Casselton, North Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

526
FXUS63 KFGF 202015
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
315 PM CDT Sun Jul 20 2025

.KEY MESSAGES...

- Severe storms developing over south central North Dakota will
  push into eastern North Dakota late tonight. There is a level
  1 out of 5 risk of severe thunderstorms across much of
  eastern North Dakota and west central Minnesota.

- Smoke from Canadian wildfires will degrade air quality
  through Monday.

- There is a level 1 out of 5 risk for severe storms Monday and
  a level 2 out of 5 risk for Tuesday.

&&

.DISCUSSION...
Issued at 315 PM CDT Sun Jul 20 2025

...Synopsis...

Near zonal flow with various embedded shortwaves will continue
into tonight and tomorrow. Weak ridge amplifying over the upper
midwest, but flow remains fairly flat and several weak
shortwaves will continue to move through during the first part
of the work week. Additional weak shortwaves will come through
the near zonal flow/flat ridge through the end of the week and
into next weekend, bringing periodic shower and thunderstorm
chances. Rising heights should boost temperatures to above
average values by the end of the period.

...Tonight`s severe chances...

Thunderstorm complex that moved from south central ND into our
southeastern ND counties continues to weaken, with lightning
activity decreasing and cloud tops warming. The bulk of the
instability remains over western ND, with around 40 kts of deep
layer bulk shear also in that area. A few outlier CAMs develop
storms in central ND this afternoon/evening, but think the
majority of the solutions that start initiating storms further
west are more likely given the current environment. That slower
solution would put a thunderstorm complex in our counties well
after midnight, perhaps closer to early morning. There will be
decent MU CAPE and 35 kts of shear so some elevated hailers are
not out of the question late tonight. Marginal risk messaging
still seems reasonable for our area.

...Smoke in northwestern MN...

Hard to see current smoke on satellite due to cloud cover, but
still getting some 4-6SM in haze across many of our observation
sites. HRRR and Canadian smoke models continue to have near
surface smoke rotating down from Canada across the Great Lakes
and back northwestward into our MN counties. Some air quality
issues will continue through tonight before there seems to be an
eastward shift with the surface smoke tomorrow.

...Severe chances Monday and Tuesday...

Convective chances for the first part of the work week will be
highly dependent on how the activity late tonight/early Monday
plays out. Some of the CAMs have one round coming through early
Monday morning and another in the early afternoon, while others
have convection weakening to showers. A bit of a stronger
shortwave and associated surface low on Tuesday so think the
better chances for something more organized will be during that
time period.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1244 PM CDT Sun Jul 20 2025

A mix of light rain showers and, at KGFK and the MN airports at
least, surface smoke reducing visibility to 4-5SM at times.
Thunderstorms just west of our forecast area should weaken as
they move east, leaving mostly showers and the smoke continuing
into the evening. Some better thunderstorm chances later
tonight, but not confident enough to include in the TAFs.
Ceilings are mostly VFR and will remain so through most of the
afternoon and evening, with some MVFR ceilings coming in towards
Monday morning. Winds will continue out of the southeast mainly
at 5 to 15 kts, but some gusts to around 20 kts are possible
this afternoon or towards the end of the period.

&&

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

&&

$$

DISCUSSION...JR
AVIATION...JR