Duluth, Minnesota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

563
FXUS63 KDLH 282338
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
638 PM CDT Sun Jun 28 2026

.KEY MESSAGES...

- Scattered thunderstorms are possible tonight and early Monday
  morning. While most storms are not expected to be severe, an
  isolated strong to severe storm or two capable of producing
  large hail can`t be ruled out.

- A conditional chance for strong to severe storms exists Monday
  and Tuesday. There will be additional chances of thunderstorms
  Wednesday through next Sunday.

- Hot and humid weather is expected starting Monday and lasting
  through this week. Extreme Heat Warnings and Heat Advisories
  have been issued for east-central Minnesota into northwest
  Wisconsin Monday into Tuesday.

&&

.DISCUSSION...
Issued at 400 PM CDT Sun Jun 28 2026

This afternoon and tonight:
We have a fair amount of cloud cover over the region this
afternoon, and this has suppressed thunderstorm activity this
afternoon. We do have some clearing down towards the Twin Cities
with some building instability down there where a warm front is
present. This warm front will slowly lift northward tonight, but
the actual surface front will still remain pretty well south of
our area. Elevated instability associated with strong warm air
and moisture advection will gradually increase overnight, and we
may see some scattered showers and thunderstorms develop. CAMs
have been struggling to paint a reasonable picture of what might
happen later tonight as they fail to capture current conditions
well, placing rain showers where none is currently falling. The
overall synoptic pattern tonight will be broad ridging aloft
without much focused synoptic support for storms. Therefore, we
essentially have some factors favoring storms (increasing
instability) and negating factors (lack of broad synoptic
support). Any showers and storms that develop are expected to be
elevated. We will have potential for 2-3k J/kg of MUCAPE, but
that`s only if some of the capping can be eroded, which isn`t a
guarantee. So, the risk for severe weather tonight looks pretty
isolated. Large hail is looking to be the primary hazard in
addition to the usual thunder/lightning and heavy rain threat
with general thunderstorms.

Monday and Monday night:
As has been the story of this weather pattern, whatever
thunderstorm activity happens tonight will at least partially
determine how storms and heat end up panning out for Monday and
Monday night. In addition to that, guidance in the broader sense
seems to have a bit of a Fujiwara effect between an upper low
over Montana and a trough moving north across the Dakotas
Monday. Convection over there may take more of a northerly
trajectory that could bring the risk for severe weather further
north into Canada. With all that said, we will be dealing with
substantial instability and heat on Monday in our area with 3-4k
J/kg of MUCAPE (most of which will probably be elevated and
capped during the day Monday). Some CAMs bring nearly all
convection north of the Canadian border while some develop a
squall line that, if it happened, could bring a threat for large
hail (to about golf ball size, perhaps larger), strong winds
(to about 70 mph), and perhaps a tornado or two. This would be
most likely in the afternoon through early overnight. This
threat remains very conditional, so stay tuned for updates.
We`ll know more once we see how thunderstorms develop Monday
morning across the Dakotas.

As for the heat, it`s still looking like it will be a hot day.
The current forecast is largely in line with the NBM, which is
on the upper end of guidance. This means there`s at least some
potential for temperatures to be a little cooler than forecast,
but not likely to be warmer. Main concerns with that are
lingering cloud cover and capping that could result in
temperatures slightly less hot than forecast. But there`s
definitely high potential for 100 degree plus heat index values
with very high dew points in the mid to upper 70s for much of
east-central Minnesota into northwest Wisconsin. Because of
this, a few Extreme Heat Warnings have been issued for
Pine/Burnett/Washburn counties and a broader swath of Heat
Advisories have been issued for east-central and all remaining
northwest Wisconsin counties. We opted not to issue for the
South St. Louis and Carlton county zone since we will have
onshore flow from Lake Superior that should keep most of the
county from reaching criteria. With that said, the far western
and southern areas of that zone should see ~100 degree heat
indices a ways away from the lake influence. Heat Advisories for
Bayfield/Sawyer counties and east go through Tuesday early
evening as lows are not likely to fall below 70 degrees Monday
night, and we`ll see another hot day there on Tuesday with highs
in the 90s and heat indices approaching 100 degrees again.
Moderate to major heat-related impacts are expected in the
advised areas.

