399
FXUS65 KBOI 070246
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
846 PM MDT Mon May 6 2024

.DISCUSSION...Tonight, a shortwave and cold front are
traversing the forecast area, for scattered showers and
isolated thunderstorms across the forecast area. Reports
indicate brief moderate rain, small hail, and wind gusts
reaching up to 35 MPH with these showers.

As of 8 PM, the cold front is advancing across southeast Oregon
and is expected to reach the Idaho/Nevada border by 9 PM MDT.
Radar imagery reveals stronger showers along the frontal
boundary, accompanied by a few thunderstorms trailing behind.
These storms are generating wind gusts up to 45 MPH, heavy
rainfall, and small hail. Anticipate their arrival in the Boise
Metro area by 10 PM MDT and the Western Magic Valley around
midnight.

Showers will persist across much of the region late
tonight through Tuesday due to the presence of an upper-level
trough over central Idaho. This will sustain a strong pressure
gradient and a robust mid- level jet, resulting in advisory-
level surface winds in the Western Magic Valley and Southern
Twin Falls County. Tomorrow`s winds are forecasted to be
stronger than today, with sustained speeds of 30-35 MPH and
gusts up to 55 MPH. Although there`s evidence in the latest
high-res models and in the EC EFI suggesting a broader area of
advisory winds, the current advisory coverage remains adequate,
focusing on the areas most likely to experience the strongest
winds at this time. No further updates are necessary at this
time.

&&

.AVIATION...MVFR-IFR showers and isolated thunderstorms persist
along a cold front this evening. Thunderstorm activity is confined
to the West Central Mtns and SE Oregon. Showers reaching KTWF KJER
around 03-06Z/Tue. MVFR visibility, graupel/moderate rain, and gusty
W-NW winds up to 35 kt possible along front. Mountains obscured.
Showers mostly dissipate by Tue/09z, but remain isolated over high
terrain. IFR and local LIFR possible in snow above 4-5kft MSL. Sfc
winds: W-NW 10-20 kt, increasing to W-NW 15-25 kt with gusts near
TWF/JER to 35-45 kt after Tue/15z. Winds aloft at 10kft MSL: W-NW 25-
35 kt.

KBOI...VFR. Scattered showers are likely to remain in the vicinity
of the terminal, but may bring brief MVFR and gusty winds if they
track directly over. Showers clearing after 09Z/Tues. Sfc winds: NW
10-15 kt with gusts to 25 kt.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Wednesday night...A cold front
will move through the region this afternoon in southeast Oregon
and later this evening in southwest Idaho. Sufficient
instability with CAPE values around 200-400 J/kg, along with
warmer air ahead of the cold front will allow for a low chance
(<30% chance) of thunderstorms this afternoon. Heavy rain
showers are more likely, with heavier snow squalls/graupel
showers above about 4000-5000 feet today. Breezy winds will
accompany the frontal passage, with brief gusts close to 30-40
kt this evening. Gusty winds will continue this afternoon in the
Magic Valley, with Jerome and Gooding already seeing sustained
winds surpass 30 mph for much of the afternoon, and gusts
reaching 45 mph. Therefore, the wind advisory will be allowed to
remain through the 6pm time frame. Afternoon winds will pick up
again tomorrow afternoon in the Magic Valley as the low
continues to push east, so another wind advisory has been issued
for the Magic Valley tomorrow afternoon from noon-9pm MDT.
Scattered terrain driven showers will continue through Tuesday
and Wednesday throughout the region. Snow accumulation is
anticipated above about 5000 feet through Wednesday morning with
elevations above 6000 feet seeing as much as 4-6 inches and
lower elevations seeing anywhere from 0.5-2 inches.

Isolated rain and snow showers will continue in southwest Idaho as
northwest flow aloft remains over our region through Wednesday,
with widespread warming and drying beginning earlier in
southeast Oregon. Breezy northwest winds will remain intact,
especially over higher terrain in the Central ID mountains and
the Magic Valley.

LONG TERM...Thursday through Monday...An upper level ridge will
begin to build into the region early on Thursday, beginning a
warming and drying trend through the weekend. Highs will be
about 10-15 degrees above normal, with about a 60-70% chance of
the Treasure Valley exceeding 80F for Saturday and Sunday
afternoon. Model agreement in clusters and deterministic
forecast models is high through Monday morning, with some
disagreement as we get into the latter part of the long term
period. There is a low chance of precipitation on Monday
afternoon, as some models show a weak shortwave trough moving
through late Monday.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Wind Advisory from noon to 9 PM MDT Tuesday IDZ016-030.
OR...None.

&&

$$

www.weather.gov/Boise

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

DISCUSSION...JDS
AVIATION.....JM
SHORT TERM...SA
LONG TERM....SA