109
FXUS65 KBYZ 291931
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
131 PM MDT Fri Aug 29 2025

.KEY MESSAGES...

- Scattered showers and thunderstorms continue across the region
  through Saturday, with locally heavy rainfall possible. Greatest
  potential for heavy rain will be east of the western foothills.

- There is a low risk of flash flooding in and near area burn
  scars today.

- Warmer and dry Sunday and Monday.

- Trending cooler and mainly dry Tuesday into Thursday.

&&

.DISCUSSION...
Through Saturday Night...

A low situated in Northern MT / Southern AB is forecast to linger
before slowly moving northwards into the prairie provinces. The
associated weak moisture return coming in off of the plains and
downslope flow from the higher elevation has set up a convergent
boundary across Eastern Montana. This boundary is forecast to
linger oriented KBIL/KSHR for the rest of the day today with the
potential for some lightning this afternoon and evening. There are
also convective cells popping along and east of this boundary
which could help to increase the coverage in storms this
afternoon. With the mean wind at roughly 20kts across the CWA,
PWATS around 1", and training storms, the potential for localized
flooding will need to be monitored for the rest of the day today.

As the low slowly drifts out of the area chances for precip will
slowly decrease from west to east during the day Saturday.
Tomorrow morning could also come with the potential for fog
across the region as well. With the recent precip over the past
several days there is ample surface moisture as as the low exits,
winds will become very light. Areas west of the CWA saw dense fog
for several hours this morning under similar conditions. The main
limiting factor seems to be that there is still a potential that
some precip could be falling during the morning hours.
Additionally, while winds are forecast to be under 5mph, the wind
direction does appear to be downslope which could limit fog
development. All this to say that there could be fog tomorrow
morning, however, the chance is highly conditional.

Some mid-range models show a weak vort max zip through the area
Saturday night into early Sunday which could being widely isolated
showers early Sunday. WMR


Sunday through Friday...

Sunday and Monday will feature increasing temperatures and drier
conditions as ridging moves in from the west keeping us in
northwest flow. Temperatures are expected to be in the 80s F both
days. The rest of the long term forecast will be dominated by a
large 500 mb trough that will descend from Canada and settle in
over the Great Lakes. This is expected to drop a cold front
through the northern plains next Tuesday. The highest confidence
in a cool down is for locations near the Dakotas border such as
Baker where the NBM is giving a reasonable temperature range of
59-70 F for Wednesday, while the same for Livingston is 69-83 F.
Looking at WPC clusters, there is high confidence in the overall
pattern, but significant uncertainty in how far west the impacts
will reach. The coldest morning looks to be Thursday morning with
locations near the Dakotas border and Sheridan County Wyoming
having a 20-40% chance of getting below 40 F with 0-20% chances
elsewhere. There is good agreement that by Friday the upper level
trough will begin to move to the east bringing increasing heights
and temperatures to Montana. Overall, a dry next 7 days is
expected. Torgerson

&&

.AVIATION...

18z Discussion...

An area of showers and thunderstorms is expected to continue
through 06z across the forecast area with the highest coverage of
precip oriented along a line roughly from KBIL to KSHR. Both of
the aforementioned sites will see SHRA with isolated TSRA through
at least 00z. While VFR will prevail, a brief period of MVFR to
IFR cannot be ruled out; however, due to the isolated nature, this
was not included in the TAFs. Some VCSH may materialize in the
mountains near KLVM between 22z and 06z. Expect at least partial
mountain obscuration for the entirety of the period.

Saturday morning there is a low chance of some FG developing at
any of the sites. Due to the lower confidence of this
materializing, this was omitted from the TAFs as well. Just be
aware that IFR vis is possible (20%) from 08z through 14z across
the forecast area. WMR
&&

.PRELIMINARY POINT TEMP/POPS...

    Sat     Sun     Mon     Tue     Wed     Thu     Fri
-----------------------------------------------------------
BIL 057/081 055/088 057/088 058/083 053/078 050/081 052/084
    32/T    00/U    00/U    01/B    21/U    00/U    00/U
LVM 048/080 048/085 049/086 050/083 047/080 046/082 047/083
    22/W    00/U    00/U    01/U    11/U    10/B    01/U
HDN 055/079 052/087 053/088 054/083 050/078 047/081 048/084
    43/T    10/U    00/U    01/B    21/B    00/U    00/U
MLS 059/078 056/086 055/086 056/081 050/073 046/078 049/079
    43/T    10/U    00/U    11/B    21/U    00/U    00/U
4BQ 057/074 053/081 055/084 057/081 050/072 047/075 049/078
    54/T    20/U    00/U    01/B    21/B    10/U    00/U
BHK 054/075 052/081 053/084 053/078 044/069 042/075 046/076
    34/T    11/U    00/U    11/B    21/B    00/U    00/U
SHR 050/076 048/083 050/084 051/083 048/075 044/078 046/080
    45/T    11/U    00/U    01/U    22/W    10/U    00/U

&&

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

&&

$$
weather.gov/billings