767
FXUS63 KDLH 300514
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1214 AM CDT Mon Jun 30 2025

.KEY MESSAGES...

- Showers and thunderstorms will continue to be possible this afternoon
  and evening, especially along the North Shore and in
  northwest WI.

- Isolated severe thunderstorms are possible today, mainly in northwest
  WI. Potential hazards include large hail up to 1.5" in
  diameter and gusty winds up to 60 mph.

- Several chances for additional showers and storms this
  upcoming week with temperatures becoming warm in the latter
  half of the week.

&&

.DISCUSSION...
Issued at 300 PM CDT Sun Jun 29 2025

Scattered showers and thunderstorms will be developing this
afternoon as a weak cold front propagates through the CWA. Aloft, a
500mb trough over the north-central CONUS will move east towards the
Great Lakes region today through tonight. This trough will help
promote overall synoptic lift, while the weak cold front will be the
primary lifting mechanism of interest this afternoon and evening. As
of 18z, this cold front has been analyzed to be draped from central
St. Louis County into central Aitkin County.

Radar reflectivity from KDLH early this afternoon has shown a lake
breeze moving inland along the North Shore. The sfc convergence
between this lake breeze boundary and the approaching cold front has
developed a line of scattered showers and thunderstorms. Given that
the thermodynamics in northern MN are very favorable, with MUCAPE of
around 2000-3000 J/kg, these storms have rapidly developed. While
growth has been rapid, these strong to severe storms are expected to
be relatively short-lived over the next couple hours due to a
marginal shear environment of around 30 knots of effective wind
shear.

Attention turns towards northwest WI later this afternoon and
evening, where there is a small potential for isolated severe
thunderstorms. Latest mesoanalysis shows lingering MLCIN remaining
over the WI portion of the CWA. The expectation over the next couple
hours is that this MLCIN will begin to decrease allow for additional
convective initiation to occur. MLCAPE by late this afternoon will
be around 1500 J/kg, which may develop an isolated strong to severe
storm. The main limiting factor this afternoon and evening in
northwest WI will be a fairly weak 0-6km bulk shear environment of
around 20-25 knots. However, this amount of shear will still be
sufficient to develop thunderstorms as the cold front sweeps
through. Primary hazards will be large hail up to 1.5" in diameter
and damaging winds up to 60 mph.

Expect showers and thunderstorms to come to an end tonight following
the cold frontal passage. As the 500mb trough propagates through the
CWA on Monday, scattered diurnal showers with isolated thunderstorms
will be possible in the late morning through the afternoon. Severe
thunderstorms are unlikely on Monday due to a weak shear environment
and lack of strong sfc forcing mechanism. The remainder of this up
coming week will remain moderately active with additional chances
for rainfall on Wednesday and again on Friday. Temperatures
will be on an upward trend in the latter half of the week,
likely reaching the 80s CWA wide on Friday.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1213 AM CDT Mon Jun 30 2025

Will have to watch for areas of fog tonight forming tonight in
inland northern Wisconsin which may locally reduce visibilities
down to IFR conditions; Hayward TAF amendments may also be
needed if it sets up at that terminal from 08-12Z this morning.
Diurnal cumulus form late this morning regionwide as a broad
swath of general thunderstorms are likely today from 18-23Z;
have maintained PROB30s at all terminals for this likely
scenario as a result. An upgrade to either TEMPOs or prevailing
thunderstorm mentions may be needed though in subsequent TAF
issuances.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 300 PM CDT Sun Jun 29 2025

Thunderstorms this afternoon into the early evening hours will be
moving across western Lake Superior. A few storms may be capable of
producing large hail to quarter size and/or wind gusts to 50 kt.
However, since the marine layer of air over the lake is stable,
strong winds will be less likely than large hail. Winds will be
southwesterly on Monday with gusts to around 20 kt in the early to
mid afternoon hours. Additional non-severe storms are possible on
Monday (50% chance).

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...NLy
MARINE...Unruh