147
FXUS65 KBYZ 140916
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
316 AM MDT Mon Jul 14 2025

.KEY MESSAGES...

- Hot today (low to upper 90s) ahead of a cold front this
  evening/night. Strong thunderstorms possible this afternoon and
  evening ahead of the front with gusts to 60 mph the main
  threat.

- Much cooler with a good chance of widespread precipitation
  Tuesday through Wednesday.

- Conditions become dry with highs near normal (mid 80s to low
  90s) by the end of the week.

&&

.DISCUSSION...

Through Tonight...

Satellite imagery early this morning showed an upper low centered
over southern British Columbia. The low and an associated cold
front are expected to drop south and east through the Pac NW and
into the northern Rockies this evening/night, setting the stage
for much cooler and wetter weather.

Today will be hot and dry for most of the day with pre-frontal
conditions in place. Temperatures will warm into the lower to
upper 90s, with a few locations approaching 100 degrees. A weak
wave moving through westerly flow and modest instability over the
region (CAPE values of 500-1000 J/kg), along with increasing
moisture will bring isolated to scattered (15 to 40% chance)
thunderstorms during the afternoon and evening. Deep layer shear
is fairly limited however, with 0-6km shear averaging 25 kts or
less. Thunderstorms are expected to lift off of the mountains,
moving north and east, while a second area of focus will be over
far southeast MT. Strong thunderstorms are possible, with wind
gusts to 60 mph the main threat this afternoon and evening. The
aforementioned cold front is progged to drop through the area this
evening into tonight, bringing in breezy north to northeast
winds, much cooler conditions, and increasing chances for
precipitation into Tuesday. STP

Tuesday through Monday...

Pattern change to cooler and wetter conditions is still on track
for Tuesday and Wednesday. An upper level wave will create a
region of low pressure stretching from Wyoming into South Dakota.
The associated cold front will advect in moisture and colder
temperatures. Highly anomalous PWAT values in excess of 1 inch are
expected for all of southeast Montana. 850 mb winds will quickly
shift to become out of the east bringing favorable upslope across
the region through mid week. Periods of widespread showers and
embedded thunderstorms at times will move through the area Tuesday
through Wednesday.

Expected precipitation amounts continue to increase with this
system. WPC QPF clusters show two different scenarios that could
play out. The lower probability scenario (20%), composed mostly
of the GEFS, shows widespread precipitation amounts of 0.25-0.5
inches with up to 1 inch in favorable upslope locations. The
solution favored by most models (80%) indicates widespread 0.75-1
inches of precipitation and greater than 1.5 inches for favored
locations. The NBM is giving the region a 30-50% chance of getting
greater than 1 inch of rain. There is still some uncertainty in
how long precipitation continues on Wednesday.

Tuesday and Wednesday will also feature anomalously cold
temperatures with the ECMWF EFI tables showing values of -0.95 to -0.99.
This will mean temperatures in the 60s F Tuesday and Wednesday
over the lower elevations, with even a few locations perhaps not
making it out of the 50s. This is a good 20-30 degrees below
normal for this time of year. With the cooler conditions, snow
levels will drop towards 11,000 feet, with some light snow
accumulations over the highest peaks of the Beartooths. Be
prepared for wet and cool conditions if recreating in the high
country. Temperatures Thursday morning are expected to be in the
40s for most locations.

Thursday through the rest of the long term, the upper level
pattern is expected to remain active though nothing impactful is
expected. Temperatures are expected to warm to seasonal values by
Thursday and remain that way. Generally dry conditions are
expected during this timeframe. Torgerson/STP

&&

.AVIATION...

In general, VFR conditions will prevail through today. Isolated
to scattered showers and thunderstorms (15-40%) are expected to
develop over the mountains this afternoon and move north and east
through the area this evening (after 21z). Gusty winds to 50 kts
and local MVFR conditions are possible with the strongest storms.
A cold front will drop through the area this evening/night
bringing north to northeast winds of 15-30 kts, increasing light
rain and low stratus producing MVFR to IFR conditions into
Tuesday. STP

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Tue     Wed     Thu     Fri     Sat     Sun
-------------------------------------------------------
BIL 097 060/066 055/062 051/080 058/084 060/089 061/090
    2/T 47/T    97/T    11/U    11/U    11/U    11/U
LVM 096 054/067 049/066 046/084 050/086 052/090 053/089
    2/T 48/T    95/T    11/U    11/U    11/U    11/U
HDN 098 060/068 054/062 049/083 056/084 059/090 060/090
    2/T 46/T    97/T    10/U    11/U    11/U    11/U
MLS 099 060/067 052/062 050/080 057/084 059/087 061/089
    0/U 47/T    87/T    20/B    21/U    11/U    21/U
4BQ 098 063/071 055/062 051/079 059/083 060/087 063/088
    1/U 35/T    87/T    30/U    20/U    11/U    21/U
BHK 096 056/065 049/060 045/073 052/081 054/083 058/085
    1/U 37/T    87/T    31/B    21/U    11/U    22/T
SHR 097 057/071 052/065 047/083 054/085 054/088 056/088
    2/T 36/T    88/T    21/U    11/U    11/U    11/U

&&

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

&&

$$
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