692
FXUS63 KDLH 082321
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
621 PM CDT Tue Jul 8 2025

.KEY MESSAGES...

- High pressure and quiet weather mid week with near average
temperatures.

- Increasing humidity and chances for precipitation in the second
half of the week, most likely Friday. Isolated severe storms and
areas of heavy rain are possible.

- Some areas of scattered showers and wildfire smoke could be
possible through the weekend (uncertainty high at this point).

&&

.DISCUSSION...
Issued at 149 PM CDT Tue Jul 8 2025

A couple wrap around showers are slowly spinning over the Northland
this afternoon, expected to wind down into the evening. An isolated
shower could turn into a thunderstorm. We may see some dense fog
formation overnight into early Wednesday morning.

Ridging and high pressure should be overhead for Wednesday with a
quiet weather day expected. High temperatures in the mid to high 70s
expected with dew points in the 50s.

Thursday, an upper level shortwave begins to move out of the central
Plains with an attending upper level trough sweeping out of the
Canadian Rockies. This will lead to southerly flow pulling up
moisture from the Gulf and the the Corn Belt which will bring our
next chance for rain and thunderstorms beginning late Thursday
afternoon, but the better chances don`t arrive until after midnight
Friday. Chances for precipitation (50-80%) continue through the day
Friday, highest in the afternoon and early evening hours.

An axis of PWATs 1.5"+ rides up into the Red River Valley Thursday
and then pushes east, bringing a blob of MUCAPE 1500-3000 J/kg which
could work alongside meso to synoptic scale forcing to spur isolated
severe storms overnight into Friday. However, bulk shear is low (10-
25 knots) and most model soundings are capped through much of Friday
which is a limiting factor for severe storm risk. Primary severe
hazards would be large hail and wind. There could be a lull between
thunderstorm threats, the first overnight Thursday into Friday
morning, and then the second Friday afternoon and evening after
instability has returned and better forcing arrives in the form of a
cold front pushing west to east.

This system is expected to be a fairly saturated one, with plenty of
moisture to work with and boundary parallel flow. Model Corfidi
vectors are very slow ahead of the Friday evening cold front. This
may lend itself to slow moving storms, training, and heavy rainfall
amounts, which could produce areas of isolated flash flooding.

That southerly flow will also bring warmer temperatures in the 80s
Thursday, along with dew points in the mid to high 60s, making
Thursday a rather sticky day ahead of the rain.

The cold front Friday evening should usher along widespread
precipitation out of the region and take dewpoints down a notch.
However, due to its point of origin it may also have the potential
to bring some Canadian wildfire smoke into the region. Some wrap
around precipitation chances linger into the weekend.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 620 PM CDT Tue Jul 8 2025

Diurnal cumulus is spread across the region with a few showers
percolating this afternoon. This activity will quickly diminish as
the sun retreats for the day. Overnight there is an inconsistent
signal for some fog to spread across the region and impact most of
the terminals. For now, we have a mention of it in the TAFs.
Satellite does show a fog bank on Lake Superior rolling into Saxon
Harbor, but confidence is low on how much this will push inland
given the spread of solutions. Regardless, all the models that do
show fog overnight have good agreement on it not sticking around
long after sunrise. Another VFR day tomorrow after fog clears in the
morning.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 149 PM CDT Tue Jul 8 2025

The general pattern over Western Lake Superior continues to be that
of persistent northeast or onshore winds through Friday. At the head
of the lake and in the outer Apostle Islands, this will likely lead
to some persistent wave action with a mix of wind driven waves in
the afternoon/evening and then turning into swell overnight into the
morning hours. Some gusts of 15-20 knots are possible in the
afternoons, especially at the head of the lake.  With high pressure
overhead, Wednesday will likely see some of the quietest winds of
the week. Chances for thunderstorms return at the end of the week,
most likely Friday.

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...Levens
AVIATION...Britt
MARINE...Levens