FXUS65 KBOI 172154
Area Forecast Discussion
National Weather Service Boise ID
254 PM MST Sat Nov 17 2018
.SHORT TERM...Tonight through Monday...A dry northerly flow will
remain over the forecast area, associated with an area of high
pressure over the Pacific coastline. This ridge will leave dry
conditions with generally light wind. A few areas of patchy fog
will be possible Sunday morning, mainly across the Long Valley.
Temperatures through the period will be around or just above
normal seasonal values.
.LONG TERM...Monday Night through Thursday...Upper level ridge
will bring warmer and dry conditions through Tuesday. A more
active pattern will begin on Wednesday as the first of a series of
troughs moves into the Pacific Northwest. Widespread
precipitation will begin Wednesday afternoon with passage of a
weak trough. A warm front slowly pushes north through the day on
Thursday and possibly stalls through Friday. Snow levels remain
high (4000-5000 feet) through Thursday as the much of the region
will remain in the warm sector. Temperatures are expected to be
near normal through the period.
Thursday night through Saturday night...An unsettled progressive
pattern is in store as a series of trough-ridge couplets
sequentially push through. The sun may make brief, limited
appearances during this transition. Models are initially in
general agreement with the handling the first system, but starting
Saturday they quickly part ways. Initial windy southwest surface
flow should taper down to breezy with the passage of the first
system starting late Saturday. Look for widespread precipitation
across the area with rain as the predominant type and snow
confined to the mountains. Rain amounts should be lighter along
the valleys due to the wind shadowing effect. By the end of the
period, the possibility for snow will increase as snow levels
lower (to around 3500 feet) reducing rainfall coverage to the
Treasure and Magic valleys.
.AVIATION...VFR. Mid-high level clouds and isolated showers are
clearing from north to south this morning. Some mountain
obscuration. Fog possible in mountain valleys through 17/16Z.
Surface winds: West/northwest around 10 kts or less. Winds aloft
near 10 KFT MSL: North 10-20 becoming East/northeast after 17/21Z.
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