445
FXUS63 KDLH 242321
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
521 PM CST Mon Nov 24 2025

.KEY MESSAGES...

- A large system moving north will bring rain then snow to the
  Northland starting tonight through Wednesday. Windy conditions
  and possibly some blowing snow will accompany it.

- Enhanced snowfall is expected from a potent FGEN band over
  the Arrowhead, a gravity wave over far northwestern Wisconsin,
  and lake effect snow along the South Shore.

- Light lake effect snow will linger across the South Shore into
  the weekend, and another system over the latter half of the
  weekend may bring another round of snow.

&&

.DISCUSSION...
Issued at 232 PM CST Mon Nov 24 2025

We have an interesting pattern set up for the next few days. Two
troughs, one in the Southern Plains and one moving across the
Pacific Northwest will work together to bring an impactful
system to the Northland through Wednesday. The southern system
is helping to bring warm, moist air northward and will be a
major source of moisture for this system. As the southern trough
moves north, it will be somewhat "absorbed" into the overall
flow, but the northern trough will be close behind and will
provide the forcing for when the system moves over the
Northland. At the surface, the associated surface lows will work
together to create one large overall system throughout the
eastern half of CONUS.

One surface low currently near eastern SD/NE and western IA is
slowly moving north, producing light to moderate rain showers.
Onset time of precipitation has slowed due to fighting dry air
to the north, and will take a bit to fully saturate the vertical
column. However, we are expecting rain to start reaching the
ground early Tuesday morning across northwest Wisconsin.
Meanwhile, a second surface low associated with that northern
trough will move east across the Northern Plains, already
contributing to some snow across ND and will bring light snow to
northwest and north central MN early Tuesday morning as well.
These two systems will combine as they move through the area,
and precipitation types will remain divided with snow across the
Iron Range and Borderlands with rain elsewhere across
northwestern Wisconsin. In between will be the transition zone
from the Brainerd Lakes region to the Twin Ports and up the
North Shore throughout Tuesday morning. The line of rain
switching to snow will move southeast throughout the day as cold
air is advected from the north.

As we head into Tuesday evening, a band of frontogenesis
combined with strong forcing and divergence will create a band
of enhanced snowfall in the TROWAL region of the now-combined
system. Where exactly this band will fall remains uncertain, but
confidence is high (80%) that it will fall somewhere in the
Arrowhead and/or far northwest Wisconsin. Additionally, as flow
begins to turn to the northwest, CAMS are showing a potential
for a gravity wave to set up over Douglas/Bayfield counties,
which could lead to over an inch per hour rates at times in
localized areas.

A break in the snowfall may be seen in our southern line of WI
counties as the dry line moves east just to our south. The exact
track of the dry line should stay largely to the south, so a
break in precipitation should be brief.

Early Wednesday morning, as winds shift further to the
northwest, lake effect snow will begin over northwest Wisconsin.
Since we have had temperatures averaging above normal for the
last few weeks, Lake Superior water temperature is still in the
40s. With the CAA, the air mass will be much colder than the
water, which will enhance the lake effect snow further along
with sufficient mid level lapse rates (5-7 C/km) increasing
throughout the morning (7-9 C/km). Snowfall across the region
will begin to exit Wednesday morning, but lake effect snow will
continue for Ashland and Iron counties through Wednesday and
into the latter half of the week.

Overall, a majority of the area will see 6"+ except for far
north central Minnesota and central Wisconsin. Areas under the
TROWAL could see up to a foot of snow, and the gravity wave/lake
enhancement across the South Shore counties will lead to 10-15
for most, with bullseyes of 20"+ in northern Iron County.
Therefore, with the additional nudge that travel will be
heightened from the Thanksgiving holiday, have opted to include
most of our area in a new Winter Storm Warning starting at
various start times over Tuesday. Koochiching and the bottom
tier of our Wisconsin counties are under a Winter Weather
Advisory. However, the Wisconsin counties may need to be
upgraded if the snow gradient continues to move further south.

Winds throughout the system will be strong as well, increasing
initially from the northeast before backing to the northwest.
Gusts up to 35 mph are expected, especially on Wednesday, which
could lead to any snow that hasn`t already compacted to be blown
around. A cool down is also expected behind the system, where we
will have temperatures below freezing for the rest of the
forecast period. High temperatures will be in the twenties and
possibly even the teens by next week.

There is the potential for another system to bring light snow
next weekend, but global model discrepancies in the path of the
system makes it difficult to conclude anything concrete on
whether there will even be any precipitation.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 521 PM CST Mon Nov 24 2025

VFR conditions are currently over the Northland. Satellite does
show an area of IFR ceilings just on the periphery of HYR.
Based on the latest trends and model guidance we expect this
cloud deck to stay south of the terminal until after midnight.
Overnight, cloud cover will increase across the region as our
first winter system of the season takes aim at the Northland.
Rain is expected to begin tomorrow morning with ceilings
dropping to IFR/LIFR before noon. The exception to this may be
INL, the latest guidance has shown a slight southern shift in
the system which may leave the terminal with just some MVFR
ceilings and light snow. For the rest of the region, colder air
will filter in from the NW and we will see a transition from
rain to mixed precipitation and eventually all snow by late
Tuesday. The heaviest snowfall rates are expected to be tomorrow
evening and overnight. The initial wave of snow will be of the
heavy wet variety but as the event continues it will alter to a
more fluffy and powdery type.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 232 PM CST Mon Nov 24 2025

A deepening low pressure will move across the Upper Great Lakes
Tuesday into Wednesday resulting in Gale-force winds over Lake
Superior. Northeast winds increase late tonight into Tuesday
leading to building waves through the day Tuesday. By Tuesday
evening the low center will be just south of Duluth, and as it
tracks east- northeast towards the Upper Peninsula of Michigan,
winds across western Lake Superior will increase and become more
northerly Tuesday night, out of the northwest by daybreak
Wednesday. Northwest winds of 25-30 knots with gale-force gusts
to 40 knots Wednesday evening. On Wednesday evening, winds will
start weakening as the low exits and an area of high pressure
builds in from the west. The probability for gale-force gusts
(34+ knots) is 80-100 percent, greatest for the north shore
north of Grand Marais. Storm-force gusts over western Lake
Superior are less likely, with around a 10 percent chance for
Storm-force (48+ knots) gusts north of Grand Marais.

Beyond the storm, northwest winds linger through the rest of the
week into the weekend at 10-15 knots Thursday, then less than 10
knots Friday, Saturday, and Sunday.

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

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Winter Weather Advisory from 6 AM Tuesday to noon CST
     Wednesday for MNZ010.
     Winter Storm Warning from noon Tuesday to midnight CST
     Wednesday night for MNZ011-012-019>021-037.
     Winter Storm Warning from 6 AM Tuesday to noon CST Wednesday
     for MNZ018-025-026-033>036.
     Winter Storm Warning from 6 PM Tuesday to 6 PM CST Wednesday
     for MNZ038.
WI...Winter Storm Warning from 6 PM Tuesday to midnight CST
     Wednesday night for WIZ001-002.
     Winter Storm Warning from 6 PM Tuesday to 6 AM CST Thursday
     for WIZ003-004.
     Winter Weather Advisory from 6 PM Tuesday to 6 PM CST
     Wednesday for WIZ006>009.
MARINE...Gale Watch from Tuesday evening through late Wednesday night
     for LSZ121-140>148-150.

&&

$$

DISCUSSION...KML
AVIATION...Britt
MARINE...KML