Casselton, North Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

034
FXUS63 KFGF 282327
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
627 PM CDT Sun Jun 28 2026

.KEY MESSAGES...

- Risk of severe storms tonight and Monday. All hazards are
  possible Monday.

- Heat Advisory in effect Monday: Noon to 8pm for the Southern
  Red River Valley and west central Minnesota.

- Potential for heat impacts next week, including the Fourth of
  July weekend.

&&

.DISCUSSION...
Issued at 331 PM CDT Sun Jun 28 2026

...Synopsis...

Well established upper trough over the northern High Plains into
southern BC/AB is promoting southwesterly flow aloft over the
Northern Plains into Upper Midwest, with an expansive upper
ridge over the eastern half of the CONUS. This pattern is
promoting moderate to very strong instability over portions of
the Dakotas and Minnesota, along with moderate to strong
available shear to organize thunderstorms should they develop.
This will provide ingredients for severe storms to develop
tonight and/or Monday. More details on these below.

There is potential for heat related impacts Monday afternoon as
very high moisture (upper 70s dew points) combine with
temperatures into the 80s, perhaps low 90s, in the southern Red
River Valley into west-central MN. Later in the week,
additional heat-related impacts are possible. This includes the
Fourth of July weekend.

...Severe storm potential tonight...

Despite favorable instability and shear parameter spacing, there
is a general lack of focused ascent to spark and sustain severe
storms this afternoon. Thus, general trend in our messaging has
been to omit severe risk from this afternoon. During the
overnight, focus for ascent may become more prevalent near
central ND, perhaps allowing some isolated elevated supercells
into northeast ND early tonight. This activity would be capable
of hail to the size of golfball before quickly pushing into
Canada. Couldn`t rule out severe storms moving into southeast ND
from SD late tonight / early morning Monday. Should this occur,
very large hail in excess of 2 inches may be possible, as well
as very gusty winds to 80 mph. This scenario is low in
confidence, however.

...Severe storm potential Monday...

While there is a deft in features to help force thunderstorms to
life today, much better forcing will come tonight and Monday as
a surface low pressure deepens within the eastern Dakotas,
propagating northward into Canada by Monday afternoon.
Additionally, richer low level moisture (comprised of surface
dew points in the mid to upper 70s) will likely overspread
portions of eastern ND and northwest into west-central MN. This
is also a result of the jet aloft overspreading these regions,
increasing overall shear.

Latest guidance offers a couple of scenarios that could unfold:

1) Well developed severe storms move out of South Dakota into
eastern ND traveling northeast. These storms would be capable
of large hail (perhaps very large hail in excess of 2 inches)
and gusty winds (perhaps very gusty winds up to 80 mph). These
storms start elevated in altitude and nature, becoming more
surface based into the afternoon. This would eventually
introduce potential for tornadoes among other hazards like large
hail and gusty winds. Given the very unstable airmass and
strong shear, couldn`t rule out strong tornadoes (EF-2+).
Thunderstorms begin to exit to the north and east late afternoon
into early evening.

2) Overnight thunderstorms within SD diminish before reaching
ND, allowing a lull period in the morning. This is before
robust thunderstorm development near the surface low that
propagates north through our area by early afternoon. This
activity will likely reach severe thresholds, potentially
significantly severe - especially if storms can remain more
discrete and surface based. This would keep large to very large
hail and risk for tornadoes at the forefront of hazards, with an
attendant isolated damaging wind risk as well. In this
scenario, strong tornadoes again can`t be ruled out (EF-2+).

Again, both scenarios hold the risk for tornadoes (potentially
strong). At this time, relatively higher chance for tornadoes
exists near and just ahead of the surface low within northeast
ND to northwest MN during the afternoon.

Uncertainty still exists in overall convective evolution that
would dictate storm mode as well as whether or not storms would
be more surface based or elevated. More elevated storms would
have a hail-forward hazard, whereas surface based storms would
allow for all hazards.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 627 PM CDT Sun Jun 28 2026

TAFS will become increasingly messy after 06z as ceilings plunge
in MVFR and IFR. LIFR will be possible in KDVL and KBJI but is
not a foregone conclusion (timing would be anywhere from 06z to
15z). Winds will be of lesser concern compared to ceilings and
eventual thunderstorms on Monday (late morning through
afternoon) with currently southeast winds becoming more easterly
by 12z and increasing to 10-15kts around 18z with gusts as high
as 25-30kts outside of thunderstorms (could gust over 50kts in
that instance). Best guess on thunderstorm location is just
that, a guess, but KDVL, KGFK, and KTVF look the most certain to
see activity with greater uncertainty for KFAR and seemingly a
lower threat overall for KBJI all together but wont rule it out.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Heat Advisory from noon to 8 PM CDT Monday for NDZ039-053.
MN...Heat Advisory from noon to 8 PM CDT Monday for MNZ002-003-024-
     027>032-040.

&&

$$

DISCUSSION...CJ
AVIATION...TT