Area Forecast Discussion
Issued by NWS Boise, ID

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
000
FXUS65 KBOI 242003
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
203 PM MDT Sun Mar 24 2024

.SHORT TERM...Tonight through Tuesday night...As a large upper
low moves SE out of our area, northwest flow will prevail behind
it through the short term. A few weak disturbances will lead to
periods of increased precipitation tonight and Tuesday. However
precipitation remains possible through the period. The
instability tonight will be the highest in the short term
period thanks to the cold airmass and a shortwave, with
numerous convective showers and isolated thunderstorms area
wide. Snow levels 4000-5000 ft MSL. Any thunderstorms that do
develop may produce pea-size hail and locally gusty/erratic
winds, while we expect lightning coverage to be fairly limited.
Thunderstorm development is expected to cease just after sunset
while a few showers may linger into the night. The shortwave
will also cause winds between Mtn Home and the Magic Valley to
gust up to 40 mph. Breeziness returns each afternoon, with the
strongest winds staying in the Magic Valley area. Temps hold
steady at just below normal, leading to little change in the
snow levels. Coldest low temps are expected Monday morning, with
many locations in the Snake Plain at or just above freezing.
Tuesday night the unsettled weather ends as an upper ridge
moves in from the west.

LONG TERM...Wednesday through Sunday...A pronounced ridge aloft
will develop briefly on Wednesday, in response to a deepening low-
pressure system along the Pacific Northwest Coast. This will result
in slightly above-average temperatures and predominantly dry
conditions throughout the region for a majority of the day. An
associated cold front will traverse the Pacific Northwest and enter
the Intermountain West, bringing snowfall in mountainous areas and
rain in valleys late Wednesday night into Thursday. Snowfall is
anticipated at elevations of approximately 4500-6000 feet over an
extended period, with substantial accumulations possible in the
Central Idaho mountains. Thursday appears to be the most favorable
day for snow accumulation. Warmer temperatures will maintain snow
ratios below normal levels, particularly in mountain valleys.
Ensemble forecasts indicate a 50% probability of a 24-hour snowfall
total exceeding 6 inches in McCall, Idaho, assuming a snow-to-liquid
ratio of 10 to 1. Most guidance suggests snow-to-liquid ratios
ranging from 5 to 8 to 1 with surface temperatures near freezing,
which would significantly reduce snowfall amounts.

There is improved agreement among ensemble forecasts regarding the
path of a low-pressure system next weekend. A majority of ensemble
solutions, both clustered and deterministic, indicate that the low
will descend off the California coast. The highest probability of
precipitation with significant snow accumulation at high elevations
(40-50% chance) will be near the Nevada border on Friday and
Saturday, with light showers anticipated (30-40% chance) over
mountainous terrain in the Central Idaho Mountains. This will also
maintain temperatures close to normal levels. Ensemble forecasts
remain in good agreement regarding a tilting ridge over the region
as the low deepens over Southern California by late Sunday. This
will result in a return to above-average temperatures and
predominantly arid conditions late Sunday.

&&

.AVIATION...Scattered MVFR rain and snow showers return this
afternoon, mainly to the higher terrain. A few lightning strikes are
possible with the stronger showers this afternoon. Mountains
obscured in low ceilings and precipitation. Surface winds: W-NW 10-
20 kt except W-NW 20-30 kt near KJER/KTWF. Winds aloft at 10kft MSL:
W-NW 15-30 kt.

&&

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

&&

$$

www.weather.gov/Boise

Interact with us via social media:
www.facebook.com/NWSBoise
www.twitter.com/NWSBoise

SHORT TERM...JM
LONG TERM....JDS
AVIATION.....JDS


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.