568
FXUS63 KDLH 151739
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1239 PM CDT Mon Jul 15 2024

.KEY MESSAGES...

- A couple rounds of showers and storms today. There`s a ~5%
  chance that a few storms could be strong to severe, possibly
  containing damaging winds and large hail.

- Temperatures cool off a bit mid-week and rain chances
  decrease.

- Temperatures warm back into the low 80s for highs over the
  weekend with a little rain possible.

&&

.DISCUSSION...
Issued at 339 AM CDT Mon Jul 15 2024

We have some mixed weather conditions out there this morning. A
potent trough roughly over the ND/MN border is producing showers
and thunderstorms, the anvils of which are bringing higher
clouds mainly to north-central MN at this time. Further east and
south, where skies are clear to partly cloudy, some fog has
developed. Expect cloud cover to increase this morning as the
upper level trough approaches from the west.

There is a small (and decreasing) threat for a few strong to
severe storms this morning (<5% chance) for southern parts of
Cass/Crow Wing counties along with general chances for showers
and storms across the region (~40-75% chance). The most likely
scenario is that storms will continue to track along a CAPE
gradient that is roughly situated along the I-94 corridor,
keeping most (if not all) of the severe weather threat this
morning south of the Northland. The storms that will affect the
Northland this morning should all be elevated, and as such,
threats for large hail or damaging winds are certainly minimized
(but not zero). Some of the stronger storms could produce wind
gusts to around 50 mph and small hail around the Brainerd Lakes.
Storms will continue to weaken as they move east during the
morning as they run into more stable air, and as such, the main
threats will be the usual thunder/lightning and occasionally
heavy rain.

As the upper level trough slowly pushes through this afternoon,
the CAPE gradient will slowly move east along with it. With
increasing daytime instability, additional storms are likely to
fire across northeast MN first around mid-day to early
afternoon, then move into northwest WI through the afternoon.
The most unstable air associated with warm air advection will
remain to our south, but just enough may inch northward to keep
a ~5% chance for damaging winds (to 60 mph) and large hail (up
to 1" to 1.25") especially in northwest WI. Hodographs are
largely unfavorable for tornadoes, but there might be the
smallest sliver of a chance (~1%) for a brief spinup with some
low-level veering under the warm air advection regime this
afternoon, again mainly over northwest WI. The afternoon threat
for any strong/severe storms is expected to be short-lived, and
storms should exit the region to the southeast by sunset.

We will have PWATs hovering around 1.25" today. This is in the
higher end of climatology, but less than 90th percentile. Most
places can expect to see up to half an inch of rain, but locally
higher amounts up to 1"-2" can`t be ruled out in the more
persistent thunderstorms. This could lead to some brief ponding
of water, but the progressive nature of these storms is expected
to keep any flooding threats very minimal.

After the main trough passes through this afternoon, the showers
and storms could largely clear out with northwesterly flow, weak
cold air advection, and drier air moving in. A few models
suggest the possibility for a few lingering light showers into
tonight, but confidence isn`t high enough to include a mention
in the forecast at this time.

Going into Tuesday, we start a noticeable cool down in
temperatures as more relatively colder air moves in from the
northwest. In addition, another upper level trough may bring
some showers and possibly a few non-severe thunderstorms to
parts of the region, especially along the Canadian border.

Wednesday is looking like the coolest day of the week with high
pressure settling roughly over the ND/MN border. Highs in the
upper 60s and low 70s will allow us to give air conditioners a
bit of a break!

A southwesterly flow pattern will gradually set up later in the
week into next weekend, which should warm temperatures up again.
Rain chances don`t look impressive, but there are some hints for
some sort of weak system over the weekend that could bring a
little rain.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1230 PM CDT Mon Jul 15 2024

Isolated thunderstorms forming along a cold front draping
through the Arrowhead and into the Brainerd Lakes early this
afternoon will continue to push eastward this afternoon. BRD and
DLH are the most likely terminals to have a vicinity
thunderstorm through 21Z before the better chances shift into
northwest Wisconsin, including HYR. Large hail around the size
of a Quarter and erratic wind gusts to 55 knots are the most
likely hazards from 20Z - 00Z this evening along the I-35
corridor and across northwest Wisconsin. Quiet weather sets up
after 02Z this evening with all storms south of the Northland.
Another round of non-severe -TSRA/-SHRA form mainly north of US
Hwy 2 in northern Minnesota after 16Z Tuesday - impacting HIB
and INL mostly.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 339 AM CDT Mon Jul 15 2024

Wind directions will be a bit variable this morning with speeds
less than 10 kt, then becoming mostly westerly by the afternoon
with gusts to around 15 kt. There will be rain and thunderstorm
chances today (50-80%). Isolated strong to severe storms can`t
be ruled out, which could produce strong winds or hail up to
quarter size (<5% chance). West to northwest winds persist
through Tuesday with gusts not expected to exceed 15 kt for the
most part.

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

&&

.HYDROLOGY...
Issued at 619 AM CDT Mon Jul 15 2024

A Flood Advisory continues across portions of the Rainy River
Basin, extending from Lac La Croix to as far west as the Rainy
Lake outlet. This advisory has now been extended again through
Tuesday afternoon as high water has been slow to move through
the system due to the heavy rains in June and more intermittent
rainfall in the first half of July. The Vermilion River has now
fallen below action stage, and Lake levels on Lac La Croix and
Crane Lake have already passed their crests last week, but are
still elevated and very slow to fall. Lake Namakan and
Kabetogama both reached their crests this weekend, and are also
very slow to fall. Rainy Lake also appears to be cresting as the
flood wave moves through.

Both Rainy Lake and Namakan lake levels are still exceeding the
rule curve, however we should see lowering water levels
throughout the week even despite the spotty 0.5-1 inch of
additional rainfall forecast with storms today (Monday). This
additional rainfall may cause brief rises in tributaries and
extend the period of high water, but is not expected to
significantly change water levels. Boaters should expect high
water, potentially hidden underwater hazards (including
submerged docks), and strong currents in constricted areas. Some
of the storms today 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...JDS
AVIATION...NLy
MARINE...JDS
HYDROLOGY...Rothstein