436
FXUS65 KBOI 061549
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
949 AM MDT Mon May 6 2024

.DISCUSSION...A low pressure system moving away to our east is
enhancing the pressure gradient in s-central Idaho. Winds in the
Western Magic Valley are already near advisory levels. Jerome
airport is reporting sustained winds near 30 mph. A Wind
Advisory is in effect for the Western Magic Valley and Southern
Twin Falls County today. The precip associated with the exiting
low has ended, but an upper trough to our west will bring a
round of showers later today through tonight. There is enough
instability for isolated thunderstorms this afternoon, some of
which will be capable of producing gusty winds to 45 mph and
small hail. No updates planned.

&&

.AVIATION...MVFR-IFR in showers this morning, becoming VFR.
Snow level 4000-5000ft. Mountains obscured. MVFR-LIFR showers
and thunderstorms form along a cold front this afternoon, around
21Z/Mon KBKE KBNO, reaching KONO KEUL KBOI 01-02Z/Tue and KTWF
KJER around 04-05Z/Tue. Low visibility, graupel/heavy rain, and
gusty W-NW winds up to 40 kt possible along front. Sfc winds:
W-SW 10-20 kt, with gusts up to 35 kt near KTWF KJER. Winds
aloft at 10kft MSL: W-NW 25-40 kt.

KBOI...VFR with lingering low clouds near the foothills this
morning. Scattered showers in the vicinity of the terminal after
22Z/Mon. Brief MVFR to LIFR thunderstorms/heavy rain with NW
gusts up to 45kt possible 02-03Z/Tue along front. Showers
clearing after 09Z/Tues. Sfc winds: NW 8-12 kt.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Wednesday night...The back edge of
precipitation accompanying a large low pressure system is
exiting Oregon early this morning and will clear SW Idaho zones
by mid-morning. The pressure gradient on the back side of the
the departing low will feed gusty winds through the Snake Plain
especially across the western Magic Valley. Have kept with the
Wind Advisory for today though this event looks to be on the
lower end. After a brief break, the next round of showers will
fire off this afternoon ahead of a shortwave trough pushing in
from the coast. This is a dynamic, cold-core system that will
support showers and isolated low-topped thunderstorms as it
advances through the region through this evening. Gusty winds to
45 mph and graupel or small hail are possible from stronger
showers/storms. Showers continue overnight, mainly in the
mountains and along the foothills as we remain on the western
edge of a broad upper trough. Daytime instability on Tuesday
will return a low chance of showers (15-25%) to the valleys
while mountain sites keep a 50-80% chance of snow showers
through sunset. Snow levels of 4-5kft today will lower to
3500-4500 feet on Wednesday. Accumulation of up to 2 inches is
possible in mountain valleys with an additional 3 to 8 inches
above 5500 feet. The thunderstorm threat for Tuesday is minimal
(10% across higher terrain) so have left it out of forecast.
Wednesday will trend drier across the region as an upper ridge
folds pushing the lingering trough to our south and east.
Temperatures are 10-15 degrees below normal through Wednesday,
with Tuesday being the coldest day in the period.

LONG TERM...Thursday through Monday...An upper level ridge is
forecast to build over the Pacific NW and southwest Canada on
Friday into the weekend with dry conditions. Record breaking
temperatures possible over portions of the Pacific NW and
British Columbia, but the center of the ridge will be north and
west of our area, where the warmer temperatures are. This will
keep a slightly cooler north-northwest flow aloft over the area.
Temperatures raise to around 10 degrees above normal for
Saturday through Monday.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Wind Advisory until 6 PM MDT this evening IDZ016-030.
OR...None.

&&

$$

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DISCUSSION...BW
AVIATION.....SA
SHORT TERM...DG
LONG TERM....KA