952
FXUS63 KBIS 030601
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
101 AM CDT Wed Jun 3 2026

.KEY MESSAGES...

- Isolated to scattered thunderstorms expected tonight.

- Isolated to scattered severe thunderstorms possible over
  central into eastern North Dakota on Wednesday.

- Low to medium chances of showers and thunderstorms Thursday
  through the remainder of the week.

- Highs in the 70s and 80s through the workweek, warming into
  the 80s and lower 90s for the weekend.

&&

.UPDATE...
Issued at 1243 AM CDT Wed Jun 3 2026

Made some adjustments to sky cover and pops based on the latest
radar and satellite analysis. Otherwise no changes to the going
forecast at this time. Scattered elevated convection continues
in a broad line from southwest through northeast North Dakota. A
marginally severe hail or wind report can not be ruled out
through the overnight hours. Also very heavy rainfall rates have
been noted over portions of central ND, mainly Sheridan and
Wells counties and extending northeast to the Devils Lake
region. Currently little response noted in the CREST Max Unit
Streamflow, but there have been some small areas of rainfall
rates of over 2 inches per hour. Will continue to monitor.

UPDATE
Issued at 1032 PM CDT Tue Jun 2 2026

The Severe Thunderstorm Watch has been allowed to expire at 10
PM CDT. Low level jet will continue to bring showers and
thunderstorms across central portions while the upper level wave
is developing the next round of showers and thunderstorms across
the west. Overall this thunderstorm activity slowly push
east.There is enough elevated cape and modest shear to provide
for at least an isolated severe weather threat through tonight.
Main hazards would be wind to 60 mph and hail up to quarter
size. Given the isolated and elevated nature of the severe
thunderstorm threat have let the Severe Thunderstorm Watch
expire. Will continue to monitor through the night for any more
stronger development. Slow moving thunderstorms combine with
high amounts of moisture could bring localized heavy rain
tonight, and some localized flooding potential.

UPDATE
Issued at 700 PM CDT Tue Jun 2 2026

** MESOSCALE DISCUSSION **

Thunderstorms have formed along the pre-frontal wind shift/
differential mixing boundary from near Fessenden southward
to the Pettibone, Tappen, Napoleon, Wishek, and Ashley areas.
In this area, capping has been eroded in the absence of the high
clouds that have resulted in more MLCIN further west. There is
large bouyancy with MLCAPE around 2000 J/kg, but effective shear
is generally less than 30 kt, and those vectors are oriented
parallel to the wind shift. This means that we have seen and
will continue to expect multicell, pulse-type storms along this
axis, with a marginal risk of hail to around half dollar size
and damaging wind gusts up to 60 mph. Note that given the weak
shear environment, hail diagnostic tools such as MRMS and
single-radar MESH will tend to overestimate hail sizes with
these storms.

Further west, storms along/ahead of the cold front, e.g., in
Sioux County, have struggled to become established in the face
of larger MLCIN. Similarly, post-frontal convection, such as
that near Glen Ullin and Center as of 00 UTC, has also been
struggling to intensify. These areas of convection represent
only a low risk of intensification and severe-storm risk for
the remainder of the evening. As observational trends allow,
we will cancel western and northern portions of the Severe
Thunderstorm Watch early in collaboration with SPC.

CJS

UPDATE
Issued at 410 PM CDT Tue Jun 2 2026

** MESOSCALE DISCUSSION **

A severe hail and wind risk will continue across central ND the
next several hours, with only a low tornado risk. In this
scenario, the main hazards will be from large hail and damaging
winds, which is why a Severe Thunderstorm Watch has been issued.

Technical discussion: As of 21z, thunderstorms including some
previous marginal supercell structures are focused in the
McHenry, Pierce, and Sheridan County areas. This is along a pre-
frontal trough, and possibly where the cold frontal zone has
begun to merge with that trough, resulting in additional low-
level convergence. MLCAPE on the order of 2000 J/kg and
effective-layer shear on the order of 35-40 kt in that zone
favor the marginal supercell structures with an attendant large
hail and damaging wind risk. However, anvil-level flow does
weaken with northward extent, and the orientation of deep-layer
shear vectors to the surface boundaries suggests gradual upscale
growth will occur in this area if or when additional initiation
occurs.

Further southwest, the prefrontal surface trough is seen on
radar fine-line from near Mercer to Price, Crown Butte Lake,
and Carson. The 18z KBIS RAOB sampled residual capping with
MLCIN around -50 J/kg. As surface temperatures reach the mid
80s F, that capping becomes minimized, but high-level clouds
spreading across Grant, Morton, and into Burleigh Counties
casts some doubt on the timing of convective initiation. We
believe that eventually additional development will occur
in south central ND, but robust development may take some
time and additional frontal lift to overcome the residual
capping layer. The highest probability of development may
initially be over Sioux and southern Grant Counties, where
satellite trends suggest more robust upstream development
occurring in an area where downstream high-cloud shading is
less prevalent.

