Twin Falls, Idaho 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

282
FXUS65 KBOI 211054
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
354 AM MST Thu Nov 21 2024

.SHORT TERM...Today through Saturday night...The atmospheric
river will continue to impact the region today, especially in
our northern areas which will see the bulk of the precipitation.
Latest radar shows widespread precipitation extending from
eastern Oregon into central Idaho and little to no activity
south near the Nevada border. Snow levels will continue to rise,
reaching 8000+ feet near the Nevada border and 5500-6000 feet
from Baker City to McCall. A Winter Weather Advisory remains in
effect until 5 am MST this morning. The snow has already
changed over to rain in McCall, but will likely see a mix this
morning before changing over to all rain by this afternoon.

The precipitation is expected to decrease in intensity
temporarily on Friday as drier air advects into the region
within a south-southwest flow aloft, although light
precipitation will continue across the northern high terrain.
The warming trend continues as well with highs getting into the
50s across the lower valleys, with a few locations possibly
reaching into the lower 60s. A cold front is still on track to
move through Friday night, accompanied by widespread
precipitation - which may be locally heavy in the northern high
terrain. Snow levels lower to around 5000 feet behind the front
by Saturday morning. The heaviest snowfall is expected to be
limited to elevations above 6500 feet where additional snowfall
totals will likely exceeding a foot.

The widespread precip associated with the front shifts east on
Saturday, but transitions to a showery regime as moisture and
instability arrives with an upper trough. Latest models are
indicating that it will be unstable enough to support a slight
chance (20 percent) of thunderstorms in the afternoon.
Temperatures will be several degrees cooler.

.LONG TERM...Sunday through Thursday...A weak ridge will move
through the forecast area Sunday, creating a brief break from
the active wet weather. Another Pacific low will approach
Monday, spreading new rounds of moisture and precipitation
across the area for Monday and Tuesday. Snow levels will be
around 3500-4500 ft MSL, with light snow accumulations expected
in the mountains. As the low continues eastward, most model
guidance suggests a drier, northwest flow will develop for
Wednesday and Thursday. A chance (15-35%) of showers is forecast
both days, however, as weak shortwaves propagate through the
northwest flow and potentially trigger shower development.
Temperatures are expected to be right around normal for the
week.

&&

.AVIATION...Mostly VFR. Widespread rain/snow creating MVFR/IFR
at times, with a focus on high terrain. Mountain obscuration.
Snow levels 5500-7500 ft MSL. Areas of low level wind shear this
morning. Surface winds: S to SE 10-20 kt, gusts 25-35 kt,
decreasing this evening. Winds aloft at 10kft MSL: SW 35-50 kt.

.KBOI...Mainly VFR, with frequent periods of rain. MVFR
ceilings possible in heavier rain. Potential for low level wind
shear this morning. Surface winds: S to E 7-17 kt with gusts up to
20-30 kt.

WEEKEND OUTLOOK...Periods of MVFR/IFR in precipitation Friday,
with best chance from KBNO-KBOI-KSUN and north. Mountains
obscured. Snow levels around 7000ft MSL. Surface winds SE-SW
10-20 kt, with gusts 25-40 kt. Cold front Fri night thru Sat,
bringing widespread rain/snow and MVFR to LIFR conditions at
times. Lowering snow levels to 4500-5500ft MSL Saturday. Surface
winds becoming SW-NW 5-15 kt, gusts to 20-30 kt. Drier and VFR
Sunday, except in patchy fog.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory until 5 AM MST early this morning
     IDZ011-013.
OR...None.

&&

$$

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SHORT TERM...BW
LONG TERM....SH
AVIATION.....SH