Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 241406
AFDBYZ

Area Forecast Discussion...Updated
National Weather Service Billings MT
806 AM MDT Sun Mar 24 2024

.UPDATE...
Update to increase POPs for current trends. Main forcing is to
E/SE of Yellowstone County at this time under upper
divergent/lower convergent couplet...with light snow to the west
and pockets of snow to the east. Latest short term models hold on
to precip in eastern sections longer than inherited POPs
suggested, so evening POPs were increased in east as well. BT

&&

.DISCUSSION...
Today through Monday Night...

...Forecast snowfall totals have decreased around Billings and
areas north and west with some downgrades to Winter Weather Advisories
likely. More on snowfall totals below.

...Strong winds (30s kts) near the Dakotas border will bring the
potential for blowing snow impacts.

...Cold temperatures come in behind the storm with much of the
area east of Billings having a >50% chance of getting into the
single digits Monday morning.

Were getting some reports of freezing drizzle and other
precipitation types tonight. Soundings indicated at low level
moist layer in the absence of precipitation above that was near
freezing leading to slippery surfaces around some of the forecast
area. Went ahead and added some friezing drizzle until 15Z today.
Fog and low ceilings have also been an issue tonight for many
locations across the reign. Went ahead the kept fog in the
forecast until 15Z today.

As the latest model runs came in there was good agreement in lower
snowfall totals for Yellowstone County and locations to the north
and west. Some of these locations no longer meet warning criteria
leading to the likely downgrade of Yellowstone and Musselshell
Counties from Winter Storm Warnings to Winter Weather Advisories.
This is likely due to the more northerly winds and better forcing
moving to the east than previously expected. Much of the region
east of Billings can expect 4-8 inches with generally 2-4 inches
for Billings and locations east. Blowing snow will be a concern
for locations in far Southeast Montana, especially Fallon and
Carter Counties. This will be the case even though the strongest
winds will not coincide with the best snow conditions. Winds will
be strongest tonight before falling into the 20s kts during the
day today. Elsewhere, winds will be strong enough to lead to
reductions in visibility but wont have the same level of impacts
as areas near the Dakotas border.

Snow showers are currently making their way across Southeast
Montana and will continue to move west to east throughout the day
today before coming to an end this evening. Expect visibility
reductions in these snow showers and use caution while driving.

Lowered temperatures for today as deterministic NBM was above the
50th percentile. This combined with winds turning out of the
north throughout the day, and new snow cover for much of the
region led me to believe we likely would not reach our forecasted
highs. Cold temperatures are still on track to affect the region
as a lobe of cold air makes its way down from Canada. Highs today
will be in the 20s with 20s to low 30s by Monday. Tuesday
morning, many locations will be in the single digits with
locations in Carter and Fallon counties having a >70% chance of
getting below zero. Torgerson


Tuesday through Saturday...

Cyclonic NW flow and a lee side surface high will linger through
Tuesday. Thus, it will be another colder than normal day (highs
20s east to lower 40s west), with a low chance (20-40%) for light
snow mainly near the mountains and foothills. Temps aloft remain
relatively cold so there will be some instability to work with.
Tuesday night will be chilly with temps falling to the single
digits in the east.

Wednesday into early Thursday should be a mostly dry period
underneath a building ridge. The ridging will promote downslope
warming and temps should return to the lower-mid 50s across our
west, with breezy winds along the foothills.

A Pacific wave is expected to break down the ridge and introduce
the next chance of showers Thursday afternoon and night. Lower
elevation ptype will be rain but mountains should pick up a
little snow.

Friday through next weekend looks potentially interesting as a
trof deepens over the western CONUS. Ensemble consensus is for a
low to close off somewhere over the southwest next weekend, and
while this location is far from us, we could see shortwave energy
lift north and interact with colder Canadian air and upslope flow
to produce our next opportunity for lower elevation wet snowfall.
Must stress the uncertainty in details at this time. It is
entirely possible the low cuts off quickly and our region remains
mostly dry. It is also plausible that our upslope areas receive
significant precipitation (ensembles show tremendous spread). All
of that said, expect a cooling trend with increasing chances of
rain/snow from Friday through Sunday. Stay tuned.

The probability for 2+ inches of snow in the 72hr period ending
Sunday afternoon is 20-50% at lower elevations (highest west).
The probability for 8+ inches over the mountains is 60-80%.

JKL


&&

.AVIATION...

The combination of snow, low clouds and localized fog will result
in poor flying weather across the area today and tonight (snow
will taper off tonight but low clouds/fog will remain). Expect
widespread MVFR-IFR with areas of LIFR, as there will be some
blowing snow east of KBIL today. Mountains will be obscured. JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Mon     Tue     Wed     Thu     Fri     Sat
-------------------------------------------------------
BIL 024 015/030 015/038 024/054 033/058 033/053 031/045
    +/S 31/E    12/J    10/U    14/W    43/O    45/O
LVM 030 015/037 020/043 026/051 035/053 029/050 029/044
    8/S 31/B    13/J    10/N    26/W    43/O    56/O
HDN 025 012/032 011/037 019/055 028/060 031/054 028/047
    +/S 42/S    11/B    10/U    13/W    53/O    45/O
MLS 021 012/024 005/028 008/043 024/052 030/046 025/043
    +/S 50/E    00/B    00/U    01/B    32/O    23/O
4BQ 025 013/025 005/032 014/049 026/058 031/050 028/048
    9/S 61/E    00/U    00/U    01/B    32/O    33/O
BHK 019 007/022 903/023 003/038 019/047 025/043 023/042
    +/S 70/B    00/U    00/B    01/B    32/O    23/O
SHR 029 012/032 011/038 020/052 027/060 029/052 026/048
    9/S 41/E    00/B    10/U    02/W    43/O    44/R

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory in effect until midnight MDT tonight
      FOR ZONES 29-34-40-42-56-63>66-139-141-170>173-228-235.
     Winter Storm Warning in effect until midnight MDT tonight FOR
      ZONES 30>33-36-37-57-58-138-169.
WY...Winter Weather Advisory in effect until midnight MDT tonight
      FOR ZONES 198-199.

&&

$$
weather.gov/billings


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