384
FXUS65 KBYZ 150930
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
330 AM MDT Tue Jul 15 2025

.KEY MESSAGES...

- Much cooler conditions and breezy northerly winds today behind a
  cold front. The cool temperatures continue through Wednesday.
  Highs today and Wednesday mainly in the 60s F.

- Good chances for widespread significant rainfall (0.5-1.0 inch)
  through Wednesday.

- Seasonal temperatures return Thursday and Friday becoming above
  normal for the weekend.

&&

.DISCUSSION...

Through Wednesday night...

A strong cold front was dropping south overnight, bringing with it
north to northeast winds gusting 30-45 mph. Isolated to scattered
showers and thunderstorms were found over northern areas and far
southeast MT. As low level moisture has increased from the north,
low stratus and higher humidity has advanced south into the area.
Low clouds and light rain/drizzle will fill in for many areas by
sunrise as upslope flow builds into the southern mountains.

Cool and damp conditions can be expected today as an upper level
wave drops south and east through western and central MT today.
Low stratus will hold on for most areas through the day, with
light rain/drizzle over the area through midday. Heading into the
afternoon and evening, as the upper wave begins dropping into the
area and stronger jet energy moves in overhead, heavier and more
widespread precipitation is expected to move through the area.
Widespread showers and isolated to scattered thunderstorms will
spread over the area from west to east later this afternoon and
evening, continuing into Wednesday. Precipitation will end from
west to east Wednesday afternoon. Despite the cool conditions,
modest instability will be in place over the southern mountains
and foothills (MUCAPE of 500-1000 J/kg) with deep layer shear of
30-40 kts this afternoon and evening. Strong thunderstorms are
possible over the southern mountains and foothills, where winds to
60 mph and large hail are possible this afternoon and evening.
SPC has a marginal risk of severe thunderstorms over the southern
mountains and foothills, increasing to a slight risk as you head
farther south into Wyoming. With precipitable water values over an
inch, heavy rainfall rates are also possible, and the WPC has a
marginal risk for excessive rainfall over the area today into
Wednesday.

Precipitation totals are expected to range from 0.50 to 1 inch for
many areas through Wednesday, with locally higher totals possible,
especially for areas that see thunderstorms. The probability of
precipitation totals exceeding an inch from the NBM currently
range from 25-50%, highest over central and southeast areas.

Temperatures will be running a good 20-30 degrees below normal
(normal highs are currently in the upper 80s) for this time of
year today and Wednesday. Highs are forecast in the 60s for most
locations, with a few remaining in the 50s. Lows tonight and
Wednesday night will range from the 40s to lower 50s. Despite the
cold temperatures in the forecast for the lower elevations, snow
levels stay relatively elevated with this system. While a few
flakes may make it down to 9500 feet (36 degree line),
accumulating snow is expected to stay above 11000 feet. This
should bring minimal impacts to the Beartooth Highway. Those
hiking or recreating in the high country should be prepared for
cold wet conditions over the next 48 hours at all elevations, but
especially over the highest terrain. Hypothermia is a definite
danger in these conditions for those caught unprepared. STP

Thursday through Tuesday...

By Thursday, upper level troughing will have moved off to the
east. An upper level wave will move across southern Canada. This
along with southeasterly winds over the plains will bring
precipitation chances (30-40%) Thursday night. Generally zonal
flow will bring downsloping winds and temperatures returning to
more seasonal values around 80 F Thursday and Friday.

Over the weekend and through early next week, there is the
potential for a blocking pattern to set up off the Pacific coast
bringing successive upper level waves our way. This will lead to
daily 20-30% chances for showers and thunderstorms. Models are
also indicating this will bring the potential for persistent lower
heights across the region early next week. This being said,
significant weather events are not forecast and seasonal
conditions are expected throughout the period.

Temperatures are favored to increase slightly over the weekend
into the high 80s and low 90s F. Early to middle next week could
see cooler temperatures with increased troughing, though this is
uncertain at this time. Torgerson

&&

.AVIATION...

Cold front has ushered in gusty north to northeast (25-35kt)
winds overnight along with MVFR stratus. Most areas will see low
stratus by sunrise, with areas of light rain/drizzle common this
morning into the afternoon producing MVFR to IFR. Widespread
showers and isolated to scattered thunderstorms are expected to
move from west to east through the area this afternoon and
evening, continuing overnight into Wednesday. Some of the
thunderstorms could be strong to severe over the southern
mountains and foothills, including near KSHR this afternoon and
evening. Wind gusts to 50 kts and large hail are the main threats.
Mountain obscurations can be expected through the period. STP

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Wed     Thu     Fri     Sat     Sun     Mon
-------------------------------------------------------
BIL 062 052/065 051/084 059/084 060/090 061/090 060/087
    8/T +5/T    00/U    11/U    11/U    11/U    11/U
LVM 064 046/067 046/088 051/087 051/090 053/089 052/087
    9/T 93/W    01/U    12/T    11/U    11/U    11/U
HDN 065 053/066 048/085 058/085 057/091 060/091 059/088
    7/T 96/T    10/U    11/U    11/U    21/U    11/B
MLS 065 052/065 050/083 058/084 059/090 063/091 062/087
    7/T 96/W    10/B    30/U    11/U    32/T    21/U
4BQ 067 054/061 051/081 059/084 060/087 063/090 063/087
    5/T 97/T    10/B    20/U    21/U    21/U    11/U
BHK 064 048/062 044/076 053/082 055/085 059/086 058/085
    7/T 96/W    10/B    41/U    12/T    42/T    21/B
SHR 068 050/065 047/085 055/085 055/089 056/090 056/087
    7/T 98/T    10/U    11/U    21/U    11/U    11/U

&&

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

&&

$$
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