473
FXUS63 KDLH 131933
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
233 PM CDT Sun Sep 13 2026

.KEY MESSAGES...

- Frost is expected tonight into early Monday morning for much
  of northeast MN and northwest WI. Frost Advisories are in
  effect. A couple hours with patchy temperatures around
  freezing are also possible early Monday morning.

- Widespread showers with embedded thunderstorms are expected
  Monday into Monday night. Rainfall potential of 1" or greater
  (40-80% chance) for areas south of the Iron Range.

- Near-normal high temperatures in the mid 60s to low 70s for
  the later half of the work week with additional periods of
  rain chances.

&&

.DISCUSSION...
Issued at 233 PM CDT Sun Sep 13 2026

Rest of Today - Tonight:

High pressure is solidly in place over the Upper Midwest, with
partly cloudy skies this afternoon due to diurnal cumulus
clouds. High temperatures top out near 60F to the upper 60s,
warmest in Pine County to northwest WI. A few diurnal
sprinkles/very light showers are possible near the international
border/tip of the Arrowhead through early evening, but little to
no accumulations are expected. Daytime west to northwest winds
with gusts to 20 mph become light this evening.

Calm to light winds and clear skies for most of the Northland
tonight will allow for good radiational cooling. This will push
low temperatures tonight into early Monday morning down into the
low to mid 30s, coolest in inland northeast MN and northwest
Wisconsin. The typical cold spots in inland northwest WI and
northeast MN could even touch freezing or slightly below
freezing for a couple hours towards sunrise early Monday
morning. Widespread freezing temperatures are not anticipated,
so will maintain Frost Advisories with this forecast update. Warmer
temperatures in the upper 30s to low/mid 40s are expected near
Lake Superior, and in the Brainerd Lakes due to increasing high
cloud cover ahead of an approaching low pressure system on
Monday.

Monday - Tuesday:

The high pressure will be departing to our east early Monday as
a strengthening and increasingly vertically-stacked low pressure
system over Montana early Monday slides northeast into southern
Manitoba Monday evening and far northwest Ontario Monday night
into early Tuesday. An attendant surface occluded front with
this system will also be moving west to east across the
Northland late Monday evening and night. Expect strong moisture
advection ahead of this system/front, leading to strong
isentropic ascent and widespread rain showers with embedded
thunderstorms spreading from southwest to northeast across the
Northland from late Monday morning through afternoon. Showers
and embedded thunderstorms continue into Monday evening and
night, ending from west to east as the occluded front sweeps
through. While severe weather is not expected, some elevated
instability (MUCAPE around 200-500 J/kg), being highest in Pine
County to northwest WI, combined with marginal lapse rates aloft
(6 degC/km or less) and strong bulk shear vectors in the late
afternoon and evening could lead to some small hail (pea size
to one-half inch). Since a surface inversion should remain in
place, strong thunderstorm winds are not expected. However,
gusty southeast synoptic winds increasing throughout the day
will reach upwards of 35 mph in the afternoon and evening hours
and accompany the precipitation.

Speaking of precipitation, the current deterministic rainfall
forecast calls for amounts of 0.3-1.25" on Monday into Monday
night, being lowest (0.3-0.5") north of the Iron Range, and
higher along/south of the Iron Range. While most locations south
of the Iron Range should top out at around or less than 1",
both NBM >1" probabilities (60-80%) and HREF 24-hour LPMM
highlight areas of the Brainerd Lakes and east-central Minnesota
into the Twin Ports/parts of the North Shore that could see
upwards of 1.5". These higher amounts would be tied to higher
rainfall rates associated with any embedded thunderstorms that
could lead to some ponding of water on urban surfaces. Given
that these areas are not co- located with where recent heavy
rains fell Friday night, flooding concerns remain low.

Expect strong west to northwest winds with gusts up to 30 to
locally 40 mph on Tuesday behind the occluded front, gradually
decreasing late in the day. Slightly below seasonal high
temperatures in the low 60s to around 70F are forecast for
Tuesday. Light winds and mainly clear skies Tuesday night as
high pressure settles overhead will bring cooler low
temperatures back into the area in the upper 30s to mid 40s.
Can`t rule out some mid-30s in the typical cold spots, but the
potential for more widespread frost appears low (less than 30%
chance) at this time.

