427 
FXUS65 KBOI 311048
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
348 AM MST Tue Dec 31 2019

.SHORT TERM...Today through Friday...Low clouds and fog will 
linger this morning before clearing out as the flow aloft 
increases. A stream of subtropical moisture arrives this 
afternoon across the northern zones as a frontal system moves into
the region. This will bring moderate snow accumulations to the 
mountains this evening lasting into Thursday morning. Expect 6-12"
of snow in the mountains. Warmer air associated with the system
will move into the region on Wednesday morning, as snow levels 
rise to around 7000-8000 feet in eastern OR and south of the Snake
Basin in Idaho. As the warmer air moves into the region, cold air
trapped in the valleys of Idaho and Baker County Oregon will 
create a threat of freezing rain on Wednesday morning before 
changing over to rain below 4000ft. A cold front will move 
through on Wednesday afternoon and precipitation will become
showery in nature and mainly focus over the mountains. 
Precipitation will taper off on Thursday as an upper level ridge 
begins to build into the region by Friday. Temperatures will be 
near normal today before the cold front brings warmer air to the 
valleys on Thursday and Friday. Temperatures on Thursday and 
Friday will be 5-10 degrees above normal.

.LONG TERM...Friday night through Tuesday...A moist northwest flow 
aloft will continue to provide the region with periods of 
precipitation through the weekend, mainly across the northern high 
terrain. Snow levels of 3000-4000 feet will lower to valley floors 
on Sunday. Light snow accumulations are possible, mainly in the 
northern mountains. Temperatures will be 5-10 degrees above normal 
on Saturday and around 5 degrees above normal on Sunday. Drier air 
arrives early next week, although there is still a slight chance of 
precipitation in the northern mountains. Temperatures will be a few 
degrees above normal. 

&&

.AVIATION...Widespread MVFR in stratus and patchy fog with mountains 
obscured today. Snow will develop across the north (KBKE-KMYL), with 
IFR conditions in the mountains after 18Z. Surface winds variable 
less than 10 kts. Winds aloft at 10k ft MSL northwest 25 to 40
kts.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory from 5 PM this afternoon to 11 AM MST 
     Wednesday IDZ033.
     Winter Weather Advisory from 5 PM this afternoon to 11 PM MST 
     Wednesday IDZ011-013.
OR...None.

&&

$$

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SHORT TERM...KA
LONG TERM....BW
AVIATION.....BW