489
FXUS65 KBYZ 171743
AFDBYZ

Area Forecast Discussion...Updated
National Weather Service Billings MT
1043 AM MST Mon Feb 17 2025

.KEY MESSAGES...

- A persistent period of snow is occuring for central and western
  portions of the forecast area (including Billings) through
  Tuesday. Heavy snow accumulations are possible during this
  prolonged snow event.

- Bitter cold temperatures and wind chills are expected through
  Wednesday.

- Much warmer temperatures arrive for the end of the week into
  next weekend.

- Windy conditions expected next weekend in the foothills.

&&

.UPDATE...

Light to moderate snow continues to move over western and central
areas this morning as moisture overruns the cold air in place at
the surface. Totals have range from 5 to 9 inches from Harlowton
to Billings to Lodge Grass and west through Big Timber and
Livingston, with even a few locations approaching a foot of snow.
Lesser totals of 2 to 5 inches have bordered these areas. Snow
remains efficient with a good dendritic growth zone still in
place. Snow may lighten up some this afternoon, before increasing
into this evening as a reinforcing shot of cold air works south,
and upper level energy increases from a jet max nosing overhead.
Expect the snow to push south into the foothills overnight,
gradually decreasing into Tuesday. Another 3 to 6 inches of
snowfall are possible for most of the central and western areas,
with lesser totals the farther north and east you move away from
Billings. Temperatures will stay cold today, with highs in the
single digits above zero, to single digits and even some teens
below zero in the east. The current winter and cold highlights
remain in good shape and will make no changes to them at this
time. Have updated PoPs, precipitation amounts and temperatures
through tonight. STP

&&

.DISCUSSION...

Today through Tuesday...

A deep dendritic layer remains in place over the region, along
with an area of strong isentropic lift/frontogenesis from a
Harlowton to Billings to Lodge Grass line. The greatest snow
accumulations are expected through this evening. Then, as
temperatures drop and forcing decreases, snow will become lighter
before gradually ending Tuesday afternoon into evening.

Through Tuesday, an additional 4-8 inches of snow are expected
under the band of frontogenesis, with generally a 50-70% chance of
at least another 6 inches of snow. Over the foothills, an
additional 3 to 6 inches is expected, and over the western
mountains, an additional 10 to 18 inches. For the Pryor and
Bighorn mountains, an additional 5 to 10 inches is expected.
Winter highlights remain in effect into Tuesday evening.

Temperatures will remain cold, with highs today and Tuesday
ranging from below 0 over the east to single digits above over the
west. Lows tonight will range from -20s near the Dakota border to
generally negative teens over the rest of the region. Temperatures
are expected to become even colder Tuesday night, although models
continue to disagree on how far west the cold air will shift.
Currently, lows are expected in the -30s near the Dakota border
to -20s as far west as Columbus. Cold weather highlights remain
in effect into Wednesday.

If you must travel during this time, call 511 to check the latest
road conditions, dress in layers, and pack a vehicle emergency
kit. Archer



Wednesday through Monday...

Bitter cold continues Wednesday but conditions look dry outside of
a few snow showers in the western mountains. Warming trend gets
going Thursday and models are trying to boost highs into the 30s
from Billings west into the foothills. This seems a bit optimistic
as there is a disturbance moving through from the west that will
increase cloud cover/precipitation chances, and more to the point
will prevent strong westerly flow from developing until it exits
the area on Friday. As things stand would expect to see this
strong warmup on Thursday get pushed more into Friday. Will keep a
close eye on this warming trend as it will be accompanied by gusty
to possibly strong wind gusts and blowing snow concerns. Local
guidance really holds back on stronger wind potential until Friday
evening into Saturday, yet another factor pointing to a slower
warm up.

Friday through the weekend look mainly dry and much warmer with
highs in the 40s and a few 50s being advertised. Guidance is also
trying to keep lows above freezing by Sunday morning. Again, given
the abundant snowpack this rapid temperature adjustment to above
seasonal temperatures seems a bit overdone, especially for
overnight lows where even a few breaks in the cloud cover can
produce much colder temperatures than are currently advertised.
Would expect some moderation in the temperature trends going
forward. If not and the guidance is correct will see a good deal
of melting by early next week, with the possibility of a quick
melt that could cause some overland and stream flood concerns (Ice
Jams) as the ground is frozen at least a foot deep under this
snowpack. Will continue to monitor this potential and increase
messaging toward mid week if the warming trend currently
advertised remains in the forecast. Chambers

&&

.AVIATION...

Persistent area of snowfall will be located west of a Forsyth to
Broadus line over the next 24 hours. To the east of this line
occasional light snow can be expected but VFR conditions should
prevail, with localized periods of MVFR. To the west of the line
IFR conditions will prevail with occasional LIFR during heavier
periods of snowfall. All mountains/passes will be obscured during
this period. Temperatures will be very cold over the next 72
hours, especially over SE Montana. Those flying unpressurized
aircraft should be prepared for the extreme cold temperatures and
its impacts to aircraft and persons flying. Chambers

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Tue     Wed     Thu     Fri     Sat     Sun
-------------------------------------------------------
BIL 901 911/000 922/004 905/033 019/040 027/044 033/047
    +/S 95/S    10/B    22/S    10/B    00/N    00/N
LVM 009 906/010 905/025 013/040 022/041 026/046 031/049
    +/S 95/S    11/B    44/S    10/B    00/N    01/N
HDN 005 912/003 930/010 909/029 013/040 020/043 026/047
    +/S 96/S    00/B    12/S    10/B    00/B    00/B
MLS 904 913/903 924/002 909/018 006/035 022/040 028/045
    2/S 31/I    00/B    01/B    10/B    00/B    00/B
4BQ 000 911/002 924/007 907/023 011/038 023/043 029/048
    7/S 73/S    00/U    01/B    10/B    00/B    00/B
BHK 910 924/907 931/901 916/013 000/034 019/039 025/044
    1/I 12/S    00/I    01/U    10/B    00/B    00/B
SHR 009 908/005 918/016 001/032 013/040 019/047 025/052
    8/S 88/S    10/U    02/S    11/B    00/B    00/B

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Storm Warning in effect until 5 PM MST Tuesday FOR
      ZONES
      29-34-40-42-57-63-65-67-68-138-141-169-170-172-173-228-235.
     Cold Weather Advisory in effect until noon MST Wednesday FOR
      ZONES 30-31-36-63.
     Winter Weather Advisory in effect until 5 PM MST Tuesday FOR
      ZONES 30-31-36-56-58-64-66-139-171.
     Extreme Cold Warning in effect until noon MST Wednesday FOR
      ZONES 32-33-37.
WY...Winter Weather Advisory in effect until 5 PM MST Tuesday FOR
      ZONES 198-199.

&&

$$
weather.gov/billings