Blizzard Warning 5, NWS Billings, MT

Area Forecast Discussion...Updated
National Weather Service Billings MT
1030 AM MST Wed Dec 21 2022

.UPDATE...

Snow was gradually shifting south this morning as the arctic cold
front continues to push south through the region. Much of the
area has received 1 to 3 inches of snowfall, with a bit higher
totals towards the western foothills. Gusty north to northwest
winds were also causing areas of blowing snow. Temperatures are
currently in the teens to 20s below zero, and don't expect
temperatures to warm much from where they are at through the day.
Very cold to dangerous wind chill values can be expected today,
with most places seeing wind chills of 40 to 60 below zero. Have
gone ahead and extended the Winter Weather Advisory for northwest
zones through the day, and added Powder River and Carter counties
to the advisory, where falling and blowing snow are causing
visibility reductions. Have updated pops, wind and weather through
the day. The rest of the forecast remains on track and the
previous discussion is below. STP

&&

.DISCUSSION...

Today through Thursday...

A 1040mb surface high was sitting over Great Falls at the moment.
This high will sink south today and bring the coldest air of the
season into the forecast area. The surface high is forecast to
strengthen to 1061mb by early Thursday, which was approaching
record values. The all time record for high surface pressure for
Montana is 1064mb on Christmas Eve of 1983. The record for
Billings is 1058.4mb on that same Christmas Eve of 1983.

High temperatures today will be in the morning with temperatures
falling deep into the teens below zero this afternoon. Readings
were currently in the single digits below zero across the area.
Temperatures over northern Montana were in the 20s below zero,
and that air will advect in today and tonight. Tonight will be the
coldest night in quite a while. The last time Billings fell below
20 below zero was February 23rd of this year. The overnight low
in Billings is forecast to reach 28 below zero tonight. The last
time we got near that cold was February 6th of 2014, when the low
was 23 below zero. The last time we hit 30 below was January 12th
of 1997. The NBM probability of Billings reaching 20 below zero
or colder tonight is 88%, 25 below zero or colder is 63%, and 30
below zero or colder is 23%.

Temperatures on Thursday will be very cold, giving such a cold
start, with highs expected in the single digits and teens below
zero. Forecast highs may be a little warm on Thursday, as some of
latest guidance was indicating Billings would not get above -10
(current forecast is -7). Subsequent shifts will have to keep a
close eye on this. Be aware that adjustments to the colder side
may be needed for Thursday.

For snowfall today: the rush or arctic air and frontogenetic lift
with a shortwave driving through, will produce a quick period of
snow. The snow will taper off from north to south as the frigid
air deepens. Strong dendrite growth zone will be over the area
early this morning for the best chance of accumulation. Snowflake
size will be very small by late morning, with the cold air
deepening, and thus dramatically reducing snow accumulation
potential. Looking at 1-2 inches from this event with around 1
inch this morning. NBM probabilities put a 50% chance of Billings
picking up an inch of snow this morning. The snow will be done
for most places this afternoon.

Lastly need to talk about wind chills because they will be rather
dangerous. North to northwest winds of 10-20mph today will create
wind chills of 40 to 60 below zero, which is very dangerous! Skin
freezes very, very quickly in those conditions. Upgrading the
Wind Chill highlight to a Warning yesterday was a great call by
the day crew, as these dangerous readings will stay through Friday
morning. Please take this cold very seriously and limit your
outdoor exposure. Make sure to limit time outdoors for your pets
and livestock as much as possible as well. Stay safe! TWH

Thursday night through Tuesday...

Thursday night into Friday morning will still be pretty brutally
cold night, especially from Rosebud County east. While areas to
the west will not be quiet as cold mostly in the teens to around
20 below, the east still has high chance (80 percent or greater)
of reaching -30.

That should mark the end of the most extreme temperatures as the
arctic will start to retreat Friday. While it will start to
retreat, it will remain cold and the real moderation will not
start until Saturday. Highs Friday for most of the area will
likely (70 percent or greater) be in the single digits above with
only a low chance (30 percent or less) of getting into the teens
above. The two exceptions will be along the foothills where winds
will be increasing and highs will likely (around 80 percent) get
into the teens and a moderate chance (around 50 percent) of
getting into the 20s. The other exception will be southeast
Montana, where given the colder overnight lows, will likely (75
percent or greater) remain below zero through the day.

