635
FXUS63 KFGF 102010
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
310 PM CDT Sun Aug 10 2025

.KEY MESSAGES...

- A level 1 out of 5 risk for severe weather covers most of the
  area Monday afternoon and evening. The main hazards are
  lightning, winds up to 60 mph and hail to the size of a
  quarter.

- A potentially active weather pattern returns late this week.

&&

.DISCUSSION...
Issued at 310 PM CDT Sun Aug 10 2025

...Synopsis...

Northwest flow has reestablished itself behind the departing low
that brought us showers and thunderstorms yesterday. In turn, smoke
has started to return from Canadian wildfires. Smoke has been dense
upstream, reducing visibility down to a mile in spots this morning
near the MT/ND border. Smoke should not be as dense when it arrives
in this FA, but air quality and visibility impacts will still
be experienced. A 500 mb jet on Monday will allow for a trough
to dig down into the Dakota`s. This will aid in pushing smoke
slowly east Monday afternoon, clearing late in the day across
the western FA. This trough however will also spark off showers
and thunderstorms, some of which could be strong to severe.

By midweek, upper flow turns southwesterly. Moisture return ahead of
an approaching trough will cause buoyancy to build across the
Northern Plains. This sets the stage for thunderstorms, some
potentially severe Wednesday through Friday across the region.

...Strong to Severe Storms Monday...

Thunderstorms are expected to develop late Monday afternoon into the
evening as a 500 mb wave propagates through the region. A ribbon of
MLCAPE of up to 1500 J/Kg should snake northward somewhere across
southeastern ND into northwestern MN. Shear isn`t great, but is
there, occasionally touching on 30 knots when looking at 0-6 Km
values. Sounding advertise an inverted V, which does allow DCAPE to
climb into the 800 to 900 J/Kg range, especially in the south. Those
values rely on us getting up into the mid 80s though, which with
smoke and clouds (as we are seeing today here and further west),
could be hard to achieve. All told, we have had several events with
this synoptic setup over the summer in a similar environmental
parameter space, which usually have resulted in very isolated,
marginally severe storms. Therefore, kept potential hazards as
winds to 60 mph and quarter sized hail, with the expectation of
more storms being on the `strong` side then the `severe` side of
the table.

...Active Late Week...

As we return to southwesterly flow mid to especially late week,
chances for thunderstorms return. Southerly low level flow will
advect warmer and humid air into the region, with dew points by
Thursday returning to the 70s. However, timing of waves that could
spark storms remains uncertain, with models all over the place. All
said, the most interesting day right now is Thursday, when a large
pool of CAPE values in excess of 2000 J/Kg will set up somewhere
over the Dakotas into MN. The timing of the forcing responsible for
getting storms going that afternoon/evening will determine the
convective evolution and thus impacts to this FA. Machine learning
is also hinting on Thursday being a day to watch closer, as even if
the main forcing is further west, storms overnight could push
through the region. Definitely a timeframe to keep an eye on as
it approaches.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1243 PM CDT Sun Aug 10 2025

MVFR ceilings have persisted through much of the morning, but
are slowly lifting. They should continue to slowly lift from
west to east. Behind the clouds, smoke will advect into the
region. Upstream visibilities have been in the MVFR range.
Therefore, added that into the TAF at KDVL and KGFK, timed out
as best as possible for when they will arrive. For other TAF
sites, its more uncertain just how dense the smoke will be by
the time it reaches them, so maintained 6SM visibility. If smoke
is as dense as it is upstream by the time it reaches KTVF and
KFAR, they also could see MVFR visibilities. Smoke should become
less dense Monday, but still persist area wide.

&&

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

&&

$$

DISCUSSION...Rafferty
AVIATION...Rafferty