Area Forecast Discussion
Issued by NWS Boise, ID

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
000
FXUS65 KBOI 210958
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
358 AM MDT Thu Mar 21 2024

.SHORT TERM...Today through Saturday night...A shortwave trough
will move east of our area today. Scattered showers this morning
across the mountains will taper off this afternoon. Temperatures
will be 5-10 degrees cooler than yesterday. Winds will be breezy
today behind the departing trough, strongest this afternoon
across south-central Idaho with gusts to 30 mph. On Friday, an
upper level ridge will move overhead as a deep Pacific trough
approaches the coast. Southwest flow aloft will develop and
temperatures will warm several degrees, with lower valleys
approaching 70 degrees. However, mid to high clouds may hold
back the full heating potential. Winds will remain breezy out of
the south on Friday, strongest across south-central Oregon with
gusts to 40 mph.

A major pattern change will take place Friday night as the
large Pacific trough starts to move inland and pushes a
shortwave trough and cold front through our area, with the front
reaching the Magic Valley by mid to late Saturday morning.
Precipitation will develop along the front, with rain in the
valleys and rain and snow in the mountains. Snow levels will
lower from around 6500-7500 feet MSL ahead of the front to
4500-5500 feet behind the front. Several inches of snow are
expected above 5500 feet, with little to no accumulation
expected in locations such as the Long Valley as temperatures
remain above freezing. Showers will continue Saturday afternoon
as cold air aloft supports daytime instability, but
precipitation will not be as widespread as the morning. There is
also a low (less than 10%) chance of thunderstorms, which was
too low to include in the official forecast at this time.
Temperatures will decrease 10-15 degrees from Friday, resulting
in highs being near normal. Winds will be breezy, especially in
the higher terrain and across south-central Idaho.

.LONG TERM...Sunday through Thursday...The large Pacific trough
will slowly move across the Pacific Northwest on Sunday with a
couple of weak shortwave troughs rotating through the flow.
This will bring additional showers to the area, along with
continued (and slightly stronger) breezy winds and cool
temperatures. Snow levels of 4000-5000 feet will allow for light
snow accumulations in the mountains. Precipitation will decrease
Sunday night as the trough exits to the east.

For Monday through Thursday, the pattern will remain active as a
series of Pacific troughs moves through the western US under
prevailing west to northwesterly flow aloft. The first weak
system will arrive Monday into Tuesday, with chances of
precipitation increasing to 30-70% each period, highest in the
mountains. Snow levels will fluctuate around 3000-4500 feet with
additional light snow in the mountains. Winds will remain
breezy with temperatures around 5 degrees below normal. The next
and stronger system will arrive Wednesday into Thursday and
will contain more moisture. The highest (50-80%) chance of
precipitation is currently Wednesday afternoon and evening.
Southwest flow ahead of this system may push snow levels up
about 1000 feet on Wednesday before falling once again on
Thursday behind a cold front. Significant mountain snows are
possible with this system, but precipitation totals are still
uncertain. Temperatures will remain cool with winds still
remaining breezy.

&&

.AVIATION...Mainly VFR. Isolated to scattered showers this
morning in the central ID mountains will decrease this afternoon.
Areas of MVFR/IFR and mountain obscuration in precipitation.
Snow levels 6000-7000 feet MSL. Elsewhere, mid to high level
clouds will persist. Surface winds: W-NW 5-15 kt, with gusts
20-30 kt developing this afternoon across s-central ID. Winds
aloft at 10kft MSL: W 20-30 kt.

Weekend Outlook...Mid to high clouds will remain overhead on
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.

&&

.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...ST
LONG TERM....ST
AVIATION.....ST


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.