Latest Duluth Area Text Forecast Discussion product from NWS:
657
FXUS63 KDLH 182355
AFDDLH
Area Forecast Discussion
National Weather Service Duluth MN
555 PM CST Thu Dec 18 2025
.KEY MESSAGES...
- Low pressure moving through the area will bring a combination
of snowfall, strong winds, and rapidly falling temps to the
area this afternoon into tonight. A Winter Weather Advisory is
in effect for all counties this evening.
- Strong winds along the North Shore are expected this evening
with wind gusts up to 60 mph centered around Grand Marais. A
High Wind Warning is in effect for southern Cook County and a
Wind Advisory is in effect for southern Lake County.
- A second Clipper arrives late Friday into Saturday morning, with
additional light snow accumulations of 3" or less forecast.
Another round of breezy winds are likely with this Clipper.
&&
.DISCUSSION...
Issued at 331 PM CST Thu Dec 18 2025
Active weather continues this afternoon as a vertically-stacked low
pressure moves through the CWA. Earlier this morning, a dry slot was
in place across much of the area, which led to drizzle and freezing
drizzle as low-levels remained saturated and weak isentropic
ascent occurred. This afternoon, this dry slot has been
advecting to the east with an area of moderate to heavy snow
moving into northern MN as the trowal propagates into the CWA. A
band of strong near sfc FGEN in the 950-900mb layer around the
Iron Range into the Arrowhead combined with deep saturation with
the DGZ has allowed for very low visibility at times as low as
one quarter of a mile. While snowfall rates have been moderate
to heavy early this afternoon, the best dynamic forcing will be
relatively quick in its eastward progression this afternoon and
evening. This will limit snow accumulations across the majority
of the CWA to an additional 1-3 inches today through Friday
morning. Winter Weather Advisories remain in effect for all
counties in the CWA.
In addition to the synoptic snow accumulations expected from this
messy Clipper, lake effect snow is also expected along the South
Shore after winds shift to the north to northwest. Amounts will be
highest near the Penokee Range in northern Iron County, with 5-7"
forecast. The Bayfield Peninsula also has the potential for locally
high accumulations in the 3-5" range from a gravity wave developing
in the lee of the North Shore terrain ridge.
Other concerns from the ongoing system include strong winds and
flash freeze conditions. A surge of Arctic air is already moving
into the Red River Valley and northwest MN this afternoon, causing
temps to fall into the single digits above and below zero. As these
very cold temps advect across the CWA this afternoon and evening,
previously wet surfaces are expected to quickly freeze as low temps
tonight fall into the single digits to negative teens. Coldest wind
chills tonight into early Friday morning will be approaching -30
degrees in the Borderlands, but since coverage will be limited,
opted against issuing a Cold Weather Advisory for tonight`s cold.
Regardless, exposure should be limited as apparent Ts tonight
plummet to the negative teens to negative 20s across the CWA.
This drastic temperature drop will also be accompanied by strong
north to northwest winds this afternoon into tonight along a tight
pressure gradient. Near dry-adiabatic lapse rates in the low levels
combined with strong winds around the 900-850mb layer will allow for
strong winds to mix to the surface as this surge of cold air
advection occurs. Wind gusts of 25 to 35 mph have already been
observed early this afternoon into north-central MN, and are
expected to expand eastward into this evening. Along the North
Shore, katabatic winds are very likely with a 70% chance for very
strong wind gusts up to 60 mph around Grand Marais to Hovland this
evening. With the high confidence in strong winds, a High Wind
Warning was issued for southern Cook County this evening into
tonight. In southern Lake County, winds will be slightly weaker but
still could gust up to 50 mph, especially around and north of Silver
Bay near the shore.
This Clipper departs the CWA by Friday morning, with a brief lull in
the pattern progged around midday. This lull will be short-lived
though as a second Clipper arrives into the CWA late Friday into
Saturday morning. Snow accumulations from this second Clipper are
extremely likely (95% chance) to be light with less than 3" of new
snowfall forecast. Most accumulations across the CWA are forecast to
be in the trace to 2" range, with higher amounts in the tip of the
Arrowhead and north-central WI. In addition to light snowfall,
breezy west to northwest winds are expected.
Following this early weekend Clipper, another surge of Arctic air
arrives albeit slightly warmer than tonight`s low temps.
Temperatures moderate heading into next week with high temps
generally increasing into the 20s to low-mid 30s. Additional chances
for wintry precipitation are currently on track to arrive Monday and
Thursday, but overall impacts appear minimal at this time.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 555 PM CST Thu Dec 18 2025
Low pressure moving through the area has brought strong winds
and poor flying conditions to the terminals this evening. These
conditions will linger into tonight, with most sites at least
starting out with MVFR ceilings and MVFR/IFR visibilities. The
strong north-northwest winds with gusts of 25 to 35 kts are
causing copious blowing snow, helping to reduce those
visibilities. Winds are expected to slowly diminish overnight
with a gradual diminishment in the light snow as well, allowing
the terminals to return to VFR both ceilings and visibilities in
the 06z-09z time frame. There may be some intermittent MVFR
conditions lingering until 12z. VFR conditions are expected to
linger through the end of the TAF period. Our next chance of
snow begins to lower cloud bases after 21z, but do not reduce to
MVFR until well after 00z.
&&
.MARINE...
Issued at 331 PM CST Thu Dec 18 2025
A strong Clipper will continue to move east around western Lake
Superior this afternoon and evening, with strong winds expected to
occur around the tight pressure gradient force. For much of western
Lake Superior, Gale Warnings are in effect this afternoon into
tonight with north to northwest gales up to 45 knots expected. Along
the North Shore from Taconite Harbor to Grand Portage, downslope
winds from the higher terrain are expected to create northerly wind
gusts up to 50 knots this evening. Therefore, a Storm Warning is in
effect for these nearshore zones. In addition to the strong winds
occurring this afternoon through tonight, heavy freezing spray is
expected along the South Shore as high waves up to 8 feet occur in
conjunction with sub-freezing temperatures.
A second Clipper arriving on Saturday morning will bring another
chance for gale force winds across western Lake Superior through the
day into Saturday night. A Gale Watch has been issued for all
nearshore waters, with the highest potential for gales being along
the North Shore above Silver Bay and around the Apostle Islands.
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Winter Weather Advisory until midnight CST tonight for MNZ010-
011-018>020-025-026-033>038.
Wind Advisory until 4 AM CST Friday for MNZ020.
Winter Weather Advisory until 4 AM CST Friday for MNZ012-021.
High Wind Warning until 4 AM CST Friday for MNZ021.
WI...Winter Weather Advisory until midnight CST tonight for WIZ001-
006>009.
Winter Weather Advisory until 6 AM CST Friday for WIZ002>004.
MARINE...Gale Warning until 4 AM CST Friday for LSZ121-142>148-150.
Heavy Freezing Spray Warning until 7 AM CST Friday for LSZ121-
145>148-150.
Gale Watch from Saturday morning through late Saturday night
for LSZ121-140>148-150.
Storm Warning until 4 AM CST Friday for LSZ140-141.
Winter Weather Advisory until midnight CST tonight for LSZ142.
Wind Advisory until 4 AM CST Friday for LSZ142.
&&
$$
DISCUSSION...Unruh
AVIATION...Unruh
MARINE...Unruh
NWS DLH Office Area Forecast Discussion
