Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 230907
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
307 AM MDT Sat Mar 23 2024

.SHORT TERM...Today through Monday night...Strong southeasterly
winds are keeping temperatures in the upper 50s across the Snake
River Valley tonight, with an observed temperature of 59 at the
Boise airport as of 3am MDT. An upper level low off the Oregon
Coast is moving inland, which will bring a cold front into the
region later this morning. There are some pre-frontal light
showers moving across southeast Oregon as of 3 am MDT. Dry and
warm air near the surface will keep some of these pre-frontal
showers as virga, with potentially lower precipitation totals
than previously forecast. High-resolution model guidance
(especially the HRRR) suggests stronger showers and breezy
northwest winds as the cold front moves into southwest Idaho
this morning, with the potential for a lightning strike or two
in the Lower Treasure Valley and over Baker County-West Central
Mountains. Warmer than modeled air across the Snake River Valley
could help amplify some instability as well.

Light snow accumulations are still anticipated today across the
mountains, with anywhere from 1-3 inches expected over the
Central ID mountains above ~5500 feet. Another push of
instability and moisture will allow for a better chance of
thunderstorms in the afternoon-evening, mainly near the Nevada
border and over high terrain in Central ID/Baker County, OR.

By late Saturday, the upper level low will be to our south, and
cold northerly flow will remain over the region. Isolated
showers will mainly be over high terrain on Sunday, with snow
levels lowering to around 4000-5000 feet. Another weak
shortwave trough with some accompanying showers will move
through early on Monday, lowering snow levels to around
3500-4500 feet. A brief snow shower is possible (<10% chance)
across the Boise metro area on Monday morning, although
confidence is low.

LONG TERM...Tuesday through Saturday...It will remain cool and
unsettled through the long term period. Northwesterly flow aloft
under weak troughing will keep showers going into Tuesday,
especially over the mountains. Snow levels will remain 3500-4500 ft
MSL with highs a few degrees below normal. Northwest winds will be
breezy, especially in the afternoon. The trough will move east
Tuesday night into early Wednesday as an upper level ridge moves
overhead, bringing drier conditions. However, this will be short-
lived as another deep Pacific trough will begin to move inland
Wednesday night and Thursday. Strong southwesterly flow aloft will
develop as the system approaches, bringing gusty winds especially to
southeast Oregon on Wednesday. Temperatures will also warm several
degrees with snow levels rising to around 6000 ft MSL ahead of a
cold front. Precipitation chances will increase through the day,
peaking Wednesday night at 60-90% across the area as the cold front
moves through. Moderate snow accumulations are expected in the
mountains with generally light to moderate rainfall in the lower
valleys.

The trough will slowly move across the western US Thursday through
Saturday. This will keep temperatures near to slightly below normal
with periodic chances of precipitation, especially with the passage
of any shortwave troughs. Snow levels will hover around 3500-4500
feet. Winds will continue to be breezy, especially each afternoon.

&&

.AVIATION...Widespread rain/snow will move east across the area this
morning along a cold front. VFR/MVFR in rain showers, and MVFR/IFR
in snow showers. A strike of lightning or two cannot be ruled out
along the front. Mountains becoming obscured. Snow levels 6-7 kft
MSL lowering to 5-6kft along and behind the front. After the frontal
precipitation moves off to the east, numerous showers and isolated
thunderstorms will develop this afternoon and evening. Surface
winds: S-SE 5-15 kt, becoming SW-NW by this afternoon behind the
front with gusts to 25 kt. Winds aloft at 10kft MSL: W-SW 20-35 kt.

Sunday Outlook...Scattered to numerous showers will continue into
Sunday with snow levels 4-5 kft MSL. The highest coverage will be in
the afternoon across the mountains. Surface winds W-NW 10-25 kt,
strongest across s-central ID where gusts 30-40 kt are expected.

&&

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

&&

$$

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SHORT TERM...SA
LONG TERM....ST
AVIATION.....ST


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