Duluth, Minnesota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

074
FXUS63 KDLH 141738
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1238 PM CDT Wed May 14 2025

.KEY MESSAGES...

- Isolated showers and storms possible (20-30%) today.

- Widespread rain chances Thursday through Saturday

- Strong to severe thunderstorms are possible Thursday afternoon and
  evening in northwest Wisconsin and portions of northeast Minnesota.

- Cooler weather for the weekend with overnight low near freezing
  for portions of the region

&&

.DISCUSSION...
Issued at 359 AM CDT Wed May 14 2025

Current Conditions/Today:

The rex blocking pattern has largely broken down as remnants of the
upper level low have transitioned into an open wave moving over the
Ohio River Valley. The Northland still finds itself caught between a
surface low to our west and high pressure to the east but with
slightly higher moisture return along the southeast winds expected
to today. The combination of diurnal heating and some left over
vorticity couplets aloft should provide some scattered showers and
storms. CAMs are also hinting at some convection firing off the Lake
breeze boundary, particularly in northwestern WI. Any storms that do
form are expected to stay sub severe. While we do manage to have
some decent instability with MLCAPE in excess of 1000 J/kg we are
lacking in the bulk shear department. Storms will grow upscale
quickly but end up collapsing on themselves unable to generate the
tilted needed for sustainability. With that being said the primary
hazards would be hail of pea to dime size and some strong outflows
from collapsing storms.

Thursday:

A negatively tilted trough will rotate out of the Northern Plains on
Thursday leading to a strengthening surface low. A broad warm front
will stretch from ND through MN and WI and begin to occlude through
the day as an upper level jet runs through the tilted trough.
Ahead of this boundary we will see enhanced buoyancy across the
region as dewpoints climb into the 60s. Some discrete cells
ahead of the boundary will be possible initially, but the latest
CAMs are showing agreement with the storm structure turning
more linear as the boundary wraps NE through the afternoon and
evening. Primary hazards would be damaging winds and large hail
with NW WI being in the best corridor of favorable steep mid
level lapse rates paired with strong shear. QLCS tornadoes will
also be possible with helicity of around 200. The SPC is still
carrying an Enhanced Risk (3 out of 5) into NW WI with a slight
expansion westward. The Brainerd lakes region up through the
Twin Ports and Silver Bay are highlighted in a Marginal Risk. (1
out of 5).

Friday:

The main line of convection will move out of the region Thursday
night as a dry slot filters in behind the front. The vertically
stacked low will be slow moving on Friday as it slides through the
Northland. Wrap around moisture will still provide rain chances with
a few rumbles of thunder possible on Friday. What will be most
notable will be the drop in temperatures. Highs will go from 70s and
80s on Thursday to 50s and 60s on Friday. Rain totals from this
system still have a broad range. Probabilistically we still have a 60-
80% of widespread 0.50 inches of rain. This latest update has seen a
slight reduction along far northern MN with probabilities dropping
to 30-50%.

Weekend:

Remnant rain showers will be tapering off Saturday. There still
remains some high discrepancies with how quickly the system departs
this weekend. The GFS and its family members is favoring a quicker
exit while the Euro has the wrap around moisture and low lingering
over Lake Superior through the day. For now we will carry a 30%
chance of PoPs for the day. Widespread 50s are expected across the
Northland with our overnight lows dropping to near freezing. Frost
Advisories may be needed.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1235 PM CDT Wed May 14 2025

Scattered rain showers and thunderstorms are likely in northwest
Wisconsin this afternoon, and more isolated coverage into
northeast Minnesota. A few thunderstorms could (30-40% chance)
approach area terminals in far eastern Minnesota and northwest
Wisconsin; this is shown by PROB30 and TEMPOs at DLH and HYR for
this afternoon and early evening. Even high heavy rainfall and
widespread thunderstorm chances increase from south to northeast
after 15Z Thursday first in the Brainerd Lakes region. Severe
storms are possible with this round of thunderstorms Thursday
mid-day to afternoon.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 1040 AM CDT Wed May 14 2025

Update - Open water dense fog seen on satellite imagery has
moved onshore to the North Shore where webcams over last half-
hour. Short-term high res guidance keeps this fog bank moving
southward so Dense Fog Advisories have been issued for today
along the North Shore and Outer Apostle Islands, and then for
the southwest arm of the lake this evening into Thursday
morning. The rest of the previous discussion stands below.

Northeast winds today of 10 to 15 knots with a few gusts to 20
knots. There may be a brief period of gusts to 25 knots around 5PM
this evening at the head of the Lake as funneling winds crash
onshore. But the better chances for more widespread windy conditions
will be on Thursday as a system approaches from the west. There are
several chances for storms the next couple days as well. Today will
be diurnally driven storms which may impact the nearshore waters
this afternoon and evening. Thursday has a more linear storm
projected to move over the Lake in the afternoon and evening hours
and may produce severe weather. Lastly, there is a signal for dense
fog engulfing much of the Lake tonight.

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...Dense Fog Advisory until 10 AM CDT Thursday for LSZ140>142-150.
     Dense Fog Advisory from 7 PM this evening to 10 AM CDT
     Thursday for LSZ143>146.

&&

$$

DISCUSSION...Britt
AVIATION...NLy
MARINE...NLy