293
FXUS63 KDLH 122347
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
647 PM CDT Fri Jul 12 2024

.KEY MESSAGES...

- Hot weather continues through the weekend.

- Severe weather chances through the weekend, especially in the
  afternoons. Highly conditional conditions will affect
  where/when severe weather will occur.

- Cooler temperatures and continued chances for scattered
  showers and storms in store for next week.

&&

.DISCUSSION...
Issued at 211 PM CDT Fri Jul 12 2024

Diurnal cumulus are popping across the Northland today. So far,
there does not seem to be any precipitation due to dry
conditions. These should clear as the sun sets this evening.

From dissipated storms in Manitoba this morning, the outflow
boundary is moving southeast across northwestern Minnesota. It
is starting to trigger some storm cells on the Manitoba/Ontario
border, but has not produced any on the US side. This boundary,
combined with a small shortwave expected to move over northern
Minnesota, is expected to initiate a linear MCS overnight and
move southeast through the Northland in the early morning.
A LLJ should help keep instability over 1000 J/kg in the
surrounding area where the MCS is expected to form. Wind shear
is modest overnight, but still sufficient enough for storms at
25 kts. Severe weather is possible, with damaging winds as the
main threat, but probability seems low as the system will be
elevated. Saturday morning, a surface trough moving east from
the Rockies across ND/northern MN will help surface lift for
Saturday afternoon, which will be the main time for rejuvenation
or second initiation of storms. MLCAPE will be more than
sufficient in the 2000-3000 J/kg range, and shear will increase
throughout the day as well to 30-40kts by mid afternoon. The
thermal cap that has inhibited storms is still expected to
weaken for Saturday afternoon, allowing for easier initiation.
Large hail and damaging winds will be the main threat, but a
tornado or two cannot be ruled out. High PWATs over the area
highlights chances for minor flooding, especially if storms
train over an area. These storms will continue into the
overnight hours, and could linger into Sunday.

Sunday comes with a bit of uncertainty both in storms and
temperature. Based on what manages to initiate tonight through
Saturday will not only affect the possibility for strong storms
on Sunday, but also the possibility for hot temperatures as
well. Lingering outflow boundaries could help keep temperatures
lower than forecasted in some areas. Strength of storms in the
afternoon Sunday are highly conditional of these factors as
well. Though, a few strong storms are still possible with large
hail and damaging winds.

A closed low will move south over the Upper Great Lakes for
early to mid next week and we will see temperatures drop into
the 70s for highs. Persistent northwest flow and CAA will keep
diurnal shower and storm chances up, but no severe weather is
expected during this time period. Models start to diverge for
the late week, but do hint at gradually warming temperatures
once again.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 647 PM CDT Fri Jul 12 2024

VFR conditions are expected to prevail through much of the
period. There is still the potential for a complex of
thunderstorms to move through the region after sunrise and into
early afternoon, but models remain mixed on the timing and
placement of the activity. Have highlighted the most likely
times with VCSH/VCTS with this update with later updates needed
as the threat comes into better focus. There may be brief
periods of IFR or lower conditions in the storms. The storms may
also contain gusty winds as well, primarily across the
Minnesota terminals. Additional showers and storms will be
possible Saturday afternoon, but that development depends
greatly on what happens late tonight into Saturday morning. Due
to this uncertainty, have left out with this update aside from
INL where better chances are expected.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 211 PM CDT Fri Jul 12 2024

Quiet conditions on Lake Superior continue with southwesterly
flow. Winds 15 kts or less are expected. A couple rounds of
severe weather this weekend may affect the near shores,
especially Saturday and Sunday afternoons. Large hail and strong
winds will be the main threats.

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...KML
AVIATION...BJH
MARINE...KML
HYDROLOGY...Rothstein