Severe Thunderstorm Warning 21, NWS Duluth, MN

Area Forecast Discussion
National Weather Service Duluth MN
223 PM CDT Wed Jun 10 2026

.KEY MESSAGES...

- Several rounds of thunderstorms develop this afternoon and
  evening, with numerous severe storms possible. All severe
  hazards are possible, including large to very large hail,
  damaging wind gusts, tornadoes, and locally heavy rainfall.

- Hot and humid conditions continue today away from Lake
  Superior, where high temperatures should be in the 80s with
  dew points in the 60s to low 70s. Northwest Wisconsin may need
  a Heat Advisory, but cloud cover and storms may mitigate this
  need.

- Additional, non-severe showers and storms on Thursday with
  cooling temperatures into the weekend.

- Dense fog on and near Lake Superior today and tonight.
  Visibility below one-quarter of a mile is expected on land and
  below 1 mile on Lake Superior.

&&

.DISCUSSION...
Issued at 204 PM CDT Wed Jun 10 2026

The severe thunderstorm threat for this afternoon and evening
and its associated threats will be the forecast challenge.
Plentiful buoyancy with surface dewpoints in the mid to upper
60s, with a few dewpoint readings in the 70s, is in place.
Effective deep layer shear of 30-40kts this afternoon is
forecast to increase to 40-50 kts this evening as a strong mid
level jet propagates across northeast Minnesota and northwest
Wisconsin. This bouyancy-shear space is favorable for
supercells, with storms becoming more organized and likely more
intense late this afternoon and into the evening as the shear
increases and low level buoyancy increases as well. All severe
are hazards expected. This includes large to very large hail,
potentially in excess of 2 inches, damaging winds in excess of
60 mph in northeast Minnesota and potentially in excess of 70
mph in northwest Wisconsin, and a few tornadoes. The greatest
relative risk for tornadoes is across the I-35 corridor in
northeast Minnesota and across most of northwest Wisconsin. With
multiple rounds of thunderstorms expected until the cold front
clears with multiple impulses moving across the area aloft,
locally heavy rainfall and flash flooding will also need to be
monitored.

The one limiting factor to storm organization and intensity
thus far is backing winds in the mid levels, resulting in a bit
less favorable hodographs for intense supercells. This mid level
wind backing is depicted in forecast hodographs into the early
evening. Another caveat to the hail threat in northeast
Minnesota is upscale growth into a line along the cold front,
which would limit the hail threat some, but make damaging winds
the primary threat.

Looking ahead into the weekend and into next week, it will be
cooler even away from Lake Superior with high temperatures in
the upper 60s and lower 70s under cyclonic flow aloft. The
overall airmass will also be drier. However, embedded impulses
in the cyclonic flow means the forecast will not be
precipitation free, with near daily chances for rain showers and
thunderstorms in the afternoon through sunset across northeast
Minnesota and northwest Wisconsin. Severe weather is not
expected.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1225 PM CDT Wed Jun 10 2026

Severe thunderstorms with large hail, damaging wind gusts in
excess of 50kts, a few tornadoes and very heavy rainfall will
develop across northwest Wisconsin and northeast Minnesota this
afternoon and evening. Storms will increase in coverage after
20Z this afternoon. The threat will decrease after 05Z. LIFR
conditions in very heavy rainfall is also expected. Dense fog
near and on Lake Superior will also continue today and tonight.

&&

.MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 902 AM CDT Wed Jun 10 2026

Dense fog with visibility below one mile will continue today
through Thursday morning. A Marine Dense Fog Advisory is in
effect.

Northeast winds continue today. Some afternoon gusts of 10-15
knots are possible at the head of the lake today, as well as
15-20 knots in parts of the North Shore this afternoon. Expect
thunderstorms again this afternoon and evening. Some storms
could become severe, with damaging winds (best chance closest to
shore), large hail, and frequent lightning. Overnight into
Thursday, winds becoming southwesterly with some stronger gusts
approaching 20-25 knots at times, mainly in the Outer Apostles
and portions of the North Shore. Hazardous conditions for small
craft may be possible, but confidence was not high enough to
issue with this update. Additional rain showers are possible on
Thursday.

