865
FXUS65 KBYZ 181927
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
127 PM MDT Fri Jul 18 2025

.KEY MESSAGES...

- Seasonal temperatures today (upper 70s and 80s), becoming above
  normal for the weekend (80s and 90s).

- Isolated to scattered mainly afternoon and evening showers and
  thunderstorms each day through the weekend. A few isolated
  strong to severe storms are possible today mainly south of
  Billings. Main threats are strong winds, hail, and heavy rain.

- Early next week continues to look cooler (70s and 80s) with
  continued daily chances of precipitation.

&&

.DISCUSSION...

Through Sunday...

As a weak shortwave through propagates down the main flow into
northern WY this afternoon, chances for thunderstorms return to
the region. A majority of the thunderstorms should be confined to
near the MT/WY border as well as locations near the mountains.
With how weak the advancing energy is, storms may need to utilize
the terrain as the primary forcing mechanism. SB CAPE values in
the foothills may approach 2000 J/Kg this evening which is plenty
supportive of strong thunderstorms. Additionally, with the
advancing shortwave, wind sheer will also be plenty sufficient
with widespread values of Effective Bulk Sheer in excess of 40kts
across the CWA by 22z per RAP forecasts. The main limiting factors
here appear to be the weak forcing as well as high PWAT values
which could limit the severe wind threat as the SFC could still be
decently moist throughout the day. Regardless, the strongest of
the storms that do make it off the terrain could be severe this
afternoon and evening.

Temperatures more reflective of summer will return for much of
the region this weekend with highs in the 90s both Saturday and
Sunday. A broad ridge will dominate much of the CONUS but with our
area being on the far west side, daily chances for showers and
thunderstorms will continue as the broad southwesterly flow will
allow for weak vort maxes to continue to ride up into the area.
Also expect PWAT values to be above 1" across the eastern 2/3 of
the CWA due to the generally easterly surface winds. This pattern
lends itself very well for the repeated chances for isolated
thunderstorms over the weekend, some of which could be strong with
gusty winds and hail. The forecast for these daily storms will
likely change frequently so be sure to check back for updates.
Additionally, with the highly conditional setup and storms being
isolated in nature, it is important to note that most of the CWA
will remain dry throughout the weekend. That being said, be sure
to keep an eye to sky as any storm could be strong and have a
heavy downpour as we will remain in a high PWAT regime. WMR

Sunday through Friday...

Active weather is expected to continue next week, with a nearly
daily opportunity for t-storms.

Look for near normal temps but slightly drier conditions (and less
instability) on Sunday, thus convective potential looks a bit
subdued, but a few afternoon and evening t-storms are possible.
The more interesting time period is Monday to Wednesday when we
will experience troffing over the PacNW and northern Rockies, an
increase in precipitable waters (1-1.25" per ensembles), and a
series of weak shortwaves that will provide forcing. As a result,
expect scattered t-storms each of these days with progressively
cooler temps as a trof eventually swings across the region. The
high pwats suggest a risk of heavy rain, and there is potential
for severe wx as well (though confidence is low so far in
advance). Keep tabs on the forecast if you have outdoor plans the
first half of next week. Temps will turn a little cooler than
normal (upper 70s & 80s), but not nearly to the magnitude of the
cool down we experienced earlier this week.

Thursday is looking warmer and drier, perhaps, as pwats drop and
ridge begins to rebound. T-storm potential should begin to
increase by Friday as more energy emerges from the SW flow aloft.
There is increasing uncertainty in the specifics for the end of
the week, but there is confidence for a return to hotter temps
with highs back to the lower-mid 90s.

July 25th (next Friday) is the only day in July on which the
Billings airport has never reached 100F, going back to when
records began in 1934. In fact, the daily record is a "mere" 98F.
This is an amusing oddity that will eventually end. Current
indications are for a high in the lower to mid 90s, but we do
expect a little ridge amplification ahead of a Pacific coast trof,
so this is something to watch. Today`s 13Z NBM calculates a 1%
chance of reaching 100F, but adding local knowledge w/ 700mb temps
possibly reaching +15C would push that up to ~5%. Stay tuned.

JKL
&&

.AVIATION...


VFR conditions will prevail over the next 24 hours, but there will
be periods of convection. Expect isolated to scattered showers
and t-storms late this afternoon and evening, especially near the
MT/WY border. Airports along the foothills (KLVM, KRED & KSHR)
have the best chance of seeing TS (15-30% chance). Potential
impacts from t-storms include gusty winds, hail, and brief MVFR
conditions from heavy rain. After a break late tonight and
tomorrow morning, isolated t-storms are possible again Saturday
afternoon, with a few severe storms capable of producing hail,
strong winds and heavy rain near the Dakotas border (possibly
affecting KBHK & K97M). JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    Sat     Sun     Mon     Tue     Wed     Thu     Fri
-----------------------------------------------------------
BIL 061/094 061/090 061/088 059/083 060/085 061/092 061/093
    22/T    11/U    22/T    32/T    42/T    21/U    12/T
LVM 052/091 051/087 052/086 051/082 050/087 052/090 054/091
    32/T    12/T    12/T    23/T    32/T    11/U    12/T
HDN 060/096 058/091 060/090 058/085 058/087 059/093 058/094
    23/T    11/B    22/T    32/T    42/T    21/U    12/T
MLS 062/094 062/090 062/088 061/083 060/085 061/092 062/094
    26/T    31/B    32/T    43/T    52/T    21/U    11/U
4BQ 061/093 063/089 063/090 063/086 062/085 062/089 063/091
    36/T    21/U    21/B    32/T    52/T    31/U    21/U
BHK 056/083 057/084 058/084 058/081 056/080 057/086 059/089
    16/T    62/T    32/T    43/T    52/T    22/T    11/B
SHR 055/093 055/092 055/090 055/085 054/086 055/091 056/091
    33/T    11/U    12/T    22/T    32/T    22/T    12/T

&&

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

&&

$$
weather.gov/billings