098
FXUS65 KBYZ 010749
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
149 AM MDT Mon Sep 1 2025

.KEY MESSAGES...

- Dry and warm through Tuesday with hazy skies.

- Late Tuesday cold front brings cooler temps, breezy winds and a
  few light showers Tuesday night and Wednesday for eastern MT.

- Tuesday night cold front may bring Canadian wildfire smoke into
  the eastern plains.

- Mostly dry with seasonable temps Thursday and Friday.

&&

.DISCUSSION...

Through Tuesday Night...

Satellite imagery shows strong/dry ridge over the northern
Rockies and an upstream cut off low just off the WA coast, the
latter of which is spreading some high clouds to the west half of
MT. The Pacific low is a non-player for us, but looking north
there is a shortwave approaching northern AB that will eventually
evolve into a deep trof over the upper Mississippi Valley,
bringing us modest backdoor cooling behind a late Tuesday cold
front. Currently, there is low stratus advecting into Fallon and
Carter Counties from the southeast. Expect stratus and localized
fog from Baker to Ekalaka and Alzada thru early this morning.
Drier/mixed NW winds will spread across our far east today,
finally eroding the existing moist boundary layer in that area.

Today & Tuesday will be warm and dry with temps in the mid 80s to
lower 90s, not hot enough to threaten daily records but still
8-12F above normal. Afternoon humidities will likely drop to
15-20% from Rosebud County westward. Not much wind to be concerned
about today, but winds will increase a bit late Tuesday (15-25
mph gusts) as a Canadian front drops into the area. Though we`ve
had a stretch of "humid" days and fairly widespread precip
recently, the next two days could promote greater wildfire
activity. Otherwise, no real chance of precip anywhere from now
through Tuesday morning. There may be a low risk of high-based
t-storms Tuesday afternoon, followed by a bit better chance of
light showers over the east half of our forecast area Tuesday
night as the cooler air backs in and combines with a hint of mid
level frontogenesis in the NW flow. We are looking at very little
actual rainfall, only 0.05" or less. The probability of a wetting
rain (0.10" or more) is a mere 5-15% from Miles City to Broadus
eastward...and even this may be generous.

Well to our north in the NW Territories of northern Canada, there
is a large number of active wildfires and plenty of smoke. The
Canadian front could spread near-surface smoke into eastern MT
Tuesday night as winds shift to the NE-E. This is something to
watch.

JKL

Wednesday through Sunday...

For Wednesday into Thursday, an upper level ridge axis will be in
place west of the region and a strong upper low will be over
Ontario into the Great Lakes region, resulting in NW/N flow over
the region. This pattern isn`t favorable for precipitation,
however, PWATs over the mountains will be around 120% of normal so
an isolated shower or weak thunderstorm over the mountains remains
possible (10% chance) during the afternoon and evening hours.

Friday into the weekend, the upper level pattern gradually shifts
east, becoming more of a ridging pattern and leading to a warming
trend. With this change, an increased push of moisture will move
in over the western mountains and slowly spread east through the
weekend. The highest PWATs over the west are expected to be
around 130-150% of normal. The chance of showers and thunderstorms
each afternoon will increase from 10-30% over the western
mountains Friday to 30-60% over the mountains and 10-30% as far
east as Billings and Sheridan Sunday.

High temperatures Wednesday will range from the upper 60s near the
Dakota border to low 80s over the west. Thursday will be slightly
warmer, with highs in the upper 70s to mid 80s. Then, a weak cold
front dropping through late Thursday will bring highs generally in
the 70s Friday. Under the upper level ridge, highs will increase
back to upper 70s to mid 80s by Sunday. Archer

&&

.AVIATION...

Areas of low stratus and localized fog expected over the east,
including KMLS and KBHK, through 14Z. Wildfire smoke aloft will
reduce slant range visibility at times. Otherwise, VFR conditions
and mostly light winds will prevail. Archer

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Tue     Wed     Thu     Fri     Sat     Sun
-------------------------------------------------------
BIL 091 058/091 057/079 056/085 051/077 051/083 056/086
    0/H 00/H    00/U    00/U    00/U    01/U    11/B
LVM 088 051/090 050/085 052/085 047/080 047/082 050/080
    0/H 00/H    00/U    00/U    01/U    12/T    23/T
HDN 091 054/092 054/077 049/083 046/078 046/085 051/086
    0/H 00/H    10/U    00/U    00/U    00/U    11/B
MLS 090 057/088 054/073 048/080 046/073 046/079 051/084
    0/H 00/H    20/U    00/N    00/U    00/U    00/B
4BQ 087 058/086 055/071 048/078 047/071 047/079 052/083
    0/H 00/H    20/B    00/N    00/U    00/U    11/B
BHK 088 053/083 047/069 043/078 041/070 040/075 046/080
    0/U 00/H    30/U    00/N    00/U    00/U    00/B
SHR 089 052/090 051/077 049/081 046/076 046/081 050/083
    0/H 00/H    00/U    00/N    00/U    01/U    11/B

&&

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

&&

$$
weather.gov/billings