128
FXUS65 KBYZ 160807
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
207 AM MDT Thu Oct 16 2025

.KEY MESSAGES...

- Lower elevation rain and mountain snow through evening;
  heaviest precipitation east of Billings; snow levels fall to
  around 7000 feet.

- Brisk wind and a little warmer Friday; then scattered showers
  likely Friday night through Saturday morning.

- Dry and warmer Sunday (temps in 60s to near 70F).

- Turning cooler with chance of precipitation again Monday;
  followed by drier conditions and seasonable temps Tuesday and
  Wednesday.

&&

.DISCUSSION...

Today Through tonight (Thursday)...

Satellite imagery showed an upper low spinning over Utah pushing
toward southwest WY while a deformation zone and diffluent upper
flow were shifting east across southern MT and northern WY. Enhanced
cloud tops were indicated in these areas as well as SE
MT...evidence of strong ascent associated with the system.

As the upper low tracks northeast across WY today we will see
favorable dynamics for ascent persist over our forecast area,
while moist northerly flow develops in the low-mid levels. Areas
of showers should be expected, possibly heavy, especially across
the eastern sections (Rosebud County eastward into Fallon County).
The probability of 0.50 inches of precipitation through this
evening ranges from 15% over Park County to 85% at Miles city and
Baker. In the meantime snow levels will drop to around 7k ft
through the day with 4-8 inches of additional accumulation
possible from now through this evening. Greatest accumulations
wil be above 8k ft on north/northwest facing slopes, with only
light accumulations expected in the Cooke City vicinity. The Big
Horn Mtns should see only 1-4 inches of accumulation over higher
elevations. Temps today will remain below seasonal averages with
readings in the mid to upper 40s common. Look for brisk northwest
wind to 10-20 mph to make it feel a little cooler.

The upper low is progged to be over SE MT by evening, and heading
into the high plains of the Dakotas. Cross sections show much
drier air quickly moving into our western areas as the upper low
exits to the east. So look for decreasing precipitation from west
to east during the evening. Tough outdoor conditions will linger
though in our far east with pockets/bands of rain and westerly
winds 20-35 mph within a trowal that develops over the east
central zones (Fallon area) in the evening. Rainfall should be
about done after midnight and winds decrease before sunrise
Friday.

Friday and Saturday...Look for a period of subsidence and drying,
with gusty west winds on Friday. Ensembles suggest the
probability of gusts exceeding 40 mph is 40-70% for most areas,
but as high as 90% for our western foothills thanks to a decent
pressure gradient and 700mb winds 30-40 kts. Cannot rule out gusts
to 50 mph at Harlowton, Big Timber or Livingston. Highs on Friday
will be in the mid 50s to lower 60s.

A fast-moving shortwave in WNW flow aloft will push across the
area Friday night through midday Saturday. This feature will
bring more showers to lower elevations Friday evening through
Saturday morning along with a few inches of mountain snow,
followed by another dose of breezy W-NW winds. Highs on Saturday
will be a little cooler than Friday, mainly in the 50s.

Sunday...
This is a dry and warmer day under a brief period of shortwave
ridging. Look for highs in the 60s. There remains a sign of some
enhanced gap flow Saturday night into early Sunday, and perhaps
40-50 mph gusts at Livingston and Nye (50% chance).

Monday through next Wednesday...
Cluster analysis indicates better agreement that a broad low
amplitude trough will push across Montana Sunday night through
Monday bringing another shot of rain showers and mountain snow.
This looks to be followed by modest ridging or westerly zonal flow
Tuesday and Wednesday with seasonal temps and mainly dry
conditions. BT

.AVIATION...

Widespread showers will continue to impact eastern MT and
northern WY, gradually expanding west towards KBIL through the
morning. Low stratus/fog will continue through this evening,
slowly dissipating as the system moves east. MVFR/IFR conditions
will be common with IFR/LIFR possible under heavy rain and very
low ceilings. Mountain obscurations can be expected through the
period. TS

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Fri     Sat     Sun     Mon     Tue     Wed
-------------------------------------------------------
BIL 048 040/063 037/056 039/066 041/052 034/054 035/058
    9/W 30/U    40/U    01/B    54/W    11/B    10/B
LVM 048 032/060 028/054 034/064 030/048 026/052 029/055
    7/W 10/N    50/U    04/W    75/W    11/B    11/B
HDN 047 037/062 035/055 033/066 038/054 031/055 032/058
    +/W 70/U    61/U    01/B    64/W    21/B    10/B
MLS 050 040/059 035/053 034/066 040/054 032/054 034/058
    +/W 90/N    30/U    00/B    32/W    10/U    10/B
4BQ 048 041/058 036/051 034/067 041/054 032/053 034/055
    +/W 80/U    40/U    00/U    32/W    11/U    10/U
BHK 051 037/060 032/053 029/066 036/055 029/053 030/057
    +/W 91/N    20/N    00/U    21/N    10/U    10/U
SHR 046 032/061 030/052 029/068 034/052 026/053 029/055
    +/W 60/U    61/B    00/U    55/W    21/U    10/U

&&

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

&&

$$
weather.gov/billings