853
FXUS63 KBIS 251103
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
603 AM CDT Fri Jul 25 2025

.KEY MESSAGES...

- Scattered severe thunderstorms are possible this afternoon and
  evening. Golf ball sized hail, wind gusts up to 70 mph, and a
  tornado or two are the primary threats.

- Periodic showers and thunderstorms are expected to continue this
  weekend and into early next week. A few severe storms are
  possible.

- Hot and humid today and Saturday with highs in the mid 80s to
  mid 90s, followed by a cooling trend beginning Sunday and
  continuing into the middle of next week. Heat index values may
  approach 100 degrees in parts of the south central, including
  the James River Valley, on Saturday.

&&

.UPDATE...
Issued at 603 AM CDT Fri Jul 25 2025

Isolated showers and a few thunderstorms persist mainly over
northwestern and central ND. The most active thunderstorm is in
Mountrail County where a little more effective shear and a
little higher instability is present. The expectation remains
that most showers and thunderstorms will rapidly dissipate after
sunrise this morning as the LLJ weakens. However, a couple may
persist through the morning hours.

&&

.DISCUSSION...
Issued at 356 AM CDT Fri Jul 25 2025

A few showers and thunderstorms are present across parts of the
forecast area along the nose of a LLJ. Most of these showers and
storms should dissipate after sunrise as the LLJ weakens,
however, a few may persist through the morning. Severe weather
is not expected this morning.

Of greater concern at this time is this afternoon and evening.
Fairly broad high pressure over the east CONUS will help pump
Gulf moisture back into the state. This will result in mixed
layer dewpoints of around 65 degrees and surface dewpoints of
around 70 degrees across much of central and eastern North
Dakota. In turn, this will produce a very buoyant and unstable
atmosphere with MUCAPE values potentially in excess of 3500
J/kg, while capping doesn`t appear likely to be much of an
issue today.

With the anticipation of a very unstable environment and a lack
of solid capping, there are two other factors that will greatly
determine if severe weather will develop and to what extent.
The first is forcing mechanisms. There is no obviously potent
shortwave, however, subtle shortwave energy off central Canadian
low pressure may pass through the area. That combined with
diurnal heating may be enough to fire off showers and
thunderstorms by mid to late afternoon. Where these will fire is
anyone`s guess as some CAMs start them in eastern Montana,
while others fire off storms in south central ND. That said, the
very latest trend in the CAMs is more towards the former
solution, but definitely wouldn`t discount them flipping back to
the latter solution either.

The second factor in regard to the extent of severe weather is
wind shear. Models remain fairly consistent with one another in
limited shear with 0 to 6 km bulk shear generally progged to
range from around 25 to 35 kts. While this is adequate given the
ample instability, it may very well limit the peak intensity
and duration of storms that develop. Whether actual shear where
storms fire winds up closer to 25 or 35 kts can make a
significant difference.

In regard to hazard types for this afternoon, that will largely
depend on storm mode and where storms develop. Despite limited
shear, it seems that hail up to the size of golf balls and a
tornado or two is possible should any discrete storms develop in
the mid to late afternoon, with the tornado threat mainly in
the south central along and east of Highway 83. CAMs favor storm
mode rapidly developing into a cluster or MCS. When/if this
happens, hazards will primarily become hail up to the size of
quarters and 70 mph wind gusts. Most CAMs favor storms
dissipating or exiting the forecast area within a few hours of
sunset. However, flip flopping runs between the HRRR and NAMNest
suggest a low chance that activity could continue well into the
night most likely in the far south central east of Highway 83
and south of I94.

Beyond tonight, dry conditions are expected Saturday morning
and early afternoon before another round of thunderstorms, a few
potentially severe, develop. Environmental conditions don`t
appear too dissimilar Saturday from today. However, there may be
a little more capping to overcome and once again, the lack of a
great forcing mechanism. Beyond Saturday, periodic showers and
thunderstorms remain possible through early next week, with at
least a low end severe threat possible each day. Drier
conditions are favored for the latter half of the workweek,
though low chances for showers and thunderstorms remain each day
for at least some part of the forecast area.

As assumed from the severe weather discussion, hot and muggy
conditions are expected for today and Saturday. Widespread heat
indices in the upper 80s to low 90s are expected this afternoon,
and the 90s across most of the area, except the northwest, on
Saturday. Heat indices reaching 100 degrees are possible for
parts of the south central, including the James River Valley, on
Saturday. Will have to keep an eye on the trends over the next
24 hours to see if any heat related headlines will be warranted.
Beyond Saturday, expect a cooling trend to begin Sunday and
persist through the middle of next week. The middle of next week
may see highs mostly in the mid 70s to low 80s.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 603 AM CDT Fri Jul 25 2025

Isolated showers and thunderstorms are present over northwestern
and central ND, with the most active thunderstorm approximately
40 SM west of KMOT. There is fair confidence that this
thunderstorm, or one of the weaker cells just to the south of it,
will impact KMOT within the next couple hours (before 13Z). By
mid-morning, most of these showers and thunderstorms should
dissipate before additional scattered showers and thunderstorms
develop mid to late afternoon. Showers and thunderstorms later
today are likely to persist through the evening, and potentially
into the overnight hours. A few of these storms may be severe
with large hail and erratic winds possible.

&&

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

&&

$$

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