003
FXUS65 KBOI 220253
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
853 PM MDT Fri Mar 21 2025

.DISCUSSION...At 8 PM MDT KCBX radar showed pcpn echoes in
eastern OR spreading into western ID. Light rain should begin
in the Boise metro by 10 PM MDT, while snow at McCall (which
began around 730 PM MDT) also increases by 10 PM MST. A cold
front from the northwest will move through our CWA overnight
followed by decreasing rain and snow showers by sunrise, but
continuing in the west-central Idaho mountains due to upslope
enhancement. Snow level will also lower behind the cold front
to near 4000 feet MSL, but convective downdrafts may bring
heavier snow showers down to valley floors in ID north of the
Snake Basin. As noted in the previous discussion, westerly
winds will increase to advisory speeds in south-central ID
Saturday afternoon. A Wind Advisory is in effect there. One
last warm front with light rain and snow is still indicated
for late Saturday night/Sunday morning before clearing later
Sunday, followed by steady warming Sunday through mid-week.
Current forecast covers all this. No updates needed.

&&

.AVIATION...VFR, With MVFR/IFR in eastern Oregon and West-Central
ID Mountains. Showers continue across the area tonight resulting
in lower ceilings and mountain obscuration, snow levels around
5000 feet MSL lowering to 2500-3000 feet MSL in the north.
Spotty showers continue through Saturday but generally VFR.
Low-level wind shear tonight in Treasure Valley. Surface winds:
SW-NW 10-15 kt gusting to 25kt (20-25 kt gusting up to 40 kt in
western Magic Valley). Winds aloft at 10kft: W-NW 30-50 kt.

KBOI...VFR, with rain showers overnight. Chance (20-30%) of MVFR
conditions Saturday morning before 12UTC. Low-Level wind shear
through early morning. Surface winds increasing Saturday afternoon.
Showers Saturday afternoon may produce MVFR conditions although
chances are low (10-15%).

Sunday Outlook...VFR Saturday night and Sunday with showers
clearing except for the East-Central Oregon and West-Central
Idaho Mountains. Snow levels rising to 7000-8000 feet MSL.
Surface winds 10-15 kt with winds aloft at 10kft W at 20-30
kt.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Sunday night...A warm front will
continue to spread precipitation across the area through this
evening. Only light amounts are expected in the valleys as most
of the precip will occur in the mountains, especially in central
Idaho. A cold front will slide through from the north late
tonight through Saturday morning, accompanied by snow showers
and lowering snow levels. Most of the showers will continue in
central Idaho. Instability is not quite enough for thunderstorms,
but an isolated strike can`t be ruled out. The hi-res models
are indicating banding of the showers with bursts of heavier
snow within the the bands as they move across central Idaho.
Several inches of snowfall are expected in central Idaho, mainly
above 5000 feet, so a Winter Weather Advisory is in effect.
Winds increase behind the frontal passage Saturday morning,
especially in s-central Idaho where a Wind Advisory is in effect
through the afternoon. The showers and winds will diminish by
Saturday evening. Light precipitation is expected in the north
(Baker County to central Idaho) along a warm front late Saturday
night through Sunday. Additional snowfall amounts of less than
2 inches are expected in the higher mountains as snow levels
rise behind the warm front. Temperatures warm from slightly
below normal on Saturday to several degrees above normal on
Sunday. Winds are expected to be light on Sunday as high
pressure builds into the area.

LONG TERM...Monday through Friday...A strong long wave ridge
building into the Northwest region is expected to continue the
dry and warm conditions, with higher than normal daytime
temperatures ranging from the mid 60s to the lower 70s through
Monday and Tuesday. Snow levels are expected to remain on the
high-end from 7000-9000 ft until late next week. Combined with
the higher than normal temperatures, snowmelt will remain a
concern for river/stream/creek flows across lower and middle
elevations. Through the later hours of Wednesday into the end of
next week, forecast guidance continues to indicate a strong
trough building in across the Pacific Northwest, with rain
expected across the valleys and snow across the mountains. The
associated frontal passage is expected to drop snow levels to
4000-5000 ft. There is still considerable uncertainty with QPF
amounts due to guidance disagreements on the arrival of the cold
front and the track of the incoming low.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory until noon MDT Saturday IDZ011-013.
     Wind Advisory from 8 AM to 6 PM MDT Saturday IDZ016-028-030.
OR...None.

&&

$$

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DISCUSSION...LC
AVIATION.....NF/DG
SHORT TERM...BW
LONG TERM....JY