FXUS65 KBOI 201813
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
1213 PM MDT Wed May 20 2026

.UPDATE...Updated aviation discussion.

&&

.KEY MESSAGES...
- Mostly dry with temperatures warming through Friday. 

- Well above normal temperatures over Memorial Day Weekend.
  Gusty winds and a few mountain showers on Memorial Day.

- Turning cooler with gusty winds and increasing chance of 
  precipitation starting Tuesday.

&&

.SHORT TERM /Through Friday Night/...
Issued 303 AM MDT WED MAY 20 2026
The cool upper level trough of the past several days will be briefly 
reinforced from the north today in MT and eastern ID, close enough 
to delay warming, and for a slight chance (10-20%) of showers in 
eastern Valley County and southern Twin Falls County late today and 
tonight. On Thursday the trough will exit east and steady warming 
and drying will take place.  Hi-res models show light to moderate 
(10-20 mph) northwest winds this afternoon, then slightly stronger 
(15-25 mph with gusts 30 mph) Thursday afternoon, strongest in the 
Snake Basin southeast of Boise.

&&

.LONG TERM /Saturday through Wednesday/...
Issued 303 AM MDT WED MAY 20 2026
The warming trend will continue through the weekend and peak 
Monday (Memorial Day) when high temps reach 85 to 93 in the 
valleys (hottest near Grand View, ID) and 70s to mid 80s in
the mountains. By then flow aloft will become southwesterly and
increase as a deep cold upper low approaches from the Gulf of 
Alaska. A strong cold front is now forecast for Tuesday, with 
the upper low forecast to pass directly over us on Wednesday. 
There are similarities with Tuesday's cold front to the one 
that occurred last week with the strong winds and blowing dust,
so this event may become our main concern in the coming days.

&&

.AVIATION /18Z Wednesday through Thursday/...
Issued 1208 PM MDT WED MAY 20 2026
VFR. Scattered to broken middle and high clouds. Isolated
showers and thunderstorms over the mountains NE of KMYL this 
afternoon. Surface winds generally NW 10 to 15 KTS today,
increasing through Baker Valley 15 to 20 kts tonight. Winds
aloft at 10kft NW 20 to 30 kt.


KBOI...VFR Scattered mid level clouds this afternoon. Surface
winds NW 12 to 18 kts.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.

OR...None.

&&

$$

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AVIATION.....JB
SHORT TERM...LC
LONG TERM....LC