246
FXUS63 KDLH 292000
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
300 PM CDT Sun Jun 29 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 /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1231 PM CDT Sun Jun 29 2025

A cold front sweeping through the area, already having moved through
KINL and KBRD, will likely develop scattered showers and storms this
afternoon. Since scattered storms will likely be fairly short-lived,
confidence in exact timing and coverage is moderate-low. Therefore,
PROB30 lines were used to account for the storm potential today
instead of TEMPO. Following the cold frontal passage, VFR
conditions are anticipated for tonight into tomorrow. There is a
low 15% chance for MVFR to IFR fog in KHYR late tonight into
early Monday morning. Since this fog is largely dependent on
rainfall over the terminal, decided against reducing visibility
at this time due to the uncertainty today. Scattered showers are
likely to start tomorrow morning in northern MN with breezy
west-northwest flow.

&&

.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...Unruh
MARINE...Unruh