783
FXUS63 KFGF 030344
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1044 PM CDT Tue Sep 2 2025

.KEY MESSAGES...

- Below average temperatures will occur mid to late week, with
  morning frost likely over parts of the region. This includes a
  40% chance for below freezing temperatures in northwest
  Minnesota Thursday morning.

&&

.UPDATE...
Issued at 1044 PM CDT Tue Sep 2 2025

Smoke has overspread much of the ND side of the FA, with some
sites falling into the 3 to 5 mile range. In other news, clouds
have cleared out temporarily in the north, allowing for
efficient radiational cooling, causing temperatures to quickly
drop into the mid 40s near Langdon. Not sure temperatures will
drop much more, as dew points are in the mid 40s, and another
deck of low clouds north of the TransCanada Highway in Manitoba
are racing southward, which should insulate us again after
midnight. Therefore, made minimal changes to the going forecast
with this update. A cool but calm night looks to be in store.

UPDATE
Issued at 647 PM CDT Tue Sep 2 2025

A few radar echos have popped up on our far western FA border,
with surface obs showing very little reaching the ground. Clouds
have overspread basically the entire FA now, as the post cold
front airmass advects through the region. Smoke has also started
to come southward out of Canada, reducing visibilities in our
northern tier of counties down into the 2 to 5 mile range. This
smoke will continue to advect southward through the evening and
overnight hours. Made minor tweaks to the grids to match
observations, otherwise the forecast remains on track.

&&

.DISCUSSION...
Issued at 252 PM CDT Tue Sep 2 2025

...Synopsis...

Upper low over northern Manitoba will dig down into Ontario and
northern MN later tonight. The cold front is through all but our
four southeastern counties, and should push the rest of the way
through by the evening. There is some elevated instability behind
the front, but also subsidence and cumulus has has been on a
downward trend in that area. According to CAMs, still could see
a cell or two develop in southern Otter Tail or Grant county
before moving southeast, but many of the ensemble members keep
convection southeast of our CWA. Probabilities of strong updraft
helicity tracks from the HREF are less than 20 percent, and most
of the severe impacts will be down over central MN.

The upper low will continue to dig into MN/WI tomorrow, with
surface high pressure building into the Plains. Northwesterly
flow continues through the rest of the week and into the
weekend, with one strong reinforcing shortwave coming down on
Thursday and another weaker one Saturday. Flow starts to become
less amplified by the end of the weekend, with another shortwave
coming through by Monday into Tuesday and temperatures climbing
back closer to seasonal values.

...Frost/freeze potential...

There is little question that temperatures will dip down to
below seasonal values, with the ECMWF EFI showing a strong
signal for a cool trend. Exactly how cold and if we get any
frost to form will depend on cloud cover. With the reinforcing
shortwave on Thursday and the possibility of clouds coming in
before the precipitation arrives, we won`t have the typical
conditions for frost formation. That being said, there is still
high probability of getting down to 36 degrees or below east of
the Red River and a 40 percent chance of reaching 32 degrees in
northwestern MN Thursday morning. Will continue to keep
mentioning the cooler temperatures and possibility of freeze,
but too much uncertainty for any headlines yet.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1044 PM CDT Tue Sep 2 2025

Very few changes to the new set of TAFs. MVFR CIGs are still
expected to develop Wednesday morning at KTVF and KBJI. I did
extend MVFR CIGs back west a bit into KGFK Wednesday morning
with this set of TAFs, as the deck of MVFR clouds currently
north of Winnipeg look to remain on their present trajectory,
and should impact the terminal for at least a few hours.
Ceilings are anticipated to lift slowly from west to east during
the afternoon, taking longest at KBJI. All terminals will be
VFR by late evening. A few showers are possible during the mid
morning through late afternoon, but chances are too low to
introduce a PROB30 anywhere at this time. Winds will be gusty
out of the north from late morning through the mid evening.

&&

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

&&

$$

UPDATE...Rafferty
DISCUSSION...JR
AVIATION...Rafferty