413
FXUS65 KBYZ 170902
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
302 AM MDT Thu Jul 17 2025

.KEY MESSAGES...

- Areas of fog into this morning, with locally dense fog possible
  at times.

- A few strong to severe thunderstorms are possible over
  northeastern areas, including Miles City and Baker this evening.
  Strong winds and large hail are the main threats.

- Seasonal temperatures today and Friday, becoming above normal
  for the weekend. Isolated to scattered mainly afternoon and
  evening thunderstorms are possible each day through the weekend.

- Early next week is trending cooler and unsettled with another
  storm system working into the region.

&&

.DISCUSSION...

Through Friday night...

Southeast to east flow remained over the area early this morning
with areas of low stratus (greatest in upslope areas) and patchy
fog. Dewpoint depressions were 4 degrees or less most places, and
patchy to areas of fog remain possible into the morning hours,
where the low clouds are able to clear off. A few isolated showers
are possible near the Dakotas border into the early morning with
a southeasterly low level jet in place.

Heights begin to rise today with westerly flow over the region.
Temperatures will climb into the 70s and 80s, a good 10 to 20
degrees warmer than the past couple of days. A shortwave is
expected to drop south and east out of southern Canada through
northeast MT this evening, and into the Dakotas by Friday morning.
Isolated to scattered showers and thunderstorms (15-30%) are
possible over northeastern areas and areas near the Dakotas border
this evening into tonight. A couple thunderstorms could be strong
to severe, with modest instability (CAPE values increasing
towards 1000 J/kg) and good deep layer shear (40-60 kts).
Southeasterly winds will transport moisture into the area, with
PWATs at an inch or more. Latest hi-res guidance shows the
potential for a couple long tracked storms crossing areas near
Miles City and Baker this evening into the early morning hours.
Main threats are strong winds and large hail. The SPC has put
northeastern areas into a marginal to slight risk for severe
weather this evening into the overnight.

Shortwave ridging builds into the area for Friday, before a wave
moving in from the southwest brings isolated to scattered showers
and thunderstorms (20-40% chance) to the mountains Friday
afternoon, spreading north and east through the evening. High
temperatures will warm a few degrees further for Friday (80s),
closer to seasonal levels. STP

Saturday through Thursday...

The long term looks to be dominated by a pattern in which we are
caught between upper level blocking in the Gulf of Alaska and high
heights over the southern US. This will keep upper level heights
normal to slightly below normal leading to seasonal conditions.
Persistent troughing to our west will bring southeast winds over
the plains and above average PWATS throughout the period. This
agrees with long term convective outlooks indicating frequent
chances for thunderstorms.

Ensembles are showing the potential for more significant troughing
to our west early to mid next week. Ensemble systems are not
indicating significant precipitation at this time though the
potential exists. Currently 75th percentile precipitation values
on the ECMWF ENS are less than 0.1 inches but 90th percentile
values are near 0.5 inches. This warrants keeping an eye on this
system for potential strengthening.

Temperatures throughout the long term will be in the 80s to low
90s F. Torgerson

&&

.AVIATION...

Low stratus and patchy to areas of fog will persist over the area
into the morning hours with weak upslope flow in place. Expect
VFR conditions to develop across the area mid to late morning,
with reduced flight conditions holding in longest along east
facing foothills and across far southeast Montana. A disturbance
dropping out of southern Canada, through NE MT and into the
Dakotas will bring isolated to scattered shower and thunderstorm
chances to northeastern areas later this evening into tonight.
This includes KMLS and KBHK. Thunderstorms could be strong to
severe, with wind gusts to 50 kts and large hail possible, along
with local MVFR conditions. STP

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Fri     Sat     Sun     Mon     Tue     Wed
-------------------------------------------------------
BIL 085 058/086 061/094 063/092 061/090 061/087 060/084
    1/U 10/U    11/U    11/U    21/B    22/T    22/T
LVM 089 049/088 052/091 053/089 052/088 050/086 051/085
    1/K 11/U    11/U    11/B    22/T    22/T    22/T
HDN 085 057/088 060/095 060/093 059/091 058/088 059/086
    1/U 10/U    21/U    11/U    21/U    21/U    21/B
MLS 084 057/085 061/094 064/093 063/091 062/088 061/086
    1/B 20/U    23/T    31/U    31/B    21/B    31/U
4BQ 084 059/084 063/091 065/092 063/092 063/090 062/085
    1/B 20/U    22/T    21/U    21/U    21/U    21/B
BHK 076 051/080 056/083 060/088 059/088 058/086 058/084
    2/W 20/U    23/T    32/T    32/W    22/T    32/W
SHR 086 054/086 055/091 057/093 055/092 056/089 055/086
    1/U 11/U    21/U    11/U    11/U    11/U    21/B

&&

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

&&

$$
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