Duluth, Minnesota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

609
FXUS63 KDLH 252319
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
619 PM CDT Sat Jul 25 2026

.KEY MESSAGES...

-  Hot conditions are expected today and Sunday, with Heat
Advisories and Extreme Heat Warnings in effect.

- Conditional threats for severe thunderstorms from late tonight
through Monday morning. If thunderstorms develop, isolated to
scattered severe storms are likely, capable of producing damaging
winds, large hail, and frequent lightning.

- Near to slightly above average temperatures continue through the
coming week, with occasional precipitation chances.

&&

.DISCUSSION...
Issued at 214 PM CDT Sat Jul 25 2026

Clouds are clearing this afternoon under west to northwesterly flow,
with a hot and humid day developing. Temperatures should jump up
quickly with sunnier skies, pushing high temperatures into the 80s
to near 90F with moist dewpoints. A Heat Advisory remains in effect
for portions of the area through this evening.

As an upper level high pushes east overnight, a weak upper level
disturbance along its periphery along with a marginal LLJ could
force a couple storms out of a well-capped and somewhat dry air mass
along the International Border and into the MN Arrowhead. The
primary issue here is the actual development of storms, if that can
occur, decent MUCAPE and ample bulk shear should allow for storms to
grow into a respectable elevated storm severe threat, with damaging
winds and large hail as the primary hazards. As the LLJ weans into
Sunday morning, any areas of precipitation that do develop should
weaken or diminish.

Sunday, a hot and moist airmass should push from the Dakotas into
the Northland. Widespread high temperatures in the 90s (near 100F in
the Brainerd Lakes region) combined with dew points in the upper 60s
to mid 70s will make for an uncomfortable, and at times somewhat
oppressive, heat. Heat Advisories and Extreme Heat Warnings are in
effect. With that heat and humidity, an impressive reservoir of
instability is expected to develop, with models suggesting 3000-
4000+ J/kg of MUCAPE across Minnesota, Wisconsin, and the UP. Along
with that, around 50 knots of bulk shear could combine with steep
mid level lapse rates to develop clusters of storms from the
International Border and southeastward across the aforementioned
region. With the heat we`re expecting, there will be a cap to
overcome, which seems most likely to occur in the late afternoon to
evening hours, but the potential for the cap to not break is there,
limiting our PoP forecast for now. Storms will likely be pretty
quick if they develop, cruising from northwest to southeast with a
damaging wind and large hail threat. Our entire area is in a Slight
Risk (level 2/5) for Sunday. As additional upper level shortwaves
continue to move along the edge of the high pressure, some storms
could continue to form and propagate over the MN Arrowhead into NW
WI Monday morning, where a Day 3 Marginal risk is in effect.

Monday and through the work week, temperatures temper slightly, but
are still largely expected to be around to above normal with
afternoon highs in the upper 70s to upper 80s and overnight lows in
the 50s and 60s. We remain in a somewhat stagnant pattern stuck
between an upper level high over the Southwest to Central Plains and
semi-transient upper level lows moving over central to eastern
Canada. This should continue to put us in position to see the
influence of occasional ridge running disturbances which could bring
spotty rain showers and thunderstorms. Some global models are
suggesting the potential for a slightly stronger upper level
shortwave to bring a more potent system to the area late in the
week, but confidence is extremely low in any solutions that far out
at this point.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 619 PM CDT Sat Jul 25 2026

Cloud cover is eroding across the region with satellite showing a
few pockets of MVFR retreating across NW WI. A fair amount of smoke
aloft will remain present but VFR conditions are expected through
most of the overnight hours. Early tomorrow there may be pockets of
fog that impact a few terminals, this fog will quickly dissipate
after 14Z. High pressure will be moving across the region with winds
shifting from out of the south tomorrow to out of the northwest near
the end of the forecast period. There are concerns for severe storms
to develop tomorrow, but timing and placement remain nebulous when
compared to the available guidance. Most of the guidance is favoring
a later start time of after 22Z.

&&

.MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 214 PM CDT Sat Jul 25 2026

|Southwesterly winds continue to die down through this afternoon and
evening. An area of shallow dense marine fog along the North Shore
should persist into this evening, and then slowly become less
widespread overnight. Sunday, winds switch around and come onshore,
with some afternoon gusts up to 15 knots possible for the head of
the lake and South Shore. Monday, breezy northeast winds pick up,
with some afternoon gusts of 15-20 knots for the head of the lake
and Outer Apostle Islands. This time period will need to be
monitored for possible Small Craft Advisories. With continued high
dewpoints, areas of dense fog could be possible on the lake.
However, with northeast winds expected to reduce the upwelling cold
water along the North Shore, the coverage and magnitude is
uncertain. There is a slight chance for thunderstorms, some possibly
severe, very late tonight through Monday morning, with the best
chance Sunday afternoon and evening. Strong winds, large hail, and
frequent lightning could be possible with any storms that
develop.

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

&&

.FIRE WEATHER...
Issued at 214 PM CDT Sat Jul 25 2026

Looking ahead, the pattern for fire weather concerns is fairly rinse
and repeat each day. We have slightly above normal temperatures,
leading to afternoon relative humidity dropping into the 40-50%
range most days. There are currently no signals for periods of
significant winds, but afternoon gusts 10-15mph are possible through
much of the week. From late tonight through Monday morning, some
areas of showers and thunderstorms are possible, but not guaranteed.
If thunderstorms do form, isolated to scattered severe storms are
possible, capable of producing large hail, damaging winds, and
frequent lightning. Precipitation amounts will be spotty, dependent
on where the thunderstorms end up, but those areas that do get
showers/storms could see 0.25-1" of quick rainfall. Monday and
through the week, we remain in a pattern that could bring more
spotty chances of showers and thunderstorms on and off but
confidence is low in timing and placement.

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

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Heat Advisory from 11 AM to 9 PM CDT Sunday for MNZ010>012-
     019>021.
     Heat Advisory until 9 PM CDT this evening for MNZ010-018-019-
     025-026-033>038.
     Extreme Heat Warning from 11 AM to 9 PM CDT Sunday for MNZ018-
     025-026-033>038.
WI...Heat Advisory from 11 AM to 9 PM CDT Sunday for WIZ004-009.
     Heat Advisory until 9 PM CDT this evening for WIZ001>003-
     006>008.
     Extreme Heat Warning from 11 AM to 9 PM CDT Sunday for
     WIZ001>003-006>008.
MARINE...Dense Fog Advisory until 9 PM CDT this evening for LSZ140>143.
     Heat Advisory from 11 AM to 9 PM CDT Sunday for LSZ142.

&&

$$

DISCUSSION...Levens
AVIATION...Britt
MARINE...Levens
FIRE WEATHER...Levens