149
FXUS63 KDLH 022330
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
630 PM CDT Sat Aug 2 2025

.KEY MESSAGES...

- Stagnant weather pattern remains in place with a strong high
  pressure over the region trapping smoke at the surface. Air
  Quality Alerts remain in effect across the Northland

- Pattern change begins Sunday with precipitation chances of
  10-30% entering from the west starting in the morning.

- A Rex blocking pattern sets up over the Northland leading to
  off and on rain and thunderstorm chances through the work
  week.

&&

.DISCUSSION...
Issued at 300 PM CDT Sat Aug 2 2025

Summary:

Not an overly exciting forecast. Blocking pattern aloft will
result in only minimal changes from day to day over the next
week. As high pressure creeps slowly eastward over the next few
days, rain chances will begin to tick upward and spread east
each day. Temperatures will remain close to normal.

Tonight through Tuesday night:

High pressure centered over Wisconsin will every so slowly
drift eastward and weaken tonight through Tuesday. Meanwhile a
convectively-fueled upper-level low pressure system will drift
slowly toward western Minnesota. Scattered showers and a few
thunderstorms have been noted with this feature over the past
day or two over the Plains. As that feature migrates into north-
central Minnesota by Monday there will be a slight increase in
rain and storm chances. Think the max probabilities are around
30 percent. CAMs notoriously struggle with weakly forced
scenarios and while confidence is high in the slow eastward
progression, questions remain as to how much instability and
precipitation will be generated. The blocking upper-level
pattern and daily convection may keep that feature intact into
Tuesday. Rain and storm chances will spread eastward with the
progression of that feature.

Wednesday through next Saturday:

A convectively enhanced shortwave trough is forecast to
propagate eastward out of the Northern Rockies and into the
northern Plains on Wednesday. Surface low pressure over the
Canadian Prairies should result in a modest warm front lifting
northward across the northern Plains and Upper Midwest. In the
wake of the warm front southerly warm air advection will
increase and will result in a noticeable increase in potential
instability by Wednesday afternoon. The GFS seems to bring a
nose of 1000-2000 J/kg of MUCAPE into central and north-central
Minnesota by early Wednesday evening. A cool front might yield
enough low-level convergence to touch of organized showers and
storms. Thus Wednesday will likely see the best chance of storms
for the week.

Warm air advection will return Thursday although forcing will
be hard to come by. Think we may see a few thunderstorms, fewer
and less widespread than Wednesday.

A slight chance of scattered shower and storm chances persist
Friday and Saturday as a few more weak shortwave troughs may
propagate through the region.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 630 PM CDT Sat Aug 2 2025

A large area of near-surface smoke continues in the Upper
Midwest this weekend. Visibilities in smoke have been a mix of
VFR and MVFR this afternoon but should decrease back to MVFR
tonight for most terminals as smoke settles back down to the
ground with the loss of daytime heating and mixing. There is a
signal for fog again tonight at DLH/HIB/HYR, with MVFR to IFR
visibilities generally in the 08-14Z timeframe. There is also a
20-30% chance that these terminals see visibilities in fog dip
below 1SM. Some chance for isolated to scattered showers to
enter central and northern Minnesota, possibly impacting BRD and
INL as early as late morning, but becoming more likely (30 to
50% chance) during the afternoon and evening. The best
precipitation potential will be at BRD. Confidence in
visibility forecast remains medium with this update.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 300 PM CDT Sat Aug 2 2025

West to southwest winds will persist over western Lake Superior
this afternoon and tonight. Winds may be a bit gusty between
Isle Royale and Grand Portage with gusts of 20 to 25 knots.
Think the strongest winds will be farther aloft and opted not to
issue a Small Craft Advisory for now. That decision may need to
be revisited if ROAM4 shows higher gusts later this afternoon.
Winds will remain in the 3 to 10 knot range through early next
week and hazardous conditions are not expected.

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.

&&

$$

DISCUSSION...Huyck
AVIATION...Rothstein
MARINE...Huyck