242
FXUS65 KBOI 170235
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
835 PM MDT Sun Jun 16 2024

.DISCUSSION...PoP, QPF, and snow amount forecasts have been
updated through Monday night based on latest model trends and
hi-res info. Models have trended gradually wetter since this
morning especially in northern zones. Radar imagery at 8 PM MDT
showed scattered light rain showers in eastern Oregon and
beginning to enter western Idaho near Farewell Bend and the
Owyhee Mountains. No changes were made to Temp, wind, and
thunderstorm forecasts. The very cold upper low center is
forecast to move eastward across our northern zones Monday but
will still be close enough to continue showers (snow above 5000
feet MSL) in Idaho north of the Snake Basin Monday night.
Warming trend starting Tuesday will lead to hot weather late
next week, possibly reaching 100 degrees in the lower southern
valleys Saturday.

&&

.AVIATION...Showers increasing overnight. Isolated thunderstorms
developing Monday afternoon, mainly over the central ID mountains.
Showers will be most numerous across Baker County OR and the west-
central ID mtns. Snow levels 4500-6000 ft MSL. Areas of MVFR/IFR
conditions developing and mountains becoming obscured as
precipitation expands. Surface winds: W-NW 10-20 kt with gusts
20-30 kt tonight into Monday. Winds aloft at 10kft MSL: SW 15-25
kt, becoming W-NW 15-30 kt after Mon/09Z.

KBOI...Rain showers developing between Mon/08Z and Mon/19Z. 20-40%
chance of rain at the terminal during this period and temporary MVFR
ceilings, with the highest chance late Monday morning. Surface
winds: NW 5-10 kt, increasing to 10-20 kt with gusts 20-30 kt.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Tuesday night...An upper low will
bring unseasonably cool, showery, and windy conditions to the
region on Monday. A cold front out ahead of it will move through
tonight, accompanied by gusty winds to around 30 mph. Showers
associated with the low initiate over SE Oregon this evening,
then SW Idaho on Monday as the core of the low moves through
central Idaho. The bulk of the showers and greatest precip
amounts are expected in central Idaho. Snow levels lower to
around 4500 feet with some light snow accumulations above 5000
feet, including McCall where around an inch of snow is forecast.
Only minor road impacts are anticipated, and mainly in the
early morning hours. Total snowfall amounts of 3 to 6 inches are
forecast for the northern mountains above 6000 feet through
late Monday. Shower chances and precip amounts are much lower in
the valleys (20-40 percent chance with less than a tenth of an
inch), including the Treasure Valley. Winds increase during the
afternoon, especially in south-central Idaho east of Mountain
Home where speeds/gusts will approach advisory levels (sustained
near 30 mph with gusts near 45 mph). Marginal instability due
to the cold air aloft will lead to a slight chance (less than 20
percent) of afternoon thunderstorms. Showers and winds diminish
Monday night as the low exits to the east. A weak upper trough
arrives from the northwest on Tuesday for a chance of
showers/slight chance of afternoon thunderstorms (15-30 percent)
in central Idaho. The unseasonably cool temperatures on Monday
(15-20 degrees below normal) trend 5-10 degrees warmer on
Tuesday.

LONG TERM...Wednesday through Sunday...The cooler/showery/windy
weather early in the week will be long forgotten by the end of
the week as hot temperatures return. Southwest flow aloft develops
midweek and lasts into next weekend, supporting a gradual
warming trend each day. Highs are favored to reach the lower 90s
in the valleys by Friday and mid-upper 90s Saturday and Sunday.
There is not enough moisture in the flow to warrant any
convection, although even limited moisture could yield
afternoon convection as the heat builds. For now, the forecast
remains dry.

&&

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

&&

$$

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DISCUSSION...LC
AVIATION.....JR
SHORT TERM...BW
LONG TERM....BW