FXUS65 KBOI 190908

AFDBOI



Area Forecast Discussion

National Weather Service Boise ID

308 AM MDT Thu Mar 19 2026



.KEY MESSAGES...

- Record high temperatures today and tomorrow with dry 

  conditions.



- Breezy conditions and low relative humidity will create fire

  danger concerns for areas near the NV border Thursday and 

  Friday afternoons.



- A pattern shift with a cold front on Saturday will bring

  cooler temperatures, mountain precipitation, and breezy

  westerly winds.



&&



.SHORT TERM /Through Saturday Night/...

The ridge of high pressure will continue to build over the 

region through the end of the work week. Record highs will 

continue until a cold frontal passage on Saturday. Valleys will 

see temperatures in the upper 70s to low 80s, with mountain 

locations exceeding the 60 degree mark. Dry conditions with low 

relative humidity values less than 15% will accompany these high

temperatures. Elevated afternoon wind gusts will increase fire 

danger today and tomorrow in pre-green up lower elevations 

southwest of the Snake River Valley and the NV border. By midday

Saturday, the cold front will move through the region bringing 

a 10-15 degree temperature drop, cloudy skies, mountain 

precipitation in southwest Idaho (30-50% chance), and breezy 

westerly winds. Snow levels will stay above 8000 feet on 

Saturday, with minimal rainfall accumulations of less than a 

tenth of an inch with the frontal passage as well. Instability

remains weak, primarily due to dry air aloft, with very low

confidence in any convection during the frontal passage. 



&&



.LONG TERM /Sunday through Thursday/...

Zonal flow aloft will help push cold air over the Pacific 

Northwest on Sunday. Conditions will generally be dry, with 

cooler temperatures near normal on Sunday and Monday. A ridge of

high pressure will build in briefly on Tuesday, with 

temperatures rising above 70F in the valleys. By Wednesday, a 

trough extending from a low off the British Columbia coast will 

move in to the region, bringing another push of cold air and 

increased chances of precipitation. Thunderstorms cannot be 

ruled out with this initial frontal passage, but current 

forecasts show low instability over the region. The best chance 

for showers (20-40%) remains over high terrain in southwest 

Idaho, with snow levels staying high initially at just over 8000

feet MSL. Once the colder air moves in, snow levels will drop 

to 6000-7000 feet by late Wednesday. Showers will taper off on 

Thursday, with cool and dry conditions returning. 



&&



.AVIATION /06Z Thursday through Friday/...

Issued 1156 PM MDT WED MAR 18 2026



VFR with high clouds. Surface winds: variable up to 10 kt. Then, SW-

NW 5-15 kt by Thu/18Z. Afternoon gusts to 20-30 kt for E Oregon and 

near NV-ID border. Winds aloft at 10kft MSL: W-SW 15-30 kt. 



KBOI...VFR and mostly clear. Surface winds: SE 5-10 kt, then NW-N 

around 5 kt in the afternoon.



&&



.BOI WATCHES/WARNINGS/ADVISORIES...

ID...None.



OR...None.



&&



$$



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SHORT TERM...SA

LONG TERM....SA

AVIATION.....SH