FXUS65 KBOI 091710
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
1010 AM MST Fri Feb 9 2024

.DISCUSSION...A weak upper level trough will move over the area
today, bringing light snow much of the region. Not much
accumulation expected, ranging from a dusting to a half inch in
most areas, with up to 1-3 inches in Owyhee County and the
central ID mountains. Will have some partial clearing this
afternoon, which will aid in the development of snow/graupel
showers on the Idaho side (due to cold 500mb temps aloft of -30C).
These showers will mainly be south of the Snake Plain, and over
the central ID mountains. After sunset, showers should quickly
dissipate. An upper level ridge will build over the area on
Saturday and Sunday with dry conditions and temperatures near
normal. No updates.

&&

.AVIATION...Widespread IFR in light snow across SE Oregon and
portions SW Idaho west of KJER/KTWF this morning. Valleys improve to
VFR after 18Z with IFR in snow showers across mtns through 00Z this
evening. Mountains obscured in snow and low clouds. Surface winds: W-
NW 5-15 kt. Winds aloft at 10kft MSL: N-NW 10-20 kt.

Weekend Outlook...Areas of IFR in fog/stratus Saturday morning
portions of the Snake Plain KBOI-KJER/KTWF and sheltered mtn
valleys. Otherwise VFR through Sunday under dry NW flow aloft.
Surface winds 5-15 kt.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Sunday night...A short wave trough
currently over Washington will bring snow showers to our Oregon
zones this morning and Idaho zones mid-morning through early
afternoon, ending from north to south along the ID/NV border
this evening.  Snow amounts will be minimal, ranging from a
dusting to a half inch in most areas, up to several inches in
Owyhee County. The Treasure Valley has less than 30 percent
chance of receiving as much as 1/2 inch, with most of the snow
falling between 6 AM and noon. This timing may slightly impact
the morning commute in the Boise metro with a few slippery roads
after 7 AM and reduced visibility in falling snow. Light to
moderate northwest winds today, with gusts to 20 mph in the
Snake Basin east of Boise this afternoon. The short wave
trough will continue to move south tonight into the existing
larger scale upper trough over the Great Basin. Colder and
drier northerly flow aloft late tonight through Saturday will
bring mostly clear skies, except patchy valley fog, and more
winter- like temperatures to our CWA. An upper ridge will come
in from the Pacific with milder temperatures at higher
elevations beginning Sunday and in the valleys beginning Monday.
A weak upper trough from the north Pacific will increase clouds
Sunday night, with flurries in northern areas.

LONG TERM...Monday through Friday...A shortwave trough from
the Gulf of Alaska will move into the Pacific Northwest on
Monday. Models differ on how far south this will reach, but the
system is not expected to contain much moisture. This results in
a 20-40% chance of snow over the northern mountains, with less
than a 15% chance of precipitation elsewhere. On Tuesday and
Wednesday, another trough is expected to move south from Canada,
but its progress may be impeded by an upper level ridge along
the West Coast extending into the Desert Southwest. Models also
differ on whether a trough from the eastern Pacific will move
through the ridge and bring increased moisture into our area
during this time. Chances of precipitation will remain similar
to Monday as these systems approach our area. Uncertainty
increases further Thursday and Friday with the evolution of the
ridge and additional systems arriving from the west. A more
amplified pattern would shift moisture to our north, while a
weaker ridge would allow more moisture to move into our area.
Precipitation chances increase Thursday and Friday, but still
remain relatively low (15-30%) due low confidence in the
pattern. Temperatures are forecast to gradually increase through
the period, starting from near normal on Monday and ending
around 5 degrees above normal by Friday.

&&

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

&&

$$

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DISCUSSION...KA
AVIATION.....DG
SHORT TERM...LC
LONG TERM....ST