325
FXUS63 KBIS 312023
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
323 PM CDT Thu Jul 31 2025

.KEY MESSAGES...

- Areas of smoke will continue through at least Friday afternoon
  across portions of western and central North Dakota,
  potentially limiting visibility and impacting air quality at
  times.

- Below average temperatures are expected through the rest of
  the week and weekend, with highs mainly in the lower 70s to
  lower 80s and lows in the lower 50s to lower 60s.

- Periodic low to medium chances of showers and thunderstorms
  (20 to 60 percent) are possible through the remainder of the
  week and into early next week.

&&

.DISCUSSION...
Issued at 323 PM CDT Thu Jul 31 2025

This afternoon, ridging aloft over the Northern Rockies
extended into the Canadian Prairies, with troughing across both
the northeastern CONUS and off the west coast. Surface high
pressure was centered over northern Minnesota, with a modest
pressure gradient across western North Dakota leading to breezy
southeast winds. Main forecast concern through the day has been
near- surface wildfire smoke, which has kept visibilities in the
5 to 6 mile range, most consistently across the east and parts
of the north central. Scattered clouds have been persistent
across most of the forecast area, and where there aren`t clouds,
smoke is keeping skies hazy.

We are carrying low to medium chances for showers and
thunderstorms through this afternoon and tonight across western
and south central North Dakota, as embedded impulses ride
through the ridge across Montana. MLCAPE is marginal at best,
generally up to 1000 J/kg (although higher looking into eastern
Montana), while bulk shear is lacking at only 20 to maybe 30
knots. The only parameter that SPC mesoanalysis is advertising
as moderately high is low- level lapse rates, but otherwise the
environment is not supportive of severe thunderstorms. Can`t
rule out getting a stronger storm with initial development due
to the lapse rates and bit of buoyancy, but the lack of shear
signals storms won`t be long- lived if they do become strong.
The slow storm motion will also be something to watch, with
potential for very localized higher rain amounts. We are already
seeing one cell develop in eastern Montana, although latest
CAMs keep convection quite limited until later this evening.

More of the same on Friday, with near-surface smoke focused
across the central and eastern parts of the state. Although it
doesn`t look like true split flow, there are some ensemble
members favoring a more zonal southern stream across the Dakotas
this weekend, allowing shortwaves to cross the subregion.
Current blended POPs have the highest probabilities for showers
and thunderstorms across the southwest and far south central
Friday and Friday night. The chance for severe weather is
overall low, although there are some pretty large differences
among deterministic guidance regarding the forecast amount of
0-6km shear, and CSU machine learning does have low
probabilities for severe hail extending across the southwest and
south central. High temps on Friday will be in the lower 70s to
lower 80s.

There are widespread low chances for showers and thunderstorms
during the day Saturday, increasing to a broad 35 to 50 percent
chance Saturday night through Sunday night. Could be some
potential for a few stronger storms across the south on
Saturday, depending on the placement of the wave and how high
bouyancy ends up. Highs will be in the 70s on Saturday and
Sunday.

Ridging builds and shifts east for next work week, leading to a
slight warming trend to bring temperatures back closer to
normal. Daily chances for showers and thunderstorms persist
through much of the work week, with NSSL and CSU machine
learning severe weather probabilities still low but a bit more
widespread by the middle of the week.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 106 PM CDT Thu Jul 31 2025

Some low VFR to MVFR ceilings continue across western North
Dakota to start the afternoon. Near surface smoke continues to
bring visibility down, dropping to as low as 4 to 6 miles. Smoke
is expected to dissipate some through this evening before
another wave moves in. Low confidence in extent of visibility
reductions through the end of the TAF period, but highest
probability of consistent impacts at KJMS. Lower ceilings start
to move into the southwest towards the end of the TAF period,
with precipitation chances increasing.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Jones
AVIATION...Jones