There is also a low to medium probability that the line of
cumulus from Kidder south into Emmons Counties, on the edge of
richer low-level moisture representing a differential heating
boundary, could result in pre-frontal initiation. However, deep-
layer shear is weaker there and would result in more marginal,
multicellular type of storms.

Generally-speaking, low-level hodographs are relatively small,
and accordingly, low-level SRH ahead of the front in the buoyant
sector is 100 m2/s2 or less. Deep-layer shear vectors are also
oriented parallel to the front, favoring upscale-growing and
messy modes. This all suggests that the tornado risk is low
overall.

CJS

&&

.DISCUSSION...
Issued at 151 PM CDT Tue Jun 2 2026

Relatively well stacked low pressure is present over southern
Saskatchewan. This low will very gradually slide eastward over the
next couple days. During this timeframe, an associated very
slow moving cold frontal boundary currently draped north to
south over western North Dakota will slide eastward. This
frontal boundary will likely become quasistationary, and
possibly retrograde, at times. Showers and thunderstorms are
present and will continue to frequently develop along and ahead
of this frontal boundary.

High pressure over the Great Lakes region will continue advecting
moisture from the Gulf of America into the Northern Plains. This
added moisture, with boundary layer dewpoints in the mid 50s to low
60s will help produce a buoyant atmosphere. In addition, deep
layer shear along and ahead of the front is generally progged at
around 35 to 45 kts with a southwesterly component. Combined,
this should produce the conditions for isolated to scattered
severe thunderstorms this afternoon and evening. With the
southwesterly component of the 0 to 6 km bulk shear vectors and
a north to south frontal boundary, suspect clusters are the most
likely thunderstorm mode along most of the front. Considering
there is already a clusterish line of showers and thunderstorms
along the frontal boundary, suspect a limited timeframe for any
discrete cells to develop this afternoon. Though one has
already developed near the Turtle Mountains as of this writing.
This means that while there may be a window for golf ball size
hail and an isolated tornado threat, this may wind up being a
case where widespread marginal severe thunderstorms prevail
overall. In addition, slow moving storm motions with the
potential for training could lead to heavy rain and a localized
flooding event.

Of note, a mesoanalyst will produce a mesoanalysis discussion
within the next hour or two. This will provide even further
details in regard to the severe weather threat based on the
evolving severe weather environment. Depending on how the
environment evolves, changes to the above threat expectations
are not out of the question.

While there may be initial LLJ development this evening mainly
over the eastern half of the state, it does not look to persist
through the night. Therefore, while isolated to scattered
showers and thunderstorms are likely to persist through at least
parts of the area through tonight, the severe threat will
likely wane rapidly as the sun sets, instability decreases, and
capping increases. Still, a few strong storms are not entirely
out of the question overnight.

For Wednesday, the aforementioned frontal boundary will continue to
gradually shift eastward and as such, so will the severe threat.
Therefore, concur with SPC that the highest severe potential for
Wednesday will be in the south central (mainly east of Hwy 83)
and in eastern North Dakota. The biggest threats will remain
strong winds and large hail, though an isolated tornado threat
could return mainly in the far southeast, including the southern
James River Valley of ND.

Gulf moisture will be, at least temporarily, cut off behind the
frontal boundary. However, a deepening low pressure over the
Central Plains could bring the return of showers and
thunderstorms mainly to southern North Dakota Thursday through
Friday. The severe threat is favored to remain south for the
most part at this time, though will keep an eye on that over the
next couple days. Saturday is favored to remain mostly dry,
after which periodic showers and thunderstorms are possible to
start next week. CSU machine learning suggests at least low
severe weather potential most days to start next week.

Slightly above average temperatures with highs in the mid 70s to
low 80s are expected to continue through Friday. Well above
average temperatures are then expected to return this weekend
and are favored to continue into the middle of next week. Lows
will start out mostly in the mid 40s to low 50s before
increasing to the 50s to low 60s next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1243 AM CDT Wed Jun 3 2026

Isolated to scattered thunderstorms extending from southwest to
northeast ND to begin the 06Z TAF period. Included a VCTS at
KDIK early in the TAF period, otherwise No Thunder at any other
TAF site to begin the period. KXWA could see some shower
activity overnight but will be the most likely TAF site to
remain free of Thunder through the TAF period. Otherwise KDIK
initially, but moreso, KMOT, KBIS and especially KJMS will have
the potential for thunderstorms with KJMS having the highest
potential for strong to severe storms this afternoon and early
evening. Any thunderstorm activity will have the potential for
MVFR-IFR Visibilities in heavy downpours, and gusty and erratic
winds. Otherwise there is the potential for some MVFR ceilings
Wednesday morning, mainly southwest and central portions of the
state, before lifting to VFR Wednesday afternoon. Generally
light southerly surface flow will turn westerly from west to
east through the day.

&&

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

&&

$$

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