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878
FXUS65 KBOI 122152
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
252 PM MST Thu Dec 12 2019

.SHORT TERM...Tonight through Saturday...An ongoing stream of
moisture will continue to impact the area. A northern push will
keep mountain snow and valley rain for much of southwestern Idaho
through Friday morning, with weakening intensity through the day.
Another more southerly push will begin Friday afternoon and will
impact the southern third of the forecast area. Snow levels
currently keep a good coverage of snow-rain mix present across the
area. Temperatures continue to be monitored in case values cool
enough to result in more widespread snow with more significant
impacts. For now, the main impacts remain with the initial push
through tomorrow morning, with an ongoing Winter Weather Advisory.
No changes planned to these products with this forecast package.
Also of note, by Saturday morning snow levels are anticipated to
drop to valley floors, which will permit light snow showers across
the Treasure and Magic Valleys as moisture weakens across the
area. Improved conditions expected by Saturday afternoon with
drier conditions.

.LONG TERM...Sunday through Tuesday...A system will weaken as it
travels across OR on Sunday, keeping a threat of snow showers,
mainly across the mountains. Upper level ridging begins to build
into the region on Monday and Tuesday, with dry conditions expected.
Temperatures will be near normal through the period.

Tuesday night through Thursday night...Partly cloudy skies are the
expected conditions at the start on Tuesday as dry, stable ridging
dominates the region. However, conditions will deteriorate, starting
Wednesday, as the ridge begins to break down, allowing some moisture
to spill into the forecast area. This will increase the chances for
precipitation, mostly across the northern tier counties. By
Thursday, precipitation chances will pickup (increase) even more
(starting in southeast Oregon) and continue to spread eastward as a
moist, unsettled trough rolls in from the west. Look for widespread
snow to blanket the region. High and low temperatures are expected
to measure in a few degrees above normal.

&&

.AVIATION...Mountains obscured. Generally low VFR to MVFR
conditions. Showers at times with MVFR to IFR conditions. A slight
chance of thunderstorms this evening. Snow levels 5000-6500 ft MSL.
Surface winds SW-SE 5-10kt. Winds aloft at 10k ft MSL W-NW 30-40kt
easing to W 15-25kt by 18z/Fri.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory until 5 AM MST Friday IDZ011-013.
OR...None.

&&

$$

www.weather.gov/Boise
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SHORT TERM...KB
LONG TERM....KA/WH
AVIATION.....KA