651
FXUS63 KFGF 171200
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
700 AM CDT Thu Sep 17 2026

.KEY MESSAGES...

- Dense fog parts of eastern North Dakota and northwest and west
  central Minnesota thru mid morning.

- Chance for 1 inch or more of rain 30-40 percent far southeast
  North Dakota and parts of west central Minnesota.

&&

.UPDATE...
Issued at 514 AM CDT Thu Sep 17 2026

Dense fog advisory issued after coord with BIS/ABR/DLH offices
for areas roughly near and south of Hwy 2. In this area skies
are clearer, though clouds behind an advancing front is
improving things slowly from the north. Sufficient fog and
reduced vsbys below 1/2 mile.

Rainfall for Friday is over the southern fcst area, with latest
probabilities for 1 inch or more of rain 30-40 percent Wahpeton
to Wadena and 45 percent Elbow Lake, to less than 10 percent
Fargo.

UPDATE
Issued at 1140 PM CDT Wed Sep 16 2026

Backdoor cold front continues to sag into the CWA, with the main
stratus band still near the Canadian border, but some fog
starting to form in the clear areas ahead and behind the cloud
deck. Visibility has gone down to 1/4 mile at Bemidji airport,
but web cams in the area show fairly patchy coverage and not
totally socked in yet. Models are all over the place with some
showing low visibility in a few spots while others develop cloud
cover. Confidence is low in where or if any dense fog will form,
so will just keep an eye on things for now.

&&

.DISCUSSION...
Issued at 337 PM CDT Wed Sep 16 2026

...Synopsis...

Upper pattern this week can be characterized as zonal flow
aloft with progressive, weak shortwave troughs traversing
through the flow. This will offer opportunities for periods of
rain lasting into the weekend. This will also keep temperatures
near average through at least mid next week.

A weak cold front moves into our area from Canada tonight into
Thursday morning. This will drive tonight`s fog potential within
eastern ND and the northern Red River Valley.

...Rain chances ahead...

Zonal flow aloft with entrance region of an upper jet is being
observed over the Northern Plains into Upper Midwest. This is
allowing a weak and progressive shortwave trough/upper ascent to
migrate west to east across our area this afternoon into evening.
While synoptic forcing is expected to remain weak and moisture
return meager, a slight increase in instability is accompanying
this forcing/moisture. This will keep the possibility for weak
thunderstorms this afternoon into early evening in the southern
Red River Valley into west-central MN. Very little rainfall
amounts are expected with this, despite the convective behavior.

On Friday, a rather robust banded-rain event is expected with
strong forcing from frontogenesis fed by rich moisture and
instability. Current guidance keeps majority of this rainfall
(in excess of 3 inches) south of our area, within eastern SD
into southern/central MN.

However, given the majority of this forcing driven by mesoscale
processes like fgen and ripe instability, confidence in
location is not great. Vast majority of guidance keeps the
lion`s share of this rainfall south of our area, however a
small cluster of guidance does allow focus of forcing for ascent
and moisture northward toward the SD border into west-central
MN Friday. Thus, there remains potential for this banded heavy
rainfall to eek into locations near the SD border into west-
central MN. Should this occur, aforementioned locations are
liable to see 1 inch of rainfall. Even with a further north
evolution, the chance for 3 inches or more is very low.

Into this weekend - what was once looking like a more
consolidated shortwave trough is progged to translate across our
region looks more disorganized and weak. Thus, a lessening trend
is being noticed in the forecast regarding the chance for
widespread rainfall this weekend. There is still a chance for
rain, just not nearly as widespread as previously forecast.

...Fog potential tonight into early Thursday...

Confidence is medium in the occurrence of fog somewhere within
eastern ND, although confidence greatly diminishes where this
occur with more precision. Driving the fog production is a weak
cold front moving into ND from Canada, bringing with it ground-
scraping low clouds behind the front. Confidence remains low in
more precise locations, with uncertainty mainly stemming from
questions on influence of mid level cloud cover.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 657 AM CDT Thu Sep 17 2026

Clouds just behind a southward moving weak cold front is helping
to clear out the fog that formed while skies were clear earlier
in the night. That is what happened at KGFK. But still have fog
and pockets of 1/4 to 1/2SM vsby Cooperstown thru Mayville to
Fosston and Bemidji and south. This fog will burn off, likely
not equally, but should burn off in most areas by 15z. This will
leave a scattered to broken cloud deck in the 4000-6000 ft agl
range today into this evening. Light winds today, predominately
though north-northeast 5-8 kts this afternoon turning more east
or east-southeast tonight 5-8 kts.


&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Dense Fog Advisory until 10 AM CDT this morning for NDZ014-024-
     026>030-038-039-049-052-053.
MN...Dense Fog Advisory until 10 AM CDT this morning for MNZ001>003-
     013>017-022>024-027>032.

&&

$$

UPDATE...Riddle/JR
DISCUSSION...CJ
AVIATION...Riddle