Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 232158

Area Forecast Discussion
National Weather Service Boise ID
258 PM MST Tue Jan 23 2018

.SHORT TERM...Tonight through Thursday...Increasing clouds today
as a weak warm front brings generally light precipitation to the
northern portions of the forecast area, from Baker County and
east through the West Central Idaho Mountains. Snow levels will
range between 2500-4000 feet. A southwesterly flow aloft will
increase tonight ahead of another round of moisture set to move in
from the west Wednesday afternoon along a cold front. Snow levels
associated with this system will begin around 3500-4500 feet and
slowly drop to valley floors by Thursday afternoon. This drop will
be just in time to bring a wintry mix to the Treasure Valley
Thursday morning, but will taper off quickly with little impact
expected as the front pushes east. Light snow accumulations are
expected elsewhere with the highest snow accumulations forecast
along the tallest peaks, at and above 7000 ft, with 8 to 10 inches
expected over the 24 hour period. Winds will increase Wednesday
ahead of the front, with breezy to locally windy conditions,
especially from Caldwell, Idaho and east along the Snake Plain.
Temperatures will increase slightly tomorrow with highs reaching
into the mid 40s to low 50s in most locations, and mid-to-upper
30s in mountain valleys. Highs will decrease by a few degrees

.LONG TERM...Thursday night through Tuesday...A progressive
pattern in the extended period will keep the chance of rain and snow
across much of the region through the weekend. The first round moves
through on Friday with a passing short wave trough. Snow levels will
hold around 3k feet MSL, so expect a rain/snow mix across lower
valley sites. Any valley accumulations would be light (likely less
than an inch) and limited to sites at or above 3k feet through
midday Friday. By afternoon temperatures will warm enough to limit
accumulations to above 4k feet. The rain/snow continues on Saturday,
but a shift to a more westerly flow will bring milder air and
increase snow levels to 4-5k feet by Saturday night. Conditions dry
from south to north Sunday into Sunday night as an upper ridge
builds over the Great Basin. Monday looks dry across the entire area
as the focus of precipitation shifts into the ID panhandle. A cold
trough will likely return by the middle of next week with more
rain/snow. Temperatures are near normal through Saturday, warming
above normal for Sun/Mon with a return to normal by Tuesday.


.AVIATION...Mostly VFR. Lower ceilings across east-central Oregon
and the west-central Idaho mountains tonight with local IFR in snow
developing north of a KBKE-KMYL line after 24/00Z. VFR conditions
elsewhere overnight. Easterly to southerly surface winds to 15 kts
with local gusts to 30 kts. Winds 20-35kts at 10k feet MSL.





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