084 
FXUS65 KBOI 051545
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
945 AM MDT Thu Jun 5 2025

.DISCUSSION...Weak troughing over the area today will bring
precipitation and isolated storms to the Central Idaho
mountains. Activity will be focused along the eastern part of
our forecast area, with a 20% chance of precipitation in eastern
Valley and Boise counties, and a 10-20% chance of thunder in the
same area. Outflows up to 30 mph possible near storms, but are
most likely east of the area. As the trough exits southeastward
tonight, a warming and drying trend sets in while high pressure
builds aloft. No updates to the previous forecast.

&&

.AVIATION...VFR. A 10-20% chance of rain showers and possibly a 
thunderstorm over the eastern Boise/western Sawtooth Mountains 
between 20Z and 02Z today. Surface winds: Variable less than 10
kt becoming mostly W-NW 5-10 kt this afternoon. Winds aloft at 
10kft MSL: NW-N around 10 kt.

KBOI...VFR with surface winds variable less than 10 kt, 
becoming W-NW under 10 kt this afternoon.

Weekend Outlook...VFR. Building heat will result in high density 
altitude, especially Sunday into Monday. Generally light west to 
northwest winds surface and aloft.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Saturday night...Weak troughing 
over the region will support afternoon cumulus buildups over 
the mountains with deeper development over the eastern Boise 
Mountains. Have introduced a 20% chance of showers and 10-15% 
chance of thunderstorms east of an arc from Yellow Pine to 
Lowman to Atlanta, ID. This area has the best combination of 
dynamics, heating and instability through early evening. Baker 
County mtns could also see buildups this afternoon, but timing 
of the trough is a little too fast to support showers/storms. 
Lower elevations remain dry and stable today. Friday and
Saturday will see dry northwest flow as an upper ridge builds 
offshore. Temperatures warm about 5 degrees each day with highs 
on Saturday 10-15 degrees above normal, reaching the low 90s at 
lower elevations.

LONG TERM...Sunday through Thursday...Hot and dry weather
continues into early next week as upper ridging takes hold over
the western US. The heat will peak Sunday and Monday with lower
elevations reaching 95-100 and mtn valleys into the mid-80s. 
The 00Z deterministic models are in agreement on the ridge 
breaking down Tue/Wed in response to passage of an upper trough.
This is a favorable pattern for thunderstorms, especially with 
the hot air mass in place to start the week and injection of 
anomalous moisture from the Desert SW. Precipitable water values
increase to the 80-90th percentile just ahead of the trough. 
For now guidance has a 20-30% chance of showers and 
thunderstorms across higher terrain Tue/Wed. If this system 
holds together as current guidance shows, would expect 
probabilities to increase, even at lower elevations. Thursday 
is mostly dry with lingering high elevation showers as a broad 
trough remains positioned along the West Coast. After topping 
out around 15 degrees above normal Sun/Mon, temperatures pull 
back to around 10 degrees above normal Wed/Thur.

&&

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

&&

$$

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DISCUSSION...JM
AVIATION.....JY
SHORT TERM...DG
LONG TERM....DG