317
FXUS63 KDLH 202352
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
652 PM CDT Thu Aug 20 2026

.KEY MESSAGES...

- Showers and thunderstorms through this evening and early
  overnight. A few strong to severe storms are possible between
  about 3 PM and 10 PM. Large hail is the main threat, but some
  gusty winds cant be ruled out.

- Fog with areas of dense fog possible tonight into early Friday
  morning.

- Lingering isolated showers and possibly a storm or two are
  possible Friday.

- Mostly sunny weather with seasonable temperatures are expected
  this weekend into early next week.

- Additional shower/storm chances arrive around Monday night into
  Tuesday night.

&&

.DISCUSSION...
Issued at 137 PM CDT Thu Aug 20 2026

The main story for this afternoon and evening will be
thunderstorm chances. As of the early afternoon, a broad swath
of clouds with embedded showers and storms cover much of the
Northland with some pockets of clearing. The current
showers/storms are associated with the warm sector of a low
pressure system, which is centered near the Canadian Border over
northwest/north-central Minnesota. The low is expected to move
southeast this afternoon, and there is an area of clearing out
near Upper/Lower Red Lake that could be a focus for additional
thunderstorm development this afternoon. Some surface-based CAPE
on the order of 1-2 kJ/kg is supportive for some strong/severe
storms. Theres some modest ~20-30 kt effective shear and
generally less than 700 J/kg of DCAPE. If storms fire this
afternoon, they will likely be focused in the vicinity of the
cold front, affecting areas roughly along the US-2 corridor and
south, and maybe up to the Iron Range. Hail looks to be the
primary threat, and we could see some quarter size to maybe ping
pong ball size hail in a few storms. Some gusty winds or
perhaps a very brief tornado cant be totally ruled out (~2%
chance) with at least marginally favorable southwesterly winds
and low-level shear ahead of the cold front, but there does look
to be a general mismatch where the best shear early this
afternoon may not coincide with the best instability in the
later afternoon and evening such that the tornado risk is low.
The strong/severe storms may develop around 3 PM this afternoon
and linger as they move into northwest Wisconsin through about 9
or 10 PM. They should weaken pretty quickly after sunset (at
least as far as the severe threat goes), though they wont
dissipate completely as they move east with the front. After the
front, for the rest of the night, isolated pop-up showers cant
be ruled out with a little lift aloft and moisture remaining.
An overall drying trend is expected though.

On Friday, a secondary cold front and cyclonic vorticity
advection aloft may trigger some afternoon showers and perhaps
some storms. At this point, severe weather isnt expected with
pretty much straight northwest flow expected, but we could see
just under 1 kJ/kg of MUCAPE in the afternoon that could support
a few non-severe storms. Otherwise, skies are looking partly
cloudy in the afternoon after mainly overcast skies during the
morning with fog (possibly dense for some areas, especially
around the head of Lake Superior with a period of northeast
winds likely later tonight into Friday morning). Isolated
showers could linger into Friday evening.

Going into the weekend, broad ridging across the western CONUS
with surface high pressure over Manitoba/North Dakota will bring
us some slightly cooler weather with northwest flow. The weather
is looking very quiet and dry over the weekend. The only main
concern will be some lower RH values falling a bit below 40%,
especially on Sunday, which could lead to some slightly
elevated fire weather concerns. But, winds will be pretty light
Sunday/Monday when the driest conditions arrive, so even this is
a small concern.

Next week, another low pressure system may bring some warm air
advection-induced showers and storms Monday night into Tuesday.
A potential low pressure system may take a similar track as
today`s low, bringing another cold front through sometime around
Tuesday evening/night.

For the rest of the week, generally northwest flow aloft should
keep us in a quiet weather pattern to end the week.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 654 PM CDT Thu Aug 20 2026

Clusters of showers and storms are moving southeastward across
the area tonight, and have timed out impacts at terminals based
on current radar trends. Main focus is currently from HIB to BRD
and locations eastward. Main threat with any stronger storm will
be large hail, frequent lightning, and brief heavy rainfall.
Cannot rule out a wind gusts of 20-25kts.

As activity moves eastward, expect fog and potentially low cigs
to develop, with LIFR conditions possible at most terminals.
There is a 50-60% chance of vis less than 0.50 mile at DLH, HIB,
and HYR overnight. Fog and low cigs will slowly improve through
Friday morning, with winds from the northwest at 5-10kts.

&&

.MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 137 PM CDT Thu Aug 20 2026

Expect scattered showers and thunderstorms through this evening.
Severe weather is not expected, though a stray storm or two
could produce some hail or gusty winds. Otherwise, a cold front
will pass through and then high pressure. Winds are expected to
become light and variable into Friday. Winds become
predominantly northwesterly going into Saturday with some 15-20
kt gusts, highest along the North Shore. A brief period of
northeasterly winds is likely on Sunday. Aside from this
evening`s storm chances, hazardous weather is not anticipated
Friday through Sunday.

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

&&

.FIRE WEATHER...
Issued at 138 PM CDT Thu Aug 20 2026

Severe thunderstorms are possible today mainly south of the Iron
Range from late afternoon to sunset today. The main hazard would be
large hail to 1.5 inch in diameter...50 mph gusty and erratic
outflow winds though cannot be ruled out either. Any rainfall would
be localized from where these isolated storms pass over. South winds
today shift to northerly behind a passing cold front tonight. For
Friday daytime, isolated non-severe thunderstorms could bring cloud
to ground lightning and gusty, erratic wind gusts to 30 mph. These
Friday daytime shower chances generally taper by late evening
tomorrow. No rainfall is expected this weekend. Northwest winds
sustained around 10 mph gust to 20 mph Saturday before becoming
light and variable Sunday. Next week for Monday night into Tuesday
there is the next thunderstorm chance after Friday evening.

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...JDS
AVIATION...HA
MARINE...JDS
FIRE WEATHER...NLy