Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 240532
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1232 AM CDT Sun Mar 24 2024

.KEY MESSAGES...

- Messy winter storm moves into the area through the day Sunday.
  Heavy wet snow, high winds, mixed precipitation, and ice all
  expected. Blizzard conditions along the North Shore.

- Heavier precipitation wraps up through Tuesday with some light
  scattered snow showers possibly lingering into Thursday.

- Temperatures warm slightly into the weekend along with our
  next chance for precipitation.

&&

.DISCUSSION...
Issued at 329 PM CDT Sat Mar 23 2024

One last quiet day today is slowly fading into the rear-view mirror
with our impending winter storm coming up on the horizon. The first
vestiges of high cirrus clouds thrown off the system are beginning
to move over the Northland this afternoon, ahead of a warm frontal
region stretching over the Dakotas. As a shortwave drops down over
the International Border, a much deeper trough develops over the
Southwest into midday Sunday. This will bring the first push of snow
to the area over the next 24 hours. A weak frontal area out in front
of the larger system may bring some light snow to southern portions
of the CWA (Brainerd Lakes to Pine County) as early as midnight
Sunday, but the better chances will move into the area from
southwest to northeast through the morning Sunday. As winds turn
northeasterly off Lake Superior, some early low clouds and light
snow may develop along the higher terrain in the Twin Ports and up
the North Shore ahead of this larger area of snowfall. Much better
synoptic forcing and deep moisture sweeps into the Northland through
Sunday afternoon, bringing the first push of widespread snowfall to
the area, the majority of it along and south of the Iron Range.

Into Sunday evening and overnight into early Monday morning, the
deep trough begins to lift to the northeast, now becoming stacked
over the surface low. A stout frontal zone lifting northward and
wrapping into the TROWAL of this larger low will have the potential
to bring some more serious snowfall rates to NW WI, having both the
benefit of good synoptic support and moisture, and coming overnight
when there wont be any influence from our higher late March sun
angle. The probability of snowfall rates in excess of 1" per hour
blossoms to 60-80% for a period of time Sunday evening in Northwest
Wisconsin. Folks in NW WI could wake up to up to a foot of snow
Monday morning, but not too long after, the low continues to lift to
the northeast, bringing a change in precipitation type to that neck
of the woods. With this further northeast lift, areas in north-
central to northeast Minnesota will come under the weakening TROWAL
of the low, continuing to see snowfall. However, a warm nose and dry
slot begin to work in from the south, first changing precipitation
to rain over northwest Wisconsin, and then bringing a chance for
rain and freezing drizzle just over the border into Minnesota. This
could bring a glaze to a tenth of an inch of ice to areas around the
I-35 corridor and up the North Shore. Further west, predominant p-
type will likely stay snow, but become very heavy with more of a
sleet mixing in at times.

From the Twin Ports and up the North Shore snowfall is expected to
be enhanced by both Lake Superior and the terrain through most of
the duration of the event. Snowfall rates of 1" per hour are likely,
especially in the higher terrain. There is still pretty large
uncertainty about precipitation type along the coast, but generally
temperatures are expected to be cool enough to be mostly snow until
the warm nose arrives Monday afternoon. After that, a switch to rain
is possible while the higher terrain sees more freezing drizzle.
Additionally, winds off Lake Superior are expected to be very
strong, with gusts of 40 to 50 mph or greater. This is expected to
lead to blizzard conditions up the North Shore, with blizzard
conditions possible in the Twin Ports. Have stuck with a Winter
Storm Warning for Twin Ports zones for now, but depending on trends
as we get closer to our period of strongest winds Monday, an upgrade
to a Blizzard Warning may be needed. Totals along the North Shore
are currently forecasted to be around 13 to 20", but there is about
a 20-30% chance of seeing totals over 2 feet in the higher
elevations of the Sawtooths. Elsewhere in NE MN, highest totals are
still expected around the Brainerd Lakes of 12 to 18 inches, but
really low SLRs on Monday afternoon could bring those down. Then
snowfall totals decrease to the north with 8 to 12 inches expected
along and north of Highway 2 away from Lake Superior.

Winter Storm Warnings and Blizzard Warnings remain unchanged with
this forecast package over NE MN. In NW WI, the watch has been
upgraded to a Winter Storm Warning, but with the exception of
Douglas County this warning only runs through 18Z Monday, after
which point p-type is expected to predominantly rain with minimal
further snowfall accumulations. 0.5 to 1 inch of rain is possible
over NW WI, which could lead to some nuisance flooding in low lying
and poor drainage areas, along with the melting of heavy wet snow.

Further into the week, CAA under northwesterly flow behind the front
may bring a prolonged period of partly cloudy skies and scattered
light snow showers, with weakly enhanced lake effect snow showers on
the South Shore. Temperatures warm slightly into the weekend and our
next chance of more widespread precipitation arrives, but solutions
are still very widespread.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1228 AM CDT Sun Mar 24 2024

Mostly VFR though there will be a slow descent into poor flight
cats through the period. Chances for LIFR increase from
southwest to northeast after 15Z. Winds pick up from the east
gusting to 25 to 30 kt with snow and blowing snow increasing and
eventually becoming +SN by the end of the TAF period. High
confidence in IFR or lower after 20Z.

&&

.MARINE...
Issued at 329 PM CDT Sat Mar 23 2024

Fairly quiet conditions continue through mid Sunday morning, when
easterly winds begin to pick up. It will be a quick ramp up from
there with winds becoming east-northeasterly and increasing through
the day Sunday and into Monday. While the main period of gales is
expected to begin overnight into Monday morning, there may be a
couple hours Sunday afternoon when gale force gusts are possible
from the Twin Ports to Silver Bay, then winds decrease slightly
before the main event begins. Winds continue to increase through the
day Monday, hitting their peak magnitude Monday afternoon and
evening. Some storm force gusts are possible, mostly from Taconite
Harbor to Grand Marais in that time period. Winds steadily decrease
through the day Tuesday, but large waves will likely take some time
to calm.

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Winter Storm Warning from 1 PM this afternoon to 7 PM CDT
     Tuesday for MNZ010>012-018-019-026.
     Blizzard Warning from 1 PM this afternoon to 7 PM CDT Tuesday
     for MNZ020-021.
     Winter Storm Warning from 10 AM this morning to 7 PM CDT
     Tuesday for MNZ025-033>038.
WI...Winter Storm Warning from 10 AM this morning to 7 PM CDT
     Tuesday for WIZ001.
     Winter Storm Warning from 10 AM this morning to 1 PM CDT
     Monday for WIZ002>004-006>009.
MARINE...Small Craft Advisory from 10 AM this morning to 4 PM CDT
     Tuesday for LSZ121-148.
     Small Craft Advisory from 10 AM this morning to 1 AM CDT
     Monday for LSZ140>145.
     Gale Warning from 1 AM Monday to 4 AM CDT Tuesday for
     LSZ140>145.
     Small Craft Advisory from 10 AM this morning to 10 AM CDT
     Monday for LSZ146-147-150.
     Gale Warning from 10 AM to 10 PM CDT Monday for LSZ146-147-150.

&&

$$

DISCUSSION...Levens
AVIATION...Wolfe
MARINE...Levens


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