Duluth, Minnesota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

582
FXUS63 KDLH 191129
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
629 AM CDT Sat Jul 19 2025

.KEY MESSAGES...

- Rain showers and isolated non-severe thunderstorms will come
  to an end this morning. High pressure building in for this
  weekend will likely keep conditions benign.

- Wildfire smoke will be moving into the area today and linger through
  Sunday. An Air Quality Alert is in effect for all MN counties
  in the area starting at 1 PM today and continuing until 9 AM
  Monday morning.

- An active pattern is likely to settle over the area starting
  on Monday, with multiple chances for showers and thunderstorms
  through the upcoming week.

&&

.DISCUSSION...
Issued at 349 AM CDT Sat Jul 19 2025

Today will start off on a wet note for some, as scattered showers
with isolated non-severe thunderstorms are occurring early this
morning. Looking at the big picture, these showers and storms are
being synoptically forced by a postively-tilted shortwave trough at
500mb. This trough axis, currently centered in southern Manitoba
into western Ontario, will propagate towards northern Lake Superior
late this morning into the afternoon. The showers and storms
developing ahead of this shortwave this morning are expected to come
to an end across the CWA by the late morning hours as the trough
axis moves downstream of the area. In addition to the precipitation,
patchy fog will continue early this morning until being dissipated
shortly after sunrise as diurnal heating occurs.

Surface high pressure is expected to develop today, which will
result in mostly sunny skies by the afternoon hours. While skies
will be clearing, expect a hazy appearance to the sky today as
wildfire smoke is advected into the CWA. Deep mixing within the
boundary layer this afternoon will allow for this smoke to reach the
sfc and reduce air quality. Since winds will be light across the CWA
this weekend due to high pressure, smoke is expected to linger
through the weekend per the HRRR smoke model. The Minnesota
Pollution Control Agency has issued an Air Quality Alert for all of
the MN counties in the CWA starting at 1 PM today and continuing
until 9 AM Monday.

A pattern change is expected this upcoming week, with the high
pressure this weekend transitioning into a more active pattern with
multiple opportunities for showers and thunderstorms. The overall
pattern for much of this upcoming week will be a large upper-level
ridge and high pressure being located over the southern CONUS. The
northern periphery of this ridge will be over the Upper Midwest,
which will keep the CWA underneath the jet stream. Embedded
shortwave impulses moving through our region will be the primary
forcing mechanisms for this upcoming week`s precipitation chances.

The first time period of interest is Monday and Monday evening. A
plume of moisture with dewpoints in the mid to upper 60s and
moderately steep mid-level lapse rates around 7.5-8 degC/km will
move into the north-central CONUS by Monday afternoon. This will
increase MUCAPE values by late Monday afternoon into the 700-1000
J/kg range, which will be occurring alongside modest 0-6km bulk
shear around 30-35 knots. While several ingredients of severe
convection will be in place, one of the largest limiting factors
will be a strong capping inversion around the 750-850mb layer. While
severe thunderstorms are unlikely due to the strong cap and
relatively weak forcing, there is still a small potential in the
Brainerd Lakes area on Monday. The Storm Prediction Center reflects
this small potential in the recent Day 3 Outlook, highlighting the
southwestern corner of the CWA in a Marginal Risk (level 1 out of
5).

Another round of precipitation is likely (60% chance) to move into
the CWA on Tuesday and continue into Wednesday as several shortwaves
move through the region. One potential hazard that stands out with
this midweek chance for rain is heavy rainfall leading to localized
flooding concerns. Deep Gulf moisture advection will be increasing
PWAT in excess of 1.5" and potentially approaching 2". In addition
to high PWAT, deep warm cloud layer in excess of 10,000 feet and a
LLJ potentially developing will create favorable conditions for
heavy rainfall rates. Global ensembles reflect this potentially high
ceiling for QPF, with several members showing QPF in excess of 2".
While there are signals for potentially heavy rainfall, it is
important to note that the potential for this is still only around
10%. However, this will be something to monitor heading into mid
next week.

The remainder of the upcoming workweek will have on and off chances
for showers and thunderstorms with a slight upward trend in high
temperatures. High temps by late next week currently show
values in the low to mid 80s.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 629 AM CDT Sat Jul 19 2025

Lingering IFR and LIFR cigs early this morning, patchy fog, and
scattered showers will dissipate later this morning. As high
pressure builds, expect an improvement to VFR to occur across the
region later this morning into the early afternoon. Wildfire smoke
will be arriving this afternoon in northern MN and persisting into
Sunday, leading to hazy skies. Another round of patchy fog will be
possible tonight, currently most likely in KDLH and KHIB.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 349 AM CDT Sat Jul 19 2025

There are minimal forecast concerns across western Lake Superior
over the next 48 hours as high pressure builds today. Expect wind
direction to be variable through the weekend with wind speeds of 10
knots of less and waves around 1 foot or less. An isolated
thunderstorm will be possible early this morning along the South
Shore, but severe weather is not expected. Anticipate hazy skies to
develop this afternoon and persist through Sunday as wildfire smoke
enters the region.

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...Unruh
AVIATION...Unruh
MARINE...Unruh