928
FXUS63 KFGF 100251
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
951 PM CDT Tue Sep 9 2025

.KEY MESSAGES...

- Dense fog is likely to develop from west-central Minnnesota,
  northeastward through the Bemidji area tonight.

- There is a 50% chance for thunderstorms near the International
  Border Thursday into Thursday night. There is also a 30%
  chance for thunderstorms area wide Saturday afternoon and
  evening.

&&

.UPDATE...
Issued at 948 PM CDT Tue Sep 9 2025

Dense fog is still expected to develop across portions of
northwest Minnesota tonight and this will improve after sunrise
tomorrow. Fog will be the only weather impact overnight as winds
will be fairly light with mostly clear to clear skies expected
overnight.

UPDATE
Issued at 704 PM CDT Tue Sep 9 2025

A Dense Fog Advisory has been issued for a corridor stretching
from Wilkin County up through southern Beltrami County. This is
the region with the highest probabilities from HREF for dense
fog and the presence of light winds and clear skies indicates
this is the most favorable corridor for dense fog to develop.
Additional fog will likely develop north and westward, but is
less likely to be dense enough to warrant an advisory at this
time.

&&

.DISCUSSION...
Issued at 314 PM CDT Tue Sep 9 2025

...Synopsis...

Ridging remains in charge through Wednesday, with dry conditions,
light winds and sunny/mostly sunny skies. Fog was a problem this
morning, albeit cloud cover blowing off of an area of thunderstorms
in SD kept the areal extent at bay from what it could`ve been. With
the entire FA expected to see clear skies tonight, it is not a
question of if we will see radiational fog, but rather where/how
widespread. Dewpoint depressions are smaller from the southern James
River Valley through much of the Red River Valley into MN. Thinking
this zone is the most likely to see fog, potentially dense, develop
after midnight. Fog will last through mid morning Wednesday.

A large upper low positioned over Northern California will provide
for a more active pattern late week into the weekend. This active
spell will start with the ejection of a 500 mb shortwave on
Thursday. The shortwave will provide enough forcing for showers and
thunderstorms to develop in the afternoon/overnight period.
Progressing into the weekend, cluster analysis is in good
agreement that the main trough will take on a more negative
tilt as it lifts northeastward, providing the needed forcing
for more on and off precipitation chances Saturday through
Sunday, perhaps stretching into Monday. Temperatures do not look
to vary much even with this active period of weather ahead,
with highs remaining consistently in the 70s to low 80s through
the weekend into early next week.

...Thunderstorm Potential...

As the initial shortwave pushes across the Northern Plains on
Thursday, a plume of higher dew points and instability will stretch
northward. At this time nearly all model guidance keeps the highest
values to the west of our FA. Therefore, while thunderstorms are
forecasted late in the day into the overnight period, severe weather
is not anticipated.

Another plume of moisture and instability traverses north on
Saturday. This does look to overspread much of our FA, but its
exact placement and orientation are still in question even with
cluster analysis in generally good agreement on the broad
synoptic pattern. This goes to show that while the synoptic
pattern may be more predictable, there remains just enough
uncertainty in the synoptic scale features placement/timing
that it impacts the details within the mesoscale. Which in turn
will ultimately determine this weekends thunderstorm potential
for our FA. Therefore, predictability remains low as to how
thunderstorms play out Saturday into Sunday, before more general
showers become the predominate form of precipitation late
Sunday into Monday.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 948 PM CDT Tue Sep 9 2025

Fog is likely to develop and impact FAR and BJI. Additional
visibility reductions are possible at TVF/GFK/DVL, but the
probability is too low to add to the 06z TAFs. Fog will improve
after sunrise. VFR conditions will prevail thereafter with
southeasterly winds increasing to generally 8-11 knots.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...Dense Fog Advisory until 10 AM CDT Wednesday for MNZ016-017-
     023-024-027>032-040.

&&

$$

UPDATE...Perroux
DISCUSSION...Rafferty
AVIATION...Perroux