256
FXUS63 KDLH 071949
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
249 PM CDT Mon Sep 7 2026

.KEY MESSAGES...

- Widespread showers and thunderstorms are expected tonight into
  Tuesday morning. A few storms may become strong to severe,
  capable of producing damaging winds, large hail, and very
  heavy rainfall.

- Strong west-northwest winds are very likely on Wednesday, with
  gusts of 30 to 40 mph forecast. Winds are most likely to be
  strongest in the Minnesota Arrowhead.

- Additional precipitation chances arrive late this week into
  the weekend. A pattern change to cooler temperatures is
  favored this weekend into early next week.

&&

.DISCUSSION...
Issued at 249 PM CDT Mon Sep 7 2026

Partly to mostly cloudy skies are occurring early this afternoon
across the region ahead of an approaching 500mb trough. Ongoing
southerly flow is expected to provide deep moisture advection into
the CWA this evening into tonight, with IVT showing moisture coming
both from the Gulf and some moisture from Tropical Storm Marie
offshore from Baja California. The 12z sounding from KINL revealed
an already moist PWAT of 1.47", which is above the 90th percentile
of 1.14". As moisture advection occurs tonight, these PWAT values
are progged to increase up to around 2", which would be towards, if
not breaking, the max of climatology.

This surge of moisture, combined with a deep warm cloud layer in
excess of 12,000 ft, will likely lead to localized very heavy
rainfall rates this evening through tonight. Flash flooding concerns
are somewhat mitigated due to drier soil moisture conditions across
a large portion of the CWA, although areas north of the Laurentian
Divide show soil moistures in the 50-60% range per MRMS CREST soil
moisture. That being said, there is still a minor concern for flash
flooding tonight, including the northwest Wisconsin portion of the
CWA, as very heavy rainfall occurring over the areas experiencing
Extreme (D3) drought could potentially lead to rapid runoff.

In terms of QPF, heaviest rainfall is expected to be overnight as a
quasi-stationary warm front remains parked north of the CWA and a
cold front approaches from the west. 24-hour LPMM QPF forecasts from
the 12z HREF suggest the potential for 2-3" of precip occurring from
multiple rounds of showers and thunderstorms moving through tonight
into early Tuesday morning. Confidence in the area of heaviest QPF
is fairly low, although it does appear more likely along and south
of US-2, where PWATs will be higher. Storm motion will be relatively
progressive tonight, which limits flood concerns, although training
storms will be something to monitor tonight into tomorrow morning.

Besides potential flash flood concerns, there is also a Marginal
Risk for severe thunderstorms today through tonight for portions of
north-central MN around the Brainerd Lakes. MUCAPE per the RAP is
forecast to increase in excess of 1000-1500 J/kg overnight, with a
stout 850mb LLJ of 30-40 knots and 0-6 km bulk shear of 40-50 knots.
These overnight storms will most likely be elevated, with large hail
and damaging winds being potential hazards. Confidence in severe
storms tonight is low, as CAMs show somewhat weak mid-level lapse
rates and the warm nose associated with the LLJ will likely keep
storms decoupled from the surface.

A Marginal Risk for severe thunderstorms persist on Tuesday morning
in the Arrowhead, I-35 corridor, and northwest Wisconsin. However,
this threat of severe storms will most likely be remnants of the
convection tonight as the cold front sweeps through and will
therefore share similar limitations to severe hazards as previously
mentioned. Expect showers and thunderstorms to largely come to an
end across the CWA by Noon on Tuesday. Sprinkles and the occasional
shower may linger through the afternoon as the sfc cold front
continues to move through.

Following the cold frontal passage on Tuesday, a more benign pattern
settles over the CWA around mid-week as high pressure builds. Ahead
of this high pressure, west-northwest winds are very likely to
become strong during the daytime hours on Wednesday. Wind gusts of
30-40 mph are forecast, strongest in the Arrowhead. A few gusts in
excess of 40 mph are not totally out of the question, although the
NBM probability for inland locations along the North Shore is a low
10-20%. Wind Advisories may be needed on Wednesday, especially if
winds show an increasing trend.

The next chance for precipitation arrives late into the week into
the weekend as additional troughs potentially propagate through the
CWA. One upcoming pattern change of note is a temperature change
arriving this weekend into early next week. While high temps most of
this workweek will be in the 70s for most, high temps by this
weekend into early next week will likely be in the 60s (with a few
upper 50s not out of the question!).

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1248 PM CDT Mon Sep 7 2026

Partly to mostly cloudy skies are expected this afternoon, with cigs
being predominately VFR, and breezy southerly winds. Occasional
reductions to MVFR are expected to occur this afternoon. Widespread
showers and thunderstorms arrive tonight, which is anticipated to
lower conditions to MVFR and IFR. A few storms around KBRD may
become strong to severe, capable of producing large hail and
damaging wind gusts. Elsewhere, the main concern is very heavy
rainfall. Expect showers and thunderstorms to begin exiting from
west to east starting late tonight and continuing into Tuesday
morning.

&&

.MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 249 PM CDT Mon Sep 7 2026

Winds will continue to increase this afternoon and evening, slowly
turning to the south this evening. By early Tuesday morning,
widespread wind gusts of 25 knots or greater are expected across
western Lake Superior, with gales expected from Grand Portage to
Grand Marais. The Gale threat diminishes Tuesday afternoon, although
a Small Craft Advisory will likely be needed for these nearshore
waters Tuesday afternoon. Widespread Gales continue to look likely
for Wednesday as a tight pressure gradient develops. Therefore, a
Gale Watch was issued across western Lake Superior on Wednesday.

Outside of the expected elevated winds, thunderstorms are forecast
tonight into early Tuesday morning. A few storms may be strong to
severe, capable of producing wind gusts in excess of 34 knots, large
hail, and frequent cloud-to-water lightning.

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

&&

.FIRE WEATHER...
Issued at 249 PM CDT Mon Sep 7 2026

Widespread showers and thunderstorms are expected to arrive tonight
and continue into Tuesday morning, accompanied by strong south
winds. At least 0.5" of rainfall is forecast across the area, with
the potential for localized amounts of 2-3" most likely to occur
along and south of US-2. Expect gusty and erratic winds around
thunderstorms, in addition to frequent lightning and potentially
large hail. Expect a gradual wind shift to occur on Tuesday, with
winds coming from the west-southwest by Tuesday evening as a cold
front moves through.

Strong west-northwest winds are very likely to arrive on Wednesday,
with the potential for gusts of 30-40 mph. Strongest winds on
Wednesday are most likely to be in the Arrowhead, especially on
exposed ridges. While winds will be strong, lingering moisture will
result in min RH of 40% or greater on Wednesday afternoon. Winds
ease Wednesday evening as high pressure builds into the area.

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 Tuesday to 7 AM CDT Wednesday
     for LSZ121-142>148-150.
     Gale Watch from Wednesday morning through Wednesday afternoon
     for LSZ121-140>148-150.
     Small Craft Advisory from 7 PM this evening to 4 AM CDT
     Tuesday for LSZ140.
     Gale Warning from 4 AM to 1 PM CDT Tuesday for LSZ140.
     Small Craft Advisory from 7 PM this evening to 7 AM CDT
     Wednesday for LSZ141.

&&

$$

DISCUSSION...Unruh
AVIATION...Unruh
MARINE...Unruh
FIRE WEATHER...Unruh