386
FXUS63 KDLH 140615
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
115 AM CDT Sun Jul 14 2024

.KEY MESSAGES...

- Additional storm chances return late tonight through Monday
  with some storms being strong to severe.

- Trending cooler Tuesday with a gradual warmup late this week.

&&

.DISCUSSION...
Issued at 321 PM CDT Sat Jul 13 2024

Challenging forecast this afternoon with poor model guidance
across the board. There are two sectors of concern this
afternoon. The first sector is over NW WI which has the least
potential to produce additional strong to severe storms. The
current wave is exiting into the UP and NE WI. There is some
additional development moving up central WI but extensive cloud
cover has not allowed much recovery from the morning storms. The
second area of concern is along the Iron Range. A line of
storms which initially began near the Red Lakes have slowly been
moving east through the late morning hours. This line is
entering an uncapped environment helping to sustain the storms.
Wind shear is a bit lacking with speeds around 20 kts. Current
radar signatures suggest some small hail possible but storms are
slow moving and vertically stacked. Severe threat remains low
with this line of activity into the afternoon and early evening
hours.

This evening a weak cold front is expected to drop down from SE
Manitoba and ignite another round of storms. CAMs currently
show varying flavors in terms of timing and location of this
line, plus it is a little concerning that these CAMs have failed
to capture this afternoons convection, further lowering
confidence. However, looking at satellite we can see ample
amounts of clearing behind the line of storms in northern MN and
surface observations are reading highs in the upper 80s and
dewpoints in the 70s. Suffice to say the atmosphere is
recovering fairly fast from the passing convection.

As of writing this forecast discussion the aforementioned
boundary can be seen firing some supercells in southern
Manitoba. It is also worth noting that a lingering boundary can
be seen north of the Grand Forks radar. The latest 18Z run of
the NAMNEST is suggesting a slightly different flavor of
convection with some initiation off this boundary leading to an
earlier start time for storms in our area. It does still carry
the main boundary through this evening as well but the
environment may be a bit exhausted by the first wave should
storms begin to develop off the boundary in ND.

Overall, the evening convection will carry the better chance
for severe storms. A shortwave passing over the region will see
mid level lapse rates increase to 8C/km and bulk shear values in
excess of 40 kts. With the QLCS set up the primary threat will
be damaging winds of 70 mph. Secondary threat of hail of 1" in
diameter and a few tornadoes remain possible. If this line of
storms does manage to form it should advance through the region
at a fairly good clip. Activity is expected to taper off around
midnight.

The weak cold front propagating the aforementioned storms will
stall out south of our CWA Sunday with high pressure filling in
behind. Opted to bump temperatures down a bit across northern MN
with the cooler air mass nearby. That being said we will still
be looking at highs in the 80s across northern MN and upper 80s
for NW WI. Some diurnal cumulus will be possible but the
subsidence in the region should prohibit storm activity.

Not quite done with the active weather just yet. Sunday night
another shortwave crosses the Northern Plains with storms
entering from the west. The convective parameter space looks
supportive of severe weather chances once again through at least
Monday morning with the primary threat being damaging winds and
secondary threat being large hail. Activity may continue
through Monday as a surface low rides along the International
Border. There still remains some disagreement with this features
placement and timing.

Severe weather chances taper off by Tuesday but we will
maintain some rain chances. An upper level low will be parked
over Ontario allowing for cyclonic flow aloft and likely diurnal
showers with isolated storms. High pressure settles in for
Wednesday and Thursday allowing for a break in the active
weather.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 115 AM CDT Sun Jul 14 2024

The risk of widespread storms has ended. A few isolated storms
are still possible early this morning. Latest high-resolution
model guidance isn`t handling existing storms from CYQT to KCKC
nor the convection in east-central MN and western WI, so
confidence in additional storms is low. HYR probably has the
greatest risk of an additional storm. Otherwise the main concern
will be whether skies can clear allowing fog to develop. HYR is
an exception at the moment with 1/2sm fog reported between 05Z
and 06Z. Think the fog will fluctuate at that site until the
arrival of an outflow boundary near I-35 as of 06Z. That will be
around 10Z. Until then, expect variable visibility. HIB is the
other location to watch for possible fog. After sunrise, expect
VFR conditions. There will be another chance of thunderstorms
Monday morning, possibly as early as 15.10Z at INL.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 321 PM CDT Sat Jul 13 2024

Southwest winds are streaming across the Lake this afternoon and are
expected to turn to out of the northwest later tonight with the
passage of a line of storms. This line of storms may bring damaging
winds and some large hail. Look for this line to exit the Lake after
midnight. Additional storm chances will return Sunday night
through Monday, these storms will also have the potential to be
severe.

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

&&

.HYDROLOGY...
Issued at 648 AM CDT Fri Jul 12 2024

A Flood Advisory continues across portions of the Rainy River
Basin, extending as far east as Lac La Croix and as far west as
the Rainy Lake outlet. This advisory has now been extended
through Monday afternoon. Lingering high water from rains in
June continue across the Rainy River Basin. The Vermilion River
continues to fall. Lake levels on Lac La Croix and Crane Lake
have crested, but are still elevated and slow to fall. Lake
Namakan looks like it is now cresting as of Friday morning.

All this high water continues to lead to slowing rises on
downstream lakes, notably Kabetogama (Kab) lake where minor
flooding continues, and on Rainy Lake where levels are still
exceeding the rule curve. Kab and Rainy Lake crests should
occur this weekend. This could bring Nam/Kab just under 1120
feet with a peak level somewhat similar to the high water during
the summer of 2014. This is still 2 feet or more below the high
water levels of Spring 2022 - we are nowhere close to that
level of flooding and extreme rises to that point are currently
not expected. As is usual for this basin, water will move slowly
and recessions will happen at glacial speeds with some flavor
of high water possibly continuing through the month. However,
peak should happen soon, based on latest observations.
Additional rainfall may cause brief rises in tributaries and
extend the period of high water in core lakes depending on where
and how much rain falls with several rounds of showers and
thunderstorms late tonight through Monday. Boaters should expect
high water, potentially hidden underwater hazards (including
submerged docks), and strong currents in constricted areas. Some
of the storms this weekend could be strong to severe, which
could lead to erratic gusts out of thunderstorms and impact wave
heights, as well.

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
MARINE...None.

&&

$$

DISCUSSION...Britt
AVIATION...Huyck
MARINE...Britt
HYDROLOGY...Rothstein