Star, Idaho 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

350
FXUS65 KBOI 252124
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
224 PM MST Wed Dec 25 2024

.SHORT TERM...Tonight through Friday night...A potent system off
the Pacific NW coast will bring precipitation to the region late
this evening into Thursday with breezy conditions. Snow levels
are forecast to be near the lowest valley floors on Thursday
morning before rising to 3000-4000ft MSL by the afternoon. While
it may start off as snow in the Treasure Valley, temperatures
are forecast to remain above 33-35F, so little to no
accumulations for the Boise metro including Caldwell, Nampa,
Meridian, and Eagle. There is a 60 percent chance of exceeding
an inch of snow from east of Boise (Micron) through Mountain
Home to the Magic Valley on Thursday morning, which may make for
a tricky commute along the I-84 corridor. Thus have issued a
winter weather advisory for slippery roads on Thursday morning
for the Treasure Valley southeast of Boise through the Magic
Valley. Precipitation transitions into a showery regime on
Thursday afternoon, and some showers over the mountains could
produce locally heavy snow squalls. There is a slight chance of
thunder in these showers too, but did not mention it in the
forecast. Showers taper off in the evening hours for a few hours
before the next system arrives on Friday morning. This will
bring another round of precipitation to the area with snow
levels around 3500-4500 feet. Precipitation tapers off late
Friday afternoon. Total snow accumulations through Friday will
be 6 to 12 inches in the mountain valleys, 12 to 18 inches in
the mountains above 6000 feet including the Camas Prairie, Boise
Mountains and West Central Idaho Mountains. Elsewhere, snow
amounts of 1 to 5 inches across Baker County and the Upper
Weiser River Basin. Lowest snow amounts in the valleys near
Baker City and Richland. There will be snow across Harney and
Malheur Counties, but will come in two separate systems with
minor accumulations. Across the Treasure and Magic Valleys,
total snow accumulations up to two inches along the Interstate
84 corridor southeast of Boise, except between 2 and 4 inches
north of Gooding. Little to no snow accumulation in the Boise
metro area.

.LONG TERM...Saturday through Wednesday...An atmospheric river
and series of troughs will bring significant rain and snow
Saturday through Sunday night. Snow levels will stay around 4000
ft in our northern areas and 7000 ft in the south. Heaviest
precipitation will be over terrain, as strong westerly flow
enhances orographic effect. This will cause rain and snowfall
amounts to vary greatly with elevation, and the westerly
component means Snake Plain locations are unlikely to be
shadowed. The strong flow will lead to gusty ridgetop and
highland winds through the event, with brief periods of valley
gusts. Total rainfall (or liquid equivalent where it snows) will
generally be between 0.3 to 0.5 inches in lower elevations of
Oregon, 0.5 to 1 inches in lower elevations of Idaho, and 1 to
2.5 inches in mountains. This translates to 1 to 3 feet of snow
above 6000 feet, with 4 to 12 inches forecast in the mountain
valleys. The steady rainfall over multiple days may lead to
rises in some rivers, though impacts are unlikely. The Weiser
River at WSRI1 only shows a 10% chance of exceeding action stage
on Monday and has slowly been trending down. As the primary
trough moves inland on Monday, moisture will be mostly cut off.
Lingering light showers will continue in terrain later Monday
and Tuesday. This will also funnel winds up the Snake Plain,
leading to gusty winds in the Magic Valley and upper Snake Plain
earlier Monday.

Temperatures will be about 10 degrees above normal over the
weekend, but will cool to around normal by Tuesday. An upper
level ridge will briefly move overhead on Tuesday bringing dry
conditions and light winds. On Wednesday, the deterministic GFS
is resolving a shortwave bringing another pocket of moisture to
the area. However, the ensembles and deterministic EC and
Canadian continue to build the ridge. While the forecast is
uncertain given the disagreement, the ridge/high pressure
solution seems more likely with a majority share of the models,
including the ensemble means.

&&

.AVIATION...Mainly VFR. Low stratus sticking around in the
vicinity of KJER, though still MVFR. The system arriving
tonight will kick off multiple days of precipitation. Mountains
obscured. Snow above 3-4 kft MSL, mixed precip and rain below
tonight and Thursday morning. MVFR/IFR conditions in
precipitation, with rates being light to moderate. Surface
winds: Variable 5-10 kt today, becoming S-SE 5-15 kt with 20-30
kt gusts tonight. Winds aloft at 10kft MSL: W-SW 15-25 kt,
becoming 20-40 kt this evening. Areas of low level wind shear
developing tonight.

KBOI...VFR. High clouds will increase through the day. A
rain/snow mix will move in around 08Z/Thu. Little to no snow
accumulation expected as any snow would be completely or
partially melted as it falls. Low confidence in the visibility
forecast as it will depend heavily on precip type. Surface winds
NW 3-7 kt today, becoming SE 5-10 kt this evening, increasing
to 10-20 kt with gusts to 25 kt tonight.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory from 11 PM this evening to 5 PM MST
     Friday IDZ011-013-028.
     Winter Weather Advisory from 11 PM this evening to 11 AM MST
     Thursday IDZ014-016-033.
OR...Winter Weather Advisory from 10 PM this evening to 10 AM PST
     Thursday ORZ062.

&&

$$

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SHORT TERM...KA
LONG TERM....JM
AVIATION.....JM