908
FXUS63 KBIS 290229
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
929 PM CDT Fri Aug 28 2026

.KEY MESSAGES...

- Isolated to scattered showers and a few thunderstorms are
  expected tonight.

- Additional isolated to scattered strong to severe storms are
  forecast for Saturday and Sunday.

- Near to slightly above average temperatures will persist
  through late next week.

- Breezy to windy conditions combined with lower humidity
  values may bring increased fire weather concerns on Monday.

&&

.UPDATE...
Issued at 929 PM CDT Fri Aug 28 2026

No lightning strikes have been observed across the CWA in the
past 45 minutes or so, though scattered showers remain present
over parts of western and south central North Dakota. These are
expected to continue through the night, though a few isolated
thunderstorms could return. With thunderstorms failing to
organize earlier this evening, the probability for severe
weather is decreasing across the forecast area overnight, though
remains greater than zero. If any severe weather manages to
develop tonight, it will most likely be off a strengthening LLJ
and would mostly impact the James River Valley before moving
eastward relatively quickly.

UPDATE
Issued at 646 PM CDT Fri Aug 28 2026

A few showers and thunderstorms have developed in southwestern
North Dakota where skies were mostly clear until about an hour
or so ago. However, incoming clouds have rapidly overtaken clear
skies and seem to be helping inhibit most organized convection
at this time. A lack of shear has also helped limit storm
development. As storms progress eastward, they should begin to
enter a higher shear environment. However, there is some
question as to whether or not relatively weak forcing will be
able to tap further into modest elevated instability as the sun
sets and surface CIN continues to increase.

&&

.DISCUSSION...
Issued at 120 PM CDT Fri Aug 28 2026

Early this afternoon, a subtle shortwave upper trough was rounding
the northern periphery of a mid/upper ridge centered over the
southern Rockies and High Plains. An attendant band of mid-level WAA
is aiding in the persistence of showers and thunderstorms from
southwest Manitoba to northeast South Dakota. This activity is still
forecast to be placed across eastern North Dakota later this
afternoon and evening. An axis of modest instability (around 500-
1000 J/kg MUCAPE) and sufficient effective shear (around 30-40 knots)
will continue to support the potential for occasional and isolated
instances of hail around pennies to quarters in association
with this elevated convection. Also later this afternoon,
another subtle shortwave trough will translate eastward across
southern Montana with a jet max nosing into western South
Dakota. Despite ample convective inhibition, CAMs are insistent
that convection will develop ahead of this wave given robust
synoptic ascent. However, this activity will likely struggle
given the aforementioned CIN, and it`s possible only a very
small window exists for the potential of severe weather across
southern North Dakota during peak diurnal heating late this
afternoon. Therefore, if a storm can develop during the time of
minimum CIN and can remain discrete, there is a chance this
hypothetical storm could produce quarter to golfball size hail
along with up to 60 mph wind gusts. Most likely though, much of
the activity today will struggle which is largely the reason SPC
has maintain a marginal (1/5) risk for severe weather for today
and tonight.

Very late tonight into Saturday morning, short range guidance is
hinting at the potential for a loosely organized backwards
propagating MCS across southeastern North Dakota. This could
potentially impact portions of the area from Jamestown to Oakes;
however much of this activity should remain just east of the area,
especially given that the LLJ will have veered out and is forecast
to nose into central Minnesota by daybreak Saturday morning.
Most of Saturday will end up on the quieter side with afternoon
highs generally a tick above average in the mid to upper 80s.
Another subtle shortwave is forecast to round the northern
periphery of a strong mid/upper ridge (generally centered over
the central and southern plains), and will be the primary
catalyst for another round of thunderstorms Saturday evening and
night. Generally speaking, sufficient instability and shear
should be in place across the southern half of North Dakota to
support strong to severe storms capable of large hail and
damaging winds. It`s possible a messy storm mode could limit the
large hail threat to an extent; however, DCAPE in the
neighborhood of 750-1000 J/kg could support some localized
downbursts with up to 60 mph wind gusts possible. With the loss
of diurnal heating Saturday eve/night, the intensity of
thunderstorm activity should gradually decrease. That being
said, convective inhibition after sunset should be fairly weak,
and continued broad ascent from a train of perturbations
embedded in southwesterly flow aloft should continue to support
sub-severe shower and thunderstorm activity well into the
overnight hours.

It`s a little unclear exactly how activity on Sunday will
evolve. Mid-range guidance appears fairly confident showers and
storms will be ongoing through much of the first half of Sunday
across a large portion of the state well out ahead of a the
primary trough axis. Given this, it`s a bit difficult to pin
point whether or not the atmosphere will destabilize enough
before the main trough ejects out across the northern plains
and southern Manitoba. This potential atmospheric
destabilization will be key to whether or not widespread strong
to severe storms develop across western and central North Dakota
Sunday afternoon and evening. Given this level of uncertainty,
SPC elected to go with a marginal (1/5) risk of severe weather
on Sunday. Details should become clearer over the next couple of
days. Regardless of what occurs on Sunday, a weak cold front is
forecast to sweep across the state Sunday night. This will
generally lead to temperatures returning to near average for the
beginning of next week. Also, guidance appears to be in good
agreement that a strong surface low across southern Saskatchewan
will result in a tight pressure gradient across the northern
half of the state on Monday. Currently, forecast max wind gusts
Monday afternoon are hovering around 35 to 45 mph. However,
model soundings indicate deep mixing and uniform flow in the
boundary layer which could allow for locally higher gusts from
time to time. Additionally, lower RH across the western portions
of the state together with the windy conditions could present
some fire weather concerns. The parade of upper troughs is
likely to return by Tuesday and persist through the end of the
work week next week. Thus, periodic chances for showers and
storms Tuesday through Friday have been maintained in this
forecast package.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 646 PM CDT Fri Aug 28 2026

Isolated showers and thunderstorms are present in southwestern
North Dakota. This is currently impacting KDIK, though the more
organized reflectivity cores are currently staying both north
and south of the terminal. Barring redevelopment, these
thunderstorms should be east of the terminal by 0030Z.
Otherwise, isolated to scattered showers and thunderstorms are
expected across much of the state tonight, with the highest
probabilities over the southern half. Additional showers and
thunderstorms may begin to develop in central and especially
western North Dakota Saturday afternoon.

&&

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

&&

$$

UPDATE...Telken
DISCUSSION...JC
AVIATION...Telken