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000
FXUS65 KBOI 240926
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
326 AM MDT Wed Apr 24 2024

.SHORT TERM...Today through Friday night...Southwest flow aloft
preceding an approaching upper trough near the coast will spread
some moisture into the region today. Isolated light rain showers
or sprinkles this morning will expand in some areas during the
afternoon, becoming scattered in central Idaho and at least
scattered (>40 percent) coverage in southern areas near the
Nevada border this afternoon. There is enough instability to
warrant isolated thunderstorms south of the Snake Plain this
afternoon, accompanied by wind gusts to 40 mph. High
temperatures will be on par with yesterdays readings, generally
in the 60s mountains and 70s valleys.

A cold front arrives from the northwest and sweeps through the
region tonight. A cooler/stable air mass will spread into the
area for drier conditions on Thursday, along with breezy
northwest winds. Another upper trough, which will be colder and
more moisture-laden, spreads into the area on Friday.
Precipitation chances are highest in the mountains for at least
a 60 percent chance of measurable rainfall. Precip chances in
the valleys generally range from 30 to 50 percent. Snow levels
lower to 5500-6500 feet with light snow accumulations possible
in the higher mountains. The colder air aloft associated with
the trough could provide enough instability to support a slight
chance (less than 20 percent) of afternoon thunderstorms. Breezy
northwest winds persist into Friday. Temperatures also cool
several more degrees with highs slightly below normal.

.LONG TERM...Saturday through Wednesday...An upper level
trough will exit our area to the east on Saturday. A 20-70%
chance of showers will continue on Saturday as moisture lingers
behind the departing trough, mainly over eastern areas and the
central Idaho mountains. Gusty winds will develop behind the
trough, especially in the Snake Plain east of Boise. A deep
upper level low will move across the Gulf of Alaska over the
weekend, placing our area in southwest flow aloft by Sunday.
Models then struggle with the progression of this low as it
approaches the coast. A majority of ensembles keep the low
offshore through the beginning of next week, with a cold front
stalling near our forecast area for several days. The location
of the front will have a big impact on temperatures, and highs
could end up anywhere from 10-15 degrees below normal to 10-15
degrees above normal. Moist southwest flow will keep a 10-50%
chance of showers going across our area, with the best chances
each afternoon in the mountains. Snow levels are generally
expected to remain above 5500 feet, but this will also depend on
the progression of the front. Breezy conditions will continue
through the period.

&&

.AVIATION...Mainly VFR. Isolated showers/virga this morning,
then scattered showers and isolated thunderstorms developing
this afternoon and evening, mainly near the Nevada border. Brief
MVFR/IFR conditions and mountain obscuration in storms. Gusty
and erratic winds up to 35 kt near thunderstorms. Surface winds:
variable 10 kt or less, then W-NW 10-15 kt after Wed/21Z. Gusts
to 25 kt tonight as a cold front crosses the area. Winds aloft
at 10kft MSL: SW-NW 10-20 kt.

KBOI...VFR under mid to high level clouds. Isolated showers
today, mainly this morning. Surface winds: variable 6 kt or less
this morning, then NW 8-12 kt after Wed/18Z.

&&

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

&&

$$

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SHORT TERM...BW
LONG TERM....ST
AVIATION.....ST