Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 221743
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1243 PM CDT Fri Mar 22 2024

.KEY MESSAGES...

- A strong CO Low will impact the Northland Sunday through the early
  portions of next week. A Winter Storm Watch has been issued
  for the entire area with a Blizzard Watch for the North Shore.
  Heavy snow along with strong winds will hammer the region
  with the worst conditions expected Sunday afternoon into
  Monday afternoon.

- Clipper system exits later this morning with light snow
  tapering off across our southern tier counties. An additional
  inch or two is expected before departure.

- Near critical fire weather conditions today and likely again
  tomorrow due to low RHs over northern MN. Winds are slightly
  stronger today with gusts in the teens this afternoon out of
  the NW.

&&

.DISCUSSION...
Issued at 438 AM CDT Fri Mar 22 2024

Current conditions:

A clipper system is traversing across our southern counties
this morning spreading light snow. Radar had shown an intense
snowband overnight south of the CWA fueled by a tight 700mb FGEN
ribbon. This has since dissipated and surface observations are
slowly showing signs of improvement to the west as the system
continues it`s easterly trek. An additional inch or two will be
possible in NW WI before the system exits by late morning.

Today:

Cool dry air moves in from the north as high pressure fills in
behind the exiting clipper this afternoon. Decreasing clouds for
northern MN will lead to Min RHs dropping into the lower 20s leading
to elevated fire weather concerns once again. Wind speeds are also
slightly elevated with gusts in the upper teens out of the northwest
this afternoon.

Friday:

The polar air mass lingers into Friday with clearing skies and highs
in the 20s and 30s. Dry conditions at the surface will likely lead
to elevated fire weather concerns. Fortunately with the high
pressure directly overhead winds will be minimal.

Sunday-Monday/Colorado Low:

All eyes are on the impending Winter Storm for Sunday into the early
portions of the next week. The consistency of the collective
ensembles and deterministic weather models continues to be
impressive given how far out this has been forecasted. A Colorado
Low is projected to develop Sunday morning. The strength of this low
is quite anomalous for this time of year with it`s pressure falling
outside the bounds of climatology. Both the GEFS and Euro
ensembles all paint the same trajectory for the low, tracking
out of the Central Plains up towards the Great Lakes. As the
Low approaches it will be able to tap into two moisture sources.
Remnants of an atmospheric river from the Pacific and the rich
Gulf of Mexico moisture. While the overall PWAT values nearing
half an inch aren`t overly impressive for a Spring system the
residency time more than makes up for it. The deformation axis
is forecasted to set up nicely over the region Sunday into
Monday as the jet stream becomes coupled by Monday. Another
feature that the system has in it`s favor is a strong low level
jet of 50 kts screaming out of the south helping to fuel
moisture into the system.

Snow will be the primary precipitation type to kick things off
Sunday. Dry air in place from the exiting high pressure may take a
little of time to saturate but the consensus right now is that light
snow begins in the Brainerd Lakes region Sunday morning. Synoptic
and mesoscale forcing increases Sunday afternoon with snow
spreading northeast and increasing in intensity. The Northland
will enter a prolonged period of snowfall paired with increasing
winds that will lead to blowing snow through Monday. Strong
winds off of western Lake Superior has potential to lead to
blizzard conditions along the North Shore and into the Twin
Ports.

Based on the high confidence in the models and ensembles we have
issued a Winter Storm Watch for the entirety of the Northland. The
North Shore also has a Blizzard Watch due to the strong winds off
the Lake. Snowfall ranges still have a rather large spread with the
minimum sitting around 8" and the high end around 30". Overall, the
timing for the worst of the storm is expected to be Sunday afternoon
into Monday afternoon.

As the Low encroaches on the Northland we will see some warm air
working it`s way in as well. Based on the 00Z suite of guidance this
will lead to a rain/snow mix over NW WI Monday afternoon and
will likely lead to lowering SLRs across northern MN. Lack of a
refreezing layer paired with warming surface temps has us less
concerned about ice at this time.

Tuesday through the extended:

Models diverge a bit with handling the departure of the system as
placement of the upper level jet ranges from Lake Michigan to WI.
The overall trend looks to be continued precipitation for Tuesday,
albeit at a lesser rate with warmer air also intruding. We may still
have lingering precipitation chances into Wednesday depending on how
the wrap around moisture interacts with high pressure building in
from the Canadian Prairies.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1238 PM CDT Fri Mar 22 2024

Northerly flow over the Northland keeps winds 10 knots or less,
gusting to 15 knots during the daytime. Scattered to broken MVFR
ceilings under isolated snow showers in northwest Wisconsin drop
southward and decrease in coverage this afternoon near HYR. VFR
conditions prevail otherwise across the Northland under diurnal
cumulus from 4 to 7 kft agl into early evening.

&&

.MARINE...
Issued at 438 AM CDT Fri Mar 22 2024

Light northerly winds to start today that will become northwesterly
in the afternoon. A few gusts to 20 kts will be possible. A strong
CO Low is projected to head for the Great Lakes late Sunday into
early next week. A prolonged period of snow and high winds are
anticipated for the Lake. A Gale Watch has been issued starting
Sunday night.

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Winter Storm Watch from Sunday morning through Tuesday morning
     for MNZ010>012-018-019-025-026-033>038.
     Winter Storm Watch from Sunday afternoon through Tuesday
     morning for MNZ020-021.
WI...Winter Storm Watch from Sunday morning through Tuesday morning
     for WIZ001>004-006>009.
MARINE...Gale Watch from late Sunday night through late Monday night
     for LSZ140>147-150.
     Small Craft Advisory from 10 PM this evening to 4 AM CDT
     Saturday for LSZ150.

&&

$$

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


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