Cass Lake, Minnesota Weather Forecast Discussion

843
FXUS63 KDLH 221738
AFDDLH
Area Forecast Discussion
National Weather Service Duluth MN
1238 PM CDT Mon Sep 22 2025
.KEY MESSAGES...
- Additional rounds of overnight fog will occur tonight into
  Tuesday morning, and possibly again Tuesday night into
  Wednesday morning. Dense Fog Advisories are likely to again be
  needed.
- Largely dry with above normal temperatures Tuesday and
  beyond.
&&
.DISCUSSION...
Issued at 400 AM CDT Mon Sep 22 2025
The cut off low which has brought several days of clouds,
scattered rain showers, a few rumbles of thunder, fog, damp and
cool conditions will finally slide off to our east today. An
area of rain showers currently over east-central MN and western
WI will affect a few of our counties in northwest WI today,
though we may get a lull about mid-day before more showers pop
up over parts of NW WI and the MN Arrowhead for this afternoon.
Farther west, from the Brainerd lakes north through the
International Falls area, there should be quite a bit of
sunshine this afternoon, with slightly warmer temperatures in
the low 70s, vs the 60s to around 70 for areas with more clouds.
Dense fog formed around the Twin Ports and up the North Shore
last evening, and expanded rapidly overnight to a large portion
of the forecast area this morning. It seems the fog around the
Twin Ports and up the North Shore is advection/terrain induced,
with much of the remaining area getting radiational fog. This
radiational fog should burn off more quickly in the morning than
the advection fog, so the Advisory for areas away from Lake
Superior extend until 16z this morning, with areas closer to the
lake continuing until 17z or even 18z depending on location.
Unfortunately, this pattern repeats again tonight, with areas of
fog, and guidance indicates it will be dense once again. We may
need additional Dense Fog Advisories once again tonight.
The forecast becomes much quieter and gradually warms up through
the work week with high temperatures rising in the low to mid
70s for a large part of the area for Wednesday and Thursday.
There is a surface ridge and upper level ridging that will
produce that quiet weather through at least Wednesday. There is
an upper level shortwave and trough axis that should slide
through the forecast area Thursday night into Friday, followed
by another Friday night into Saturday. However, there is enough
uncertainty in the timing and strength of these waves and how
much moisture they may have with them that the forecast remains
effectively dry for now.
&&
.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1236 PM CDT Mon Sep 22 2025
IFR ceilings will slowly lift and scour out this afternoon,
except along the North Shore. The terrain ridge is expected to
remain within LIFR to VLIFR ceilings and visibility through
Tuesday morning. Another round of dense fog is expected again
tonight at many terminals. Fog again lifts 14-17Z Tuesday.
&&
.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 400 AM CDT Mon Sep 22 2025
Light northeast winds of 5 to 10 knots this morning are expected
to continue through Tuesday night before backing into the north
on Wednesday, remaining light. There may be some afternoon gusts
which approach 15 knots. These light winds and lingering
moisture from the last few days is going to contribute to
persistent fog over western Lake Superior today and tonight.
There may be a few hours, mainly during the afternoon where
visibilities improve to a mile or better, but the fog will close
back in once we get cooler in the evening. A Dense Fog Advisory
has been issued for all the nearshore waters through Tuesday
morning. This pattern may repeat once again Tuesday night into
Wednesday morning.
For the open water discussion, refer to the NWS Marquette Area
Forecast Discussion at weather.gov/mqt.
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Dense Fog Advisory until 11 AM CDT Tuesday for MNZ020-021.
WI...None.
MARINE...Dense Fog Advisory until 10 AM CDT Tuesday for LSZ121-140>148-
     150.
&&
$$
DISCUSSION...LE
AVIATION...NLy
MARINE...LE

NWS DLH Office Area Forecast Discussion