436
FXUS63 KDLH 190528
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1228 AM CDT Tue Aug 19 2025

.KEY MESSAGES...

- Showers and a few thunderstorms over the Arrowhead and NW
  Wisconsin to continue to move east through the area this late
  afternoon, with rain chances ending from west to east through
  this evening. Severe storms are not expected.

- High pressure and drier conditions build into the area for
  Tuesday into Thursday morning with warmer temperatures.

- The next chance for rain and a few storms is Thursday into
  Friday, with cooler weekend temperatures.

&&

.DISCUSSION...
Issued at 343 PM CDT Mon Aug 18 2025

Showers with a few thunderstorms extend from the tip of the
Arrowhead through the Twin Ports region and south along the I-35
corridor will continue to move slowly east for the rest of this
afternoon and evening. With little CAPE to take advantage of
and little in the way of shear, we have had only a few rumbles
of thunder so far today. These have been moving more slowly than
the models have been suggesting, so current timing might be too
fast and may need to be adjusted this evening. along with these
showers, there is a broad area of low stratus lingering over
the area, and I expect this to be very, very slow to clear. In
fact, I have it remaining cloudy/mostly cloudy overnight before
it clears out on Tuesday. Steep low level lapse rates may
produce some showers overnight into Tuesday morning as well. The
moisture beneath this lingering low level stratus will also
contribute to widespread fog tonight, with the potential for
some areas of dense fog as well. Climatologically it can be hard
to get dense fog with stratus overhead before the fog develops,
but there are pretty consistent signals from the models for it.
The stratus may keep the fog from becoming dense, so no
advisory at this time.

A ridge of high pressure noses into the area tonight into
Tuesday and lingers over the area through Wednesday night,
giving us a period of quieter and drier weather. With the clear
skies we should theoretically get some near to below normal
temperatures. Guidance is giving near to above normal however,
so we may end up knocking down those forecast temps once we see
how things behave in the next 24 hours. Afternoon high
temperatures should gradually warm through the week.

Active weather with several precipitation chances returns
Thursday into Friday with a strong upper low that moves across
the Canadian Prairies, across Ontario and into Quebec Thursday
through Saturday. Confidence is increasing in this general
scenario, but the details of the strength of the system as well
as timing have yet to be narrowed down. For now, precipitation
chances have increased for Thursday night. We should have some
warmer than normal temperatures Thursday. Temperatures shift to
cooler than normal for next weekend, and with some showers
possible through the weekend, it will feel very fall like.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1228 AM CDT Tue Aug 19 2025

An expansive stratus deck engulfs all of the Northland this evening
with ceilings down in the LIFR category. Dense fog is also expanding
leading to widespread VLIFR conditions. Models are beginning to hold
onto the fog signal a little later with each run leading to
dispersion by late morning. Ceilings will also be slow to improve
with VFR conditions likely not expected until the afternoon. Weak
forcing over the region may lead to areas of drizzle as well.
Tonight could introduce another stratus deck with fog. The latest
guidance has a 50% chance of MVFR ceilings developing over northern
MN and a 70% chance for NW WI.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 343 PM CDT Mon Aug 18 2025

Breezy east to northeast winds will continue to decrease this
afternoon and tonight, allowing our waves to also slowly
diminish. Hazardous conditions for small craft have diminished,
and will be allowing the Small Craft Advisories to expire at 4
PM. Wind gusts for most locations have dropped to 20 knots or
less this afternoon, and waves are also decreasing to 3 feet or
less. Scattered showers with a rumble of thunder or two remain
possible for a few more hours, with general thunderstorm hazards
possible. Drier conditions with winds of under 15 knots and
waves of 1 foot or less return for Tuesday and Wednesday.

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

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Dense Fog Advisory until 8 AM CDT this morning for MNZ037.
WI...None.
MARINE...Dense Fog Advisory until 9 AM CDT this morning for LSZ121-
     140>148-150.

&&

$$

DISCUSSION...LE
AVIATION...Britt
MARINE...LE