Sheridan, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

001
FXUS65 KBYZ 171913
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
1213 PM MST Fri Jan 17 2025

.KEY MESSAGES...

- Occasional light snow with areas of blowing snow continue
  tonight into Sunday; greatest amounts along north aspects of the
  Beartooth, Pryor & Bighorn Mountains (3-5").

- Very cold temperatures Saturday through Monday. Highs will range
  from single digits below to teens above zero (coldest east).
  Monday morning wind chills could reach -20 to -40 degrees.

- Windy in the foothills late Monday night through Tuesday. Much
  warmer temperatures on Tuesday.

&&

.DISCUSSION...
Through Saturday night...

The post-frontal moderate to heavy snow from earlier this morning
(2-2.5" fell at Billings) has ended, other than some light upslope
precip along the foothills, but we are starting to see increasing
radar echoes from the north in response to the next weak wave.
700mb analysis shows increased moisture and a distinct kink in the
cyclonic flow reaching the northern tier of our forecast area. Of
course, this is also within the dendritic layer. Overall, we
expect an increase in coverage of mostly light snow through the
remainder of the day. Looking upstream, there is a stronger
shortwave dropping thru northern Alberta. This wave arrives late
Saturday and in its wake there will be drying as a ~1046mb surface
high settles out of Canada. Prior to this, occasional light snow
will continue through tonight and much of Saturday, with greatest
amounts east of Big Timber/Harlowton and west of Miles City/
Broadus. Generally speaking, look for accumulations of an inch or
two in this area, with 3-5" along the north slopes of the
Beartooth, Pryor and Bighorn Mountains. The probability of
exceeding 5" over the 36-hr period is only 10%. Although the
dendritic layer is in play now it will become much shallower as
temps turn colder. In fact, 700mb temps fall to colder than -20C
by 06Z tonight, so snow will definitely turn light.

Gusty N-NW winds have produced some blowing snow today and travel
conditions turned poor over many areas, but we are starting to see
wind gusts decrease as of noon and this trend will continue thru
the day. Winds will be lighter tonight and early Saturday. By late
morning tomorrow we see another push of pressure rises from the
north and this will cause another increase in wind (gusts 20-30
mph) and potential for more blowing snow to go along with the
light snow. Winds should decrease Saturday evening.

Perhaps the biggest story is the coldest air mass yet of the
winter that is knocking on our door. Expect single digit low temps
tonight then highs only 5-15F (coldest east) on Saturday, as we
continue to cold advect w/ the aforementioned pressure rises. Lows
will fall well below zero across most of the region Saturday
night, with light winds and an anticipated period of clearing
skies. Look for lows tomorrow night of -5F to -15F most places,
and around -20F in the far east. It is expected that cold weather
highlights will be needed at least for our east beginning
Saturday evening, with wind chills falling to -25F or colder.

JKL

Sunday through Friday...

A shortwave moving through the flow will bring a 20-40% chance of
snow to the mountains and foothills Sunday. Then, upper level flow
becomes more northerly for Monday, continuing cold temperatures.

As the next system approaches, a favorable pattern for strong
winds over the western foothills may develop late Monday/early
Tuesday. If this pattern does develop, the chance of gusts greater
than 60 mph near Livingston would increase. This will be something
to watch.

With the next system, there is still uncertainty in the timing
and magnitude of impacts, although currently snow totals are
expected to remain fairly light, with only a 15-30% chance of at
least 2 inches of snow over the plains west of Miles City and a
40-60% chance of the same over the mountains and foothills through
Friday. There are signs that more Arctic air may move in next
weekend, reducing temperatures again.

Highs Sunday and Monday range from single digits below zero over
the east to teens over the west. Windchill values are expected to
be very cold Sunday night into Monday morning, especially over the
east. For Custer, Powder River, Fallon, and Carter counties, there
is a better than 75% chance of windchills below -25 F. For more on
the probability of windchills below -25 F, view the weather story
available on https://www.weather.gov/byz

Tuesday into Friday, highs are expected to gradually rise, from
low 20s to low 30s Tuesday to upper 20s to upper 30s Friday.
Archer

&&

.AVIATION...

Northerly flow aloft will bring occasional snow to the region
through Saturday. NW-N winds gusting 20-35 knots will produce
areas of blowing snow and reduced visibility until sunset today.
Winds will become lighter tonight (10-20 knots). Otherwise, flight
reductions to MVFR-IFR will be due to snow, and most likely east
of K6S0. Mountains will be frequently obscured. JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    Sat     Sun     Mon     Tue     Wed     Thu     Fri
-----------------------------------------------------------
BIL 008/015 908/014 909/013 003/031 017/032 017/032 022/036
    65/S    01/B    20/U    00/B    01/B    11/B    12/S
LVM 004/015 905/019 907/018 008/033 016/030 014/034 022/038
    22/S    01/E    10/U    00/N    01/B    11/N    13/S
HDN 006/015 911/010 915/009 907/031 014/032 014/032 017/036
    67/S    01/B    20/U    00/B    12/S    21/B    23/O
MLS 005/009 916/001 915/901 913/027 017/027 011/025 015/032
    23/S    00/U    00/I    00/B    12/S    11/B    12/S
4BQ 007/011 916/004 913/001 911/029 018/027 014/027 016/033
    25/S    10/U    00/U    00/B    11/B    21/B    12/S
BHK 003/005 922/000 921/906 916/024 013/024 007/022 010/030
    12/S    00/U    00/I    00/N    12/S    21/B    12/S
SHR 006/013 914/013 914/008 909/035 011/030 012/032 012/039
    76/S    31/B    10/U    00/B    02/S    21/B    12/O

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory in effect until 11 PM MST this
      evening FOR ZONES 56-63-66-138-169-171.
WY...Winter Weather Advisory in effect until 11 PM MST this
      evening FOR ZONES 198-199.

&&

$$
weather.gov/billings