Williston, North Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

779
FXUS63 KBIS 100838
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
338 AM CDT Sun Aug 10 2025

.KEY MESSAGES...

- Areas of smoke will reduce surface visibility today.

- Daily high temperatures through the upcoming week will mainly
  be in the mid 70s to upper 80s.

- Isolated to scattered showers and thunderstorms on Monday,
  otherwise dry through Tuesday.

&&

.DISCUSSION...
Issued at 338 AM CDT Sun Aug 10 2025

A stacked low pressure system is spinning from eastern Manitoba into
northwest Ontario early this morning. The broad circulation of the
upper low is taking on a negative tilt, but a positively-tilted
longer-wave trough extends back into northeast Utah. The west-
northwest deep layer flow has returned higher concentrations of
smoke to the region overnight, both aloft and at the surface. Early
morning observations in western North Dakota have shown visibility
as low as 3 miles, but parts of northeast Montana have seen as low
as a mile and a half. The large blob of smoke is forecast to migrate
eastward across the state this morning and afternoon, with HRRR/RAP
modeling simulating a slow dispersal of smoke in western parts of
the state this evening through tonight followed by a quicker erosion
from west to east Monday morning. Smoke is the only forecast concern
for what would otherwise be a very pleasant day, with a mostly sunny
sky, much lighter winds than yesterday, and high temperatures around
75 to 80. If the smoke aloft is thicker than anticipated, highs
could end up a few degrees cooler. Quiet weather continues through
tonight, with forecast lows around 55 to 60.

A broad but deepening mid level shortwave is forecast to dig into
the region from the northwest on Monday, with an attendant surface
cold front pushing through the state during the day. All ensemble
guidance has shown an increase and southward expansion with shower
and thunderstorm chances on Monday, but CAMs in particular are now
quite bullish on scattered convection as far south as northern South
Dakota. SBCAPE approaching 1000 J/kg and effective bulk shear
approaching 30 kts could yield a few stronger storms Monday
afternoon, but the highest CAPE and shear may not overlap, and the
timing of the cold frontal passage, for which there is still
forecast uncertainty, will likely be a determining factor in
convective coverage and intensity. The NBM high temperature spread
on Monday is surprisingly small given the frontal passage timing
differences that are being displayed across deterministic guidance,
with values ranging from the mid and upper 70s north to mid 80s
south. Breezy conditions are likely behind the cold front. While
rates of cold air advection and surface pressure rises are not
overly high, mean boundary layer winds around 30 kts could easily be
transfered to the surface, especially by showers or storms.

The post-frontal air mass is now expected to result in a very slight
cool down for Tuesday, with highs in the lower 70s to lower 80s. Dry
weather is expected during the day Tuesday under deep layer ridging.
The NBM maintains a 10 to 15 percent chance of rain with the passage
of an elevated warm front Tuesday night into Wednesday morning, but
deterministic model soundings look too dry to support any
precipitation reaching the ground. From Wednesday onward, ensembles
favor the synoptic pattern becoming much more active over the
region, with a possible transition from quasi-zonal to southwest
flow aloft by the weekend. The NBM maintains a nearly continuous 20
to 30 percent chance of showers and storms beginning Thursday
evening as there is a lack of ensemble consensus for any distinct
forcing mechanism, though there will likely be periods of
atmospheric ascent over this time frame. Deterministic models show
requisite ingredients for severe convection at times, and machine
learning guidance continues to show low severe probabilities
Wednesday through Friday. The NBM temperature distribution trend
suggests a quick warmup Wednesday and Thursday followed by a slight
cool down Friday through the weekend. The general expectation at
this time is for near or slightly below average temperatures north
to near or slightly above average temperatures south for the second
half of the week.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 338 AM CDT Sun Aug 10 2025

Smoke from distant wildfires will reduce visibility to at least
MVFR levels, if not IFR, throughout the day. The smoke is
forecast to reach central North Dakota by mid morning and KJMS
and surrounding areas this afternoon. Conditions may begin to
improve in western North Dakota this evening. MVFR ceilings are
also possible across north central North Dakota this morning,
shifting off to the east by midday. Winds will remain west to
northwest around 10-15 kts through this afternoon.

&&

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

&&

$$

DISCUSSION...Hollan
AVIATION...Hollan