089
FXUS65 KBOI 130244
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
844 PM MDT Sat Jul 12 2025

.DISCUSSION...Hot and dry conditions will continue through
Monday as a weak upper level ridge builds across the
Intermountain West. As of 8 PM MDT, the newly ignited Highland
Fire in Crook County, Oregon is producing a significant amount
of smoke, which is expected to move into Harney County later
tonight. This will add to the elevated smoke layer already
drifting in from fires in northern California and southwestern
Oregon, which is forecast to reach much of southeast Oregon
overnight. Some of this smoke may reach southwest Idaho late
Sunday, mainly south of the Snake River Plain.

A Heat Advisory remains in effect for the Lower Treasure Valley
from 12 PM MDT (11 AM PDT) to 9 PM MDT (6 PM PDT) on Monday.
High temperatures will range from 101 to 105 degrees both Sunday
and Monday in the Lower Treasure Valley, with the rest of the
Snake River Plain reaching around 100 degrees. Overnight lows
leading into Monday will remain warm, staying just above 70
degrees in the Lower Treasure Valley.

&&

.AVIATION...VFR. Localized smoke near wildfires. New fire in
Crook County, OR that may have smoke effects for KBNO. High
density altitude during afternoon hours due to hot temperatures.
Surface winds: light and variable overnight, becoming NW 5-15
kt in morning with 15-20 kt afternoon gusts. Winds aloft at
10kft MSL: NW 5-15 kt.

KBOI...VFR. Surface winds: light and variable overnight,
becoming NW 7-12 kt with gusts to 20 kt in the afternoon.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Monday night...Dry and hot through
Monday as an high pressure aloft builds across the great basin.
The Heat Advisory remains in affect for our Lower Treasure
Valley zones. from 12pm MDT (11pm PDT) until 9pm MDT (6pm PDT)
Monday. Temperatures will make it to 101-105 degrees both days
in the Lower Treasure Valley, with the rest of the Snake Plain
making it to around 100 degrees. In addition to the hot daytime
temperatures, overnight lows leading into Monday will stay a few
degrees above 70 degrees in the Lower Treasure Valley. On
Monday, model guidance continues to show monsoonal moisture
making it north of the Nevada border. Because of this moisture,
and guidance showing CAPE values >150j/kg building in, a slight
chance (10-15%) of showers/thunderstorms has been introduced
along and north of the Nevada border. The main hazards
associated with storms that develop would be gusty outflows and
lightning. Aside from that, the rest of our area is looking to
remain dry.


LONG TERM...Tuesday through Saturday...A upper-level trough
will dig down from British Columbia on Tuesday, which introduces
some uncertainty into the forecast. The Euro solutions have it
grazing our area to the north, whereas the GFS is much more
aggressive and digs it down across our area bringing a cold
front with it. For now, this feature brings a 15-20% chance of
precipitation in northeastern Valley county Tuesday afternoon.
The varying solutions also brings uncertainty into the high
temperatures on Tuesday. While much is left to be resolved, breezy
winds and low RHs associated with this feature could result in
elevated fire conditions. Beyond Tuesday, Quasi-zonal flow aloft
should keep temperatures near normal (although leaning slightly
above normal) for the remainder of the week.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Heat Advisory from noon Sunday to 9 PM MDT Monday IDZ012.
OR...Heat Advisory from noon MDT /11 AM PDT/ Sunday to 9 PM MDT /8
     PM PDT/ Monday ORZ064.

&&

$$

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DISCUSSION...JDS
AVIATION.....CH
SHORT TERM...NF
LONG TERM....NF