010
FXUS63 KDLH 180543
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1243 AM CDT Tue Aug 18 2026

.KEY MESSAGES...

- Isolated showers and a couple embedded storms ending early
  this morning in Northwest Wisconsin.

- Patchy dense fog expected to develop early this morning and
  linger through shortly after sunrise today.

- Isolated showers/embedded storm or two could graze inland northwest
  Wisconsin this afternoon. Otherwise, dry weather today
  through Wednesday.

- Additional chances for scattered showers and storms possible
  Thursday into Friday. Can`t rule out a few diurnal showers in
  the Arrowhead Saturday.

&&

.DISCUSSION...
Issued at 158 PM CDT Mon Aug 17 2026

Today-Tuesday:
Plenty of sunshine early this afternoon, but instability is
building ahead of an area of showers and isolated thunderstorms
associated with a cold front in northwest Minnesota. Surface-
based CAPE from ~500-1500 J/kg with 0-6 km shear around 30-40 kt
is becoming favorable for a few strong to low-end severe storms
to develop. DCAPE is surprisingly not as impressive, topping out
at 700 J/kg, but that could build a little more. Low-level lapse
rates around 8 C/km are quite favorable for some surface-based
development. With this, SPC has a marginal risk for severe
weather across most of northeast Minnesota this afternoon and
evening. With an ongoing cluster of showers and some rumbles of
thunder in northwest Minnesota as the catalyst for this
afternoon`s development, expect this activity to spread
east/southeast for the next few hours and potentially kick off
additional storms along/ahead of it. Storms may organize into a
line, and that`s primarily where the wind threat would come
from. This does not look to be a widespread severe event by any
means, but definitely a few strong to severe storms are possible
with widespread general showers and storms. The initial line
should pass through northwest Wisconsin through maybe 1-2 AM.
Behind that, there could be some redevelopment of some showers
along the front (the storms this evening should outrun the front
itself). Then, some decaying storms from Montana/South Dakota
could pass by to our south (though a slightly more northerly
track could clip the Brainerd Lakes into northwest Wisconsin).
For most, it should be a pretty quiet day Tuesday with post-
frontal northwest flow.

Tuesday night - Thursday:
High pressure is expected to be a dominant feature going into
Wednesday and Thursday. Light winds and clear skies Tuesday
night is looking to bring some pretty chilly lows. Lower 40s and
upper 30s are expected especially in the usual cold spots. I
wouldn`t be surprised to hear of some very isolated frost in the
coldest of the cold spots (10% chance). Lows may be chilly again
Wednesday night, but increasing clouds may keep temperatures a
few degrees warmer than Tuesday night. Highs in the 70s are
expected Wednesday-Thursday. Some 80s are likely Thursday east-
central Minnesota into northwest Wisconsin.

Thursday late Afternoon - Saturday:
There are some hints of a possible upper-level trough that could
pass through later Thursday afternoon into Thursday night. A
cold front would likely pass through as well going into Friday
at some point. Convective parameters still don`t look overly
impressive for strong storms, but we`ll keep an eye on it as
that could still change. Any rain chances through Friday look
pretty light overall as showers/storms will likely be pretty
progressive. Going into Friday night and Saturday, we`ll most
likely end up with northwest flow. The upper level pattern looks
like it will prominently feature a ridge axis to our west with a
trough to the east following behind the cold front. Surface high
pressure will likely bring us into a pretty quiet weather
weekend. There are some hints that some waves of cyclonic
vorticity could advect through the region on Saturday attendant
with the broader trough to our northeast. Some wraparound
showers can`t be ruled out in that case.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1243 AM CDT Tue Aug 18 2026

Remnant showers in portions of northwest Wisconsin exit the area
by 08-10Z. Light winds and pockets of clearing combined with the
recent rainfall will lead to patchy fog, some dense, through
shortly after sunrise this morning. The best potential is at
KHIB, though we also included some mention of fog at KDLH and
KHYR. Anywhere that saw rain on Monday could also see patchy fog
pop up. VFR conditions return for today, with northwest winds
gusting to 13-18 kts this afternoon along with some diurnal
cumulus before winds become light again around sunset this
evening. Can`t rule out some isolated showers near the western
Minnesota border grazing or remaining just south of KBRD in the
08-10Z timeframe and some isolated shower development (20%
chance or less) in the afternoon near or just south of KHYR, but
the potential for precipitation was too low at these terminals
to include in the TAF at this time.

&&

.MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 944 PM CDT Mon Aug 17 2026

Update: Winds and waves from Silver Bay to Grand Portage are
diminishing and hazardous conditions for small craft are no
longer expected. Therefore, the Small Craft Advisory has been
cancelled.

Previous Discussion: Breezy southwest winds are expected to continue
from Silver Bay to Grand Portage through this evening. Gusts to
25 mph and wave heights up to 3-4 ft remain possible,
especially up near Grand Portage. Winds will decrease later in
the evening in general, becoming northwest by early Tuesday
morning as a cold front passes through. Showers and
thunderstorms are likely along and ahead of the cold front later
this afternoon and evening. A few stronger storms capable of
producing winds to around 30 kt and small hail can`t be ruled
out. Winds will become a bit more west to southwest again
Tuesday afternoon and winds could gust in the 20-25 kt range up
near Grand Portage again Tuesday afternoon. Another Small Craft
Advisory might be needed. Winds shift northwest again Tuesday
night, then southwest again going into Wednesday.

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

&&

.FIRE WEATHER...
Issued at 158 PM CDT Mon Aug 17 2026

RH has fallen to around 40% this afternoon for many places in
northwest Wisconsin and a few in northeast Minnesota. A few
places are into the 30s. Rain is expected later this afternoon
and evening, but until then, RH is expected to remain a bit on
the low side.

A round of showers and storms is expected through this evening,
and while most places will probably see amounts around 0.2" or
less, a wetting rain of 0.25" or higher is possible for some.
Any locally heavier amounts are expected to be pretty hit-or-
miss. Any storms this afternoon and evening in northeast
Minnesota could be strong to severe with winds up to 60 mph and
hail up to 1" in diameter, but general coverage of strong to
severe storms is expected to be isolated. Storms will pass
through by around 1-2 AM tonight in northwest Wisconsin with a
few lingering showers possible behind overnight.

Tuesday into Wednesday are looking to be mainly dry weather
days. RH is likely to tank pretty low into the 30-45% range,
especially on Wednesday with high pressure in place. Winds are
not expected to be exceptionally strong with gusts to 15 mph for
most places and just a few pockets where 20 mph gusts are
possible.

Another chance for rain is possible around Thursday into Friday,
but amounts will likely be under a quarter of an inch for most
places.

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...JDS
AVIATION...Rothstein
MARINE...Rothstein
FIRE WEATHER...JDS