Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 220235
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
835 PM MDT Thu Mar 21 2024

.DISCUSSION...No showers on KCBX radar this evening but
clouds suggest light showers in Baker County and near the
ID/OR/NV corner. These should end by midnight as an upper
ridge comes in from the west. The ridge, along with southerly
surface winds, will bring several degrees warming Friday and
fewer clouds than today. Clouds will increase Friday evening
as a Pacific cold front approaches. The front will pass through
eastern OR after midnight Friday night and western Idaho early
Saturday morning, bringing showers, colder air, and lower snow
levels. Showers will decrease from west to east during the day
Saturday. Post-frontal west winds will increase, especially
across southern OR. This is all well-covered by current
forecast. No updates.

&&

.AVIATION...VFR and dry with mid and upper level clouds.
Surface winds: Variable less than 10 kt. Winds aloft at 10kft
MSL: W 15-30 kt, becoming SW by 18Z Friday.

Weekend Outlook...Mid to high clouds will remain overhead
Friday. A cold front will bring widespread rain and snow
Friday night and Saturday morning. Expect lowering ceilings
with periods of MVFR/IFR conditions and mountain obscuration.
Showers will continue Saturday afternoon into Sunday. Surface
winds S-SE 10-20 kt on Friday, becoming W-NW 10-20 kt Saturday
into Sunday. Winds generally strongest each afternoon, with
gusts to 30 kt in the higher elevations and across s-central
ID.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Saturday night...Isolated showers
through this evening, mainly over the west central ID mountains
as a warm front lifts northward into MT. Southwest flow sets up
over southeast OR and southwest ID on Friday, bringing mild
temperatures around 10 degrees above normal. Mid and high level
clouds will keep temperatures from reaching full heating
potential, but still reach the upper 60s to low 70s Friday
afternoon. A cold front will move across the region on Saturday
morning bringing widespread precipitation and lowering snow
levels. Snow levels initially start out around 7000-8000 feet,
but lower to 4500-5500 feet by Saturday afternoon. Snow
accumulations of 2 to 4 inches possible over the mountains
above 6000 feet through Saturday night. Breezy conditions
expected behind the front Saturday afternoon, with west-
northwest winds 15-25 mph with gusts to 35 mph in eastern OR
and the Magic Valley in ID.

LONG TERM...Sunday through Thursday...An upper level trough
will be well-established over the region Sunday morning. This
will bring a continued chance of showers. Snow level will
increase from around 4000 ft in the morning to 4500-5000 ft in
the afternoon. Northwest winds will be breezy, gusting 30-40 mph
over much of the area. A shortwave trough will move southeast
across mainly the northern part of the CWA Sunday night into
early Monday, resulting in additional showers and another breezy
day Monday, although not as strong as Sunday. Fairly moist
northwest flow aloft will develop behind the departing shortwave
Tuesday, as a large trough takes shape off the coast. This
trough will spread moist air over the entire region Wed into
Thursday, so showers remain in the forecast. Snow levels should
remain high enough for valley rain and mountain snow throughout
the long term period...although a few flakes down to around
3000 ft MSL are possible. At this time, it appears the best
chance for measurable precipitation arrives Sunday afternoon and
again Wed into Wed night (50-80%). Total QPF for the long term
ranges from around 0.25 inches in lower elevations to 0.75-1.00
inches in the mountains.

&&

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

&&

$$

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DISCUSSION...LC
AVIATION.....SP
SHORT TERM...KA
LONG TERM....SP


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