249
FXUS63 KDLH 070947
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
447 AM CDT Sun Jul 7 2024

.KEY MESSAGES...

- Scattered showers and a few thunderstorms expected today
  through tonight.

- A few stronger storms may form in northwest Wisconsin this
  afternoon and early this evening.

- Monday and Tuesday feature continued daytime storm chances
  before a downturn in activity is expected Wednesday and
  Thursday.

- Gradual warming trend through the week. Above normal temps
  possible Friday and Saturday.

&&

.DISCUSSION...
Issued at 447 AM CDT Sun Jul 7 2024

A closed upper low embedded within a broader upper-level trough
was centered over west-central Minnesota early this morning. As
of 4 AM a broken arc of showers and thunderstorms stretched
from southeast North Dakota into northwest Minnesota then
curving toward the southeast across portions of central and
east-central Minnesota into western Wisconsin and eastern Iowa.
The upper low is forecast to propagate northeastward into the
Arrowhead by this evening. Showers and storms will persist to
the north and east of the low center along the axis of a thermal
trough. Mostly clear skies were found over southwest Minnesota.

Shower and storm coverage is expected to increase later this
morning as the thermal trough rotates farther north into
northern Minnesota to Upper Michigan. In the wake of this
initialband of precip, expect partial clearing over the I-35
corridor and across northwest Wisconsin. High temperatures this
afternoon will climb into the middle and upper 70s in those
areas. The combination of several hours of heating and the
morning precipitation will provide modest instability with
MLCAPE of 1000-1500 J/kg by early afternoon. CAMs demonstrate a
line of storms developing along a nascent cold front from Lake
County down to near Spooner. The storms will push east-
northeastward along and ahead of the boundary through this
evening. Deep layer shear will increase to 30 to 35 knots ahead
of the front which will raise the potential for a few strong to
severe storms. Mid- level lapse rate of 6 to 6.5 degC/km are
forecast, so there will be a small risk of hail up to 1 inch in
diameter. Hodographs feature a little low-level curvature and
LCLs will be around 3kft AGL. Given these parameters, the
potential for a tornado will be low, but not zero over northwest
Wisconsin.

The upper trough pivot through the Upper Midwest Monday as the
upper low drifts into northeast Ontario. Cool air aloft will
support another round of showers and thunderstorms Monday
afternoon and evening. A shortwave trough will propagate
southeastward through the western periphery of the main trough
for Tuesday, which will support another round of diurnal showers
and storms. Ridging aloft will build for Wednesday and Thursday
which will limit our shower and storm chances as the remnants
of TS Beryl move northeastward through the Ohio Valley and into
the central Great Lakes.

With the building ridge, expect temperatures to trend gradually
warmer through the week. A few spots will have a shot at 90
degrees Friday through next weekend.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 122 AM CDT Sun Jul 7 2024

Rain showers with a few embedded thunderstorms will spread
north early this morning. A period of MVFR visibility is
expected with the showers. Patchy fog is forecast ahead of the
showers over north-central Minnesota. The fog should dissipate
as higher altitude clouds move overhead. Model guidance points
to a period of MVFR ceilings between 11Z and 20Z. Upstream obs
over west-central MN reveal IFR ceilings and there`s a chance
BRD will drop to IFR. Showers and storms will redevelop later
this morning into the afternoon. HYR has the best chance of
seeing a storm this afternoon.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 447 AM CDT Sun Jul 7 2024

Winds will generally be in the 5 to 12 knot range over the next
several days. A relaxed pressure gradient over the region should
provide offshore flow during the overnights. Weak low pressure
passing through the region today and tonight will turn winds
northeasterly and then backing southwest for Monday. There is a
slight chance of thunderstorms today and tonight, and again
during the afternoon and evening hours of Monday and Tuesday.

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

&&

.HYDROLOGY...
Issued at 440 AM CDT Sat Jul 6 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. Lingering high water from rains in June
continue across the Rainy River Basin. Headwaters gauges on the
Kawishiwi River, Basswood River, and Lake Vermilion have crested
and are slowly but surely coming down (Lake Vermilion falling
at a rate of a measly quarter inch a day). The Vermilion River
is also beginning to fall once again, after taking a turn
upwards from an additional round of heavy rains at the
beginning of July. This has allowed the lake level increases on
Crane Lake to slow considerably, nearly flatlining just above
minor flood stage. Lac La Croix levels continue to increase
though, the product of not only the high water from the Basswood
River but numerous Canadian tributaries coming out of the
Quetico as well. Latest data suggest that inflow and outflow are
nearly meeting on Lac La Croix, which could help levels begin
to crest soon.

All this high water has led to some decent rises on downstream
lakes, notably Namakan/Kabetogama (Nam/Kab) lakes (minor
flooding ongoing), as well as levels beginning to increase on
Rainy Lake (still within rule curves). Per the latest IJC water
level bulletin, dam operators are working to maximize outflow
through the basin. However, the sheer volume of water moving
through the basin will still result in additional rises on these
lakes. As water levels upstream crest and begin to come down,
rates of rise on Nam/Kab should begin to slow and eventually
crest. We`ve already seen the rates of rise begin to demonstrate
signs of slowing. From July 1 to 3rd, Nam/Kab Lakes were rising
at 2- 2.5" per day, but have recently slowed to 1-1.5"/day in
the last 48 hours or so. General guidance suggest peak levels on
Nam/Kab could be possible this coming week, but that is
uncertain. As is usual for this basin, water will move slowly
and recessions will happen at glacial speeds. Additional
rainfall may cause brief rises in tributaries and extend the
period of high water in core lakes.

Boaters should expect high water, potentially hidden underwater
hazards, and strong currents in constricted areas. Generally
light winds are expected, except for possible brief erratic
gusts out of thunderstorms, so wave heights should remain fairly
minimal. The Flood Advisory is in effect through Wednesday, but
may need to be extended based on observed conditions.

&&

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

&&

$$

DISCUSSION...Huyck
AVIATION...Huyck
MARINE...Huyck
HYDROLOGY...Levens/Huyck