Mid-Week into Next Weekend:

A primarily zonal flow pattern aloft sets up for Wednesday
through the end of the work week. High pressure should keep most
of Wednesday dry, though rain shower chances (10-40%) return
Wednesday night. Additional precipitation chances are forecast
for Friday into early Saturday as lee cyclogenesis develops a
surface low and ejects it northeast. There is some uncertainty
as to how far north the low pressure and its associated moisture
makes it into the Upper Midwest, so have maintained the broader
NBM precipitation chances of 30-55% across the region for now.
Should this system take a more northern track, the Northland
could be poised to get another round of much needed rainfall.
NBM probabilities for >0.5" are 40-55% along and south of US-2
in northeast MN and northwest WI, with decreasing probabilities
towards the International Border. Temperatures in the latter
half of the work week into next weekend remain near-seasonal
with highs in the mid 60s to low 70s. Lows are forecast to be in
the 40s to low 50s, warmest near Lake Superior.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1228 PM CDT Sun Sep 13 2026

VFR conditions through at least this evening. Scattered diurnal
VFR cumulus dissipate this evening. Gusty west to northwest
winds to 15-20 kts today become light and variable to calm
tonight with cooler temperatures. This could lead to patchy fog
at HIB/HYR, but potential is too low (less than 20%) to include
in the current TAFs. Winds increase and become gusty out of the
southeast on Monday with increasing cloud cover in the morning
from SW to NE. Widespread rain will also be building into BRD
late in the current TAF period, and then overspread the
remaining terminals Monday afternoon along with embedded
thunderstorms.

&&

.MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 233 PM CDT Sun Sep 13 2026

Small Craft Advisories remain in effect for portions of the
nearshore waters through late this afternoon and early evening
with gusts up to 25 kts. Winds will be northwest at less than
10 kts the remainder of this evening and tonight.

Hazardous marine conditions return Monday afternoon into
Tuesday as a strong low pressure system moves through southern
Manitoba and northwestern Ontario, resulting in a strong
pressure gradient across our region. Additional Small Craft
Advisory-level winds are very likely from Monday afternoon
through Tuesday afternoon. There is also a 40 to 80 percent
chance for gale force wind gusts Monday night near Grand Portage
and a 50-90% chance for much of the western Lake Superior
nearshore waters on Tuesday morning into early afternoon. These
strong winds will also build wave heights to 4 to 8 ft. Gale
Watches are in effect. These winds will start out southeasterly
on Monday and shift to southwesterly on Tuesday before ending as
westerly late Tuesday.

Winds and waves rapidly weaken by late Tuesday evening and night
and are forecast to remain 15 kts or less for Wednesday into
Friday.

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

&&

.FIRE WEATHER...
Issued at 233 PM CDT Sun Sep 13 2026

Fire weather concerns will remain low through the forecast
period. Minimum relative humidity values this afternoon dip to
33 to 50 percent across the area under mostly sunny to partly
cloudy skies, being lowest in east-central Minnesota into
northwest Wisconsin. Northwest winds with gusts to 15 to 20 mph
through early evening become calm to light and variable tonight.
Expect chilly conditions tonight with low temperatures in the
low to upper 30s for most of the area, and in the low to mid 40s
in the Brainerd Lakes and near Lake Superior.

Cloud cover increases from southwest to northeast on Monday with
widespread rain and embedded thunderstorms also arriving from
the southwest to northeast late Monday morning/afternoon and
exiting from west to east late Monday evening into early
Tuesday morning. A widespread wetting rain is expected across
most of the region, with rainfall amounts up to 1-1.5 inches possible
(60-80% chance) in the Brainerd Lakes/east-central Minnesota
into the Twin Ports and parts of the North Shore. Expect 0.5-1"
for most areas along/south of the Iron Range and generally
0.3-0.5" north of the Iron Range. Southeast winds will become
strong with gusts to 20 to 30 mph on Monday, shifting to the
west and remaining elevated with gusts of 25 to 35 mph on
Tuesday behind a cold front. Min RH on Monday afternoon could
dip into the 35-45% range before rain arrives, otherwise min RH
is forecast to remain above 40% for the remainder of the week
with winds becoming less strong for the latter half of the week.

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

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Frost Advisory from midnight tonight to 8 AM CDT Monday for
     MNZ010>012-018-019-026-035-037-038.
WI...Frost Advisory from midnight tonight to 8 AM CDT Monday for
     WIZ001>004-006>009.
MARINE...Small Craft Advisory until 7 PM CDT this evening for
     LSZ140>142.
     Gale Watch from Monday evening through Tuesday afternoon for
     LSZ140.
     Gale Watch from late Monday night through Tuesday afternoon
     for LSZ141>148-150.
     Small Craft Advisory until 4 PM CDT this afternoon for
     LSZ146>148-150.

&&

$$

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