456
FXUS65 KBYZ 160733
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
133 AM MDT Sat Aug 16 2025

.KEY MESSAGES...

- Scattered showers and thunderstorms are expected across south
  central and southeast MT today with some severe storms possible
  across the southeast.

- Daily low chances of precipitation/thunderstorms through Monday,
  turning drier for midweek.

- Temperatures by Tuesday and Wednesday could push 100 degrees.

- This stretch of warm and dry weather will bring an increased
  risk for wildfires. Take care to avoid causing a spark!


&&

.DISCUSSION...

Today through Sunday night...

Southwest flow aloft with disturbances moving through will
continue daily scattered showers and thunderstorms (30-50% chance)
through the weekend.

Today, PWATs will be around 120% of normal over much of the
region, increasing to 170% near the Dakota border. East of Rosebud
county, MUCAPE values will be around 1000-1500 J/kg. One limiting
factor for these storms is shear values are only expected to be
around 20-30 kts. With these considerations, SPC has issued a
Marginal Risk (level 1 of 5) over the east, with a small sliver
near the Dakota border in a Slight Risk (level 2 of 5). The main
threats with any severe storms will be large hail, strong winds
and heavy rain.

For Sunday, PWATs are expected to be around 130-140% of normal
over the eastern and northern portions of the region and remain
around 120% over the rest of the region. Otherwise, MUCAPE and
shear conditions will be similar to today. Currently, SPC has
issued a Marginal Risk along areas where PWATs are highest. With
these storms today and Sunday expected to be slow moving and high
in moisture, heavy rain could produce localized flooding under
any strong thunderstorm.

High temperatures this weekend will be generally in the upper 80s
to low 90s. Archer

Monday through Friday...

Heights begin to build on Monday (behind Sunday`s wave) and the
air mass begins to turn drier, but there appears to be enough
residual moisture and perhaps another weak shortwave for at least
a low risk of thunderstorms, especially for the mountains and in
the east. However the convection pans out we should see temps
begin to climb, reaching the upper 80s and lower 90s for highs.

There is strong confidence for a strengthened ridge and hotter/
drier air for Tuesday and Wednesday. Look for temps into the 90s
across the cwa Tuesday, but with a ridge axis overhead that
supports light winds. The ridge begins to flatten and shift east
Wednesday, which should be the hottest and driest day of next
week, with potential for deeply mixed and somewhat breezy west
winds in a pre-frontal regime. Look for temps in the mid 90s to
around 100F on Wednesday and would not be surprised to see some
RHs creep below 10%. Operational models show 700mb temps near
+16C...and this could translate to highs above 100F (maybe 102F to
104F?) if we see well-mixed west winds. Isolated weak high-based
convection cannot be ruled out late Wednesday, but otherwise
Tuesday & Wednesday look dry.

Given all of the above, the middle of next week is a time period
to watch with regard to fire weather conditions...especially
Wednesday and Wednesday night as the mixed west winds are followed
by a nighttime dry cold front (the timing of which is reasonably
well agreed upon by ensembles). A shift in the frontal timing
would change potential fire weather impacts so all of this will
need to be monitored. Of course, a potential fly in the ointment
could be smoke from upstream wildfires, which if thick enough may
impact temps, mixing and winds.

Thursday and Friday will be cooler w/ easterly surface winds
behind the shortwave under NW flow aloft (but still above normal
heights). The potential for showers & thunderstorms increases
again as well, with pwats returning to above normal levels, but
there is plenty of uncertainty with regard to specifics. Temps
should cool to at least seasonable levels, but some ensembles show
another dose of backdoor cooling by Friday. In any event, the
weather on Thursday and Friday should help to reduce the midweek
fire weather concerns.

One final note. Billings airport has not reached 100F yet this
summer (max is 99F on July 9th). Latest NBM probabilities show a
~50% chance of that occurring Wednesday.

JKL

&&

.AVIATION...

Slant range visibility will be reduced at times from regional
wildfires. Nearby fires in central MT and northern WY may also
cause occasional reductions in surface visibility at KLVM & KSHR,
but this is uncertain and will need to be monitored. Other than
smoke, VFR will prevail across the region today and tonight. Look
for isolated (west/central) to scattered (east) thunderstorms this
afternoon and evening. Storms could produce gusty winds, and east
of Rosebud County there is also a risk of localized heavy rain
and hail. JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Sun     Mon     Tue     Wed     Thu     Fri
-------------------------------------------------------
BIL 092 061/091 061/093 062/097 065/099 064/088 060/079
    1/B 11/U    20/U    00/U    00/U    11/U    22/W
LVM 091 053/087 052/089 054/095 057/095 055/088 052/081
    3/T 24/T    31/U    10/U    00/U    11/U    11/U
HDN 092 059/092 059/094 061/098 062/100 063/089 060/080
    1/K 11/U    20/U    10/U    00/U    10/U    22/W
MLS 092 064/092 064/091 064/097 068/099 066/088 060/078
    1/B 21/U    21/U    10/U    00/U    10/U    32/T
4BQ 090 062/090 063/090 063/095 067/099 066/089 062/078
    2/T 21/U    21/U    10/U    10/U    10/U    32/T
BHK 089 061/087 060/087 060/092 063/095 063/086 055/077
    3/T 42/T    21/U    10/U    00/U    10/U    32/W
SHR 087 056/088 056/090 058/094 060/098 061/088 056/080
    2/T 11/U    21/U    00/U    00/U    11/U    23/T

&&

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

&&

$$
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