Expecting the winds to increase along the foothills in response to
the arctic retreat. The surface pressure gradient will be steadily
increasing from Friday night through the weekend before peaking
Christmas Day. Winds will likely start to increase some from just
cold air drainage as the coldest air starts to retreat, but will
start to have a better oriented pressure gradient by Friday night.
The deterministic GFS has the Idaho Fall to Lewistown gradient
reaching 16mb by Friday evening, however this is significantly
higher than the rest of the NAEFS ensemble, and has generally be
higher than observations. Local probabilistic wind guidance has
winds likely (70 percent or greater) reaching 50 mph by Friday
night, and only around a 50 percent chance for 58 mph. The
greatest chance for potential Wind Advisory winds will be
Christmas Eve night into Christmas morning, so Santa should be
prepared to secure those presents, along with anyone else that may
be hauling light, high profile loads Saturday night. That is when
the NAEFS mean pressure gradient gets to around 12mb and local
guidance gets to around 70 percent for reaching highlight criteria
around Livingston.

Save for a couple of weak disturbances, Friday night and again
Christmas, which could bring some chances for light snow, or
possibly a rain or rain/snow mix, a ridge over the western US will
likely keep temperatures pretty moderate through early next week.
Highs will likely be running a little above normal through
Tuesday, getting in the upper 30 to lower 40s. Reimer

&&

.AVIATION...

A reinforcing shot of arctic air will be ushered in by north
winds this morning, with some gusts to 20kts. Steady snow will
develop early this morning, dropping conditions to IFR and LIFR in
snow and blowing snow. The snow will taper off by early
afternoon, allowing MVFR to VFR conditions to become more
widespread. Mountains will be obscured. TWH

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Thu     Fri     Sat     Sun     Mon     Tue
-------------------------------------------------------
BIL 911 928/907 923/008 902/036 026/046 022/044 033/047
    8/S 00/I    02/S    11/N    32/O    21/B    12/R
LVM 000 926/909 917/025 016/041 032/045 029/046 036/048
    8/S 00/I    14/S    31/N    43/O    21/N    23/O
HDN 912 932/909 930/005 908/033 016/043 015/041 026/044
    8/S 00/I    01/B    21/B    33/O    21/B    11/E
MLS 916 928/915 932/903 916/018 009/038 005/034 022/039
    7/Q 00/Q    00/I    11/B    33/O    11/B    11/E
4BQ 911 927/912 926/002 911/030 016/043 012/040 027/043
    8/S 00/Q    00/U    11/B    23/O    10/B    11/B
BHK 917 928/916 930/906 920/018 006/036 003/034 022/039
    7/Q 00/Q    00/I    00/B    33/O    11/B    11/B
SHR 907 928/910 925/013 902/038 023/045 019/045 029/046
    9/S 00/I    00/B    11/B    23/R    21/B    11/B

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Wind Chill Warning in effect until noon MST Friday FOR ZONES
      29>34-36-37-40-42-56>58-63>66-138-139-141-169-170-172-173-228-235.
     Winter Weather Advisory in effect until 6 PM MST this evening
      FOR ZONES
      29>34-40-42-56-57-63>66-139-141-170-172-173-228-235.
     Winter Weather Advisory in effect until 8 PM MST this evening
      FOR ZONES 36-37-58-138-169.
     Winter Storm Warning in effect until 6 PM MST this evening
      FOR ZONES 67-68.
WY...Wind Chill Warning in effect until noon MST Friday FOR ZONE
      199.
     Winter Weather Advisory in effect until 8 PM MST this evening
      FOR ZONE 199.

