Casselton, North Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

493
FXUS63 KFGF 262131
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
431 PM CDT Thu Jun 26 2025

.KEY MESSAGES...

- There is a 2 out of 5 risk for severe thunderstorm chances for
  late Friday afternoon into evening, as well as on Saturday.

&&

.DISCUSSION...
Issued at 345 PM CDT Thu Jun 26 2025

...Synopsis...

Weak mid level wave can be seen on water vapor imagery moving
through the tri-state area into northern Minnesota. This is
resulting in light rain for southeast ND, west-central MN, and
into north-central MN. With dry air near the low levels and lack
of instability combined with weak forcing with this wave, very
little is anticipated in terms of accumulation, generally less
than three tenths of an inch.

As this wave departs, lingering low clouds and cooling overnight
may result in areas of fog overnight into early morning Saturday
within the Red River Valley, eastern ND, and portions of west-
central MN. Some fog may be dense.

For Friday, instability increases over central ND by late
afternoon. This develops ahead of a low amplitude shortwave
trough moving out of the northern High Plains into SK/MB by
Friday evening, with attendant weak front draped north to south
across western ND. The shortwave will provide sufficient wind
shear and forcing to bring a chance for strong to severe
thunderstorms within portions of central North Dakota into
perhaps the Devils Lake basin by sunset Saturday. Eventual
upscale growth is favored as storms trek east/southeast during
the overnight hours, potentially bringing strong to severe
storms within the rest of eastern ND into portions of MN before
sunrise Saturday.

Depending on evolution of storms Friday night, ongoing storms
may be strong to severe Saturday morning. Guidance does favor a
lull in thunderstorm activity around midday Saturday before
additional thunderstorms become possible again, most likely near
west-central MN. These may be strong to severe.

Longwave trough and attendant cold front moves through the
region overnight Saturday or Sunday morning, ushering in dryer
conditions. Northwest flow and drier air mass intrusions should
promote below average precipitation, lower thunderstorm chances,
as well as near average temperatures.

... Severe risk for Friday and Saturday ...

Should storms be more discrete (more likely for locations
closer to central ND like Devils Lake basin), large hail to size
of golf balls along with wind to 70 mph. Eventual upscale
growth would favor smaller hail but still holding the potential
for gusts to 70 mph. Tornadoes are unlikely given the overall
lack of low level shear oriented in an unfavorable orientation
with respect to expected storm motion. There is a small subset
of guidance that even shows lack of thunderstorms with capping
too strong for forcing associated with the shortwave aloft
bypassing the region as it moves quicker into Canada.

Low level jet develops out of South Dakota, which should
continue to promote upstream development of thunderstorm
segments closer to southeast ND into west-central MN overnight
hours of Friday into early Saturday.

Saturday, rich instability axis moves south and east, with a
surface low/trough development in eastern SD into central MN.
Majority of guidance favors development on the northern flank of
rich instability, which may still be in portions of west-central
Minnesota by peak heating. Should storms develop here, all
hazards including large hail and tornadoes will be possible,
particularly during the first 3 hours of initiation before
upscale growth is then favored to pull thunderstorms deeper into
MN and out of our area.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 136 PM CDT Thu Jun 26 2025

Area of IFR to MVFR ceilings will continue at TAF sites like
KFAR and KBJI through at least 15Z. There is a medium chance
for additional IFR to MVFR ceilings at other sites between
06Z-15Z, in addition to low chance for dense fog at KDVL, KFAR,
and KGFK. Chose to leave the fog out of TAFs for now given low
confidence in its occurrence over these areas.

Otherwise, lighter winds under 10kt will prevail, excluding
KBJI where winds between 10-20kt out of the northeast will
prevail through 00Z.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.

&&

$$

DISCUSSION...CJ
AVIATION...CJ