FXUS63 KBIS 240003
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
703 PM CDT Sun Aug 23 2026

.KEY MESSAGES...

- Isolated isolated to scattered severe thunderstorms will be
  possible over western and south central North Dakota this 
  evening. Potential hazards include hail up to the size of ping
  pong balls, damaging winds up to 70 mph, and torrential 
  downpours.

- Isolated severe thunderstorms possible Monday afternoon and
  evening primarily over central and eastern North Dakota.
  Potential hazards include large hail up to 2 inches in
  diameter and damaging winds up to 70 mph, but still some
  question if thunderstorms can develop.

- Near-critical fire weather conditions expected over parts of 
  western North Dakota on Monday, and the far southwest on 
  Tuesday.

&&

.UPDATE...
Issued at 647 PM CDT Sun Aug 23 2026

Thunderstorms, with some being severe with large hail, continue
to push through southwest North Dakota over the area with the
greatest instability and deep layer shear. Severe threat will
continue through the mid-evening hours as storms push east, but
as they move into a lower sheared and more stable environment 
as they approach the Missouri River, expect intensity to wane. 

Storms also stretch off into north central North Dakota, with 
the storms in that area producing some higher rainfall amounts, 
and also earlier produced a strong wind gust at Minot Air Force 
Base. Expect the wind threat has diminished, but elevated 
rainfall amounts remain possible. 

&&

.DISCUSSION...
Issued at 141 PM CDT Sun Aug 23 2026

Current surface analysis places trough stretching from western
Saskatchewan through eastern Montana/Wyoming, with high over the
midwest. Upper level analysis places high over New Mexico, with
ridge stretching northward to the lee of the Rockies into the
Plains. Over our area, low level moisture continues to be on 
the increase with south-southeasterly low level flow between the
two aforementioned surface features. A line of showers with a 
few embedded thunderstorms continues to slide through western 
North Dakota affiliated with a short wave trough noted in the
flow.

For the rest of this afternoon into this evening, a tricky
forecast is on tap as some variables remain in play. It has 
been well advertised that with the returning moisture we will 
have an unstable atmosphere in place, particularly over 
southwest into south central North Dakota where CAPE values are
already in excess of 2000 J/Kg at this time over a broad part 
of the area, and that plenty of deep layer shear in in place 
(40-50 kts 0-6km) to support rotating updrafts. With that said, 
the flies in the ointment continue to be rather modest forcing, 
along with forecast soundings showing a cap that may be 
difficult to overcome. Latest short term guidance continues to 
show a variety of solutions ranging from some light showers/a 
few weak storms to a variety of severe over the southwest and 
south central, possible nudging northward. So, the severe threat
will remain conditional, but if a storm or storms were able to 
get going in earnest, large hail and damaging wind gusts remain 
a concern given the aforementioned shear/instability. A 
secondary wave pushes in from Montana later tonight, which may 
lead to some additional elevated storms, which would move 
through overnight.

On Monday, surface trough to the west pushes over western North
Dakota in the morning, into central North Dakota before stalling
mid-day. Behind the trough, drier air will move in with breezy
conditions developing, which will lead to some near-critical
fire weather conditions over the far west. Ahead of the trough,
moist air remains in place. CAPE values will again be elevated
over this area, along with similar deep layer shear as today.
Again, though, thethreat remains conditional as to whether
enough forcing will be in place in order for storms to develop.

On Tuesday, quiet weather is expected as the ridge axis re-
focuses over the Rockies, though a compact low/short wave will 
zip through southern Saskatchewan/Manitoba which may lead to a 
few showers or possibly a thunderstorm around the Turtle 
Mountains region. Northwest winds will be on the increase as the
surface low with this system moves east through Manitoba into 
Ontario. Upper ridge gradually meanders east resulting in quiet 
weather for us through Thursday before a few weak waves move 
through the ridge, bringing some low precipitation chances to 
end the week.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 647 PM CDT Sun Aug 23 2026

Thunderstorms will spread from west to east this evening. A few
severe storms with large hail or damaging wind gusts will be 
remain possible this evening, mainly over southwest and south 
central North Dakota, though some higher wind gusts also remain
possible over north central North Dakota. Additional storms may
enter western North Dakota from Montana later tonight pushing 
east into Monday morning. Isolated to scattered thunderstorms 
then possible Monday afternoon, mainly over central North Dakota
into the James River Valley.

&&

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

&&

$$

UPDATE...JJS
DISCUSSION...JJS
AVIATION...JJS