362
FXUS63 KDLH 301121
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
621 AM CDT Sat Aug 30 2025

.KEY MESSAGES...

- Areas of dense fog this morning.

- Plenty of warm, quiet weather with sunshine through Labor
  Day.

- Showers and thunderstorms are likely Tuesday and Tuesday
  night.

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

&&

.UPDATE...
Issued at 622 AM CDT Sat Aug 30 2025

Dense Fog Advisory was expanded into central Minnesota through
9 AM. Showers have become more numerous over northern St. Louis
County over the past hour or two. Raised PoPs for the next
several hours to account for the rain chances.

&&

.DISCUSSION...
Issued at 401 AM CDT Sat Aug 30 2025

Early this morning...

A broad area of high pressure centered over northern Lower
Michigan provided light winds across the Northland early this
morning. Fog and low stratus developed over northwest Wisconsin
and portions of central Minnesota and was spreading gradually
northward. Meanwhile north-central Minnesota and adjacent areas
of northwest Ontario were in a zone of weak 298-302 K isentropic
ascent which touched off a few small thunderstorms back around
06Z. GOES-East water vapor imagery revealed an east-west
oriented trough slowly sagging southward toward the Canadian
Border. Raised PoPs to include a mention of sprinkles and
showers through this morning over northern St. Louis county and
the Boundary Waters. Ascent gradually weakens later this morning
and I expect the shower chances to dwindle. Fog and low stratus
will improve later this morning. Opted for a Dense Fog Advisory
for Ashland, Iron, Burnett, Washburn, Sawyer, and Price
counties until 9 AM.

Today through Sunday night...

High pressure over the region will result in mostly sunny skies
and winds from the southwest around 5 mph today and tonight.
CAM guidance indicates a potential for isolated showers to
develop over the Arrowhead and north-central Minnesota this
afternoon. Elected to hold onto sprinkles for the time being.
Highs today will be in the middle 70s to low 80s, on the warmer
side of normal for this time of year.

Weak flow will remain in place tonight through Sunday night.
Fog is likely to develop again overnight. Weak nocturnal
convergence should support another round of a few showers or
storms overnight, although confidence in the location is low.
Convergence along the lake breeze in northeast Minnesota may
touch off showers and storms Sunday afternoon. Kept PoPs low,
around 20 percent. Highs Sunday will be similar to today, middle
70s to low 80s.

Monday...

Modest southerly return flow will develop Monday as high
pressure slides slowly to the east and the pressure gradient
tightens over the Upper Midwest and northern Plains. Highs will
be in the low 70s along the North Shore to middle and upper 70s
elsewhere. A few 80s are possible in north-central and central
Minnesota. Isentropic ascent may be strong enough to support a
few showers or storms late Monday afternoon and Monday night
over central Minnesota north to the Canadian Border.

Tuesday and beyond...

Well-advertised cold front will traverse the area Tuesday.
Airmass ahead of the front will feature weak potential
instability with MUCAPE of around 500 J/kg. Convergence along
the front may make up for the limited instability and we still
anticipated showers and a few storms to develop along the front.
Deep layer shear will be low in the warm sector, 15 to 25
knots. Thus organized severe storms appear unlikely. Shear
improves in the wake of the front, so there is at least a small
potential for a few stronger storms near the boundary late
afternoon into the evening.

Cool cyclonic flow will follow the front for Wednesday through
the end of next week care of a cutoff low pinwheeling over the
western Great Lakes. As such expect much cooler temperatures and
another taste of autumn. Highs Wednesday will be in the low 50s
to around 60 degrees. Isolated to scattered showers are likely
each afternoon through the night. Kept PoPs low during that time
due to the uncertainty and coverage of the rain chances.

Overnight lows will dip into the 30s and 40s Wednesday night
through Saturday morning. Frost Advisories may be needed. Anyone
awake during the overnight may see the first "conversational"
snowflakes of the year over northern Minnesota. Thermal profiles
will certainly be cold enough overnight for a few flakes.

Warmer temps should return for the second half of next weekend.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 622 AM CDT Sat Aug 30 2025

Isolated showers over far northeast Minnesota this morning are
expected to diminish over the next several hours. Additional
showers may develop this afternoon. Fog and low stratus will
dissipate by late morning. VFR conditions will follow until
tonight when fog will likely return.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 401 AM 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. Areas near Grand Portage may see stronger
southwest winds due to funneling between Isle Royale and the
mainland where there is a 20% chance of wind gusts greater than
22 knots this afternoon.

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. Cool air will continue to pour into the area
through the end of next week. Seasonably warm water temps will
contribute to persistent stronger winds and conditions hazardous
for smaller vessels.

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

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Dense Fog Advisory until 9 AM CDT this morning for MNZ025-026-
     033>038.
WI...Dense Fog Advisory until 9 AM CDT this morning for WIZ001>004-
     006>009.
MARINE...None.

&&

$$

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