511
FXUS63 KDLH 141752
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1252 PM CDT Mon Sep 14 2026

.KEY MESSAGES...

- Widespread showers with embedded thunderstorms are expected
  today into tonight. Rainfall potential of 1" or greater
  (50-80% chance) for areas south of the Iron Range.

- Hazardous marine conditions develop late tonight into Tuesday
  with gale force wind gusts and high waves across western Lake
  Superior.

- 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.

&&

.UPDATE...
Issued at 227 AM CDT Mon Sep 14 2026

High pressure sitting over the area early this morning, in
combination with light winds and clear skies have produced
excellent radiational cooling conditions. Temperatures have
already fallen into the mid 30s to low 40s for much of the
Northland. The Frost Advisory remains in effect until 8 AM this
morning, and I anticipate several of our COOP and RAWS sites in
colder locations will come in with overnight lows below 32.
These should still be spotty enough to not be a widespread
killing frost for vegetation, but anything exposed will be
damaged. We do have cloud cover advancing towards the area from
the southwest, plus moisture beginning to return to the area
from the southwest and winds begin to increase in advance of our
precipitation chances for later today. This should cause this
precipitous drop in temperatures to stall, and we should see our
minimum temperatures in the next few hours before holding still
and then slowly rising.

Attention then turns to the strong low pressure system that
will move across the area beginning today, and continuing
through Tuesday. Today, the main warm front will push its way
across the area from southwest to northeast, bringing increasing
clouds this morning, then a shield of rain and embedded
thunderstorms pushing from southwest to northeast from late
morning through the afternoon and evening hours. The strong warm
air advection with this warm front along with elevated
instability is likely to produce at least a few stronger storms
which may produce some small hail and locally heavy rainfall,
but severe storms are not anticipated at this time.
Southeasterly winds will increase significantly as the rain
showers move across the area, with gusts reaching 25 to 35 mph.
Tonight the wave of precipitation pushes east of the area, with
rain ending for most locations by early Tuesday morning.
Rainfall totals by early Tuesday morning will generally range
from a half inch for the Borderlands, to three quarters of an
inch or more for areas south of the Iron Range. The probability
of getting more than an inch of rainfall is between 50 and 80
percent, with the highest values from central MN east into parts
of northwest WI. Winds also become southwesterly tonight as the
warm front progresses northeast of the area. Temperatures today
will be on the cooler side with precipitation falling and the
warm front not expected until tonight, so have kept highs in the
upper 50s to mid 60s. Tonight will be mild, only falling into
the mid 40s to mid 50s.

Tuesday, the southwesterly winds veer to west and then
northwest by the end of the day as the low pressure center
passes across Ontario. We should see decreasing clouds and some
sunshine for the afternoon. A tight pressure gradient behind the
departing system will yield strong winds, with frequent gusts
of 30 to 40 mph expected across the area. These winds will
gradually relax by late Tuesday afternoon. High temperatures
will be slightly below seasonal normals, topping out in the low
to mid 60s for most locations.

&&

.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 TUESDAY/...
Issued at 1253 PM CDT Mon Sep 14 2026

Showers and a few embedded thunderstorms will continue spreading
northeast across the area this afternoon, then ends from west to
east this evening into early tonight. Ceilings and visibility
deteriorate with the precipitation, to mainly MVFR this
afternoon, and then IFR to IFR later this afternoon and evening
into tonight. Low-level wind shear looks to occur in two
rounds, first this afternoon into early evening with the round
of showers and storms. The second round will be behind a front
in the wake of the showers and storms tonight into early Tuesday
morning. Conditions gradually improve on Tuesday, though some
wrap around cloud cover could keep MVFR ceilings hanging around
for most terminals through much of the morning.

Wind remain strong out of the southeast today at 20-30 kts,
briefly weaken slightly tonight out of the south, and then
increase with gusts to 25-35 kts out of the west on Tuesday
morning into early afternoon.

&&

.MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 227 AM CDT Mon Sep 14 2026

Quiet conditions early this morning will quickly deteriorate
today as a strong low pressure system approaches. Southeast
winds will increase rapidly during the day today, with gusts
rising into the 20 to 30 knot range by late afternoon and early
evening, causing waves to build along the North Shore. Showers
with a few thunderstorms are also expected to move across the
lake this afternoon and evening. After the rain moves across the
area, winds will gradually veer to the southwest and then west,
increasing still farther for Tuesday morning. We have
increasing confidence in gales of 35 to 40 knots for most of
western Lake Superior starting early Tuesday morning and
continuing into early afternoon before diminishing once again
Tuesday night. The Gale Watches have been converted to a
combination of Small Craft Advisories and Gale Warnings which
start this afternoon, then ramp up to a Gale Warning tonight
into Tuesday. Winds and waves will subside Tuesday night.

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

&&

.FIRE WEATHER...
Issued at 227 AM CDT Mon Sep 14 2026

Fire weather concerns remain low through the forecast.
Widespread wetting rain will move across the region today and
tonight, bringing a half inch to over an inch of precipitation
to many areas. There is a 50-80% chance of getting an inch or
more of precipitation for areas south of the Iron Range, with
lighter amounts to the north. Minimum relative humidity values
will generally stay above 45 percent the next few days.
Southeast winds with gusts reaching 25 to 35 mph today will
shift to the west and gust as high as 30 to 40 mph on Tuesday
behind a departing low pressure system. Winds will diminish for
the remainder of the week.

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 PM this afternoon to 4 AM CDT
     Tuesday for LSZ121-141>148-150.
     Small Craft Advisory from 4 PM this afternoon to 10 PM CDT
     this evening for LSZ140.
     Gale Warning from 10 PM this evening to 4 PM CDT Tuesday for
     LSZ140.
     Gale Warning from 4 AM to 4 PM CDT Tuesday for LSZ141>148-150.

&&

$$

UPDATE...LE
DISCUSSION...Rothstein
AVIATION...Rothstein
MARINE...LE
FIRE WEATHER...LE