FXUS65 KBOI 032042
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
242 PM MDT Tue Sep 3 2024

.SHORT TERM...Tonight through Thursday night...Showers and
thunderstorms over the w-central Idaho mountains this afternoon
will dissipate around sunset. The thunderstorms will be capable
of producing outflow wind gusts to 40 mph. This activity is
associated with an upper trough that will exit the region
tonight, being replaced by a dry, stable high pressure aloft on
for Wednesday and Thursday. Along with warmer temperatures this
pattern will bring light winds surface and aloft impacting
mixing and smoke transport from the large number of wildfires
across eastern Oregon and western Idaho. Because of this, expect
much of the smoke output to settle into valleys through
Thursday. Besides impacting air quality, the smoke will likely
take a few degrees off of high temperature potential.

.LONG TERM...Friday through Tuesday...High pressure aloft peaks
on Friday with temperatures above normal. The ridge axis shifts
east on Saturday as an upper trough swings into northern CA.
The increased moisture and instability/lift ahead of this low
will support a 20% chance of showers and thunderstorms Saturday
afternoon across SE Oregon and higher terrain south of the
Snake Plain in Idaho. While Saturday night is currently marked
dry, will need to watch the low for the potential to extend
that coverage further north and east. Sunday and Monday are
mostly dry with increasing southwesterly flow aloft as an upper
trough approaches the Pac NW coast. Low chances for
showers/storms persist across higher terrain of south-central
Idaho where moisture and instability overlap. Tuesday will see
an uptick in the chance for afternoon showers/storms as the
trough digs along the coast. While ensemble guidance is painting
a broad area of low chance precipitation (20% or less) there
are signs of a dry slot on the east side of the trough which
could limit development. For now there is too much uncertainty
to pin down that detail. Temperatures are forecast to be well
above normal through the weekend, though mtn valleys and
possible larger valleys will continue to struggle with
mixing/heating due to wildfire smoke.

&&

.AVIATION...Low VFR, with areas of MVFR to LIFR and mountain
obscuration in smoke. Isolated to scattered showers and
thunderstorms continue through 03Z this evening, mainly in NE
Oregon along the Idaho border and across central Idaho. Surface
winds: W-NW 5-15 kt. Gusts up 25 kt this afternoon in S-central
Idaho east of KMUO. Outflow from thunderstorms will be up to 35
kt. Winds aloft at 10kft MSL: W to NW 10-20 kt.

KBOI...MVFR in smoke. Possible IFR late tonight/Wed. Surface
winds generally W-NW with gusts to 15 kt this afternoon.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Red Flag Warning until 9 PM MDT this evening IDZ402-403.
     Red Flag Warning until 4 PM MDT this afternoon IDZ400-401.
OR...None.

&&

$$

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SHORT TERM...DG
LONG TERM....DG
AVIATION.....DG