116
FXUS65 KBYZ 302051
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
251 PM MDT Wed Jul 30 2025

.KEY MESSAGES...

- A moist and unstable air mass will bring a daily chance of
  thunderstorms through the week. Storms have the potential to
  produce very heavy rainfall, and localized flash flooding is
  possible. Stay weather aware!

- Generally cooler than normal temperatures through the week.

&&

.DISCUSSION...

Through Thursday Night...

A cooler day is on tap today with highs in the 70s to lower 80s.
During the afternoon and evening, isolated to scattered showers
and thunderstorms are possible, mainly along and near the Montana-
Wyoming state line (30 to 65 percent chance). With good
instability (CAPE around 1000 to 1500 J/kg) and modest shear (25
to 40 knots), a few strong to severe thunderstorms are possible.
With this, the main threats are hail, and to a bit lesser extent,
wind. Heavy rain is also a risk today with any shower or
thunderstorm that develops as atmospheric moisture values remain
well above normal. Along with the elevated atmospheric moisture,
storm motions look to be a bit slower today with weaker flow
aloft. Therefore, there is also a risk of flash flooding across
much of the area (1/4 risk from the Weather Prediction Center). In
Carter, Powder River, southern Rosebud, southern Big Horn, and
Sheridan Counties, along with the Pryor and Bighorn Mountains, the
risk of flash flooding is a bit higher due to the recent heavy
rains. Therefore, the Flash Flood Watch remains in effect through
this evening for the locations mentioned above.

While the chance of precipitation decreases as you go north
through Billings today (10 to 30 percent chance), an isolated
shower or thunderstorm is possible, but uncertainty remains. This
is due to the lack of upper level support, as well as a cap that
may inhibit convection all together. If the cap erodes, there is
enough elevated instability for convection to develop.

Thursday will be a few degrees warmer than today with highs in
the upper 70s and 80s. During the afternoon and evening, another
round of scattered showers and thunderstorms is forecast as a more
robust wave, and diffluent flow, move into the region. With
weaker wind shear, storms are expected to remain on the weaker
side, but would not be surprised if a stronger storm or two
develops with the elevated instability. Once again, the main
thunderstorm threats will be hail, wind, and heavy rain. Will have
to see how areas in south-eastern Montana and north-central
Wyoming perform today. If heavy rains occur again, the elevated
flash flood risk may continue into Thursday as water takes time to
work through the water system. Arends

Friday through Wednesday...

Southwest flow looks to remain over the region through the end of
the week, becoming more progressive into next week, with ensembles
showing shortwaves moving through the region at times. Ample
moisture will remain over the region most of the days with PWATs
greater than an inch over central and eastern areas. This will
allow for daily shower and thunderstorm chances to continue most
days (20-50% chance). A brief drier period is possible on Monday
with shortwave ridging over the region before a trough over the
Pac NW crosses through the northern Rockies bringing additional
shower/thunderstorm chances Tuesday into Wednesday. While strong
thunderstorms are possible, not any particular day stands out as a
day for severe weather. Heavy rainfall will remain a threat.

Temperatures through the long term are forecast to range near to
slightly below normal with highs in the 80s most days. STP

&&

.AVIATION...

VFR conditions will prevail today with few to scattered low
clouds across the area. During the afternoon and evening, isolated
to scattered showers and thunderstorms are forecast. Any strong
thunderstorm that develops could produce hail, gusty and erratic
winds, and heavy rain. While thunderstorm impacts are possible at
all TAF sites, confidence is low at KBIL, KMLS, and KLVM. However,
at KSHR, there is a moderate, 50 percent chance of seeing a
shower or thunderstorm today. Arends

&&

.PRELIMINARY POINT TEMP/POPS...

    Thu     Fri     Sat     Sun     Mon     Tue     Wed
-----------------------------------------------------------
BIL 060/085 061/088 060/087 060/086 058/089 060/086 059/088
    32/T    33/T    33/T    33/T    22/T    21/B    11/U
LVM 054/081 052/087 051/085 050/083 050/085 051/083 051/087
    24/T    24/T    33/T    33/T    23/T    22/T    11/U
HDN 059/088 060/090 058/088 058/086 056/091 059/087 058/089
    22/T    43/T    43/T    33/T    21/U    21/B    11/U
MLS 061/084 063/087 062/088 061/086 060/089 062/086 061/088
    22/T    52/T    43/T    34/T    21/U    32/T    21/U
4BQ 061/082 063/086 061/087 061/083 060/088 061/086 061/088
    43/T    53/T    42/T    34/T    21/U    21/B    21/U
BHK 057/076 059/077 057/079 057/082 057/085 059/083 057/085
    32/T    53/T    43/T    44/T    31/U    32/T    32/T
SHR 055/084 055/086 054/086 053/083 053/089 055/086 055/088
    54/T    43/T    33/T    34/T    21/U    21/B    11/U

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Flood Watch in effect until midnight MDT tonight FOR ZONES
      36-37-58-138-171.
WY...Flood Watch in effect until midnight MDT tonight FOR ZONES
      198-199.

&&

$$
weather.gov/billings