907
FXUS63 KDLH 201131
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
631 AM CDT Thu Aug 20 2026

.KEY MESSAGES...

- Showers and thunderstorms are expected today, with a few
  severe storms possible in portions of east-central MN and
  northwest WI this afternoon and evening. The primary hazard is
  large hail up to 1.5 inches in diameter.

- Scattered showers will be possible on Friday afternoon, mainly
  in the Arrowhead and near the International Border.

- Pleasant weather conditions are forecast this weekend with comfortable
  high temps in the 70s for most and abundant sunshine.
  Additional shower and thunderstorm chances arrive early next
  week on Monday and Tuesday.

&&

.UPDATE...
Issued at 344 AM CDT Thu Aug 20 2026

Cloud cover has been increasing early this morning as a shortwave
and associated sfc low move closer to the Northland. Scattered
showers and isolated thunderstorms, currently in north-central MN,
will continue to move east into the CWA as isentropic upglide along
a lifting warm front occurs. Severe thunderstorms are not expected
this morning.

The forecast remains similar to the previous update, with the
potential for strong to severe thunderstorms occurring this
afternoon and evening. The Storm Prediction Center also has
maintained a Slight Risk for portions of the I-35 corridor into
northwest WI, with a Marginal Risk covering areas generally
south of the Iron Range. Southwest winds occurring ahead of an
approaching cold front will provide deep moisture advection into
the CWA, with dewpoints rising to the low to mid 60s by the
afternoon. When combined with moderate mid-level lapse rates of
6-6.5 degC/km, this moisture and warmer temps in the upper 70s
to low 80s are forecast to increase CAPE to 1000-1500 J/kg ahead
of the cold front. This instability will also be occurring with
favorable wind shear, with 0-6km bulk shear progged to be in
the 30-50 knot range by late afternoon.

It`s worth noting that a potential limiting factor for severe
thunderstorm chances today is cloud cover from this morning round of
convection. The current expectation is that there should be
enough clearing occurring around midday to allow for
destabilization to occur, but it will be something to monitor.
Assuming that severe thunderstorms develop, the primary hazard
will be large hail to 1.5" in diameter. Damaging winds to 60 mph
will be a secondary hazard as DCAPE will most likely be under
1000 J/kg, and decreasing through the evening as the nocturnal
inversion develops.

There are no major changes to the forecast following today`s severe
thunderstorm chances. A cold front is still forecast to sweep
through late tonight into Friday morning, with the potential for
scattered diurnal showers in the Arrowhead on Friday afternoon.
Still looking at a pleasant weekend forecast, with abundant sunshine
and comfortable high temps in the 70s. Additional rain chances
arrive on Monday afternoon and again on Tuesday, with Tuesday being
the next best day to monitor for severe weather chances.

&&

.DISCUSSION...
Issued at 150 PM CDT Wed Aug 19 2026

A warm front lifts through the Upper Midwest late tonight into
Thursday morning and brings about increasing rain shower
chances will early Thursday morning. Isolated general
thunderstorms develop Thursday daytime hour, first in the
Brainerd Lakes area. By Thursday late afternoon, sufficient
bulk shear approaching 50 knots and 1000 to 1500 J/kg of CAPE
within an progged 1.5 to 1.7 inches of precipitable water favor
a few severe thunderstorms first possible in the late Thursday
afternoon hours, but mainly during the evening hours, lasting
into the early overnight hours. Large hail to 1.5 inches in
diameter is the most likely hazard, with damaging wind gusts
being the secondary hazard. The area of most potential is south
of the Iron Range towards the Twin Ports in the early evening
and then areas further southward along the Interstate 35 and US
Hwy 53 corridors in the mid to late evening hours. Localized
rainfall up to 1.5 inches is possible from the strongest
thunderstorms late Thursday evening, but most areas are more
likely to receive 0.25 to 0.5 inches. While the most favored
timing window for severe weather Thursday is 4-9 PM strong
thunderstorms past 9PM to Midnight cannot be ruled out.

A cold front will drop through the area late Thursday night into
Friday morning and bring a return to northwest flow across our
region. A weak pool of instability will arrive by Friday
afternoon and combine with ongoing daytime showers to produce
some general thunderstorms, primarily focused from the Minnesota
Borderlands into the Minnesota Arrowhead region.

Behind the cold front, high pressure will build into the Northland
and provide a very nice and pleasant weekend. Abundant sunshine and
comfortable temperatures in the 70s are expected for both Saturday
and Sunday. The progressive pattern continues into early next week
as the next round of more widespread thunderstorms is forecast for
Monday afternoon and evening. Strong thunderstorms are again
possible Monday afternoon and evening for north-central
Minnesota. For Tuesday a primed environment may have finally
setup over the Northland for another round of strong to
potentially severe weather chances.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 631 AM CDT Thu Aug 20 2026

Showers with isolated thunderstorms are moving through the area this
morning. Visibility and cigs have largely been VFR, although brief
periods of MVFR visibility are expected under thunderstorms. There
will likely be a brief lull between this morning convection and
additional development occurring this afternoon and evening. A few
storms may become strong to severe this afternoon and evening,
especially in northwest WI, with large hail up to 1.5" being the
primary hazard. As precipitation comes to an end tonight, patchy fog
is very likely to develop. Confidence is increasing in widespread
IFR to LIFR visibility, which was included in this update.

&&

.MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 344 AM CDT Thu Aug 20 2026

Showers and thunderstorms are expected to arrive today and continue
into tonight. A few strong storms capable of producing small hail
are possible this afternoon and evening for the Twin Ports into the
South Shore. East to northeast winds today are anticipated to remain
15 knots or less today, with waves of 2 feet or less. Winds will
become west to northwesterly by the weekend following a cold front
passage tonight into early Friday morning.

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

&&

.FIRE WEATHER...
Issued at 344 AM CDT Thu Aug 20 2026

Showers and thunderstorms will move through today into tonight
as a warm front lifts into the area this morning and a
subsequent cold front sweeps through tonight. Since the center
of the low pressure is expected to move through the area today,
winds will be shifting through the day and speeds will generally
be on the light side with peak sustained winds of 5-10 mph and
afternoon gusts of 14 to 19 mph. A few storms this afternoon may
become severe, especially from east-central MN into northwest
WI. The primary hazard is large hail up to 1.5" in diameter,
with gusty and erratic wind gusts up to 60 mph being a secondary
hazard. A widespread 0.1" of rainfall today through tonight is
expected, with wetting rains of 0.25" to 1" being more scattered
and confined to thunderstorm cores.

Winds become northwesterly on Friday into the weekend following the
cold front tonight. High pressure builds this weekend with abundant
sunshine. Sunday looks to be the driest day in the forecast period,
with min RH reducing as low as 35%. Additional shower and
thunderstorm chances arrive on Monday into Tuesday.

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.

&&

$$

UPDATE...Unruh
DISCUSSION...NLy
AVIATION...Unruh
MARINE...Unruh
FIRE WEATHER...Unruh