649
FXUS63 KDLH 220839
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
339 AM CDT Mon Jun 22 2026

.KEY MESSAGES...

-  Marine fog over Lake Superior this morning could reduce
   visibility along the South Shore as it moves inland.

-  Widespread showers and thunderstorms arrive on Tuesday,
   moving from west to east into early Wednesday morning.

-  A few storms Tuesday afternoon and evening may become strong
   to severe west of a line from Aitkin to Nett Lake. Damaging
   winds and marginally severe hail to 1" in diameter are
   potential hazards.

-  Additional chances for precipitation linger on Wednesday
   into Thursday with more rain possible late Saturday into
   Sunday.

&&

.UPDATE...
Issued at 250 PM CDT Sun Jun 21 2026

The Northland remains under the influence of surface high
pressure this morning, with northeast to east low level winds
over the area. At the surface, winds have diminished and under
mostly clear skies, temperatures have fallen into the upper 30s
to upper 40s. Also seeing localized fog develop, near bodies of
water for inland areas, and over Lake Superior as a marine fog
deck has developed and is spreading southwestward toward the
Twin Ports and South Shore.

An area of mid to high level clouds is arriving from the west,
which should curb cooling and any additional fog development,
especially across north central and northeast MN. For the rest
of Monday, pleasant conditions are expected as winds remain
light and variable, with temperatures slightly below normal for
late June. Closer to the shore, marine fog could linger
through the morning before dissipating.

Looking to the Tuesday system, slight changes were made to the
marginal risk of severe storms, pulling the main threat area
back westward, from roughly Aitkin to Nett Lake and locations
west. This area is where better lapse rates line up with
diurnally enhanced instability, although CAPE values remain on
the weak side. There remains low confidence in the potential for
severe storms as the threat will depend on a warm front lifting
northward and whether morning showers and cloud cover limit
afternoon instabilities.


&&

&&

.DISCUSSION...
Issued at 250 PM CDT Sun Jun 21 2026

The next chance for precipitation arrives on Tuesday as
vertically- stacked low pressure and an associated shortwave
move into the Upper Great Lakes. Cloud cover is anticipated to
increase on Tuesday morning ahead of an approaching warm front
and subsequent occluded front. Scattered to numerous showers and
thunderstorms are expected (80-95% chance) to move from west to
east through the CWA on Tuesday afternoon into Wednesday
morning. Current QPF is forecast to be highest from the Brainerd
Lakes to I-35 corridor and into north- central WI, with values
ranging from around 0.5" to 1".

A few storms on Tuesday afternoon and evening may become strong to
severe from the Brainerd Lake to around the I-35 corridor, where SPC
has issued a Marginal Risk on Tuesday. While the shear environment
will likely be favorable for stronger convection, with 0-6km bulk
shear in the 30-45 knot range, instability and moisture will likely
be the limiting factors. The primary window for any strong to severe
convection will most likely be from 18-02z, as a surge of higher
dewpoints up to the low 60s advects north along the warm front. This
will help generate modest MLCAPE up to 1000 J/kg in the southern
portion of the CWA when combined with marginally steep mid-level
lapse rates around 7 degC/km. Confidence in severe convection is low
at this time, as the best PWATs and instability will most likely
remain south of the CWA. In addition, this severe chance is largely
dependent on how far north the warm front advects before the
occluded front arrives. If severe storms are able to develop this
far north, the main concern is damaging wind gusts and marginally
severe hail.

Following this mid-week severe weather chance, a fairly active
pattern is favored in the global models over the Upper Midwest. The
250mb jet streak helping to propagate the verticall-stacked low into
the region on Tuesday will begin weakening on Wednesday, slowing the
eastward progression of this low and keeping rain chances around on
Wednesday. Thursday will see additional rain chances, most likely
from diurnal showers developing in the afternoon as cyclonic flow
aloft persists. Heading into the weekend, a brief lull in rainfall
will be possible as a ridge builds over the Upper Mississippi River
valley. Additional shower and thunderstorm chances arrive though
late Saturday into Sunday as another low pressure and associated
warm front potentially moves into the north-central CONUS.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1210 AM CDT Mon Jun 22 2026

VFR conditions with light winds are forecast through 23.06Z.
Fog has developed over western Lake Superior and spread inland
over portions of the South Shore. That fog would likely remain
limited to KASX, KSUW, and KDYT. There is a smaller potential
for fog to develop at BRD, DLH, and HIB due to clearing skies
and radiational cooling tonight.

&&

.MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 250 PM CDT Sun Jun 21 2026

With light winds over Lake Superior tonight, fog has developed
with visibility reductions spreading into nearshore waters along
the South Shore. Cannot rule out this fog making it into the
Twin Ports before sunrise.

As high pressure remains near Lake Superior today, winds will
remain variable with speeds of 5 kts or less for most of the
nearshore waters. Waves will be 1 foot or less. Widespread rain
chances arrive on Tuesday, with strong thunderstorms capable of
producing gusty winds, small hail, and frequent lightning
possible in the afternoon and evening.

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

&&

.FIRE WEATHER...
Issued at 250 PM CDT Sun Jun 21 2026

With high pressure remaining over the region, moderately dry
min RH is expected today, in the 30-40% range. Winds will be
light and variable with speeds around 5 mph or less. Mid and
high level clouds are spreading into the area from the west
this morning, which could slow warming after the sun rises,
keeping min RH values slightly higher than currently expected.

Widespread showers and thunderstorms are expected (80-95%
chance) to arrive on Tuesday into Wednesday as low pressure
moves through the area. A few storms may become strong to severe
on Tuesday afternoon and evening, especially west of a line from
Mille Lacs Lake to Nett Lake. This area could also see 0.5" to
1" of rainfall. Expect lesser rainfall amounts farther east in
the Arrowhead and across northwest Wisconsin, with as little as
0.05" of rain forecast in most of Cook County.

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

&&

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

&&

$$

DISCUSSION...HA/Unruh
AVIATION...HA
MARINE...HA
FIRE WEATHER...HA