Sheridan, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

518
FXUS65 KBYZ 160157
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
757 PM MDT Thu May 15 2025

.KEY MESSAGES...

- Very windy along MT/DK border into Friday. Peak wind gusts of 45
  to 55 mph, strongest over the higher hills of far eastern
  Montana.

- Unsettled weather continues through the end of the week. In far
  eastern Montana, band of moderate rainfall is forecast
  overnight into Friday. Across the rest of the region, isolated
  to scattered showers and thundershowers are expected each day.

- Another high impact precipitation event over the region is
  anticipated for the start of next week.

- Risk of localized heavy rain and associated flooding late Sunday
  into Monday, mainly around the Big Horns region.


&&

.8pm UPDATE...
Overall the forecast remains on track. While showers will linger
across the CWA into the morning, the steady rain will be confined
to far eastern Montana, especially near and NE of Baker, MT where
they could pick up another 0.5" in the next 12-24 hours.

Gusty winds will slowly taper off for the western 2/3 of the CWA
overnight. For far eastern Montana, the pressure gradient around
the occluded SFC low will tighten up overnight, however, due to
the slight nocturnal inversion and ascent ahead of a vort max,
wind gusts will remain below 50 mph though the night. Even though
there wil be precip falling, the rainfall rate will likely not be
enough to mix the stronger winds down to the sfc. A very brief
window exists just after daybreak for the potential for some wind
gusts near 60mph. As 850mb winds will be around 50kts at this time
and this region will be on the backside of the aforementioned
vort max, some of these winds could mix down between 6-9am before
the low moves eastward. Opted to not issue any wind highlights due
to the very narrow window and low confidence. WMR

&&

.DISCUSSION...

Through Saturday Night...

Strong low pressure system over the Dakotas will continue to
influence our eastern CWA through Friday morning. Winds will
increase tonight over the MT/Dk border area with gusts 45-55 mph
expected, possibly a little higher, thanks to a tightening
pressure gradient associated with a deepening surface low over the
eastern portion of the Dakotas. However, with upper vertical
motion over the area, we think winds will remain under our high
wind hi-light criteria. The trough axis will swing around through
eastern Montana as well tonight bringing rainfall across our
eastern border counties. So a wet/windy ride for our eastern
border tonight into early Friday. In the meantime, numerous
convective showers will prevail across our west and southern
sections through this afternoon, winding down after sunset as
instability wanes. Some rumbles of thunder are possible, but CAPE
is generally low (100-300 J/kg), so strong thunderstorms are not
anticipated.

A weak flat upper ridge builds in from the west on Friday as the
Dakota upper low slowly slides east. So look for lingering light
rain along the eastern border Friday to decrease. Pacific moisture
in the westerly mid level flow will move into our west and bring
an increasing chance of showers (iso/sct) and isolated thunder by
late Friday, especially across our SW mountains
(Beartooths/Absarokas). As mid level winds back ot the SW Friday
night and 500 mb heights rise a bit, precipitation should die off.

Saturday/Saturday night...Split upper trough (northern branch
over British Columbia coast, southern branch into Nevada) will
develop to our west with southwest flow bringing some moisture
and perturbations back across our western CWA with some isolated
showers spreading east as well Saturday night. Again, some
thunder is possible, but CAPE remains under 500 J/kg and forcing
is weak, so no strong thunderstorms are anticipated.

Look for overnight lows to generally range from upper 30s to mid
40s the next few nights. We may approach the freezing mark along
portions of Fallon and Carter Counties Friday night where a brief
light frost cannot be ruled out locally (25% chance of dipping
below 32F). Daytime highs will be in the 60s at most locations
Friday with some 50s still near the Dakota border. Highs on
Saturday will be in the 60s to near 70 degrees.

As for impact precipitation...At this time, the forecast for
Baker, MT has around an additional 0.70 inches of rain for Baker
through Friday morning, but there is still a 25 percent chance
that they could see over an inch of rain from this whole event.
Luckily, soils are drier in this region at this time, so any rain
that falls should not be to much of a problem, even if the high
end amounts occur. BT



Sunday through Wednesday...

Ensembles show the next low moving into the Pacific NW coast early
Sunday. Low level easterly flow will aid in beneficial
precipitation for the region through Monday night. Uncertainty
still remains of the exact track of the low and exact precip
amounts. There is a 40-60% chance of at least an inch of precip
across the region. With instability present Sunday evening, a few
thunderstorms are possible with heavy rainfall being a concern
given above average atmospheric moisture and low level easterly
flow. Heavy rainfall potential will also lead to concern for
continued rises on small streams especially with the recent
precip. As for mountain snowfall, snow levels will begin around
8-9,000 ft Sunday evening, dropping to around 7,000 ft Monday
morning. There is about a 30-40% chance of at least a foot of
snowfall in the Beartooth/Absarokas Sunday through Monday night.
Additionally, a tight pressure gradient over eastern MT Sunday
will allow for breezy winds over SE MT. Some ensembles are
depicting lower heights with some energy moving to the north of us
late Tuesday into Wednesday, bringing low to moderate precip
chances.

High temperatures will be in the 50s and 60s Sunday, cooling to
the 50s for Monday with 50s/60s for the remainder of the period.
TS

&&

.AVIATION...


00z TAF Discussion...Flight conditions will be primarily VFR
across the area tonight into Friday. However, portions of SE
Montana including, KBHK and KMLS, will see MVFR to occasional IFR
conditions at times as a disturbance in the Dakotas continues to
back into these areas. Scattered showers further west across
central and western areas will diminish significantly as the sun
sets, though isolated patches of convection can`t be ruled out
through the night. Local MVFR conditions can be expected near any
shower activity. In the early morning hours patchy stratus/fog
can`t be ruled out in the western foothills. Elsewhere northwest
winds should limit fog/low stratus potential with many areas
seeing gusts in the 20 to 35kt range tonight into tomorrow. Low
level wind shear is possible where surface inversions get strong
enough, mainly in low lying locations though did add a mention for
KBIL. Chambers

&&

.PRELIMINARY POINT TEMP/POPS...

    Fri     Sat     Sun     Mon     Tue     Wed     Thu
-----------------------------------------------------------
BIL 044/063 044/067 048/065 045/053 043/063 044/067 045/072
    32/W    34/T    28/W    98/W    55/W    54/T    23/W
LVM 038/061 039/064 044/056 038/053 039/062 039/066 040/069
    32/W    44/T    5+/W    97/W    45/W    54/T    23/T
HDN 044/063 043/068 049/070 045/053 042/062 042/067 043/073
    32/W    23/W    28/W    99/W    66/W    54/T    33/W
MLS 047/062 040/067 047/065 043/052 042/059 042/067 044/072
    66/W    12/W    36/W    99/W    75/W    44/W    32/W
4BQ 045/058 039/066 046/066 043/050 042/056 042/064 043/070
    54/W    21/B    36/W    99/W    75/W    44/W    22/W
BHK 038/054 033/063 039/056 038/051 038/058 039/064 040/069
    88/W    20/B    35/W    89/W    75/W    33/W    32/W
SHR 040/060 038/067 044/069 040/050 038/058 037/064 038/071
    32/W    23/T    28/W    99/W    66/W    55/T    23/T

&&

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

&&

$$
weather.gov/billings