Breitung, Minnesota Weather Forecast Discussion

334
FXUS63 KDLH 201143
AFDDLH
Area Forecast Discussion
National Weather Service Duluth MN
643 AM CDT Sat Sep 20 2025
.KEY MESSAGES...
- Strong winds at the head of Lake Superior to once again
  create rip currents at beaches across the Twin Ports today.
- Areas of dense fog around the Twin Ports and along the North
  Shore to slowly diminish this morning, but should return once
  again tonight.
- On and off rain showers with a few non-severe thunderstorms
  are expected through the weekend into Monday.
&&
.DISCUSSION...
Issued at 403 AM CDT Sat Sep 20 2025
A semi cutoff upper low with several vorticity lobes rotating
around it is lingering over the Northland this morning,
continuing to bring waves of precipitation to the region. This
low is forecast to slowly, slowly move east through the weekend,
keeping the precipitation chances and generally cool and damp
conditions going through today and tomorrow, and into Monday to
a certain extent as the low slowly moves out of the area. There
should be several separate waves of showers that move across the
forecast area over the next 24 to 48 hours, as the vorticity
lobes interact with the broad isentropic lift ongoing over the
area. There is also a plume of deep moisture which has PWAT
values of around 1.38, which is over the 90th percentile for
September 20th. No wonder things feel rather damp out there. I
expect the highest precipitation chances to be on a diurnal
trend, with higher pops in the afternoon and early evening,
slowly dropping off overnight, similar to how things have
behaved over the last 24 hours. As the upper low shifts east on
Monday we should get some more sunshine and lower precipitation
chances over the western portions of the area, but the eastern
half will still trend toward cool and damp. All this cloud cover
and precipitation will keep temperatures on the cool side with
a small diurnal range. Considering how cool we stayed on Friday,
I have gone a little cooler than guidance mean for today, but
allowed a warming trend for Sunday through Monday.
Dense fog has formed around the Twin Ports this morning in the
high moisture easterly flow environment we have. Considering
this is mostly terrain/advection induced and all the cloud
cover, I do not expect it to expand significantly during the
early morning hours, though we may get poor visibilities up the
North Shore, and will be watching for that this AM. Visibilities
should gradually improve by late morning. Unfortunately, this
pattern repeats again tonight, and I expect fog development
tonight, with areas of dense fog around the Twin ports. We have
a Dense Fog Advisory out for this morning, and depending on how
things develop, we may need another one again tonight.
Persistent northeast winds today will cause a repeat of high
waves and potential for rip currents at the beaches of the Twin
Ports. While winds will not be as strong as they were Friday,
they will still be enough for rough conditions.
The forecast becomes much quieter and gradually warms up
through the work week. The weekend upper low slides to our east
even as another low intensifies as it drops across the Rockies,
and then moves out across the central plains before crossing the
Mid- Mississippi River Valley Wednesday and pushing farther
east through the rest of the week. Depending on which model
solution you look at, we may get some showers around the
periphery of this system, but most of them keep it to the south
and leave us dry for the week. Temperatures should trend near to
above normal through the end of the week.
&&
.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 643 AM CDT Sat Sep 20 2025
Flying conditions varying from LIFR/IFR for the MN terminals and
MVFR for KHYR with scattered showers will continue this morning.
Most of the terminals will see a period of improving conditions
beginning by 15z, rising to at least MVFR if not VFR for a few
hours during the afternoon, only to begin deteriorating again
after 00z. In addition to the showers, there may be
thunderstorms, mainly for KHYR, KBRD and KDLH this afternoon.
Conditions will deteriorate again this evening, with IFR/LIFR
ceilings returning in the 03z-06z time frame, with KDLH also
developing fog and LIFR visibilities.
&&
.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 403 AM CDT Sat Sep 20 2025
Northeast winds of 10 to 20 knots and gusts up to 30 knots
continue early this morning, but are expected to diminish over
the course of the day today. Lingering swell will keep wave
heights from dropping as quickly as the wind, so have extended
the Small Craft Advisories for the North Shore and the Twin
Ports into the afternoon hours. Wind speeds continue to decrease
tonight to the 5 to 10 knot range before veering around to the
southeast for Sunday, and then back to the northeast for Monday.
Once wave heights decrease today and tonight, they should
remain 2 feet or less through Sunday and Monday.
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 this morning for MNZ037.
     Beach Hazards Statement through this evening for MNZ037.
WI...Beach Hazards Statement through this evening for WIZ001.
MARINE...Small Craft Advisory until 4 PM CDT this afternoon for
     LSZ140>145.
     Small Craft Advisory until 10 AM CDT this morning for LSZ146-
     147-150.
&&
$$
DISCUSSION...LE
AVIATION...LE
MARINE...LE

NWS DLH Office Area Forecast Discussion