181
FXUS65 KBOI 052143
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
243 PM MST Wed Feb 5 2025

.SHORT TERM...Tonight through Friday night...The primary focus
remains on the approaching Pacific storm system, set to bring
snow from Thursday evening into Friday. This system has the
potential to impact the Friday morning commute, particularly
north of a Burns-Ontario-Stanley line.

This afternoon, mostly clear skies persist between systems.
However, a weak shortwave currently moving inland across
Washington and Oregon will continue eastward, bringing a 30%
chance of light snow showers, mainly affecting Baker County and
the West Central Mountains of Idaho. A slight chance (15%) of
snow showers exists for the Lower Treasure Valley between 5 PM
and midnight, though no accumulations are expected.

The next storm system is forecast to arrive Thursday evening
into Friday. Recent guidance maintains the trend of a warm front
lifting northward early Friday, concentrating most
precipitation north of the front by mid-morning. This setup
favors light to moderate snowfall potential along and north of a
Burns-Ontario-Stanley line. However, the latest guidance favors
a further northward shift of the warm front, reducing expected
snowfall amounts from the Upper Treasure Valley through the
Western Magic Valley, Owyhee Mountains, and southern Highlands.
The combination of a quicker warm frontal passage, lower QPF
totals, and a strong low-level jet (50-75 kt) supporting warmer
surface temperatures has decreased snowfall probabilities for
the above-mentioned areas. Probabilistic guidance from both the
NBM and HREF now suggests only a 30% chance of snowfall
exceeding 1 inch in these areas.

Given this downward trend in snowfall expectations over the
past two model cycles, no winter weather headlines have been
issued at this time. Currently, we have 1 to 2 inches along
US-20 from Burns to Ontario, the I-84 corridor from Ontario to
Baker City, and US-95 from Ontario to Council and 4 to 6 inches
in mountain valleys, with up to 10 inches at higher elevations.
Up to half an inch in the Upper Treasure Valley, though
accumulation on road surfaces may be limited due to above-
freezing temperatures. Following the cold frontal passage,
strong winds could develop across south-central Idaho on Friday,
with a 30% chance of reaching wind advisory criteria.

Snow will taper off Friday evening as the cold front moves
through, with colder temperatures possible depending on
lingering snow cover and the establishment of northerly flow
across the region.

.LONG TERM...Saturday through Wednesday...An upper level
trough will reside over the region Saturday through early next week
with shortwave troughs embedded in the flow. This will keep a cold
northwest flow over the area resulting in well below normal
temperatures. Northern mountain areas will have about a 20-30%
chance of snow each day in this pattern with dry conditions
prevailing elsewhere. By the middle of next week the models are less
consistent with some showing the upper level pattern shifting to a
more active westerly flow off the Pacific. Lots of uncertainty that
far out. The forecast will reflect a slight upward trend in
temperatures by the middle of next week with increased chances of
precipitation/snow as below normal temperatures continue.

&&

.AVIATION...Widespread MVFR to LIFR in mountain snow KMYL
area after 06/00Z, continuing overnight with gradual improvement
Thursday morning. Areas of MVFR to IFR in snow KBNO and KBKE areas
from 05/23Z to 06/06Z. Mountains obscured. VFR to prevail elsewhere
with a low probability (<15%) of snow in the KONO to KBOI areas
overnight. Surface winds: SW-NW 5-15 kt, gusts to 25 kt through
06/00z KJER and KTWF areas and SE Oregon. Winds becoming SE-SW 5-10
kt after 06/00Z. Winds aloft at 10kft MSL: W 30-45 kt.

KBOI...VFR. Low chance (<15%) of a snow shower/MVFR conditions near
the terminal overnight. Surface winds: E-SE 5-10 KT.

&&

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

&&

$$

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SHORT TERM...JDS
LONG TERM....TL
AVIATION.....TL