Copley, Minnesota Weather Forecast Discussion

408
FXUS63 KFGF 250430
AFDFGF
Area Forecast Discussion
National Weather Service Grand Forks ND
1130 PM CDT Wed Sep 24 2025
.KEY MESSAGES...
- Continued above average temperatures into the 70s and 80s
  along with predominately dry conditions through at least the
  weekend.
&&
.UPDATE...
Issued at 1019 PM CDT Wed Sep 24 2025
Latest guidance has backed off on the coverage/signal for fog
in southeast ND and west central MN. HRRR still shows a very
localized/spotty signal but trend is for drier air to continue
to advect to the southeast limiting fog coverage/impacts.
Radiational conditions where the surface ridge is in place are
still good and Td depressions are near zero already, so while
fog may end up more localized than previous nights/morning (and
likely shallower) there is still the potential and I will leave
patchy fog across our south/southeast.
UPDATE
Issued at 636 PM CDT Wed Sep 24 2025
Radiational fog may form overnight tonight/early Thursday
morning near the surface ridge axis in far southeast ND and west
central MN, and HREF shows a 20% chance for 1/2sm visibility in
those areas. Drier air would be working into the region as BL
flow shifts to the southwest then west, so coverage of dense fog
impacts is more uncertain than previous mornings. I expanded
where patchy fog was mentioned during the morning hours to
reflect the window/location for potential impacts. Otherwise,
forecast is on track.
&&
.DISCUSSION...
Issued at 148 PM CDT Wed Sep 24 2025
...Synopsis...
The upper pattern features weak flow aloft and block-y type
synoptic set up with the polar jet remaining well north into
Canada, and stalled stationary upper lows/troughs in the western
and eastern CONUS. Surface high pressure and subsidence aloft
will allow for another night of favorable radiational cooling
aloft. However, there is a weak frontal passage etching its way
into the area from the north, which would serve to keep winds
elevated some. This mitigates potential for fog formation at
least north of US Highway 2. But locations ahead of the front,
like those in the southern Red River Valley into lakes country
of Minnesota are liable for another morning of fog Thursday.
Ensemble guidance strongly suggests this type of synoptic
pattern persists through the weekend into next week, with upper
ridging amplifying/building into central Canada. Overall dry air
mass continues to be reinforced into the region without any
appreciable source/return flow of moisture. This along with
relatively warm temperatures aloft will continue to promote
above average temperatures well into the 70s with some low to
mid 80s into portions of eastern ND and the Red River Valley
through the rest of this week. There is potential these
temperatures (or even warmer) extends into next week given
amplifying/building ridging aloft.
It isn`t until mid next week when ensemble guidance suggests
potential for decreasing geopotential heights aloft, which would
promote ascent and possibly some forcing for showers and
thunderstorms. With above average temperatures likely to
continue through at least this weekend, thunderstorms will
remain possible although degree of severity remains in question.
As of now, there are no signals for appreciable strong to
severe storm potential given the lack more robust forcing as
well as low level moisture to increase instability.
&&
.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1130 PM CDT Wed Sep 24 2025
Surface high pressure is still holding some influence over far
southeast ND and west central MN and patchy radiation fog may
still develop. However, latest trends in guidance have reduced
the signal for fog impacts at KFAR and KBJI and the probability
for IFR conditions is now less than 10%. Winds from the south-
southwest should shift behind a front Thursday morning becoming
northerly and increasing above 12kt (gusts around 20kt during
the afternoon). These winds eventually shift to the east-
northeast and decrease again Thursday evening as surface high
builds back into the region and daytime mixing ends.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...DJR
DISCUSSION...CJ
AVIATION...DJR

NWS FGF Office Area Forecast Discussion