161
FXUS63 KFGF 110946
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
446 AM CDT Fri Jul 11 2025

.KEY MESSAGES...

- There is a level 1 out of 5 risk for severe thunderstorms this
  afternoon for portions of southeast North Dakota into
  northwest and west- central Minnesota. Main hazards will be
  gusty winds to 60 mph and hail to the size of ping pong balls.

- Wildfire smoke will degrade air quality behind a cold front
  today, potentially into the weekend.

&&

.DISCUSSION...
Issued at 404 AM CDT Fri Jul 11 2025

...Synopsis...

Well developed upper/mid level trough is easily viewable on
water vapor imagery migrating through MT and southern SK early
this morning. This will provide upper forcing for ascent for
showers and thunderstorms along/near a cold front working its
way east across ND, eventually into MN this afternoon. Some
thunderstorms this afternoon may be severe (more details below).
Behind the cold front, smoke from Canadian wildfires is being
observed, and will degrade air quality through at least today
(more details below).

As the upper/mid trough pushes east into the Upper Midwest and
western Great Lakes, drier air behind the cold front filters
into the region, although there may be some scattered showers
and/or weak thunderstorms near northwest Minnesota Saturday
afternoon.

Northwest flow aloft briefly sets up around Sunday, along with
increased shear. Meager instability and lack of more organized
forcing will preclude messaging of potential strong to severe
storms Sunday afternoon, although if either increases (either
from better moisture return and/or added moisture from
evapotranspiration; subtle impulse aloft to increase forcing),
then this chance increase.

Into next week, most ensembles favor low amplitude upper ridging
into the Northern Plains and Upper Midwest between Monday and
Tuesday, offering a chance for warming trend with increasing low
level moisture. This comes ahead of upper troughing extending
out of central Canada into the Northern Plains and Upper Midwest
mid to late next week. This increases chance for showers and
thunderstorms. There is a signal within ensemble guidance that
hints at potential heavy rainfall via increased EFI
values/probabilities within ECMWF ensemble suite. Increased
instabilty and forcing/kinematics from this trough also
increases the chance for potentially strong to severe
thunderstorms. This is backed up by AI tools like FengWu AI-NWP
forecast, namely on Monday into Tuesday.

Behind this trough, most ensemble guidance shows a much drier
and cooler air mass moving into the region by late next week.


...Severe storm potential this afternoon...

Latest high resolution guidance strongly suggests thunderstorms
to develop along/near a cold front this afternoon within
portions of southeast ND into northwest and west-central MN.
While shear is quite meager within the vicinity of
thunderstorms, rich moisture and increasing daytime temperatures
beneath cooling air mass aloft will aid in moderate to strong
instability. Given the lack of overall shear, quick upscale
growth of thunderstorms are anticipated, aided by forward
momentum of the cold front itself. While shear will be low,
there may be enough of an extension of increased flow aloft from
the incoming trough to help transfer toward the surface of
eventual MCS, also aided by cold pool organization. Thus, gusts
to 60 mph will be possible from this activity. There will still
be a short timeframe where thunderstorms initially in their
semi-discrete mode shortly after initial development will be
capable of hail to the size of ping pong balls given the
instability that will be in place.

...Degraded air quality today, potentially into this weekend...

Surface observations behind the cold front early this morning
show wildfire smoke reducing visibility less than 2 miles and
AQI values into the "unhealthy" category. This lends confidence
that smoke will infiltrate the area behind the cold front at
least through today.

Guidance also offers another round of near surface smoke behind
another cold front around Sunday. It is unclear to the degree in
which this may degrade air quality.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1144 PM CDT Thu Jul 10 2025

Isolated thunderstorms continue through the overnight, with the
best chances closer to the US/Canada border, and probabilities
too low to include at TAF sites. Better chance for showers, but
still lower coverage of thunderstorms arrive the main upper
level system moves through the region Friday morning in ND and
across northwest MN Friday afternoon. Winds shift to the west-
northwest and increase behind this front during the daytime
period Friday.

Wildfire smoke from Canada is arriving behind this front, with
MVFR visibilities reported upstream, along with a few locations
briefly dropping to IFR. This axis of smoke should move
northwest to southeast across the region through Friday morning
and eventually across MN during the afternoon.

&&

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

&&

$$

DISCUSSION...CJ
AVIATION...DJR