Tuesday and Tuesday night:
A cold front will slowly work east on Tuesday, and out ahead of
it, instability will linger mainly across northwest Wisconsin
but also perhaps a ways into east-central Minnesota. We may
start to lose some capping, so that works in favor of there
being some thunderstorms in general. A few storms capable of
producing some large hail and strong winds may be possible, and
timing of those could be morning, afternoon, or both. This
remains a conditional threat much like Monday, but with
increasing likelihood that there will be at least a few storms
out there as the cap starts to erode ahead of the cold front.

It is looking like another hot day, especially in northwest
Wisconsin. On the Minnesota side, dew points and temperatures
take a bit of a tumble, so it won`t feel quite as hot as Monday.

Wednesday through the Weekend:
On Wednesday, we`ll have to keep an eye on potential for some
more convection with southwesterly flow and a shortwave passing
by aloft. The storm threat could continue into Wednesday night.
MUCAPE in the 1-2k J/kg range may be marginally favorable for
some severe weather. Otherwise, more warm/hot weather is
expected.

General warm southwesterly flow will continue on into the
weekend, so expect more of the same with warm to hot weather and
plenty of chances for thunderstorms. Severe weather may be
possible at times.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 619 PM CDT Sun Jun 28 2026

VFR/MVFR cloud cover continues to build as warm air is advected
north this afternoon and is leading to some scattered light
showers in central Minnesota headed north. CAMs showing a
similar feature predict that these will continue to have a north
to northeast trajectory, affecting all terminals except INL.
MVFR visibilities are possible with heavier rainfall, but
restricted conditions will mainly be due to lowering ceilings
tonight. Cloud bases are expected to lift by late morning
Monday, and winds will again increase out of the southeast with
maximum gusts around 25 kts.

&&

.MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 400 PM CDT Sun Jun 28 2026

Breezy northeast winds will continue into this evening,
producing waves in the 3-4 ft range and winds gusting to around
25 kt, especially by the head of the lake. Winds will lessen
briefly tonight, though they will increase again Monday with
similar conditions as today expected. Small Craft Advisories
will likely be needed. Winds will flip over to southwesterly
following a cold frontal passage on Tuesday. Gusts to around 20
kt are expected. Downsloping winds around the head of the lake
could briefly produce some 25 kt gusts on Tuesday which may be
hazardous for small craft, especially near the shore.

Expect some on and off chances for thunderstorms the next couple
days. Scattered showers and storms tonight are possible.
Isolated large hail to quarter size could happen. More storms
are possible Monday late afternoon into the overnight and
perhaps again on Tuesday.

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

&&

.FIRE WEATHER...
Issued at 400 PM CDT Sun Jun 28 2026

Hot but also moist air is expected through Monday night. There
will be chances for showers and storms tonight and again Monday
late afternoon and night. Rainfall amounts are expected to be
highly variable with some places seeing little to none and
others seeing perhaps an inch or more locally. A few storms
could be strong to severe tonight with large hail being the main
threat. The storm chances Monday late afternoon and evening are
very conditional, but if they do happen, all hazards will be
possible including large hail, strong winds, and perhaps a
tornado or two. A cold front will lead to drier weather on the
Minnesota side on Tuesday with min RH into the 35-45% range.
Winds are also expected to gust up to around 20-25 mph from the
southwest. Winds are expected to be a bit less the rest of the
week. Overall, fire weather hazards look to be minimal given
plenty of moisture through the rest of the week.

See the Fire Weather Forecast product for a more thorough
breakdown of fire weather conditions.

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Heat Advisory from 9 AM to 8 PM CDT Monday for MNZ025-033>036.
     Beach Hazards Statement until 10 PM CDT this evening for
     MNZ037.
     Extreme Heat Warning from 9 AM Monday to midnight CDT Monday
     night for MNZ038.
WI...Beach Hazards Statement until 10 PM CDT this evening for
     WIZ001.
     Extreme Heat Warning from 9 AM Monday to midnight CDT Monday
     night for WIZ006-007.
     Heat Advisory from 9 AM Monday to midnight CDT Monday night
     for WIZ001.
     Heat Advisory from 9 AM Monday to 7 PM CDT Tuesday for
     WIZ002>004-008-009.
MARINE...Small Craft Advisory until 10 PM CDT this evening for
     LSZ140>145.

&&

$$

DISCUSSION...JDS
AVIATION...KML
MARINE...JDS
FIRE WEATHER...JDS