&&

weather.gov/billings

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BILLINGS MT
740 AM MST WED DEC 21 2022

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0600 AM     SNOW             5 SE REED POINT         45.67N 109.47W
12/21/2022  M2.0 INCH        STILLWATER         MT   COCORAHS

0600 AM     SNOW             9 E INGOMAR             46.57N 107.20W
12/21/2022  M3.0 INCH        ROSEBUD            MT   CO-OP OBSERVER

0700 AM     SNOW             7 ESE LIVINGSTON        45.64N 110.43W
12/21/2022  M4.6 INCH        PARK               MT   COCORAHS

0700 AM     SNOW             8 E COLUMBUS            45.62N 109.10W
12/21/2022  M2.1 INCH        STILLWATER         MT   COCORAHS

0700 AM     SNOW             1 NW ROUNDUP            46.45N 108.55W
12/21/2022  M2.0 INCH        MUSSELSHELL        MT   COCORAHS

0700 AM     SNOW             3 NNE BILLINGS          45.84N 108.52W
12/21/2022  M3.0 INCH        YELLOWSTONE        MT   COCORAHS

0700 AM     SNOW             15 SW ROUNDUP           46.33N 108.74W
12/21/2022  M2.0 INCH        MUSSELSHELL        MT   CO-OP OBSERVER

0739 AM     SNOW             4 SW BILLINGS           45.75N 108.57W
12/21/2022  M2.5 INCH        YELLOWSTONE        MT   CO-OP OBSERVER

&&

LT

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BILLINGS MT
854 AM MST WED DEC 21 2022

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0700 AM     NON-TSTM WND GST 4 NNW COOKE CITY        45.07N 109.96W
12/21/2022  M70.00 MPH       PARK               MT   MESONET

0700 AM     SNOW             10 ENE MELVILLE         46.17N 109.77W
12/21/2022  M4.0 INCH        SWEET GRASS        MT   COCORAHS

0700 AM     SNOW             5 SE KLEIN              46.35N 108.48W
12/21/2022  M1.0 INCH        MUSSELSHELL        MT   COCORAHS

0700 AM     SNOW             18 NNW RYEGATE          46.53N 109.34W
12/21/2022  M3.0 INCH        GOLDEN VALLEY      MT   CO-OP OBSERVER

0741 AM     SNOW             4 WSW BILLINGS          45.76N 108.61W
12/21/2022  M2.5 INCH        YELLOWSTONE        MT   COCORAHS

0800 AM     SNOW             SPRINGDALE              45.74N 110.22W
12/21/2022  M3.5 INCH        PARK               MT   CO-OP OBSERVER

0800 AM     SNOW             1 WSW LIVINGSTON        45.66N 110.58W
12/21/2022  M2.2 INCH        PARK               MT   COCORAHS

0800 AM     SNOW             5 NE BILLINGS           45.83N 108.44W
12/21/2022  M2.7 INCH        YELLOWSTONE        MT   COCORAHS

0800 AM     SNOW             25 SSE HYSHAM           45.94N 107.14W
12/21/2022  M3.0 INCH        TREASURE           MT   CO-OP OBSERVER

&&

LT

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BILLINGS MT
914 AM MST WED DEC 21 2022

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0800 AM     NON-TSTM WND GST 4 NNW COOKE CITY        45.07N 109.96W
12/21/2022  M52.00 MPH       PARK               MT   MESONET

0800 AM     SNOW             4 ENE HUNTLEY           45.94N 108.25W
12/21/2022  M2.8 INCH        YELLOWSTONE        MT   CO-OP OBSERVER

0830 AM     SNOW             10 E MOLT               45.85N 108.73W
12/21/2022  M3.5 INCH        YELLOWSTONE        MT   TRAINED SPOTTER

&&

LT

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BILLINGS MT
1024 AM MST WED DEC 21 2022

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0700 AM     SNOW             6 E MELSTONE            46.59N 107.75W
12/21/2022  M3.5 INCH        ROSEBUD            MT   COCORAHS

0700 AM     SNOW             2 W BILLINGS            45.79N 108.57W
12/21/2022  M2.5 INCH        YELLOWSTONE        MT   COCORAHS

0700 AM     SNOW             15 N POMPEYS PILLAR     46.20N 108.00W
12/21/2022  M2.1 INCH        YELLOWSTONE        MT   CO-OP OBSERVER

0900 AM     SNOW             1 SE BILLINGS           45.77N 108.48W
12/21/2022  M2.5 INCH        YELLOWSTONE        MT   CO-OP OBSERVER

0900 AM     SNOW             5 S BILLINGS            45.72N 108.52W
12/21/2022  M2.0 INCH        YELLOWSTONE        MT   COCORAHS

&&

LT

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