320
FXUS63 KDLH 132346
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
546 PM CST Sat Dec 13 2025

.KEY MESSAGES...

- Dangerous wind chills of 25 to 35 below zero are expected
  across the Northland tonight into Sunday morning.

- A Gale Warning has been issued for portions of the North Shore
  this evening, along with a Heavy Freezing Spray Warning for
  the Apostle Islands.

- Light lake effect snow continues along the South Shore, with
  up to 3 inches of accumulation possible in northern Iron
  County.

- A significant warming trend arrives next week, with
  temperatures soaring into the 30s and 40s by Tuesday.

- Possible messy p-type system Thursday.

&&

.DISCUSSION...
Issued at 146 PM CST Sat Dec 13 2025

Arctic air has firmly grasped the region this afternoon as high
pressure builds in from the Canadian Prairies. Temperatures
remain stuck in the single digits below zero for many locations,
and gusty northwest winds are keeping wind chills bitter and
dangerous. The core of this cold airmass settles in tonight,
sending actual air temperatures plummeting into the teens and
twenties below zero. When combined with the wind, wind chill
values will drop to between 25 and 40 below zero. A Cold Weather
Advisory remains in effect for the entire forecast area through
Sunday morning. Frostbite can occur quickly on exposed skin in
these conditions, so please layer up if you must be outdoors.

While most of the region sees dry and clearing skies, the northwest
flow is generating lake effect snow along the South Shore of Lake
Superior. The heaviest activity is focused on northern Iron County,
where an additional 1 to 3 inches of fluffy snow is possible
through tonight. Elsewhere along the South Shore, accumulations
will likely remain under an inch.

Sunday begins frigid, but conditions will slowly improve as the
high pressure center drifts east toward the Ohio River Valley.
Winds will gradually weaken, though wind chills will remain
biting through the morning hours. By Sunday afternoon, the
coldest air begins to depart, setting the stage for a major
pattern shift.

Forecast guidance suggests a rapid warmup to start the work week.
As the high moves off to the southeast on Monday, southerly flow
returns, pushing temperatures back into the 20s. A warm front lifts
through on Tuesday, allowing highs to climb well above freezing,
likely reaching the 30s and lower 40s. This unseasonable warmth
looks to persist into Wednesday.

The next organized weather system arrives late Wednesday into
Thursday, bringing renewed chances for precipitation. Depending
on the track of the system and thermal profiles, we could see a
messy p-type system. Confidence is increasing in this systems
occurrence as the deterministic suite of guidance all has some
flavor of this system. The origins still rest in northwest flow,
but it definitely tries to tap into southern moisture. As of
now, by the time it matures enough to usher that moisture
northward, it should be east of us leaving the Northland with
just a modest 0.25 to 0.5" of QPF to wrestle with. We`ll keep an
eye on it.

Following this system, zonal flow continues to bring active
weather with roller coaster-esque temperatures.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 545 PM CST Sat Dec 13 2025

Mostly VFR conditions across the area this evening as lower ceilings
have scattered out. There is some guidance that suggests IFR to LIFR
ceilings return overnight for INL, BRD, and HYR, but upstream
observations make this questionable. Have opted to throw in a
scattered MVFR ceiling for now until observations give us better
confidence. Northwesterly winds should peak between now and midnight,
then calming into Sunday morning. Southwesterly winds pick up
through Sunday afternoon.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 146 PM CST Sat Dec 13 2025

Strong northwest winds continue to create hazardous conditions
on western Lake Superior. A Gale Warning is in effect for the
North Shore waters from Grand Portage to Taconite Harbor this
evening into the overnight hours as drainage winds accelerate
off the terrain, producing gusts up to 40 knots. A Heavy
Freezing Spray Warning continues for the Apostle Islands until
early Sunday morning due to the combination of cold air, strong
winds, and waves. Winds will lull briefly Sunday morning before
ramping up from the southwest Sunday night, where another round
of gales are possible.

For the open water discussion, refer to the NWS Marquette Area
Forecast Discussion at weather.gov/mqt.

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Cold Weather Advisory until 10 AM CST Sunday for MNZ010>012-
     018>021-025-026-033>038.
WI...Cold Weather Advisory until 10 AM CST Sunday for WIZ001>004-
     006>009.
MARINE...Small Craft Advisory until 4 AM CST Sunday for LSZ121-142>148-
     150.
     Small Craft Advisory until 7 PM CST this evening for LSZ140-
     141.
     Gale Warning until 2 AM CST Sunday for LSZ140-141.
     Heavy Freezing Spray Warning until 4 AM CST Sunday for LSZ147-
     150.

&&

$$

DISCUSSION...Wolfe
AVIATION...Levens
MARINE...Wolfe