945
FXUS65 KBYZ 041945
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
145 PM MDT Thu Sep 4 2025

.KEY MESSAGES...

- Northwest winds gusting 30-50 mph (strongest east of Billings)
  will decrease this evening.

- Wildfire smoke is producing reductions to visibility and air
  quality. Expect improvements late this afternoon and evening.

- Seasonably cool tonight to Saturday; frost possible in eastern
  sheltered valleys Friday night.

- Warming trend through the weekend and an increasing chance for
  precip starting Sunday. Above normal temps are favored through
  next week.

&&

.DISCUSSION...

Through Saturday...

Clipper system continues to slide east, windy conditions and
Canadian smoke will continue into mid/late afternoon. A surface
high will begin moving into the region late this afternoon/early
evening. This will bringing cooler temperatures, decreasing winds
and a wind shift to the N-NE which will help push the smoke out of
the area. The highest wind gusts have been observed in the 50s
mph in the eastern zones, specifically at KBHK. NW flow favored
locations like Judith Gap and Sheridan may also see gusts near 45
mph. Across the plains and the west, gusts of 25 to around 40 mph
have been occurring. Breezy conditions are forecast again on
Friday, though gusts will be much calmer, in the 10s to 25 mph,
highest in the east.

Air quality and visibilities have been reduced to varying degrees
across the area today. Reductions to visibility from smoke have
improved since this morning (observed visibilities as low as 3SM
at several ASOS`), though reductions as low as 6SM have been
recently observed. Air quality for much of southeastern Montana
and northern Wyoming has been "moderate" to "unhealthy for
sensitive groups". There is an Air Quality Alert in effect until
12 AM Friday for Sheridan County, WY.

Fire weather concerns are marginally elevated today due to the
strong winds. The concern is mitigated by cooler temperatures in
the 70s and minimum RH values between 25-35%. That said, take care
to not spark a fire!

The chance for precipitation is low to negligible through the
short term forecast period. The southern foothills (Red Lodge,
Pryor, Sheridan) have the best chance (15 to 25%) for
precipitation this afternoon. Tonight through Saturday will remain
dry.

Fall-like temperatures are forecast through Friday night, with
high temperatures in the 60s to lower 70s Friday. Overnight lows
will drop into the mid 30s to mid 40s tonight and mid 30s to low
40s Friday night. There is a risk of frost, most notably in
eastern valleys Friday night. The probability of reaching 36F at
Baker is 50 to 60%, while there is a 10 to 20% chance of reaching
32F. Other notoriously cool spots like Mizpah & Brandenberg will
also likely see a frost. In the Sheridan Foothills there is a 30
to 60% chance of temperatures reaching 36F as well. Those with
sensitive outdoor plants/gardens may want to take precautions the
next couple nights.

Upper ridging will continue through Saturday, ahead of an
approaching upper low/trough on Sunday. High temperatures in the
upper 60s (in the east) to mid/upper 70s (central and west).

Matos


Sunday through Wednesday...

Ridging will continue to rebuild over the Northern Rockies on
Sunday. This will bring back more seasonable temperatures, in the
upper 70s to mid 80s. A weak upper wave is depicted amongst the
latest deterministic runs. This wave may bring an increased
chance for precipitation on Sunday. Currently the best chance (25-60%)
for precipitation exists in the southwestern mountains and
foothills. The threat for strong to severe weather is very low,
thanks to weak shear and low instability. The bulk of moisture on
Sunday is mid-level monsoonal moisture, while surface flow will be
mostly dry. The chance for precipitation off the mountains and
into the plains looks scant at this time.

Monday looks to be warmer, with highs in the 80s to around 90F.
There is uncertainty on the chance for precipitation, for now the
chance looks low with the best chance again in the mountains.

A slow-moving, broad upper trough is shown by ensembles moving
over the west coast Tuesday and Wednesday. There is uncertainty
with timing of potential impacts to the Northern Rockies at this
time. The current depiction of the system is one that is normally
conducive for shower and thunderstorm activity. The latest
ensembles show fairly high MUCAPE values across the CWA for this
time of the year, 100s to 1000 J/kg. It is too early to determine
the extent and strength of any storms at this time, so continue to
monitor future forecasts. High temperatures are currently forecast
to be in the 80sF to 90F, Tuesday and Wednesday. Matos
&&

.AVIATION...

A cold front will keep gusty (25 to 45kt) north winds over the
forecast area into early this evening. Winds will diminish quickly
as the sun sets. Isolated light shower activity is possible
(15-30% chance) along area foothills, including the KSHR TAF site
this afternoon. Any showers will diminish early this evening along
with the gusty winds. Smoke that has been over the area this week
will dissipate this afternoon into this evening as the northerly
winds usher in cleaner air. Local MVFR conditions early this
afternoon should give way to prevailing VFR conditions by 22-00z
this afternoon. Clear skies and light winds expected tonight
through Friday morning. Chambers


&&

.PRELIMINARY POINT TEMP/POPS...

    Fri     Sat     Sun     Mon     Tue     Wed     Thu
-----------------------------------------------------------
BIL 043/070 043/076 046/084 058/088 057/086 058/085 057/082
    00/U    00/U    01/B    01/B    12/W    22/W    22/W
LVM 038/072 038/079 044/084 050/083 049/081 048/080 047/077
    00/U    00/U    02/T    22/T    23/T    33/T    34/W
HDN 039/070 038/077 042/085 051/088 053/088 055/087 055/083
    00/U    00/U    00/B    00/B    11/B    22/W    22/W
MLS 042/066 038/071 042/082 052/089 055/088 059/087 059/082
    00/U    00/U    00/U    00/B    01/B    22/W    32/W
4BQ 042/064 039/069 042/080 054/086 056/086 058/087 059/083
    00/U    00/U    00/U    00/B    01/U    21/B    21/B
BHK 037/062 033/068 037/077 047/086 051/086 055/083 055/081
    00/U    00/U    00/U    00/B    00/U    21/B    21/B
SHR 038/068 035/074 041/082 051/085 051/085 052/086 053/082
    00/U    00/U    00/U    01/B    11/B    22/W    22/W

&&

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

&&

$$
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