174
FXUS65 KBOI 090259
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
859 PM MDT Tue Jul 8 2025

.DISCUSSION...A weak shortwave is tracking across northeast OR
this evening and has been the focus of showers and
thunderstorms north of Baker City and Burns OR. Showers and
storms should weaken with the loss of daytime heating after
sunset. A more vigorous shortwave off the northern CA coast will
move inland overnight and across southeast OR and southwest ID
on Wednesday afternoon, with scattered showers and
thunderstorms areawide. Storms will be capable of producing
outflow wind gusts up to 60 mph during the afternoon and
evening, with blowing dust reducing visibilities. Temperatures
will be around 5-10 degrees cooler on Wednesday afternoon.
Current forecast on track with no updates.

&&

.AVIATION...Mainly VFR under mid to high clouds. Isolated showers
and thunderstorms across SE Oregon and the central Idaho mountains
dissipating late this evening. Gusts up to 40 kt near thunderstorms.
Isolated to scattered showers and thunderstorms will develop across
the area Wednesday PM. Gusts up to 50 kt and blowing dust reducing
visibility will be possible. Surface winds: SW-NW 5-15 kt, except
gusty/erratic outflow winds near thunderstorms. Winds aloft at 10kft
MSL: SW 5-15 kt.

KBOI...VFR through Wednesday afternoon. Surface winds: variable less
than 10 kt tonight, except occasional outflow gusts up to 25 kt from
the W-NW this evening. Winds NW 7-13 kt with gusts to 20 kt
Wednesday afternoon.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Thursday night...Upper-level
ridging will lead to the hottest temperatures of the current
heat event this afternoon/evening, with the Treasure Valley
reaching 100-105 degrees. As a result, the Heat Advisory remains
in effect. Mid- level moisture from yesterday`s showers and
thunderstorms in central Oregon will track northeast, bringing a
15-20% chance of thunderstorms to southeast Oregon and the
west-central Idaho mountains. These storms are expected to be
small, short-lived, and produce little rainfall due to marginal
conditions and weak shear. Isolated wind gusts of up to 45 mph
are possible.

A closed low-pressure system currently off the northern
California coast will move northeast through southeast Oregon
and southwest Idaho on Wednesday, creating favorable conditions
for widespread thunderstorm development across much of the
forecast area. Steep mid-level lapse rates and DCAPE values
approaching 1500 J/KG suggest a potential for strong to severe
outflow winds (50-60 MPH), which could impact areas far from the
thunderstorms. In addition to the strong winds, blowing dust
could affect visibility. With the strong winds, dry conditions
and lightning, there is an increased risk of fires as well.
Slight cooling aloft and increased cloud cover will reduce high
temperatures by 5-8 degrees compared to today. Thunderstorm
activity will decrease early Wednesday night as the upper low
moves eastward.

Thursday will be dry and cooler, with high temperatures
approximately 5 degrees below normal. Breezy conditions are
expected, with wind gusts of 25-35 mph possible on the Snake
Plain east of Boise.

LONG TERM...Friday through Tuesday...Models and ensembles
consistently depict a dry northwest flow aloft establishing over
the region on Friday and continuing through early next week.
Temperatures will be near normal on Friday, rising to about 5
degrees above normal over the weekend, with little day-to-day
variation through Tuesday.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Red Flag Warning from 3 PM Wednesday to midnight MDT Wednesday
     night IDZ400-420-423-424-426.
     Heat Advisory until 9 PM MDT this evening IDZ012-014.
OR...Red Flag Warning from 3 PM MDT /2 PM PDT/ Wednesday to
     midnight MDT /11 PM PDT/ Wednesday night ORZ670-672>674.
     Heat Advisory until 9 PM MDT /8 PM PDT/ this evening ORZ064.

&&

$$

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DISCUSSION...KA
AVIATION.....ST
SHORT TERM...JDS
LONG TERM....BW