533
FXUS63 KDLH 251746
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1246 PM CDT Wed Jun 25 2025

.KEY MESSAGES...

- Rain and thunderstorms today through Thursday. Heavy rainfall
  amounts of 1-3", locally 4"+ possible for parts of northwest
  Wisconsin with some minor flooding possible.

- A couple opportunities for severe thunderstorms Saturday and
  Sunday.

- Hot and muggy weather is likely over the weekend. Heat
  Advisories may be needed.

&&

.DISCUSSION...
Issued at 404 AM CDT Wed Jun 25 2025

Pretty quiet out there this morning. A little patchy fog where
there are no clouds, but clouds are quickly filling in from the
south ahead of a warm front with plenty of moisture advection
and upper level shortwaves. The main story over the next couple
days will be dealing with rain potential as a warm front stalls
across southern Minnesota into central/southern Wisconsin and a
general dirty ridging pattern aloft keeps ingredients in place
for several rounds of moderate to heavy rainfall. The first
round is expected today into this evening as an initial embedded
trough passes through, then again Thursday as another upper-
level wave and surface low develop and pass through. Convective
potential as far as any strong thunderstorms go is low with
MUCAPE topping out at just a few hundred J/kg.

Rain and Flooding Potential through Thursday:

The main concern for this rainy period will be the potential for
some flooding. What we know is that PWATs will be exceptional
for the next couple days, reaching ~98th to nearly maximum of
climatology for central Wisconsin, inching up into northwest
Wisconsin. The aforementioned convective potential is low for
strong storms, but in this environment that`s setting up to be
something pretty close to the idealized environment for
efficient rainfall processes, a little CAPE with high PWATs can
do a good job at squeezing out most of the moisture that will be
around. There are really no major changes for placement of the
areas most likely to see the highest rainfall amounts. There are
still some uncertainties mainly due to the localized nature of
rain bands and areas of thunderstorms that will produce the
highest rainfall amounts, but at least in our region, it`s still
looking like the northern extent of the most efficient rainfall
processes are going to target Pine County to Price County with a
fairly sharp gradient heading north of there. There was some
discussion about the need for a Flood Watch for this event, but
at this time, we are expecting that the long duration of this
rainfall with some occasional breaks in the heavier rates should
keep flooding risks from becoming widespread. In addition, there
remains some uncertainty on exactly where the highest rains will
actually fall, though that confidence continues to increase. All
said, around 1-3" of rainfall are expected in the
aforementioned areas of the highest concern. HREF 48-hr ensemble
probability- matched mean of QPF paints some ~3-6" rainfall
areas, mainly into central MN/WI. Any slight shifts north or
south could mean more or less rain for the parts of mainly NW WI
where the risk is highest right now. Widespread flooding does
not appear likely, but there could certainly be some where
there are some training rain bands and/or if the main axis of
precipitation shifts a little further north. The main hazards
will be water level rises along local rivers and streams as well
as some urban/street flooding where rainfall rates are highest.

Quick break on Friday, then storms and heat over the weekend:

We should finally get a cold front to kick out the low pressure
Thursday night, which will lead to a dry and quiet Friday with
pretty seasonable temperatures.

Going into Saturday, deep and broad ridging over the southern
states will start to move northeast with some southwesterly
flow. With this, we`ll get plenty of warm air advection, causing
temperatures to soar into the 80s. We`re looking at a Saturday
and Sunday with wet bulb globe temps rising to close to 80 and a
moderate Heat Risk for some places. Heat Advisories may be
needed.

Along with the heat comes the potential for some strong to
severe thunderstorms. First, on Saturday, we may have an upper-
level short wave passing through with some low-end favorable 0-6
km 30-45 kt shear and MUCAPE up to or a bit over 1000 J/kg in
the early afternoon, quickly rising potentially to the 3000+
J/kg range into the early evening. It remains to be seen how
well all ingredients will arrange themselves. While instability
may increase into the evening, shear may decrease, keeping storm
mode and hazards in question. Some storms could persist into
Saturday night, then going into Sunday, with more diurnal
heating and potential for another shortwave with a cold front,
we could have yet another round of storms develop in the
afternoon/evening. Right now this looks like a high CAPE / low
shear setup, but only marginally low shear. So again, plenty of
uncertainty for hazards and coverage, but ingredients are
looking to be in place for at least some severe storms.

Next week:

After Sunday`s fun with the heat and storms, it`s looking like
we`ll find ourselves in a west/northwest flow pattern with
ridging re-developing out to the west. There could be some
embedded shortwaves that could bring the occasional shower/storm
chance, but generally it`s looking like temperatures will settle
to slightly above average with largely quiet weather for a few
days.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1245 PM CDT Wed Jun 25 2025

Light rain will continue to spread north through this
afternoon. Added a brief period of light rain to INL with this
update. BRD and HYR will experience MVFR visibility in rain.
Ceilings will gradually trend lower through this evening and
early Thursday morning except at INL where VFR conditions are
expected. The rain will end from southwest to northeast
overnight. Another round of showers is forecast to lift
northward into the region Thursday morning.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 404 AM CDT Wed Jun 25 2025

A prolonged period of northeasterly flow is expected through the
rest of the week. Wind gusts generally in the 15-20 kt range,
except some higher gusts into the 20-25 kt range on Thursday as
low pressure passes by to the south. Wave heights may reach up
to around 4 ft Thursday into Thursday evening as well. Small
Craft Advisories may be needed. Wednesday and Thursday, rain is
expected at times. Thunderstorms are generally not expected, but
a stray storm can`t be completely ruled out.


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...JDS
AVIATION...Huyck
MARINE...JDS