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Area forecast discussion 
National Weather Service Boise Idaho
252 PM MDT Tuesday Oct 21 2014

Short term...tonight through Thursday...upper trough will shift
to the east with showers decreasing over the Boise/west central
mountains this evening. An upper ridge will move in late tonight
accompanied by decreasing clouds and light winds. Mostly clear
skies and light winds...combined with recent rains...are
ingredients favorable for fog in the northern mountain valleys late
tonight through Thursday morning. The ridge will shift to the east
on Thursday as a moist SW-NE oriented Pacific plume enters the
Pacific northwest Wednesday night. The plume will slowly enter southeast
Oregon and portions of SW Idaho /excluding the western Magic
Valley/ Wednesday night and Thursday. The plume is prognosticated to
weaken and narrow as it approaches the area...thereby limiting the
quantitative precipitation forecast amounts. The more favorable areas for showers will be in the
higher terrain across the north. The gusty west-northwest winds in the
western Magic Valley will diminish this evening. Winds throughout
southeast Oregon and SW Idaho will be mainly SW-southeast tonight through
Thursday...and become breezy Wednesday afternoon through
Thursday. High temperatures will warm to slightly above normal on
Wednesday...then cool to below normal on Thursday due to the
clouds and showers.

Long term...Thursday evening through Sunday...moisture will
stream into the region Thursday night on SW flow aloft in advance
of a strong and deep trough that won't move in until Saturday
night and Sunday. In the meantime...precipitation will move north of the
area Friday as a warm front swings up into Washington and northern
Idaho...leaving US in the warm sector. This will allow temperatures to
warm up above normal. Friday night will be dry and blustery as the
strong trough approaches. Showers will move in Saturday as a
strong cold front blows through. Winds will be moderate to strong
over much of the area...especially in and near the showers. Sunday
will be cool and blustery with a continuation of showers...
especially in the west-central and Boise Mountains.

Sunday night through Tuesday...the trough will move out Sunday
night with a weak ridge building in behind it. The ridge will be
short lived as the next trough slowly starts to spin up over the
Pacific in its wake. Temperatures will be about normal for this
time of year with chances of precipitation mainly over the higher


Aviation...VFR most areas...except isolated MVFR showers will
persist in the mountains with mountains obscured through early evening.
Becoming VFR all areas tonight...except for possible fog at kmyl.
Surface winds generally west 10-20 kts this afternoon...decreasing to
less than 10 kts overnight. Winds aloft through 10 kft will be west
20-30 kts.


Boi watches/warnings/advisories...




long term....sp/ab

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