624
FXUS65 KBYZ 020253
AFDBYZ

Area Forecast Discussion...Updated
National Weather Service Billings MT
853 PM MDT Fri Aug 1 2025

.KEY MESSAGES...

- Isolated to Scattered thunderstorms through the evening, some
  may be strong to severe storms. Locally heavy rainfall can be
  expected with storms from Billings east.

- Thunderstorm and precipitation potential decrease from Saturday
  into next week.

- Seasonal temperatures for the next 7 to 10 days.

&&

.UPDATE...

A line of showers and thunderstorms was moving east across
southeast MT this evening, with a few showers lingering back over
western areas. Expect the showers and thunderstorms to gradually
lift north and east over the next few hours. Thunderstorms have
been producing small hail, wind gusts of 30-50 mph and heavy
rainfall. The threat for strong thunderstorms remains possible
through the evening. Have updated PoPs and weather into the
overnight hours to account for the latest radar and model trends.
An updated aviation discussion is below. STP

&&

.DISCUSSION...

Through Saturday night...

Ridge aloft today gets depressed by weak energy pushing out of the
PacNW into the Canadian prairie provinces Saturday into Sunday. As
the flow aloft flattens the thermal trof to the west of the divide
becomes less influential compared to the cross mountain flow lee
side troffing. This brings drier air in from the west and pushes
the juicy plains air gradually out of western and central zones.
With less moisture the probabilities for precipitation and
thunderstorms will decrease through the weekend into early next
week.

Already seeing the beginning of this process with dew points in
the western foothills currently in the low to mid 40s and Billings
sitting at 48. A pseudo-dryline from Roundup to Hardin to Fort
Smith divides the drier air to the west from the continued juicy
airmass to the east where dew points remain in the upper 50s to
mid 60s. Expect another round of thunderstorms this afternoon and
evening focused on a weak disturbance moving in from the
southwest. Storm initiation in the western mountains and foothills
gets going around 3pm according to the latest HREF, arriving in
Billings and Sheridan around 6pm and moving through SE Montana
(mainly Powder River/Carter counties) between 9pm and midnight.
Strongest storms will be over SE Montana, but areas further west
into the drier air will see an increased chance for strong wind
gusts of 40 to 50 mph near storms. Areas from Sheridan county
across SE Montana will have the best chances for locally heavy
rainfall with storms through this evening.

Looks like a quiet overnight period after convection ends tonight.
With drier air temperatures will drop into the 40s to low 50s over
western foothills locations tonight, while lower 60s will be
common elsewhere.

Despite lower atmospheric moisture levels (PWATs) for Saturday,
models are showing a better chance for showers and thunderstorms
over central portions of the forecast area (Billings vicinity)
compared to Friday. This is due to the aforementioned PacNW
disturbance crossing the area pushing a weak wind shift to the
north into the area, increasing upslope flow late afternoon into
the evening hours.  Despite the slight increase in storm coverage
over portions of the area Saturday, the threat of severe storms
and heavy rainfall looks lower overall.

Storms shift east of the area late Saturday night with clearing
and quiet conditions filling in behind. After highs in the upper
80s, Saturday night temperatures will be mainly in the 50s with
60s over the lower elevations from Billings to Miles City.
Chambers

Sunday through Friday...

A pretty typical weather pattern develops for next week.
Temperatures look to stay pretty consistent in the upper 80s to
lower 90s each day (seasonal). Precipitation chances and potential
amounts trend downward until late in the week with drier downslope
winds over the area. Late in the week the persistent Great Basin
ridge sags south into Mexico, allowing more northern stream
energy to flow across Montana. This will bring more active weather
going into next weekend. Overall a very pleasant Summer week on
tap for our portion of the northern Rockies. Chambers

&&

.AVIATION...

Isolated to scattered showers and thunderstorms, most east of
KBIL, will continue to move east and decrease through the evening
hours. Some storms may be strong, with hail, strong and erratic
wind gusts, and heavy rain as the main threats. Brief reductions
to flight categories will be possible within thunderstorms. Archer

&&

.PRELIMINARY POINT TEMP/POPS...

    Sat     Sun     Mon     Tue     Wed     Thu     Fri
-----------------------------------------------------------
BIL 060/088 060/087 059/090 060/087 060/090 061/089 061/084
    33/T    53/T    11/U    21/B    10/U    11/B    12/W
LVM 052/085 050/084 050/086 050/085 050/088 052/087 052/082
    23/T    32/T    12/T    31/U    11/U    11/B    12/T
HDN 058/088 059/086 057/092 058/088 058/091 060/090 059/084
    52/W    53/T    11/U    21/U    10/U    11/B    11/B
MLS 061/088 063/086 060/090 063/088 060/091 063/088 061/084
    42/T    54/T    21/U    22/T    11/U    21/B    22/T
4BQ 060/087 062/083 061/088 062/087 061/091 063/089 062/083
    52/W    53/T    21/U    21/U    11/U    11/B    21/B
BHK 058/083 059/081 057/085 060/086 058/088 060/086 058/082
    23/T    65/T    31/U    23/T    31/U    22/T    22/T
SHR 054/086 055/082 055/088 056/087 055/090 057/088 056/083
    32/T    44/T    11/U    11/U    00/U    11/B    11/B

&&

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

&&

$$
weather.gov/billings