897
FXUS65 KPIH 252023
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
123 PM MST Wed Dec 25 2024

.SHORT TERM...Tonight through Fri afternoon. The rainy, snowy, and
icy conditions of this morning have ceased, but this will only be
for a short time. A stronger and wetter storm will arrive during
the late night hours tonight in the central Idaho mountains and
the upper Snake River highlands, producing at first light snow.
But by Thu morning snowfall amounts ramp up strongly, with three
inches in six hours in the elevations above 6000ft elevation
possible, at a minimum. Below 6000ft elevation, it will be a
sloppy mix of snow, changing over to rain for some, then back to
snow for Thu night. Fri afternoon is colder, and only locations at
lower elevations from Pocatello southward and westward will see
rain, and in Pocatello`s case not for long. Winter Storm Warnings
were upgraded from the Winter Storm Watch for all but two watch
zones, which are on the north side of the central Idaho mountains
and are in something of a precipitation shadow, and the Bear Lake
Basin. The entire Snake River plain and the eastern Magic Valley
were placed in a Winter Weather Advisory, as 1 to 5 inches of snow
are possible in a number of locations, and will be coupled with
some gusty wind to add to the headaches. Travel to Montana and
Wyoming will be the most hazardous as snow clearance efforts will
be taxed heavily. The hits will keep on coming, as there is only a
slight decrease in snow and precipitation accumulation Fri
evening.

With all the cloud cover and a connection to northern Pacific
moisture, temperatures will continue mild both for overnight lows
and afternoon highs. For example, Pocatello should be in the mid-
teens for lows and just at freezing for highs, but overnight lows
will be very mild, near 30 deg F, and highs around 40. Look for
similar 15 deg F above seasonal normal for lows, 8 to 12 deg F
above normal for afternoon highs. Stanley at 6200ft elevation will
barely get to around freezing and will stay in the teens compared
to the normal single digit overnight lows.

Strong wind aloft will mix down partially with some brisk to windy
conditions that can drift snow, but not strong enough to make
blowing snow a widespread hazard at highway elevations, only in
the back country. Messick

.LONG TERM...Friday night through New Years Day. Wet pattern
continues with training of shortwaves crossing East Idaho. Lower
elevations continue to flirt with daytime temperatures above
freezing, which will limit overall snowfall accumulations at valley
floors. Above about 6000 ft, however, expect snowpack to continue to
build. The most impactful systems, for now, appear to occur over the
weekend, with the NBM moderating moisture amounts through the rest
of the extended period as flow aloft gradually turns a little more
northwest. This would allow for slightly cooler temps to round out
the year. DMH

$$

.AVIATION...East Idaho mainly in between systems this afternoon.
Low stratus visible on satellite imagery throughout much of the
Snake Plain, with pockets of -SN still continuing. CIGS within the
stratus vary between MVFR and IFR, and see no real signs of scouring
this out before the next system arrives overnight. Could see seeder-
feeder SN earlier than anticipated as the mid-cloud deck rolls in
overtop the stratus. However, the heavier precipitation is expected
to arrive generally after 09Z at KSUN and KBYI, spreading east to
the remainder of the terminals through the morning. Temperature
profiles appear to support all SN, but can`t completely rule out
pockets of FZRA, similar to this morning. CIGS and VIS should be
back to widespread IFR once the SN settles in. DMH

&&


.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 5 AM Thursday to 5 PM MST Friday
for IDZ051>055-061-067-069-071.

Winter Storm Warning from 5 AM Thursday to 5 PM MST Friday for
IDZ056>060-062>066-072>075.

&&

$$