020
FXUS63 KDLH 181432
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
932 AM CDT Tue Aug 18 2026

.KEY MESSAGES...

- Dry weather today through Wednesday for nearly all.

- Additional chances for scattered showers and storms possible
  Thursday into Friday.

&&

.DISCUSSION...
Issued at 127 AM CDT Tue Aug 18 2026

Current Overnight - Today:

Ongoing showers and the occasional embedded thunderstorm in
northwest WI during the current overnight will gradually exit to the
southeast early this morning prior to sunrise. These are occurring
ahead of a cold front currently situated in central to northeast MN.
Additional accumulations of largely 0.1-0.2" or less are expected.
Behind this, some isolated showers/decaying storms currently near
the southeast ND/west-central MN border track southeast during the
early to late morning hours, and could graze our far southern areas
from the Brainerd Lakes to inland northwest Wisconsin. Little to no
accumulations expected as the majority of them are currently
forecast to remain just south of the Northland. We could also get
grazed by some isolated shower/weak embedded storm development in
inland northwest WI this afternoon, but the potential remains around
20% or less.

Otherwise, expect some patchy fog development, some dense, through
early this morning as calm winds and pockets of clearing skies
combine with low-level moisture from recent rainfall. Fog dissipates
shortly after sunrise today.

Today will be drier and seasonal in the wake of the cold front as
high pressure begins to move in, with high temperatures in the low
to upper 70s. Northwest winds gust up to 15-20 mph this afternoon
then drop off quickly this evening. Cloud cover gradually diminishes
from north to south this morning, though late morning-early evening
diurnal cumulus then create partly cloudy skies.

Tonight - Early Thursday:

Mostly clear to clear skies set up Tuesday night along with
light winds under high pressure in a cooler airmass. Due to
this, we have dropped the low temperature a couple degrees into
the low to upper 40s for most of the area and slightly warmer
near Lake Superior. The typical cold spots could touch the upper
30s, and there is a 10% chance that those coldest spots could
see some frost. Wednesday night will also be on the cooler side,
but several degrees warmer (mid-40s to mid-50s) due to weak
overnight southerly winds and some increasing cloud cover. Also
can`t completely rule out a 10-20% chance for a few showers in
north-central and northeast MN Wednesday night into early
Thursday as weak shortwave troughing energy moves through
northwest flow aloft, but low-level dry air would likely
preclude any precipitation aloft from reaching the ground.

High temperatures in the low 70s to around 80 F are forecast for
Wednesday, and will be a touch higher on Thursday as low-80s are
likely in the Brainerd Lakes east to northwest WI.

Thursday PM - Saturday:

Our next round of scattered shower and thunderstorms are
favored to arrive in the Northland Thursday afternoon as a warm
front moves through the area and cold front starts to move in
late from the west. These fronts will be in association with a
surface low pressure moving near or through the area. Then
additional potential for showers and storms arrive on Friday as
the cold front moves through the remainder of the Northland. The
pattern at this time does not appear to favor strong to severe
weather potential on Thursday PM or Friday, but that will depend
on the timing of the warm sector of this system (late daytime
Thursday or Thursday night) and how quickly the front moves
through on Friday in relation to peak heating/instability. Since
this system looks to be progressive without anomalous moisture
(PWATs only around 1-1.25"), rainfall amounts should be on the
more tame side as probabilities for >0.25" are only 30-60% and
>0.5" at 20-40%. Localized areas that see thunderstorms could
see amounts approach 1", but widespread soaking rainfall is not
anticipated.

Showers may linger in the Arrowhead and parts of northwest WI
on Saturday as some shortwave energy aloft moves through in
association with an upper-low/trough in northern Ontario, with
peak potential in the afternoon with peak daytime heating.
However, little to no additional accumulation is expected.

Early Next Week:

Generally northwest flow aloft with ridging over the western
CONUS and troughing to the east. This could bring a return of
periodic rain chances through the Northland as waves of
vorticity/energy aloft move through the northwest flow. However,
poor agreement amongst ensemble members regarding amplitudes of
these waves and their timing/locations relative to the Upper
Midwest keeps forecast confidence low in this timeframe.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 630 AM CDT Tue Aug 18 2026

Patchy fog is expected to clear within the next 1-2 hours as daytime
heating begins. VFR conditions are expected through the day into
this evening, with northwest winds occasionally becoming gusty in
the afternoon. Another round of patchy fog will be possible tonight
as clear skies allows for excellent diurnal cooling to occur and
winds become light.

&&

.MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 127 AM CDT Tue Aug 18 2026

Lighter northwest winds early this morning turn southwesterly by
late morning through early evening, with gusts near Grand Marais
to Grand Portage gusting to 20-25 kt along with waves of 1-3 ft
this afternoon into early evening. Given this short window of
stronger winds, a Small Craft Advisory has been issued. Winds
shift to the northwest and become lighter again tonight into
early Wednesday, then repeat the process of turning southwest
Wednesday afternoon into early evening, albeit slightly weaker
at 10-20 kt. Winds become light and variable Wednesday night and
northeast on Thursday, but remaining fairly light at 5-15 kt.
Scattered thunderstorm chances return by late Thursday/Thursday
night.

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

&&

.FIRE WEATHER...
Issued at 127 AM CDT Tue Aug 18 2026

Predominately rain-free weather for today and Wednesday behind
a cold front as high pressure moves into the region. Can`t rule
out a 10-20% chance for stray showers grazing the Brainerd Lakes
to northwest Wisconsin starting early this morning through late
morning, with additional isolated shower chances in inland
northwest Wisconsin this afternoon, but these chances could also
remain south. Any accumulations would be minimal at best. Patchy
fog, some dense, dissipates shortly after sunrise today. Cloud
cover gradually clears from north to south through this morning,
though scattered diurnal cumulus is expected to develop late
this morning through early evening. Expect minimum RH this
afternoon to dip to 30-45%, lowest in the northwest Wisconsin
Pine Barrens and northeast Minnesota. High temperatures warm to
70-78 F today, warmest in southern areas. Northwest winds gust
to 13-18 mph this afternoon into early evening then become light
again tonight. Expect a cooler night tonight with lows in the
40s for most locations, with some upper-30s in the typical
coolest spots. RH recovers above 90% tonight.

Deeper mixing is expected on Wednesday, though west to northwest
winds will largely be under 15 mph. A couple pockets of 15-18
mph gusts can`t be ruled out in the Arrowhead during the
afternoon into early evening. Highs in the 70s to around 80 F
are forecast. Given the deeper mixing, min RH dips to 30-40% for
most locations on Wednesday. Portions of northwest Wisconsin,
particularly the Pine Barrens, could dip into the upper 20s for
min RH. Light winds return Wednesday night with RH recovering
above 80-90%.

Another round of scattered showers and storms are likely late
Thursday into Thursday night, and possible on Friday with a cold
front. Amounts will largely be around 0.25-0.5" or less for most
locations, though anywhere that gets thunderstorms could see
very localized amounts up to around 1".

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

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
MARINE...Small Craft Advisory from 3 PM this afternoon to 7 PM CDT this
     evening for LSZ140.

&&

$$

DISCUSSION...Rothstein
AVIATION...Unruh
MARINE...Rothstein
FIRE WEATHER...Rothstein