Sheridan, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

288
FXUS65 KBYZ 250128
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
728 PM MDT Thu Apr 24 2025

.KEY MESSAGES...

- Lower elevation rain and mountain snow will gradually taper off
  tonight; Areas of fog tonight into Friday morning.

- Seasonal Friday (50s to 60) and warm Saturday (60s and 70s).
  Scattered showers possible over south-central Montana Saturday
  afternoon and evening (10 to 40 percent).

- Another storm system taking shape for late in the weekend into
  early next week with significant precipitation and impacts
  possible.

- Ponding in low lying areas, rises in creaks and streams, and
  impacts to burn scar areas are possible with the next system.

&&

.UPDATE...
Satellite imagery shows weak upper trof over south central MT
moving slowly eastward. Precipitation has become much lighter over
the past couple hours but there are some showers mainly south of
Billings and over the Beartooth-Absarokas. Temps aloft in the trof
axis are relatively cold and mid level lapse rates are on the
order of 8C/km, so as the trof passes overhead the combination of
this and a healthy east wind should keep the risk of light showers
(or maybe even spotty upslope drizzle) going for much of the
night in our west. We are already seeing fog/mist early this
evening in the Sheridan area. KSHR is reporting a T/Td of 39/38F.
Similar dew point depressions exist in far southeast MT. Without
question we will see plenty of fog/stratus tonight especially in
the southeast and western/southern upslope areas. Forecast has all
of this covered well, but have expanded in time and coverage the
mention of fog for tonight. Some fog could be locally dense so a
heads up to travelers tonight, as well as during the Friday AM
commute. JKL

&&

.DISCUSSION...
Through Saturday night...

Split flow continues to bring precipitation to south-central and
eastern Montana this afternoon. Over most of the lower elevations,
this precipitation is falling as rain. However, this
precipitation is likely falling as snow over the higher hills of
far south- eastern Montana this afternoon. With that said, warming
temperatures are likely causing the snow to switch back over to
rain or a rain/snow mix. Therefore, the Winter Weather Advisories
for Powder River and Carter Counties look to be in good shape to
drop off at 4 PM MDT this afternoon. Over the mountains and
immediate foothills, all snow is falling. As we progress through
this evening into tonight, this precipitation is expected to
decrease across the area. The National Blend of Models does keep a
low chance of precipitation going across much of the area tonight
with general upslope, easterly surface winds in place, but
precipitation overnight into Friday morning will be light and
spotty if it occurs. The more likely scenario is low stratus
lingering across the region into Friday morning. Patchy fog is
also possible overnight into early Friday morning, but low status
may limit this threat.

Conditions will improve Friday as winds increase out of the east
and southeast with gusts into the 20 to 35 mph range. A few
scattered snow showers are possible over the higher terrain west
and south of Billings during the afternoon and evening (10 to 30
percent chance). Temperatures will remain seasonal with highs in
the 50s to 60 degF.

Saturday will be another mostly quiet day as temperatures warm
into the 60s and 70s across the region. During the afternoon and
evening, isolated to scattered showers, and maybe a rumble of
thunder or two, are possible over south-central Montana as a wave
of energy moves through the southwest flow aloft. Arends

Sunday through Thursday...

By Sunday morning a deep longwave trough will be progressing
through the western CONUS. The early morning will start off with
showers building into the western mountains before precip spreads
across the area quickly throughout the day.

The main challenge with this system will be figuring out the snow
levels for the foothills, especially in the Bighorn mountains.
The rapid elevation change in the Beartooth/Absaroka foothills for
this event keeps the forecast relatively easier as the lowest
snow level the NBM25% shows is just above 6,000ft which still
keeps the town of Red Lodge squarely in the rain. As you go up
US-212 south of town, expect to see a shift to snow fairly
rapidly. The snow levels for the Bighorns will be similar and
have the same certainty that the population centers will be all
rain for the duration of the event. The issue in this area stems
from the burn scar of the 2024 Elk Fire which roughly sits between
6,000 - 8,500ft. The lowest snow level values that the NBM25%
gives in this location are 5,700ft which would have snow falling
across the whole burn scar. Whereas, the 75th percentile has snow
levels around 7,000ft at the coldest part of the event and 9,000ft
at the warmest. This will put some to all of the scar under a
mostly rain scenario.

Now, the reason this is important is for the flooding potential of
the area. When looking at the NOHRSC SWE and snowpack temps,
combined with the temperature forecast over the next few days,
there should be minimal rain-on-snow impacts. Therefore, if
flooding were to occur on the Elk Fire scar, it would be a result
of the precipitation itself. There is too much uncertainty (as
shown above) at this time in order to make any concrete forecasts
but is something that will need to be monitored closely.
Regardless, some streams and creeks could see some notable rises
across the region with this event.

The other thing to look out for as this system advances is the
potential for some thunderstorms on the front side during the
afternoon Sunday. The NBM has SFC CAPE east of Billings between
400-800 J/Kg with the GFS showing SFC-3KM lapse rates of 9.5 C/KM.
This should be plenty sufficient to support some thunderstorms.
An inverted V sounding, skinny CAPE with an EL at 9km, and fairly
straight hodographs indicates that the main threats will be
strong winds with some small hail.

This system will be moving quite fast and thus we should see all
precip exiting the CWA Tuesday morning. The next chance for precip
will be courtesy of a speedy shortwave that moves in from the NW
on Wednesday. This could give us another chance for some showers
and thunderstorms Wednesday afternoon and evening. After that
shortwave exits to the east, there is great consensus in a
building ridge towards the end of the week. The specifics of
whether this ridge wil be more neutrally oriented or flopped over
a quasi-cutoff low is yet to be determined. Regardless, clear
skies and temps in the 70s seem likely late next week. WMR

&&

.AVIATION...

The lower elevation rain will gradually taper off this evening
into tonight. Behind this, low ceilings (MVFR/IFR) look to remain
with easterly surface winds in place. Patchy fog is also possible
overnight into Friday morning, but low ceilings may inhibit fog
formation. The low ceilings will also keep the mountains obscured
into Friday. Look for conditions to improve Friday as winds
increase out of the east. Arends

&&

.PRELIMINARY POINT TEMP/POPS...

    Fri     Sat     Sun     Mon     Tue     Wed     Thu
-----------------------------------------------------------
BIL 037/057 039/073 045/074 045/054 039/070 048/065 043/071
    21/L    11/B    27/T    98/W    21/B    35/W    21/U
LVM 035/054 037/070 041/069 042/053 037/068 043/062 039/070
    21/N    12/W    18/T    98/W    22/W    45/W    21/U
HDN 035/060 038/074 042/076 044/055 036/071 044/065 041/071
    41/B    11/B    27/T    +9/W    21/U    45/W    32/W
MLS 032/058 042/074 045/078 046/056 035/069 046/066 041/070
    11/B    11/B    14/T    88/W    21/U    34/W    21/B
4BQ 035/053 043/074 046/077 048/054 036/067 045/063 042/067
    21/E    01/B    12/T    79/W    30/U    24/W    21/B
BHK 028/057 040/071 041/077 043/054 031/066 041/064 037/066
    10/N    11/N    12/T    88/W    20/U    23/W    21/B
SHR 032/055 036/070 041/076 040/051 031/068 038/060 036/066
    62/W    11/B    14/T    8+/W    31/U    36/W    42/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.

&&

$$
weather.gov/billings