532
FXUS63 KDLH 131727
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1227 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 upper 60s to mid 70s
  return for the later half of the work week with additional
  periods of rain chances.

&&

.UPDATE...
Issued at 625 AM CDT Sun Sep 13 2026

Lowered forecast temps tonight by a few degrees. Opted for a
Frost Advisory for portions of north-central MN and the
Arrowhead along with most of NW WI. Main concern tonight remains
how quickly the clouds will build into the area and whether
temps will be able to plummet.

&&

.DISCUSSION...
Issued at 134 AM CDT Sun Sep 13 2026

A weak cold front/trough axis is sliding across the Northland
early this morning, which will be followed by a large high
pressure ridge building into the area today and tonight. This
high pressure will bring a couple days of pleasant early fall
weather with cooler than normal temperatures. Highs today will
only be in the upper 50s to mid 60s across the region. As the
high pressure settles in tonight, skies will clear and winds
will become light, setting the stage for good radiational
cooling. Cirrus moving in from the west ahead of our next
precipitation system could dampen the cooling effects as we get
towards morning. Otherwise, temperatures should drop into the
30s across many inland areas, resulting in patchy frost
development over parts of northern Minnesota and northwest
Wisconsin by early Monday morning.

A strong upper low pressure system moves from the northern
Plains across the southern Canadian Prairies and into northern
Ontario Monday through Tuesday. This system will bring a surge
of moisture into the region and spread a round of widespread
showers and embedded thunderstorms across our area Monday
afternoon and continue Monday night. Rainfall amounts of one
inch or greater are likely (60-80% chance) for areas south of
the Iron Range and northwest Wisconsin. There is a marginal risk
for elevated hail producing storms Monday evening for parts of
Monday evening with a strong low level jet and some elevated
instability, but at least some of this depends on how far north
the surface boundary to our south can get, and how far north the
elevated instability can be advected. We will also have a
marginal risk of excessive rainfall. There will be PWAT values
of 1-2", which would be in the 90th percentile or greater of
climatology for the upper air site in International Falls. At
this time, the ECMWF EFI is only showing QPF values in the
60-70th percentile, which decreases confidence in very heavy
rainfall. The current QPF forecast maintains the NBM solution,
which brings a broad 0.4 to 1.25" across the CWA on Monday
through Monday night. Our forecast heaviest rainfall amounts are
not co-located with the rainfall we got Friday night, reducing
concerns for flooding.

The rainfall will come to an end by Tuesday, with a cold front
bringing gusty westerly winds and another day of near to below
normal high temperatures. Expect clearing skies as drier air
filters into the area, leading to a mostly sunny Tuesday
afternoon.

A relatively quiet and seasonable pattern takes hold for the
remainder of the work week, with high pressure building in again
for Wednesday. Chances for rain showers return Wednesday night
into Thursday, and again on Friday and Friday night, as weak
systems slide through the mostly zonal flow aloft. High
temperatures Wednesday will be in the 60s for most locations,
but should gradually moderate through the end of the week so
highs on Friday and Saturday should be in the mid 60s to low
70s.

&&

.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 625 AM CDT Sun Sep 13 2026

Small Craft Advisories are in effect for portions of the waters
today. After a brief lull in wind speeds and gusts, expect wind
and waves to build during the day. Winds will be northwest at
less than 15 kts tonight.

Another period of hazardous marine conditions are anticipated to
return Monday into Tuesday as a strong low pressure system
moves through the region. Additional Small Craft Advisories are
very likely. There is also a 30 to 60 percent chance for gale
force wind gusts from the southwest to west, most likely to
occur early Tuesday morning through Tuesday afternoon. A Gale
Watch is in effect during that time.

Winds and waves relax again Tuesday night and hazardous
conditions are not expected from that time through the end of
the week.

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

&&

.FIRE WEATHER...
Issued at 134 AM CDT Sun Sep 13 2026

Fire weather concerns will remain low through the forecast
period. Minimum relative humidity values today will range from
35 to 55 percent across the area under mostly sunny skies. Winds
will remain northwest, but gusts will remain 20 mph or less
during the daytime today.

The sunshine will be overcome by incoming clouds and increasing
precipitation chances on Monday into Tuesday as a strong low
pressure system moves across the region. A widespread wetting
rain is expected across most of the region, with rainfall
amounts of 1 inch or greater likely (60-80% chance) for areas
south of the Iron Range. Southeast winds will become strong and
gusty on Monday, shifting to the west and remaining elevated on
Tuesday behind a cold front.

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.
WI...Frost Advisory from midnight tonight to 8 AM CDT Monday for
     WIZ001>004-007>009.
MARINE...Small Craft Advisory until 8 PM CDT this evening for LSZ140-
     141.
     Gale Watch from late Monday night through Tuesday afternoon
     for LSZ140-141-144>147-150.
     Small Craft Advisory until 4 PM CDT this afternoon for
     LSZ146>148-150.

&&

$$

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