337
FXUS65 KBYZ 270132
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
732 PM MDT Sat Jul 26 2025

.KEY MESSAGES...

- Isolated to Scattered thunderstorms this evening have the
  potential to produce strong/erratic wind gusts.

- Daily chance of showers and thunderstorms Sunday through much of
  next week. The threat of heavy rainfall increases. The best
  potential for more widespread precipitation is Tuesday through
  Thursday.

- Near normal temperatures (upper 80s to mid 90s) through the
  weekend turning slightly cooler than normal next week.

&&

.730pm UPDATE...

WW545 for Musselshell and Golden Valley counties has benn canceled
as all of the storms have moved out of the area or weakened. WW546
continues for Fallon and Carter counties. WMR

&& Through Sunday Night...

.DISCUSSION...

CAMs continue to point to SE corner of Montana as most likely to
see strong to severe thunderstorms this afternoon/evening.
Satellite does confirm weak perturbation tracking northward from
Wyoming toward this area where ingredients include shear values
progged to reach 35-40 kts and MUCAPE greater than 2500 J/kg all
within a thermal ridge at 700 mb. So window in Powder River/Carter
County for severe weather is from 430-730 PM with gusts 60-70 mph
and hail a possibility.

Elsewhere, PWATs are in normal seasonal range with some downslope
in mixed environments. Weak perturbations also tracking over our
west and central areas should result in typical isolated to
scattered convection coming off mountains and moving
northeast. Given inverted-v soundings and weak forcing, erratic
wind gusts 40-50 mph are most likely impacts with any of these
storms...but isolated gusts 50-60 mph are possible.

Convection will exit through the evening and this will be followed
by another dry period late tonight thru Sunday morning. It still
appears best forcing will clip our NW zones tomorrow. S expect
less coverage Sunday afternoon and evening with generally garden
variety t-storms across our west and north sections of CWA. One
thing to note is that pwats Sunday should be pretty similar to
today.

Temperatures Sunday will be slightly cooler than todays and very
close to normal. Look for highs in the mid 80s to lower 90s. BT



Monday through Friday...

For the long term, continuous disturbances under southwest flow
as well as southeast flow at the low levels will allow for daily
chances (30-60%) of showers and thunderstorms. This pattern will
lead to increased atmospheric moisture (pwats ~ 1-1.3 inches) and
thus increased instability which will allow for these daily
chances of showers and thunderstorms. Into Tuesday, southeast low
level winds will wrap around into the foothills across south
central MT. With this, the ensembles are showing anomalously high
instability levels for this time of year, especially for this
area (sfc CAPE values around 1200-1600 J/kg). With the lack of
shear in this pattern, storms will be slow moving and pose a risk
for heavy rain under any strong thunderstorms. Ensembles aren`t
quite in agreement on the placement of the heaviest rainfall, so
make sure to watch the forecast as the time approaches.

High temperatures will be in the upper 70s and 80s for the period,
with the coolest days occuring mid week. TS

&&

.AVIATION...


Expect isold/sct showers/thunderstorms through evening. Storms
will have the potential to produce strong and erratic winds
(localized gusts of 45+ knots), and perhaps brief MVFR conditions.
KRPX- KMLS-KBHK at risk for impacts this evening (30% chance).
Otherwise, VFR will prevail across the region, though slant range
visibility may be reduced at times due to wildfire smoke aloft. BT

&&

.PRELIMINARY POINT TEMP/POPS...

    Sun     Mon     Tue     Wed     Thu     Fri     Sat
-----------------------------------------------------------
BIL 062/092 060/085 061/081 061/082 061/086 061/088 061/088
    31/U    11/U    23/T    44/T    53/T    33/T    32/T
LVM 052/089 051/085 054/081 054/081 054/083 053/086 052/086
    22/T    23/T    34/T    45/T    45/T    44/T    33/T
HDN 059/092 059/088 060/083 060/084 060/087 060/089 059/089
    30/U    11/U    23/T    44/T    53/T    32/T    32/T
MLS 065/092 064/085 062/081 061/081 062/083 062/087 062/089
    31/U    23/T    33/T    43/T    53/T    32/T    32/T
4BQ 062/092 064/090 063/081 061/080 062/081 063/084 062/087
    40/U    11/U    23/T    64/T    53/T    32/T    32/T
BHK 060/091 061/082 057/079 057/078 057/079 058/081 058/084
    41/U    13/T    43/T    43/T    43/T    32/T    32/T
SHR 054/091 055/088 057/082 056/082 056/082 057/087 056/087
    30/U    10/U    13/T    56/T    54/T    33/T    22/T

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Severe Thunderstorm Watch 546 in effect until 2 AM MDT Sunday
      FOR ZONES 33-37.
WY...None.

&&

$$
weather.gov/billings