Hail in Minnesota, April 12, 2026

Area Forecast Discussion
National Weather Service Duluth MN
240 PM CDT Sun Apr 12 2026

.KEY MESSAGES...

- Strong thunderstorms are possible late this afternoon into
  this evening along and north of Iron Range.

- Inland northwest Wisconsin and east-central Minnesota could
  (30% chance) see a period of significant severe weather Monday
  late afternoon and into the evening hours. Very large hail
  exceeding ping pong ball size is the primary hazard, but
  damaging winds, and a tornado cannot entirely be ruled out.

- Areas of dense fog will continue tonight. Most likely lasting
  in the Arrowhead tonight.

&&

.DISCUSSION...
Issued at 230 PM CDT Sun Apr 12 2026

A complex and active spring weather pattern has taken hold of the
Northland, bringing multiple rounds of thunderstorms and
localized flooding along the South Shore. This afternoon, a
warm front lifting through the region has placed our area into a
warm sector, allowing temperatures to soar into the 70s for far
southern locations while Lake Superior keeps the shorelines in
the 40s and 50s. We are watching the Iron Range closely this
afternoon, as a sharp gradient exists for storm development.
Between 5 PM and 8 PM, storms are expected to fire along an
incoming cold front. Unstable cumulus clouds over Hubbard and
Wadena Counties are already forming in the narrow pocket of most
likely initiation ahead of the front. This area then pushes
into Northland over the next hour or two. Right now the the
storm initiation region appears to be the greater Cass/Itasca/west-
central St Louis County area early this evening from 4-6 PM.
These storms then become more intense into central St. Louis
County along or just south of the Iron Range around sunset and
move into the Arrowhead. There will be a fairly short window in
this time period for those strong thunderstorms to potentially
lead to an isolated severe thunderstorm as large hail around the
size of a Quarter. The strongest thunderstorms exit the area
from 10PM to Midnight tonight through the Arrowhead.

Ongoing dense fog in the Arrowhead this afternoon may mix out
from high res model guidance suggestions this evening as the
rain showers and thunderstorms pass overhead. As we head into
tonight, the concern shifts back to fog. These conditions are
currently covered by a Dense Fog Advisory issued earlier today
and runs through Midnight tonight. I would not be surprised if
after the winds decrease and temperatures drop tonight post-
front that the dense fog moves at least into the inland
Arrowhead regions. This creates a low-end chance of needing
extensions in time or areal coverage expansions of the Advisory.
Travelers should be prepared for rapidly changing visibilities
to near zero at times.

A Flood Warning for the Tyler Forks River near Mellen was issued
today for the combination of rain and rapid snowmelt forecast to
create Minor Flooding impacts. These would primarily be held to
the State Highway 169 north of Mellen as it crosses over the
Tyler Forks River. The flood stage is currently forecast to
begin Monday morning, crest Tuesday daytime and begin to recede
below flood stage late Wednesday. The rest of Ashland and Iron
Counties, along with Bayfield, remain under a Flood Watch for
the ongoing snowmelt that may interact with heavy rainfall
Monday evening and overnight.

Monday brings a much more significant severe weather threat as a
potent low pressure system moves in from the Central Plains. High
instability and strong wind shear will create an environment
favorable for supercells. The primary risk area sits south of
the Northland. The exception though is for inland northwest
Wisconsin stretching from Burnett through Price Counties and
Pine County in east-central Minnesota (Storm Risk of 3 out of 5).
Very large hail, potentially the size of golf balls or larger,
will be the main threat for any of these counties. Depending on
the location of the warm front tomorrow afternoon, southern
reaches of Douglas through Iron Counties (Storm Risk of 2 out of
5) could not be ruled out either for more notable storms
tomorrow. The confidence in any severe thunderstorms largely
diminishes though for any locations along and north of US Hwy 2
even in the Marginal Risk (Level 1 of 5). Any very large-capable
supercells Monday PM that are able to anchor onto the warm front
could then also be associated with a damaging wind threat and
limited tornado threat too for the late afternoon and evening
hours. Heavy rainfall rates within these storms will only add to
the ongoing flooding concerns.

While severe weather is expected to stay to our south, a few
thunderstorms cannot be ruled out Tuesday. Much of this week
will also feature notable lake breeze temperature gradients with
40s to 50s for shoreline locations and 60s inland. By late
Friday into the weekend, a shift to a much colder air mass is
expected. This could reintroduce snow to the region, with light
accumulations possible Friday night as lows drop into the 20s.
Any snow will be short-lived, however, as e remain in a highly
progressive and moist pattern heading into next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1242 PM CDT Sun Apr 12 2026

Warm front moved across the area this afternoon and is
triggering widespread rain showers and a few thunderstorms in
northern Minnesota. Prevailing southwesterly winds will occur
for a 6 to 9 hour period under this warm sector ahead of an
incoming cold frontal passage west to east this evening. An
isolated severe thunderstorm late this afternoon through this
evening cannot be ruled out for HIB/INL and into the Arrowhead.
Fog is likely to again setup tonight, with possibly lingering
dense fog in the Arrowhead still from today. Winds shift to
northerly and become light tonight from 06-12Z. Guidance is
pointing towards lifting ceilings from 14-17Z tomorrow ahead of
the next round of strong to possibly severe thunderstorms for
areas south of US Hwy 2 after 20Z Monday.

