313
FXUS65 KBOI 182028
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
228 PM MDT Sat May 18 2024

.SHORT TERM...Tonight through Monday night... The successive
upper level lows to our north will continue to bring near
normal temperatures and breezy westerly winds to most of the
forecast area. A low chance of showers (30% chance or less)
exists for the West Central and Baker County, OR mountains late
this evening into Sunday morning from the passing front. Snow
levels will be right around 5000 feet overnight, jumping to
6000 feet during the day, so some late showers this evening
could bring some snow flurries to mountain valleys north of
a Cascade, ID-Baker City, OR line.

Cooler temperatures are anticipated for the region late Sunday
into Monday as a trough digs into the region, bringing a cooler
air mass over the Intermountain West. This air mass will most
likely be dry, but some models are showing weak showers over the
Central ID mountains on Monday morning. This low will then
slowly move east on Monday evening, but wraparound showers are
likely (40-50% chance) over higher terrain that evening. Current
hi-res model blends show weak thunderstorms forming near the
OR-NV order and over the Snake River Valley in ID, although
confidence is low with exact locations of convective
development.

.LONG TERM...Tuesday through Saturday...An upper level trough
will move to the east on Tuesday, bringing dry and cool
northerly flow to the region as a weak ridge builds in by
Tuesday afternoon. This will bring a slight warming trend ahead
of a deep cut off low on Wednesday. There is substantial model
agreement in cooler temperatures and widespread precipitation at
some point on Wednesday-Thursday, but there`s still significant
variability in precipitation timing. Current forecasts show
around a tenth of an inch of QPF in the valleys, with up to
three quarters of an inch in the mountains by Thursday evening.
Snow accumulation is mostly isolated to above 6000 feet, with
around 1-3 inches expected by Thursday evening to those
elevations. A similar pattern to earlier in the week will
return on Friday, with dry upper level northwest flow ahead of
another potential system incoming on Saturday. Models currently
disagree much more on timing and positioning of that upper level
low.

&&


.AVIATION...VFR with some high clouds over the region. Surface
winds: SW to NW 5-15 kt with gusts to 20-30 kt. Then, NW gusts
up to 30-40 kt spreading through the Snake Plain from KBKE/KONO
to KMUO/KTWF this evening/overnight with cold front. Winds
aloft at 10k ft MSL: W 20-35 kt.

KBOI...VFR. Increasing high clouds. Winds light and variable,
becoming NW 5-10 kt around Sat/21Z. Increasing to 10-15 kt with
gusts 20-30 kt around Sun/06Z, due to cold front.

Sunday Outlook...VFR. Increasing clouds for northeast OR and
West Central ID mountains Sunday, and 20-50% of showers. Snow
levels 5000-6000 ft MSL. Surface winds: W to NW 10-20 kt on
Sunday. Local gusts to 25-30 kt in the Snake Plain.

&&

.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...SA
LONG TERM....SA
AVIATION.....SA