FXUS65 KBOI 032116

AFDBOI



Area Forecast Discussion

National Weather Service Boise ID

216 PM MST Tue Feb 3 2026



.SHORT TERM...Tonight through Thursday night...A well

established upper high will remain centered over the Interior

West through Thursday. The sinking air aloft will keep dry and 

mild weather weather in place across the region as afternoon 

temperatures reach 10 degrees above normal Wed/Thur. Surface 

winds remain light during the period and the resulting stagnant 

air mass should gradually reveal itself through increased 

fog/haze during the week, most notably across the lower Snake 

Plain and basins/valleys of SE Oregon. Through Thursday, fog 

formation in the Snake Plain will be limited to areas along the

Snake River and more broadly to points west of the Canyon/Ada 

County line into the Weiser Basin. Adjustments were made to the 

NBM forecast lows and to increase the fog coverage across lower 

valleys each morning. 



.LONG TERM...Friday through Tuesday...The upper level ridge that 

dominates the short-term period will begin to breakdown and move

east to end the week. While at least Friday and Saturday will 

remain dry, ensemble clusters are in good agreement of a pattern

change early next week as a trough moves in off the coast. 

Although exact timing can't be pinned down quite yet, 

deterministic guidance all resolve a cold front crossing over 

our area come late Sunday/early Monday. This front will be what 

mixes out our inversion with increased winds and cooling aloft. 

The front will also cool the surface to more seasonable 

temperatures by Monday. Precipitation chances will increase 

through the day Sunday, before maxing out Monday morning with a 

55-75% chance in the west central mountains and a 35-55% chance 

elsewhere. These chances will likely increase in the days to 

come as the exact timing becomes better resolved. Beyond Monday,

precipitation chances will remain non-zero, as ensemble 

clusters remain in good agreement of troughing over our area. 



&&



.AVIATION...Generally VFR. Patchy haze/fog overnight in lower

basins and sheltered valleys will result in localized 

MVFR/LIFR visibilities. Surface winds: Variable up to 10 kt. 

Winds aloft at 10kft MSL: W-NW 5-15 kt. 



KBOI...VFR under thin high clouds. Surface winds: light and 

variable, leaning SE after Tue/03z.



&&



.AIR STAGNATION...No question we remain locked in a stagnant 

pattern into the weekend. Mixing levels are forecast to stay at 

or below 1500 feet AGL in the lower valleys with light winds. 

Drainage winds in the Snake Plain (Jerome-Glenns Ferry 

corridor) will touch 10-15 mph at times, but otherwise there is 

little movement in the air mass vertically or horizontally.



&&



.BOI WATCHES/WARNINGS/ADVISORIES...

ID...Air Stagnation Advisory until 5 AM MST Monday 

     IDZ012-014-016-033.

OR...Air Stagnation Advisory until 5 AM MST /4 AM PST/ Monday 

     ORZ062>064.



&&



$$



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SHORT TERM...DG

LONG TERM....NF

AVIATION.....NF