&&

.MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 233 PM CDT Sun Apr 12 2026

A Dense Fog Advisory remains in effect for all nearshore waters
this evening. As westerly winds take hold and dewpoints decrease
behind the cold front later tonight, the dense fog may decrease
in coverage along the North Shore. Expect visibilities below
one nautical mile through early Monday morning though along the
South Shore where the Advisory lingers last. Northeast winds
will increase to 15 to 25 knots Monday night, creating
hazardous conditions for small craft in the southwest arm of
Lake Superior. Small Craft Advisories are very likely to be
needed Monday evening and overnight.

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

&&

.FIRE WEATHER...
Issued at 235 PM CDT Sun Apr 12 2026

There are no fire weather concerns at this time. An active
weather pattern for the next few days will keep rounds of rain
and thunderstorms in the forecast. Expect a few strong
thunderstorms this evening near the Iron Range and Arrowhead of
northern Minnesota. Scattered severe thunderstorms are forecast
south of US Hwy 2 Monday PM for mainly inland northwest WI, but
also east- central MN districts. Very large hail the size of a
ping pong ball is possible, along with a lower chance of
damaging wind gusts.

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

&&

.HYDROLOGY...
Issued at 345 AM CDT Sun Apr 12 2026

No changes to the Flood Watch for Bayfield, Ashland, and Iron
counties in Wisconsin for this evening through early Wednesday
morning. The watch remains medium confidence as it will be less the
traditional sense for flash flooding potential and more into the
potential for around 1-2" of rain over several days combined with
the potential for 1-5 inches of snow water to melt out of the
remaining snowpack. Given the convective nature of the
precipitation, some pockets of locally higher and lower rainfall
totals will be possible. The precipitation from this morning will
set the stage for subsequent rounds of flooding potential. However,
the QPF trends continue to shift further southeast with each model
subsequent model run. The main threat still looks to be Monday night
as a low pressure system moves across MN. A few of the deterministic
models are painting 0.50-1.00" within a 12 hr period.

We will still need to monitor for river rise/flood concerns along
the North Shore as well given the deeper snowpack to 12-24"+ of snow
depth and snow water equivalents of 5-7"+ there.
However, the trend has been for the heaviest rain to remain south of
the North Shore. Additionally, despite temperatures forecast to be
above freezing for several days in a row, Lake Superior will keep
the North Shore high temperatures about 10-20F colder and low
temperatures 5-15F colder than areas farther inland. This should
slow the snowmelt process there relative to the South Shore. Should
precipitation forecasts and/or temperature forecasts increase for
the North Shore for tonight through Wednesday, then flood headlines
may be needed.

As for river and stream concerns, the highest potential for minor
flooding remains with the Tyler Forks near Mellen, which could see
minor flooding by late Monday or early Tuesday depending on how
heavy the first couple rounds of rain are. The Bad River and Nemadji
Rivers also have some potential to rise into action stage in the
Monday to Tuesday timeframe depending on heavy rain locations and
amounts.

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Dense Fog Advisory until 1 AM CDT Monday for MNZ020-021.
WI...Flood Watch through Wednesday morning for WIZ002>004.
MARINE...Dense Fog Advisory until 1 AM CDT Monday for LSZ140>145-148.
     Dense Fog Advisory until 1 AM CDT Monday for LSZ142.
     Dense Fog Advisory until 10 AM CDT Monday for LSZ146-147-150.

&&

DISCUSSION...NLy
AVIATION...NLy
MARINE...NLy
FIRE WEATHER...NLy
HYDROLOGY...Rothstein/Britt

Hazardous Weather Outlook
National Weather Service Duluth MN
330 PM CDT Sun Apr 12 2026

MNZ010>012-018>021-025-026-033>038-WIZ001>004-006>009-132030-
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-
330 PM CDT Sun Apr 12 2026

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

.DAY ONE...This afternoon and Tonight

Strong to severe thunderstorms are possible primarily across far
northern Minnesota between through mid evening today. Large hail
would be the primary threat. Areas of dense fog persists, with the
best coverage in the Arrowhead. Rain falling on melting snow pack
may lead to minor flooding for area rivers along the North and
South Shore, particularly the South Shore. A Flood Watch is in
effect for Bayfield, Ashland, and Iron Counties.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

A second round of severe storms Monday afternoon and evening may
bring very large hail to inland northwest Wisconsin and east-
central Minnesota. There is also a potential for damaging wind
gusts and heavy rainfall in northwest Wisconsin. The continued
rounds of showers may lead to an increased flood threat,
especially over South Shore rivers.

Another round of thunderstorms is possible Tuesday and again
Wednesday.

.SPOTTER INFORMATION STATEMENT...

Skywarn spotters are encouraged to report hail of any size and
rainfall amounts to the National Weather Service.

LSZ121-140>148-150-132030-
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-
330 PM CDT Sun Apr 12 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

Areas of dense fog across the near shores of Lake Superior is
expected to continue into tonight. The North Shore is expected to
thin later tonight while fog along the South Shore may linger into
Monday morning. Dense Fog Advisories are in effect.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Northeast winds Monday evening into Monday night are likely to
produce hazardous conditions for small craft, particularly in the
southwest arm of Lake Superior. Small Craft Advisories are likely
to be needed.

Additional breezy conditions that may be hazardous for small
craft are possible late Thursday night into next weekend.

NLy

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