223
FXUS65 KBOI 040243
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
843 PM MDT Thu Jul 3 2025

.DISCUSSION...Thunderstorms developed in se Oregon late today
and this evening, not quite severe but strong enough for gusts
to 50 mph. Fewer showers and storms were occurring elsewhere
this evening. Activity will decrease but not end in our CWA
through the night then ramp up early Friday morning as a short
wave trough approaches from the southwest.

A Flash Flood Watch has been issued for The West Central Idaho
Mountains and Boise Mountains for 6 AM MDT to 2 PM MDT Friday.
The watch area includes the Wapiti Burn Scar on Idaho state
highway 21. Latest hi-res models show a distinct band of showers
and thunderstorms with embedded heavy-rain cores moving
northeastward through the watch area Friday morning, especially
between 7 AM and 11 AM MDT, although other models also have
significant rain through 2 PM MDT. This pcpn is associated
with the approaching short wave trough. After brief ridging
and relative clearing Friday afternoon a second trough is
expected Friday night. Due to the forward speed of the first
trough, rains may not last long but the intensity looks
sufficient for downpours up to .25 inch in 15 minutes.

&&

.AVIATION...Numerous showers and thunderstorms through Friday
morning, becoming scattered Friday afternoon/evening. Threats:
erratic outflow gusts to 30-45 kt, small hail, lightning,
moderate to heavy rainfall. Localized MVFR/IFR conditions and
mountain obscuration in storms. Surface winds outside of storms:
variable 5-15 kt. Winds aloft at 10kft MSL: generally SW 10-20
kt

KBOI...Mostly VFR. Periods of showers/thunderstorms through 05/14Z.
Threats: erratic outflow gusts to 30-45 kt, small hail, lightning,
moderate to heavy rainfall. MVFR conditions possible with storms,
along with foothill obscuration. Showers/thunderstorms exit after
05/14Z, then chance of thunderstorms Fri afternoon. Surface winds
outside of storms: NW 5-15 kt, becoming SW-NW 5-15 kt overnight.

Weekend Outlook...Generally VFR. A 15-25% chance of showers and
thunderstorms Saturday morning in W-central Idaho, then clearing
through Sunday. Surface winds variable or NW 5-15 kt.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Saturday night... As of writing
this (2pm MDT), thunderstorms have begun developing along the
Nevada boarder and over the Idaho central mountains with a
cumulus field developing over eastern Oregon. The expectation
is for more storms to develop, mostly in eastern Oregon, within
the next few hours before moving northeast through the evening.
Hazards associated with these storms include small hail, wind
gusts up to 55mph, and localized areas of blowing dust.
Widespread rain showers with embedded thunderstorms will develop
overnight tonight. This is thanks to the first shortwave out of
a one two punch embedded within a negatively tilted trough.
With the shortwave lowering heights and bringing cooler air in
aloft, model soundings show weak elevated instability holding on
overnight. While these nocturnal storms will be slightly
weaker, they are still capable of producing locally heavy
rainfall, small hail, and wind gusts up 50mph. In regard to
sloped terrain and burn scars, rainfall rates with this round
will generally be under 0.25 inches/hour, so have opted to not
issue any hydro products.

As the first shortwave and associated precipitation exits our
area, slight ridging builds in ahead of the next shortwave. This
will allow for a break in precipitation across most of our area
around midday. Models are showing good airmass recovery after
the morning shower/thunderstorms, and the cap associated with
the low-amplitude ridge will allow for more instability to build
with the HREF mean showing 500-1000j/kg. As the next shortwave
moves across the area Friday afternoon, this instability,
paired with shear values of 40-60 kt, mean that storms that
develop could become severe. With hazards include wind gusts up
to 60mph, hail, and localized heavy rain/blowing dust
Temperatures drop to a few degrees below normal on Friday,
staying in the 80s throughout the Snake Plain Friday/Saturday.


LONG TERM...Sunday through Thursday...Ridging is the name of
the game through next week. Models are in good agreement of an
upper-level ridge setting up over the Four Corners region, with
a trough off the coast of California keeping our area in
Southerly flow aloft. As this ridge builds, temperatures take on
warming trend reaching roughly 10 degrees above normal by
Monday. Heat headlines may be needed in the week to come as a
result of the prolonged hot temperatures.


&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Flash Flood Watch from 6 AM MDT Friday through Friday
     afternoon IDZ011-013.
     Red Flag Warning until 1 AM MDT Friday IDZ426.
OR...Red Flag Warning from 3 AM MDT /2 AM PDT/ to 11 PM MDT /10 PM
     PDT/ Friday ORZ670-672>674.
     Red Flag Warning until 8 PM PDT this evening ORZ670-672.

&&

$$

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DISCUSSION...LC
AVIATION.....SH
SHORT TERM...NF
LONG TERM....NF