958
FXUS65 KBOI 212054
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
254 PM MDT Tue May 21 2024

.SHORT TERM...Tonight through Thursday night...A strong upper
level system will move towards and then through the area tonight
and Wednesday. This will bring plenty of precipitation along
with a cold front. There is also a chance of thunderstorms
behind the front beginning Wed morning and lasting through the
afternoon. The front will enter our Oregon zones early Wed
morning, move through the Boise area around noon, and make it
through the western Magic Valley around 6 PM MDT. Showers will
occur both ahead of and behind the front, from this evening
through tomorrow. Precipitation totals are expected to range
from 0.01 to 0.30 in lower elevations, up to 1 to 1.5 inches in
higher elevations. Snow levels will start out around 7000 ft
MSL, and fall to 4500-6000 by late Wed afternoon. With snow
showers lingering in the mountains into Thu night, total
snowfall above around 7000 ft MSL will range from 6-12 inches,
with the highest totals above 8000 ft. Temperatures Wednesday
will be 15-20 degrees below normal, and it will be breezy
(gusts 30-40 mph), especially over southeast Oregon and in/near
the Treasure and Magic Valleys. However, at this time, it does
not appear as if a wind advisory is warranted. Thursday will be
breezy in the western Magic Valley, with gusts to 25-35 mph, and
temperatures will be 10-15 degrees below normal. We will dry out
Thursday night as NW flow behind the departing system backs to
zonal.

.LONG TERM...Friday through Tuesday...A weak short wave trough
will move through Friday, spreading clouds across the area, but
very little if any precipitation. A stronger system will move in
Saturday. Details on the exact path of this system are not clear
yet, but our best bet is the center will pass by to our north.
This would give us a good cold front along with showers mainly
in the higher elevations of the northern part of the CWA. Snow
levels are forecast to range from 6-7000 ft MSL. Upper level
ridging is expected to build into the area late Sunday night and
Monday, bringing dry and warmer conditions. Tuesday, we may get
a passing glance from another upper level trough, but
uncertainty is high. After climbing a few degrees above normal
Monday, temps might be 10 degrees above normal by Tuesday.

&&

.AVIATION...VFR through evening under increasing and lowering
clouds. A cold front will bring numerous showers to SE Oregon after
Wed/03Z in E Oregon, and after Wed/06Z in SW Idaho creating low-VFR
and local MVFR in valleys. Areas of IFR/LIFR in mountains obscuring
higher terrain. Snow levels 6500-7500 ft MSL through Wednesday
morning, lowering to 4500-5000 after Thur/00Z. Thunderstorms are
possible on Wednesday. Surface winds: SW to NW 5-15 kt local gusts
to 25 kt east KMUO through Wed/00Z. Widespread gusty winds to 30 kt
with cold frontal passage and continuing through Wednesday. Winds
aloft at 10k ft MSL: W-SW 10-20 kt.

KBOI...VFR. Rain beginning Wed/09-11Z with MVFR ceilings. Winds: NW
shifting to SE around sunset. Frontal passage tonight will switch
winds to NW with gusts up to 20 to 30 kt.

&&

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

&&

$$

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SHORT TERM...SP
LONG TERM....SP
AVIATION.....DG