734
FXUS65 KBOI 232134
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
234 PM MST Mon Dec 23 2024

.SHORT TERM...Tonight through Wednesday night...The region will
be between weather systems overnight through early Tuesday, with
the next system coming ashore along the coast. Enough moisture
exists for patchy fog Tuesday morning in the lower Treasure
and Long Valley. The next system is slated to move into eastern
Oregon and southwest Idaho for the latter half of Tuesday with a
mix of rain/snow for the lower valleys and snow above 6000 feet.
This next system is expected to move east of the area on
Christmas Day, with above normal temperatures and sunshine on
tap. Clouds will increase Wednesday Night into early Thursday
with snow levels dropping to near valley floors overnight ahead
of the Thursday system.

.LONG TERM...Thursday through Monday...Our much-talked about active
pattern is coming, and will be with us through the long term period.
A strong system will arrive Thursday, with additional storms coming
in Friday, Saturday, and Sunday. Monday may end up dry, but for now,
timing differences in the models make it a good idea to keep a
chance of rain/snow over most of the area Monday. Temperatures and
snow levels will be higher than normal, resulting in rain in the
valleys and snow in the mountains, with only slight exceptions. One
of those exceptions could be Thursday morning, as models are
trending colder and now show around a 50/50 split on whether the
Boise area will see a wet snow or a cold rain Thursday morning.
Regardless, if snow falls, it will melt off quickly as the high
Thursday is expected to be in the mid 40s throughout the Treasure
Valley. For the remaining systems, snow levels will vary between
4000 and 7000 ft MSL, keeping the snow well into the mountains after
Thursday morning. With such a prolonged event, snow totals in the
mountains could be quite high, with models still showing widespread
2 to 4 ft amounts, with the highest peaks potentially getting 6 ft.
McCall is currently forecast to get around 15 inches, and they may
see rain mix in with snow at times (especially Sat/Sun). Finally,
mid-elevations rain may result in rises on rivers, with the Weiser
River at Weiser (for ex) currently forecast to rise significantly
(but not to flood stage as of the latest forecast).

Temperatures will be 5-10 degrees above normal Thursday and Friday
and 10-15 degrees above normal over the weekend. Winds will be
breezy through the period with each passing system.


&&

.AVIATION...Mainly MVFR/IFR in low clouds near KONO/KEUL/KMAN/KBOI,
with low clouds also observed near KBNO and KMYL. These may briefly
improved this afternoon, but could return this evening. Surface
winds: Variable less than 10 kt today, becoming E through S through
E 5-15 kt tonight. Winds aloft at 10kft MSL: W-NW 20-35 kt, becoming
SW 20-40 kt after 03Z/Tue.

KBOI...Lowered ceilings will result in MVFR/IFR conditions this
afternoon, with a chance (60%) they will return this evening before
SE winds increase and eliminate them. This is the biggest change
from this morning`s thinking. Surface winds light and variable,
becoming SE 5-15 kt this evening.


&&

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

&&

$$

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SHORT TERM...MC
LONG TERM....SP
AVIATION.....SP