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

&&

.FIRE WEATHER...
Issued at 206 PM CDT Wed Jun 10 2026

Scattered to numerous severe thunderstorms are expected this
afternoon and evening, with all hazards possible including
large to very hail, damaging wind gusts, and a few tornadoes.
Good rainfall is expected, with widespread rainfall
accumulations of 0.5-1.0"+ likely. Scattered rain showers and
thunderstorms are forecast Thursday, and then slowly drying out
into the weekend.

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

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
MARINE...Dense Fog Advisory until 7 AM CDT Thursday for LSZ121-140>148-
     150.

&&

DISCUSSION...PA
AVIATION...PA
MARINE...PA
FIRE WEATHER...PA

Hazardous Weather Outlook
National Weather Service Duluth MN
151 PM CDT Wed Jun 10 2026

MNZ010>012-018>021-025-026-033>038-WIZ001>004-006>009-111900-
Koochiching-North St. Louis-Northern Cook/Northern Lake-
North Itasca-Central St. Louis-Southern Lake/North Shore-
Southern Cook/North Shore-North Cass-South Itasca-South Cass-
Crow Wing-Northern Aitkin-South Aitkin-Carlton/South St. Louis-
Pine-Douglas-Bayfield-Ashland-Iron-Burnett-Washburn-Sawyer-Price-
151 PM CDT Wed Jun 10 2026

This Hazardous Weather Outlook is for portions of northeast
Minnesota and northwest Wisconsin.

.DAY ONE...This afternoon and Tonight

Northeast winds around 10 to 15 mph and waves up to 2 feet today
will lead to a moderate risk for rip currents at Twin Ports
Beaches.

Several rounds of thunderstorms are expected this afternoon and
evening, with numerous severe storms possible. All severe weather
hazards are possible, including large to very large hail, damaging
wind gusts, tornadoes, and locally heavy rainfall.

The peak severe weather threat will be through around 7 PM with
some lingering storms through around midnight.

Hot and humid conditions continue today away from Lake Superior.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Isolated non-severe storms will be possible on Thursday and
Friday.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotters are encouraged to report hail of any size, wind
damage, and rainfall amounts to the National Weather Service.

LSZ121-140>148-150-111900-
Bayfield to Oak Point WI-Grand Portage to Grand Marais MN-
Grand Marais to Taconite Harbor MN-
Taconite Harbor to Silver Bay Harbor MN-
Silver Bay Harbor to Two Harbors MN-Two Harbors to Duluth MN-
Duluth MN to Port Wing WI-Port Wing to Sand Island WI-
Sand Island to Bayfield WI-Oak Point to Saxon Harbor WI-
Outer Apostle Islands Beyond 5 NM from Mainland-
151 PM CDT Wed Jun 10 2026

This Hazardous Weather Outlook is for portions of Lake Superior
and the Nearshore waters of western Lake Superior.

.DAY ONE...This afternoon and Tonight

Dense Fog will continue today and tonight with visibility below 1
mile. A Marine Dense Fog Advisory is in effect.

Severe storms are likely this afternoon and evening, with large
to very large hail and wind gusts of 40-60 kt possible.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Breezy southwest winds on Thursday and Friday may lead to
hazardous conditions for small craft.

Isolated non-severe storms will be possible on Thursday and
Friday.

JDS

More information may be obtained at the following web address:
http://www.weather.gov/duluth

Preliminary Local Storm Report
National Weather Service Duluth MN
314 PM CDT Wed Jun 10 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0300 PM     Flood            Webster                 45.88N 92.36W
06/10/2026                   Burnett            WI   Public

            Ace Hardware reports flooding on Main
            Street. Standing water on street curb to
            curb. Very heavy rain at time of
            observation.

&&

SG