182
FXUS63 KDLH 242352
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
552 PM CST Sun Nov 24 2024

.KEY MESSAGES...

- Light to moderate snow enters from the west this evening.
  Winter Weather Advisories have been expanded. The heaviest
  snow is expected in the overnight hours across NE MN. Light
  snow is expected to continue through Monday.

- A pattern change is expected to start Tuesday. Off and on snow
  chances will linger through the week as temperatures continue
  to cool.

- Prolonged lake effect snow chances are expected along the
  South Shore.

&&

.DISCUSSION...
Issued at 234 PM CST Sun Nov 24 2024

Synoptic Set Up:

The upper level ridge that has been in place over the region the
past couple days is slowly exiting to the east this afternoon as a
vertically stacked low moves across the Canadian Prairies. There is
also another surface low moving across Iowa. Both of these features
are helping to draw in some moisture to the Northland. ALPW
highlights some gulf moisture in the lower levels being pulled by
the Iowa Low and some upper level moisture from Baja mixed in with
the Canadian Low. The resulting PWATs are around 0.50 inches, well
within the normal climatology for this time of year, but enough to
provide the region with a coating of snow.

Afternoon/Tonight:

Radar has shown a few echoes this afternoon. Primarily transient
plumes of snow occasionally flowing off of Lake Superior. Webcams
have largely shown these small flurries quickly melting after
passage as high temps continue to float just above freezing.
More widespread snowfall will begin to enter from the west after
9pm as an inverted trough/occluded front moves west to east.
Vertical profiles completely saturate overnight as colder air
begins to overtake the region. Lack of a robust forcing
mechanism will lead to largely light snowfall for most of the
region. The exception to this will be along the North Shore and
into the Arrowhead. An impressively long fetch of easterly winds
across a warm lake (8C) will lead to a boost in snowfall rates.
The highest rates of 0.5" per hr are expected after midnight
across the North Shore. Thereafter, winds begin to switch to
the northeast resulting in lighter accumulations.

Monday:

Light snow will continue through most of the day as the system
progresses east. Snow totals with this forecast package have
increased. Overall widespread snow is expected with high confidence
(70%) of at least 2 inches of snow. Thanks to the contributions of
two moisture sources our QPF was boosted once again instigating an
expansion of our Winter Weather Advisories. Still believe we are a
bit shy of hitting 6" anywhere despite the HREF suggesting high
chances across the North Shore and South Shore. A few pockets of 6"
are possible thanks to the terrain boost and Lake effect but
not expecting it to be widespread enough to warrant a warning.
Winds will be backing through the day as the inverted trough
passes with northwest winds expected by the evening hours. This
change in wind direction will see lake effect mechanics switch
from the North Shore to the South Shore.

Tuesday-Weekend:

The main forcing mechanisms will depart Tuesday morning but
lingering moisture with a strong lobe of vorticity aloft will allow
for continued flurries and cloudy skies. Accumulations will be
minimal. Tuesday marks the start of a pattern change with much
colder air seeping into the Northland. By Thanksgiving our 850 temps
are expected to be around -15C. This colder air will have cascading
effects that will need to be monitored in upcoming forecasts.
Persistent NW flow will allow for continued chances for snow showers
along the South Shore. Areas downstream of large inland Lakes may
also see some Lake effect snow showers as ice production has not
settled in for the year. Look for air temperatures to decrease
through the week with highs in the teens by next Sunday.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 552 PM CST Sun Nov 24 2024

An MVFR cloud deck is present early this evening across much of
northeastern and north-central Minnesota, with IFR conditions at
DLH due to light lake effect snow streaming in from Lake
Superior. As a low pressure system moves into the region this
evening, snow will spread across the Northland from west to
east. Ceilings and visibilities will deteriorate into tonight,
with some LIFR ceilings at many locations later tonight into
Monday morning. IFR visibilities are also expected when the
highest snowfall rates are expected late this evening into early
Monday morning. Lighter snow accumulations are expected for much
of tomorrow, with lighter rates by the 14Z to 16Z timeframe.
Easterly winds back to northeasterly tonight and back further to
northwesterly by late tomorrow morning to early afternoon.
Late morning and afternoon wind gusts to 15 to around 20 knots
are expected for most terminals on Monday.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 234 PM CST Sun Nov 24 2024

Enhanced easterly winds are ramping up this evening with Small Craft
Advisories currently in effect. Radar this afternoon has shown a few
lake effect streamers at times impacting the Near Shore waters.
Overnight, a system spreads in from the west which will largely
cause rain across the warm Lake. Winds taper off and back to out of
the northwest tomorrow. These winds are expected to increase
tomorrow evening with another batch of Small Craft Advisories likely
needed.

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

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Winter Weather Advisory from 10 PM this evening to 9 AM CST
     Monday for MNZ011-018-019-026-035>038.
     Winter Weather Advisory from 10 PM this evening to 2 PM CST
     Monday for MNZ012-020-021.
WI...Winter Weather Advisory from 10 PM this evening to 9 AM CST
     Monday for WIZ001.
     Winter Weather Advisory from 10 PM this evening to noon CST
     Monday for WIZ002>004-006>009.
MARINE...Small Craft Advisory until 4 AM CST Monday for LSZ142-143.
     Small Craft Advisory until midnight CST tonight for LSZ144>147-
     150.

&&

$$

DISCUSSION...Britt
AVIATION...Rothstein
MARINE...Britt