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fxus65 kboi 201009 

Area forecast discussion
National Weather Service Boise Idaho
309 am MST Sat Jan 20 2018

Short through Sunday...upper trough over the area
will gradually shift eastward today. Meanwhile, a disturbance in
Washington and northern Oregon will move into the Idaho Panhandle
late this afternoon. Isolated snow showers are expected over the
higher terrain, except scattered snow showers across the far north
associated with the disturbance. An upper ridge will move in
tonight through Sunday morning for dry conditions. Patchy valley
fog could develop during that time due to mostly clear skies and
light winds that accompany the ridge. The next Pacific system will
move onshore Sunday morning and spread snow into southeast Oregon
Sunday afternoon. Accumulations will be light, with up to an inch
in the valleys and 1 to 2 inches in the mountains. Temperatures
will be a few degrees above normal.

Long term...Sunday night through pattern will
continue into next weekend. The next system will move across the
forecast area Sunday night into early Monday bringing snow to most
locations. Mountains will see decent snowfall of up to 6 inches
by Monday morning. The valleys will see little snow accumulations
as surface temperatures remain above freezing through the entire
event. A brief break in precipitation for late Monday night and
early Tuesday, with increasing westerly flow aloft over the area
ahead of the next system. Southeasterly surface winds will allow
temperatures to warm into the upper 40s/low 50s in the valleys
Wednesday. Snow levels between 4000 to 5000 feet will make for
mountain snow and valley rain Wednesday into Thursday. The trough
and cold front move through late on Thursday, lowering snow levels
back down to all areas. Most of the precipitation will be done by
the time the cold air moves in Thursday night. Some snow showers
in northwest flow will linger through Friday as the upper level
ridge rebuilds over the region. Another Pacific system moves into
the Pacific northwest on Saturday. Models are in good agreement
with keep much of this system north of the forecast area bring
precipitation to our northern zones. Temperatures look to be above
normal on Tuesday/Wednesday and back down near normal for
Thursday/Friday warming back above normal on Saturday.


Aviation...mostly VFR with mid-high level cloud cover. Fog in
the valleys, especially at kmyl, will dissipate by 18z. Surface
winds generally west-northwest around 10 kts. Winds aloft near 10 kft msl: northwest
10-20 kts.

Sunday outlook: mostly clear in the morning, then increasing
clouds in the afternoon, with precipitation moving in from west to
east in the evening.


Boi watches/warnings/advisories...




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