of the advisory area this evening. Majority
of the snow should fall during the night and the advisory may be
shortened as conditions dictate. But for now the expected snowfall
and temperatures look fine. Winds will not be a problem with this storm
as they were with the last storm. New snow-cover will be in place
when upper winds become north and then northeast early in the
week...resulting in very cold weather much like after the big snow in


Aviation...widespread MVFR snow with mountain obscuration and local
IFR/LIFR conditions will continue overnight. Snow will taper off
over southeast Oregon late tonight and the southwest Idaho valleys
Sunday morning. Snow will continue in the mountains through Sunday
then decrease to scattered snow showers Sunday night. Surface
winds...southeast to southwest 10 kts or less tonight becoming west
10-20 kts on Sunday. Winds aloft...northwest 25-35 kts up through
10k feet mean sea level.


Previous discussion...
short term...tonight through Monday...not a lot of change this
package. Snow has spread to Baker City and Ontario...and slick
snow-covered roads were reported across parts of the west central
mountains /Hwy 55/. A swath of moderate precipitation across NE to
east-central Oregon and central Idaho will spread east-southeast and bring a
round of snow to this area and SW Idaho through early Sunday
morning. An associated cold front affecting northwest Washington this afternoon
is expected to shift through Oregon and SW Idaho between 3 am and
9 am MST Sunday morning. Limited moisture in the northwest flow Sunday
followed by a deep cold upper low across Oregon Sunday night/
Monday...and Idaho Monday...will keep the area cold and unsettled.
With this pattern strong convective showers are possible. Went with
sref calibrated thunderstorm chances of below 5 percent and left any
thundersnow mention out. Temperatures will be below normal in the
short term and then even colder as noted next.

Long term...Monday night through Saturday...axis of upper level
trough over Idaho Monday night will slowly sink south through
Wednesday before it stalls over Southern California/southern
Utah. Slight chance probability of precipitation over the region Monday night then dry
conditions Tuesday through Thursday night. As the axis of the
trough sinks south...flow aloft will shift to the northeast
bringing cold air to the region. Coldest temperatures will be
uesday afternoon and Wednesday morning averaging 15-20 degrees
below normal. Temperatures will slowly warm Thursday through
Saturday with the next chance of precipitation Friday through


Boi watches/warnings/advisories...
Idaho...Winter Weather Advisory until 11 am MST Sunday idz011-033.
Winter Weather Advisory from 11 PM this evening to 11 am MST
Sunday idz015-016-030.
Winter Weather Advisory from 8 PM this evening to 11 am MST
Sunday idz012>014-029.
Or...Winter Weather Advisory until 10 am PST Sunday orz062.



previous short term...vm
previous long term....ja/wh

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