396
FXUS65 KBOI 230255
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
855 PM MDT Thu May 22 2025

.DISCUSSION...Westerly flow continues this evening, with showers
dissipating with the loss of the daytime heating. Expect mostly
clear skies tonight, with patchy fog over the central ID
mountains. Isolated showers and thunderstorms redevelop on
Friday afternoon, mainly over eastern OR and central ID
mountains. Current forecast on track with no updates.

&&

.AVIATION...Generally VFR. Areas of mountain obscuration.
Isolated showers and thunderstorms Friday afternoon, with
outflow gusts to 25-35 kt.Surface winds: NW 5-15kt becoming
LGT/VRB after sunset. Winds aloft at 10kft MSL: W-NW 10-20 kt.

KBOI...VFR. Wind NW 5-10kt, except LGT/VRB overnight.

Weekend Outlook...VFR and mostly clear Sat/Sun. Winds: W-NW
5-15 kt with 20-25 kt gusts on Sat, then generally E-SE 5-10 kt
Sun.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Saturday night...Afternoon showers
and thunderstorms over e-central Oregon and w-central Idaho will
diminish this evening. Outflow wind gust threat is 40 MPH for
the remainder of today. Gusty large-scale winds will continue to
gust 30-40 mph across s-central Idaho zones early this evening,
tapering off towards sunset. Tonight is dry as the first of two
shortwave troughs lifts into MT. The second trough will enter
the region on Friday elongating as it moves through the
Intermountain West. Elevated terrain will see a 20-40% chance of
afternoon showers and thunderstorms Friday. The outflow wind
potential from showers/storms on Friday will again reach 40
MPH. The Snake Plain will remain dry as conditions remain too
stable for development. Memorial Day Weekend will start off dry
as an upper ridge builds along the Cascades on Saturday. High
temperatures will warm 3-8 degrees from Friday to Saturday with
lower elevations closing in on 80F and mtn valleys nearing 70F,
or about 5 degrees above normal.

LONG TERM...Sunday through Thursday...A narrow, amplified ridge
will move overhead on Sunday, boosting temperatures to 10-15
degrees above normal with dry, calmer conditions. A weakening
Pacific trough will approach late Sunday and increase the chance
for showers and thunderstorms by Monday afternoon, but
temperatures will only lower by a few degrees as the trough
moves overhead. The trough will continue east on Tuesday, and a
chance of showers/thunderstorms will remain over central Idaho
on the backside of the trough. Models fall out of agreement on
timing and evolution, however, so forecast confidence for
temperatures and storms remains somewhat low. High pressure will
begin to build for mid-week, though lingering mid- level
moisture and increased daytime instability should re-introduce
showers and thunderstorms over the higher terrain. Currently,
Wednesday is forecast to be the hottest day of the week before
the next Pacific trough arrives Thursday.

&&

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

&&

$$

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DISCUSSION...KA
AVIATION.....KA
SHORT TERM...DG
LONG TERM....SH