001
FXUS63 KDLH 310546
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1246 AM CDT Sun Aug 31 2025

.KEY MESSAGES...

- Warm weather with isolated to scattered showers and storms
  through Labor Day. Areas of fog overnight.

- Widespread rain with a mid-week system. Thunderstorms are
  possible Tuesday and Tuesday night.

- Cooler temperatures expected Wednesday through the rest of the
  week. Frost Advisories may eventually be needed.

&&

.UPDATE...
Issued at 1245 AM CDT Sun Aug 31 2025

While METAR reports are showing calm winds at many locations,
RAWS and CWOP stations reveal winds of 1 to 2 knots nearby those
sites. Still expect fog to develop early this morning, but will
need to see temps drop a bit more and winds become calm. We may
eventually need a Dense Fog Advisory later this morning.

A shortwave trough and area of locally higher cyclonic
vorticity advection evident on GOES-East water vapor imagery
stretched from southern Manitoba through the Twin Ports and east
across Upper Michigan at 0530Z. This is also represented in the
latest RAP13 guidance as a subtle 700 mb trough. This feature
realized a narrow corridor of elevated potential instability of
100 to 500 J/kg per the 00Z NAM forecast soundings resulting in
a small cluster of shower and occasional thunderstorms. This
feature is forecast to propagate farther southwest through the
early morning hours and bring rain chances to the Twin Ports,
I-35 corridor, and portions of the St. Croix Valley through
sunrise. Raised PoPs and added thunder in a forecast update
around 05Z.

&&

.DISCUSSION...
Issued at 110 PM CDT Sat Aug 30 2025

Expect a pleasant weekend with slightly warmer than normal
temperatures in the 70s and 80s. Areas of fog are likely to
develop each night and persist into the morning hours,
potentially impacting travel.

The risk for showers and thunderstorms will increase late Monday
ahead of a cold front set to arrive on Tuesday. This slow moving
front will bring widespread rainfall (perhaps up to 1 of rainfall
in some places) and a period of showers and thunderstorms, a few
of which could become strong, marking the most significant weather
event of the week before exiting Wednesday. CAPE and shear profiles
with this are fairly meager, but height falls aloft will aid in
forcing in concert with the front. Similar to a winter system,
wrap around showers will linger into Thursday and possibly Friday
as the upper low slowly meanders east.

A dramatic shift to much colder, autumnal weather accompanies the
air mass behind the front which will linger through the end of the
week. High temperatures will plummet into the 50s and low 60s. The
primary impact will be the overnight cold, with temperatures widely
dropping into the 30s. This will likely necessitate Frost Advisories
for inland locations away from Lake Superior. The air mass will
be cold enough that the first wet snowflakes of the season may
mix with rain showers overnight, particularly across the higher
terrain of the Northland. This cool, unsettled pattern is expected
to continue until a warming trend returns late next weekend.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1245 AM CDT Sun Aug 31 2025

A cluster of showers and occasional thunderstorms stretched
from near EVM to TWM to ASX as of 0515Z and were moving south-
southwest at around 15 mph. They will move through the DLH, HIB,
and HYR terminals before 09Z. Winds will veer easterly or
northeasterly as the showers pass by. Outside of the
showers/storms we still anticipate fog to develop at most of the
terminals overnight. BRD saw visibility as low as 1 mile so
far. Expect BRD, HIB, and HYR to see LIFR conditions later this
morning. Conditions should improve by 14Z as surface wind speeds
increase and daytime heating begins. Fog is possible again
after 01.06Z.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 110 PM CDT Sat Aug 30 2025

High pressure will remain in place over the region for the next
few days. This will keep winds generally less than 10 knots
from the southwest. A cold front is forecast to move
southeastward across western Lake Superior on Tuesday. Showers
and thunderstorms are expected with the front and winds will
veer northwesterly and increase in speed behind the front.
Conditions will become hazardous for small craft for the latter
half of next week.

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

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
MARINE...None.

&&

$$

UPDATE...Huyck
DISCUSSION...Wolfe
AVIATION...Huyck
MARINE...Wolfe