023
FXUS63 KDLH 101838
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
138 PM CDT Thu Sep 10 2026

.KEY MESSAGES...

- There is a slight risk (level 2 out of 5) for scattered strong
  to severe thunderstorms Friday late afternoon and evening.

- Cooler fall weather moves in Saturday and into the foreseeable
  future.

- Widespread rain and thunderstorms are likely Monday and Monday
  night. Severe weather is not expected. Localized minor
  flooding can`t be ruled out.

&&

.DISCUSSION...
Issued at 137 PM CDT Thu Sep 10 2026

Quiet weather abounds this afternoon with weak ridging aloft. As
a surface high departs and moves into the central Great Lakes
tonight, we will remain under an upper level ridge, which will
be strengthened by a developing low-level jet tonight under warm
southwest flow. Wind speeds will increase overnight, and fog is
not expected to be a concern tonight.

On Friday, warm air and moisture advection will continue with a
trough and developing surface low moving our way from the west.
A trailing cold front associated with a low up in Canada will
combine with the warm air and moisture advection to trigger
showers and thunderstorms. The trend for storm initiation
continues to be later, favoring storm development around 6 PM or
so. Plenty ingredients will be in place for some severe storms,
including: a cold front, up to ~2 kJ/kg MUCAPE (initially
surface-based), favorable 30-40 kt 0-6 km shear (with some low-
level streamwise vorticity ingestion possible which could result
in a low-end tornado threat), and overall plenty of moisture
with PWATs inching up into the 1-1.75" range. The timing of
storm initiation will be crucial, as a delay may result in a
very narrow window for surface-based convection in the early
evening. Large hail and damaging winds are still looking to be
the main threats, especially if storms become largely elevated
by starting later into the afternoon/evening. If they can get
going early enough, a low-end tornado threat exists. The
rain/storms should be progressive enough to minimize flooding
risks, but with plenty of moisture available, any brief training
of storms could result in some very localized and short-duration
minor flooding, especially in developed areas. Storms are
expected to move out with the cold front a bit after midnight.

The gates will open to more fall-like temperatures following the
cold front into Saturday with cool northwest flow developing.
Highs are likely only to reach the 60s in Minnesota and low 70s
in northwest Wisconsin. We will remain in this cool air mass
through the weekend with otherwise pretty quiet weather.
Saturday and Sunday nights are looking rather chilly with high
pressure slowly passing through at the surface. At this point,
probabilities for temperatures cold enough for frost (~36
degrees) are about 10-15% for the usual cold spots. So, can`t
completely rule it out, but the chances are very low at this
time. With that said, lows in the upper 30s are looking likely
for the usual cold spots and low 40s for most other places.

Going into Monday, it`s looking like we`ll get a nice surge of
moisture and warm air advection with Gulf of America origins.
This should lead to more of a widespread light to moderate rain
with some thunderstorms as well (though instability isn`t
currently looking overly impressive for anything strong or
severe). There is some potential for locally heavy rainfall
just north of the surface warm front, and there`s some
uncertainty where that might set up. Wisconsin is looking to be
the main target right now, but whether means northwest Wisconsin
or central Wisconsin is still up in the air. There could be some
localized minor flooding issues with this, and part of that will
depend on how much rain falls with Friday evening`s storms (as
of now, it looks like northeast Minnesota has the best chances,
which is good news as that would spread the moisture somewhat
evenly). Overall, this should be good news for ongoing drought
with a good half inch of rain minimum for most places and >1" of
rain very possible especially in northwest Wisconsin.

Another reinforcing cold front will pass through going into
Tuesday. Some fall-style wraparound showers are possible
Tuesday, then high pressure is likely to bring quiet but cool
weather Wednesday and Thursday.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1236 PM CDT Thu Sep 10 2026

VFR conditions expected through the period. Wind direction will
be a bit variable this afternoon, then expect wind speeds to
increase overnight with gusts in the 15-20 kt range. Wind shear
is expected at all terminals as a low level jet ramps up. After
sunrise, enough mixing should cause LLWS to diminish, but gusty
southwest winds will gradually continue to increase through the
morning hours.

&&

.MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 137 PM CDT Thu Sep 10 2026

Some brief wind gusts around 20-22 kt are possible up near Grand
Portage, otherwise wind gusts below 20 kt with south and
slightly variable flow expected through this afternoon. Wind
direction will be slightly variable into tonight as well, but
trending southwesterly by morning and increasing in speed
gradually overnight. Gusts are expected to increase to the 20-30
kt range early Friday morning and persisting through Friday
night with occasional areas where gusts may drop a little below
that. There`s a ~30-40% chance for some gales near Grand Portage
mainly Friday afternoon. Small Craft Advisories and a Gale Watch
have been issued late tonight through late Friday night. In
addition, showers and storms are expected late Friday afternoon
into Friday night. A few strong to severe storms capable of wind
gusts to around 40 kt and large hail to around quarter size are
possible (there is a level 2 out of 5 risk for scattered severe
storms from the Storm Prediction Center).

Winds will shift westerly to northwesterly going into Saturday.
Small Craft Advisories are expected to be needed through around
Saturday evening with gusts in the 20-30 kt range. A brief break
in strong winds is expected Sunday, but then another potent
weather system will bring rain, thunderstorms, and more strong
winds Monday into Tuesday. Winds will be at least hazardous for
small craft and gales are possible as well.

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

&&

.FIRE WEATHER...
Issued at 137 PM CDT Thu Sep 10 2026

Minimal fire weather concerns anticipated in the next week. Some
dry weather this afternoon with some similar conditions expected
in northwest Wisconsin Friday, but overall increasing moisture,
clouds, and rain chances are expected later Friday afternoon and
evening. Some appreciable rainfall amounts are expected from
thunderstorms especially in northeast Minnesota through Friday
night with totals generally in the half inch to one inch range,
but with locally higher amounts expected from thunderstorms.
Lesser amounts are expected in northwest Wisconsin with around a
tenth to two tenths of an inch, but some scattered wetting rains
around a quarter of an inch are possible.

Dry and cooler weather is expected over the weekend with some
breezy conditions Saturday. RH may dip into the 40-50% range for
some, but with rain expected prior, fire weather conditions
should be minimal. Another round of widespread rain is likely
Monday into Monday night with a wetting rain likely for most and
accumulations over an inch quite possible, especially in
northwest Wisconsin.

High pressure will develop around mid-week with some dry and
quiet weather. RH is not expected to fall much below 50%.

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 4 AM Friday to 4 AM CDT Saturday for
     LSZ121-141>148-150.
     Small Craft Advisory from 4 AM to 7 AM CDT Friday for LSZ140.
     Gale Watch from Friday morning through late Friday night for
     LSZ140.

&&

$$

DISCUSSION...JDS
AVIATION...JDS
MARINE...JDS
FIRE WEATHER...JDS