130
FXUS65 KBYZ 140734
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
134 AM MDT Mon Sep 14 2026

.KEY MESSAGES...

- Below average temperatures through the middle of the week.

- Chance of showers (mainly light) through today. Isolated
  thunderstorms possible in southeast Montana overnight, a few
  possibly strong.

- Frontal passage brings brisk northwest winds overnight. Brisk
  west winds across the area Monday; widespread gusts of 30 to 50
  mph, strongest from Big Timber to Harlowton and near the Dakotas
  border.

&&

.DISCUSSION...

Next 7 days (Through Sunday)...

Vigorous upper trough will be tracking into and across our region
overnight and through today. Currently, upper low is centered
over NW Montana with 100kt 300 mb jet moving up into southwestern
Montana. Scattered showers and thunderstorms had developed over
portions of southeastern Montana in the warm sector ahead of this
system and will affect the far east overnight. In the meantime,
other widespread showers, and possibly embedded thunder, were
developing over our western zones and these will slide eastward
through the rest of the night. This area will be powered by the
cold front and strong upper dynamics associated with this system.
We expect to see a few elongated bands of moderate precipitation
within broader areas of light showers. This activity may also
generate a period of locally strong NW winds (30-45 mph) as it
moves east/northeast overnight.

As the upper low tracks across the MT/Canadian border today, the
better forcing will lift east of our CWA by mid to late morning.
At that point the more significant impact with this system becomes
the strong westerly winds across our region. Widespread westerly
wind gusts of 35 to 55 mph can be expected, with the greatest
wind gusts along the western foothills and out east near the
Dakotas border (Baker area). Locations from Big Timber north to
Judith Gap have roughly a 40-70% chance at seeing wind gusts of 50
mph or greater (morning), with similar probabilities near the
Dakotas border (afternoon) thanks to 700 mb wind max moving over
the region. Cannot completely rule out a local gust or two near
60 mph, but majority of peak gusts should be sub-warning criteria.
Thus, no highlights at this time. As winds drop and skies clear
out Monday night, slight chance of frost is possible for some of
the colder valley locations with temperatures dropping into the
30s and lower 40s.

Ensembles suggest another upper low developing over the Pacific
NW by midweek while zonal flow, or at best low amplitude ridging,
develops over our region. By late week, energy in that west coast
trough ejects into the Rockies and it gradually begins to move
east, pushing some moisture into our region from the south. So
look for generally seasonable temperatures through the week with
a chance of precipitation starting Thursday and increasing into
the weekend. BT


.AVIATION...

A dynamic weather system moving thru the northern Rockies will be
associated with a Pacific cold frontal passage early this morning.
The front will bring a shift to gusty westerly winds. Expect
gusts of 25-40 knots early, then widespread mixed W-NW winds of
30-45 knots through the afternoon. Highest gusts are expected to
occur along the western foothills. Winds will diminish this
evening.

Scattered showers and a few thunderstorms are expected early this
morning, through ~15z. Greatest potential for TS is east of KBIL.
Shower activity itself may produce local/brief MVFR, and any
thunderstorms could enhance wind gusts. Gusty downslope winds
become dominant by mid to late morning, and dry/VFR conditions
will prevail through the afternoon and tonight. Mountains will be
obscured at times early today.

JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Tue     Wed     Thu     Fri     Sat     Sun
-------------------------------------------------------
BIL 069 043/073 047/069 047/077 053/075 051/074 050/076
    2/W 00/U    00/U    01/U    45/T    63/W    31/U
LVM 064 035/071 040/071 041/078 046/073 044/072 043/075
    2/W 00/B    00/U    02/T    55/T    43/T    21/U
HDN 071 039/076 042/072 042/080 049/077 046/076 043/078
    2/W 00/U    00/U    01/U    35/T    64/T    31/U
MLS 070 044/071 050/074 045/079 053/078 050/074 047/076
    6/W 00/U    00/U    01/U    36/T    65/W    32/W
4BQ 071 044/073 052/076 047/081 055/078 050/074 047/077
    2/W 00/U    00/U    12/W    46/T    65/W    32/W
BHK 070 041/070 046/078 043/078 050/078 047/073 045/076
    5/W 00/B    21/U    02/W    46/T    66/W    43/W
SHR 072 036/074 042/072 041/078 047/075 043/072 040/075
    2/W 00/U    00/U    12/W    26/T    55/T    21/U

&&

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

&&

$$
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