Duluth, Minnesota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

913
FXUS63 KDLH 191114
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
614 AM CDT Thu Mar 19 2026

.KEY MESSAGES...

- Widely isolated patches of dense fog are expected this morning
  and should dissipate by mid-morning.

- Clouds and possible fog development early this morning may
  limit heating today. Temperatures will climb above freezing.
  Areas where skies are partly cloudy or clear during peak
  heating will reach the upper 40s to low 50s.

- A weak clipper will move across the Canadian Prairies and
  northern Minnesota tonight. Expect a mix of rain and freezing
  rain starting late this morning and ending tonight over north-
  central Minnesota into the Arrowhead. Ice potential is
  greatest in Cook County.

- Widespread fog is expected tonight due to snow melt and
  southerly winds. Fog will be locally dense.

- A better organized clipper will move through the region over
  the weekend. Mixed precipitation is forecast.

&&

.DISCUSSION...
Issued at 422 AM CDT Thu Mar 19 2026

A stripe of low stratus stretched from near GPZ to Upper
Michigan at 3 AM and will continue to slowly progress southward
this morning. There is a 10% chance of very light freezing
drizzle with that cloud deck. The other concern early this
morning is the potential development of fog. Low-level moisture
received a small boost from snowmelt and southerly warm air
advection yesterday afternoon. Clear to mainly clear skies over
much of northeast Minnesota along with relatively light winds
will allow for radiational cooling. The main question is whether
the cooling will be rapid enough to generate dense fog or if
direct deposition of ice onto surfaces will limit fog formation.
INL visibility was at 1/4 mile for a few minutes in the last
hour and is back to 5 miles now. Reduced visibility is expected
to become more widespread before sunrise, but widespread dense
fog appears unlikely.

A clipper located over southern Alberta early this morning will
propagate east-southeastward across the Canadian Prairies and
into northeast Minnesota by early Friday morning. The regional
radar mosaic reveals a band of light precipitation over southern
Manitoba which appears showery in nature. High-res models are
beginning to capture that precipitation. The 00Z Hi-Res FV3 and
07Z RAP seem to have the best handle at the moment. Those models
bring light precipitation into the International Falls vicinity
late this morning and into the eastern Arrowhead through early
afternoon. Temperatures are expected to warm above freezing
resulting in rain as the main weather type. There is about a 10%
chance of freezing rain even with air temperatures above
freezing as precip begins.

Elevated instability and Lifted Indices near zero this
afternoon into this evening over the Borderlands suggests a
potential for a few rumbles of thunder. Warm air aloft persists
as the second wing of precipitation advances into the Arrowhead
this evening into the overnight. Surface temperatures will drop
below freezing which raises the potential for freezing rain
mainly over Cook County. The chance of freezing rain is about
40% and the probability of 5 hundredths of an inch of icing is
around 25%.

With another warm day on tap today and strengthening southerly
warm air advection ahead of the clipper, the stage will be set
for the development of widespread fog tonight, some may be
locally dense. If the fog develops, it will be difficult to
shake until the weekend. The forecast highs for Friday will
hinge on whether fog and low stratus develop tonight. If we see
clearing, highs will reach the upper 40s to low 50s. Otherwise
we can expect upper 30s to middle 40s. I took the warmer path
for now.

Another period of precipitation is forecast Saturday and
Sunday. The persistent baroclinic zone over the Northland (an
area in the atmosphere featuring a "notable" horizontal
temperature gradient) will feed into a weak area of low pressure
traversing the Northland Saturday. That system will be similar
to today`s clipper. Precipitation chances will be greatest north
of the low track. As of this morning that area includes most of
northeast Minnesota and northwest Wisconsin. With the system
riding right along the baroclinic zone and 0 *C isotherms
bisecting the Northland, a mix of rain, snow, and possibly
freezing rain is forecast. Slight wobbles in the track of the
low and the thermal gradient aloft will influence precip types.
As of this morning snow amounts are a dusting up to an inch. The
likelihood of precip being all snow is low, around 10-30%
depending on location with the greatest odds of all snow in Cook
County. For areas where there is a mix...rain, snow, sleet, and
freezing rain are all possibilities.

Another shortwave trough will move into the region by Saturday
night. Another round of wintry mixed precipitation is favored.
The second round of precipitation is shaping up a bit stronger
with another dusting up to an inch of snow possible and higher
totals along the North Shore. Total snow between both systems
will range from a dusting up to an inch or two for most
locations and up to 3 inches in the high terrain of the North
Shore. Precipitation should taper off Sunday morning although
the GFS solution keeps light snow in the picture through Sunday.

Early next week will see warm temperatures during the day
cooling below freezing at night. There are a few additional
chances of precipitation Monday night and then Tuesday night
into Wednesday. Both of those would be clipper-type systems with
relatively light precipitation.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 614 AM CDT Thu Mar 19 2026

Pockets of low stratus and areas of fog should gradually
dissipate after sunrise. GOES-East satellite imagery suggests
the low stratus could stick around until around 17Z at DLH,
though we expect it to clear earlier. Should see temporary
visibility reductions at the terminals around and shortly after
sunrise. Visibility has been up and down at the terminals
overnight and I expect that trend to continue. Mainly VFR until
tonight. Passing clipper may bring light rain to INL this
afternoon. LLWS ramps up tonight before winds veer
northwesterly. That surface wind trajectory should advect drier
air beneath low stratus. Kept MVFR visibility in the forecast.
If surface winds remain southwesterly instead of veering,
visibility will be worse than currently forecast.

&&

.MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 422 AM CDT Thu Mar 19 2026

Winds will be from the east to southeast today and will veer
southwesterly tonight as a low pressure system propagates
southeastward across northwest Ontario. Sustained winds of 5 to
10 knots are forecast and will increase to 8 to 15 knots for the
waters of the South Shore tonight. Hazardous conditions are not
expected at this time. Fog is forecast to develop onshore
tonight and may advect onto the water. If that occurs, expect
visibility less than 1 mile near the shore. The next period of
hazardous conditions is forecast for the weekend when a stronger
low pressure system is forecast to pass over the region. Strong
east and northeasterly winds will develop Saturday afternoon
and become hazardous during the evening hours. There is a 20-30%
chance of low-end gales along the North Shore and the southwest
arm Saturday night and early Sunday morning. Waves will build
to 3 to 9 feet with the highest values in the waters of the
southwest arm and over the Outer Apostle Islands. Winds are
forecast to weaken Sunday afternoon and night. Small Craft
Advisories will likely be needed.

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

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
MARINE...None.

&&

$$

DISCUSSION...Huyck
AVIATION...Huyck
MARINE...Huyck