988
FXUS65 KBYZ 101832
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
1232 PM MDT Mon Aug 10 2026

.KEY MESSAGES...

- Wildfire smoke keeps skies hazy for the foreseeable future, and
  will occasionally reduce air quality. For the latest air quality
  visit airnow.gov.

- Slight chance of late day thunderstorms in far southeast Montana
  today and Tuesday.

- Cooler with showers and thunderstorms (50-80% chance) across the
  area Wednesday through Friday. Storms may produce heavy rain.

- Warmer with a daily chance (20-50%) of thunderstorms this
  weekend.

&&

.DISCUSSION...
Through next Monday...

Smoke Impacts: Wildfire smoke will continue to impact our region
for the foreseeable future, keeping skies quite hazy, with reduced
surface visibilities and poor air quality at times.

Satellite imagery shows dry zonal flow over the region with a weak
shortwave (responsible for the morning ACCAS field) about to exit
eastern MT. Pwats continue to increase and as of 17z are analyzed
to be an inch east of Rosebud County. As was the case yesterday,
there is potential for a t-storm or two over our far east late
this afternoon and early evening with the question being whether
or not a mid level cap can be overcome. Low levels show an area of
convergence in far southeast MT which may provide a forcing
mechanism, but otherwise we will be under large scale descent
behind the passing wave. Most CAMs show no development in
southeast MT but will keep isolated TS mentioned per the
environment. If a storm does develop it could be on the strong
side, with ample shear and 1000+ j/kg of MLCape. Early this
morning there was an area of stratus over Carter County, and there
seems to be a risk of fog late tonight into early Tuesday in our
far east, from roughly 09z-15z. Low level easterly winds will keep
boundary layer moisture elevated in this area.

Warm & dry conditions continue Tuesday, with elevated RHs in the
east and mins in the teens from Rosebud County westward. Once
again, the environment may favor a strong t-storm or two in our
far east by late in the day. Otherwise it will be dry with temps
in the upper 80s and lower 90s. Winds won`t be strong but N-NE
winds in the afternoon will be a bit gustier than today, with
gusts ~20 mph. This will keep fire weather conditions elevated.

The entire forecast area begins to turn cooler and more humid on
Wednesday, as heights fall in response to a trof dropping out of
southwest Canada, low level easterly winds moisten the boundary
layer further west, and mid/upper level moisture is increased per
monsoonal flow. All told, shower and t-storm potential increases
significantly by Wednesday afternoon and evening. SPC has the far
southeast corner of MT highlighted for a marginal risk of severe
t-storms. Heavy rain is the larger risk, especially in the east on
Wednesday.

Thursday into Friday looks to be the time when pwats are highest,
up to 1.25" as far west as Billings per ensembles. There is a
shortwave emerging from the southwest, providing ascent for what
should be a period of widespread showers and t-storms capable of
producing heavy rain. WPC has our area highlighted with a marginal
to slight risk of heavy rain. Local burn scars will be at an
elevated risk of seeing flash flooding. Regarding fire weather,
the onset of increased lightning activity may be problematic for
possible new fire starts, as almost our entire forecast area has
not seen measurable rain yet in August, but the much wetter air
mass should also keep potential fire growth in check. This will be
something to monitor.

Heights rise this weekend as another Pacific low settles off the
coast, and temps will climb again. Pwats will drop some but remain
elevated, and additional shortwaves emerging from the southwest
flow aloft will continue the daily chance of t-storms Saturday
through Monday.

Look for temperatures to cool to the 80s Wednesday then 70s
Thursday and Friday. The next warming trend begins Saturday and we
should see 80s to lower 90s return by early next week.

JKL

.AVIATION...

Wildfire smoke will continue to impact the region, reducing slant
range visibility and occasionally surface visibility to MVFR
(generally 4SM or 5SM) today into Tuesday. Surface visibility
reductions are most likely over south-central and western Montana
and northern Wyoming. This includes KLVM. While areas around and
east of KBIL will see some improvements today as compared to
yesterday, a wind shift to the northwest Tuesday morning will
bring higher concentrations of smoke back across the area.

While the majority of the area will remain dry today, there is a
low chance (around 15 percent) of showers and thunderstorms over
far southeastern Montana this afternoon and early evening. Patchy
fog may also develop tonight into Tuesday morning over far south-
eastern Montana (20 percent chance). LA

&&

.PRELIMINARY POINT TEMP/POPS...

    Tue     Wed     Thu     Fri     Sat     Sun     Mon
-----------------------------------------------------------
BIL 062/093 062/084 060/074 057/072 054/076 055/082 057/085
    00/K    01/E    56/T    96/T    53/T    42/T    31/B
LVM 050/092 052/085 050/074 048/073 045/076 045/081 048/082
    00/K    01/B    57/T    98/T    75/T    54/T    43/T
HDN 058/094 059/087 057/077 053/074 049/078 050/083 053/087
    00/K    01/E    57/T    96/T    43/T    41/B    31/B
MLS 061/093 061/084 058/075 055/073 051/075 053/082 056/086
    00/K    05/T    67/T    97/T    22/W    23/T    31/B
4BQ 061/093 062/085 060/075 057/074 054/076 055/081 057/085
    01/K    06/T    57/T    96/T    43/T    43/T    32/T
BHK 057/091 055/082 052/072 049/070 046/074 047/079 051/083
    12/T    26/T    67/T    98/T    51/B    33/T    32/T
SHR 055/092 058/086 055/075 053/073 049/074 048/079 050/083
    00/K    03/T    59/T    99/T    67/T    54/T    22/T

&&

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

&&

$$
weather.gov/billings