843
FXUS65 KBOI 031016
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
416 AM MDT Fri May 3 2024

.SHORT TERM...Today through Sunday night...Any lingering
showers wrapping around an exiting upper trough will dissipate
by mid-morning. The exiting trough is replaced by an upper
ridge this afternoon, resulting in dry weather and temperatures
5-10 degrees warmer than yesterday.

Upstream, a deep Pacific low will approach the NW coast on
Saturday. This system will be punctuated by heavy precipitation
and gusty winds as it pushes into the region late Sat/Sun. The
winds will increase out of the S-SE on Saturday in advance of
the low. Widespread sustained winds of 20-30 mph with gusts to
40 mph are expected. Locally stronger winds could set up over SE
Oregon Saturday and in portions of the Snake Plain east of
Boise that would require headlines.

A band of heavier precipitation will form ahead of a cold front
that will push into SE Oregon Saturday afternoon, then cross
into SW Idaho by evening. Marginal instability and surface
energy will support a 15% chance of thunderstorms over
s-central Idaho Saturday. Storms that do form will have a
favorable shear profile and could become strong. The front will
bring a wind shift to the NW Saturday night that will be
reinforced by flow aloft on Sunday. Precipitation will continue
on Sunday as it wraps around the low center which is forecast
to track through northern NV. The probability for precipitation
totals of over 0.25" has increased to greater than 80% across
SE Oregon and SW Idaho through Sunday. The axis of heavier
precipitation remains near the OR/ID border where the chance of
exceeding an inch of liquid through Sunday is 15-30%. Snow
levels ahead of the front will rise to 6-9kft Saturday evening,
falling quickly behind the front Sunday morning. This could
bring accumulating snow to SE Oregon as snow levels briefly
drop to around 3000 feet early Sunday. Otherwise much of the
accumulating snow is above 5500 after the frontal passage.
Precipitation continues in the mountains through Sunday night
while valleys trend drier.

.LONG TERM...Monday through Friday...Northwest flow continues in
the wake of the exiting trough on Monday. Models show trailing
shortwave energy that will keep a chance of showers over the
region through Tuesday. An upper ridge will build along the
coast Wednesday, gradually folding inland through Friday.
Deterministic and ensemble solutions are in good agreement with
with this pattern change. Afternoon instability will support a
15-30% chance of showers over the mountains while lower
elevations remain dry. Temperatures through Wednesday are 10-15
degrees below normal, warming to near normal Thur/Fri.

&&

.AVIATION...VFR. A few lingering showers over SW Idaho early
this morning will dissipate by 15Z. Local valley fog/stratus
could lower conditions to IFR through 18Z. Mountains will see
scattered to broken cumulus field with bases 3500-5500ft AGL.
Surface winds: variable or NW 5-15 kt, then S to SE 5-15 kt Fri
afternoon. Winds aloft at 10kft MSL: NW to NE 15-25 kt, veering
to S after Fri/15Z.

KBOI...VFR and clearing Friday. Light NW or variable winds,
becoming SE 5-10 kt after Fri/21Z.

Weekend Outlook...Widespread precipitation moves into SE Oregon
mid-morning Saturday, then into SW Idaho Saturday afternoon and
will continue across the region through Sunday. A 20% chance of
thunderstorms Saturday afternoon in s-central Idaho. Snow
levels 6000-8000 ft MSL, lowering to 4000-5000 ft Sunday. IFR
and widespread mountain obscuration Saturday night and Sunday.
Surface winds: SE 15-25 kt with gusts 25-35 kt Saturday
afternoon, W 5-15 kt with gusts to 25 kt Sunday.

&&

.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...DG
LONG TERM....DG
AVIATION.....DG