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Area forecast discussion 
National Weather Service Boise Idaho
301 PM MST Friday Nov 21 2014

Short term...tonight through Sunday...winter storm headed
directly into the area. Temperatures have warmed more than expected
today...and this has a direct impact on precipitation type for tonight.
We have removed almost all mention of freezing rain tonight. The
best chance appears to be along rt 95 from Midvale to Council...
where there could be a period of freezing rain after initial
snowfall and before it turns to all rain after midnight. With
confidence now so low in freezing rain...we have removed all of
the lower elevation advisories for this storm system...including
Baker County. We still believe Baker will see around an inch of
snow around an inch of wet snow before changing to rain around
midnight...but that is not enough to warrant continuing the
advisory. We imagine there will be pockets of freezing rain for a
brief time in some of the isolated valleys in Baker County as
well...but if this occurs...it will be short-lived before changing
to all rain. Elsewhere...the lower Treasure valley has warmed to
at or just above freezing this afternoon...and may also begin as a
very brief period of freezing rain. However...we are confident
that this...too...will change to all rain quickly. The advisories
remain in the mountains...where the precipitation type will be all snow
above around 4500 feet. Snowfall may exceed 24 inches at the
highest peaks...but most areas will get 3 to 9 inches. Winds on
the peaks in southeast Oregon will be strong tonight...with gusts to 50
miles per hour.

Saturday...a cold front will move through from northwest to southeast...and this
will be strong enough to scour out the remaining low-level
inversion in the Treasure valley. So oddly enough...even though a
cold front is coming through...high temperatures Sat will be higher than
today for that area. Most other areas will see high temperatures decrease
tomorrow. Precipitation will taper off Saturday night...and then pick
back up again on Sunday as another impulse moves over the area in
northwest flow. The valleys may see a mix of snow and rain Sunday
afternoon...but amounts are expected to be only a few hundredths
of an inch liquid equivalent.

Long term...Sunday night through Friday...weak shortwave exiting
the region Sunday night with northwesterly flow developing over
the forecast area behind the shortwave. Enough moisture in the
northwesterly flow for slight chance to chance probability of precipitation over the west
central and Boise Mountains Monday and Monday but dry conditions
everywhere else. Tuesday on latest model trends are building a
ridge along the West Coast for warming temperatures and dry
conditions...but...forecast confidence is low as there is no real
consistency from run to run. Have backed off on probability of precipitation for Tuesday
through Friday...but will wait for higher confidence in the models
before drying things out.

&&

Aviation...widespread rain and mountain snow will spread over
the forecast area tonight. Surface temperatures over lower
elevations have gone above freezing so the threat of freezing rain
has been greatly reduced. Snow level around 4500 feet mean sea level. As
precipitation spreads over the area mountains will become obscured
along with areas of MVFR and local IFR conditions. Surface winds
tonight will be southeast to South West 10 to 20 knots with gusts
to around 25 knots south of a kbno-ktwf line.

Saturday...precipitation will be on the decrease Saturday
afternoon with slight chance to chance showers Saturday night and
Sunday. Surface winds Saturday will become westerly 15 to 20
knots...gusts to 30 knots south of a kbno-kjer line.

&&

Boi watches/warnings/advisories...
Idaho...Winter Weather Advisory from 8 PM this evening to 11 am MST
Saturday idz011-013-028.
Or...none.

&&

$$

Weather.Gov/Boise

Short term...snow pellets
long term....ja/wh
aviation.....Ja

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