Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 271751
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1251 PM CDT Wed Mar 27 2024

.KEY MESSAGES...

- Light snow and flurries will change over to snow showers late
  this morning and this afternoon. The showers may be locally
  heavy at times with visibility dropping to less than 1/2 mile
  in the heaviest showers. The chance of visibility less than
  1/2 mile for at least 20 minutes in snow showers is 20 percent
  across the south to around 70 percent in the Iron Range and in
  the Bayfield, Ashland, and Iron counties.

- Additional snowfall through this evening will vary from a
  dusting up to a few tenths of an inch over central Minnesota
  into northwest Wisconsin to 2 to 4 inches in north-central
  Minnesota east into the Arrowhead.

- A clipper will move eastward across the region Friday and
  Saturday. Several inches of snow are likely from that system
  Friday afternoon through Saturday morning, although the
  location of the greatest accumulation is uncertain.

- There is another chance of snow early next week.

&&

.DISCUSSION...
Issued at 436 AM CDT Wed Mar 27 2024

"Snow Globe Spring" (tm) continues across the Northland today.
As of 09Z surface low pressure was centered over northeast
Ontario. The 08Z RAP valid at 09Z features a closed upper-level
low with several lobes of cyclonic vorticity rotating counter-
clockwise around the center. GOES-East IR and water vapor
imagery supports the RAP indications. Cold cyclonic flow and
ample moisture remained in place over northern Minnesota,
northwest Wisconsin, southeast Manitoba, and northwest Ontario
for overcast skies, light snow, and flurries. Overnight
accumulation will likely range from a dusting up to several
inches, with the greatest accumulation over north-central
Minnesota.

Cold cyclonic flow will continue today as the surface low
advances north-northeastward toward Hudson Bay. The trailing
upper low and associated vorticity will gradually lift toward
the northeast as well. Skies will remain mostly cloudy. The
sustained light snow will pull farther northeast with time today
leaving flurries in its wake. By late this morning or early
this afternoon, steep low-level lapse rates of 7-9 C/km are
forecast to develop in response to the cold air advection and
surface heating from the late March sun. The cloud cover and
light snow will moderate the insolation somewhat, however the
high sun angle will still allow weak surface-based CAPE to
develop. With moisture still overhead, look for the light snow
to take on a more showery nature. Snow squalls remain a
possibility this afternoon. The greatest risk will be south of
the Iron Range over Minnesota and over all of northwest
Wisconsin. GFS, RAP, and NAM solutions each paint the greatest
snow squall potential in different areas of the Northland. As
the upper low departs, clouds will thin from central Minnesota
into northwest Wisconsin, which should allow more efficient
surface heating and destabilization. Thus I`m leaning more
toward those areas having the greatest risk of squalls. Even if
the showers don`t reach "squall" intensity, visibility in the
heavier showers will likely dip to around 1/2 mile for brief
periods of time.

With light snow continuing and additional snow accumulation
over north-central Minnesota into the Arrowhead of 2 to 4 inches
expected today, we elected to expand the Winter Weather
Advisory eastward into central St. Louis County and the inland
portions of the Arrowhead. We also pushed the end time to 7 PM
for Koochiching, north Itasca, north and central St. Louis
counties and until 10 PM for the inland Arrowhead. In addition
to the snow accumulation, the afore mentioned areas are most
likely to have visibility drop to around 1/2 mile this afternoon
as they will have better moisture availability and stronger
wind gusts than areas farther south.

Quieter weather returns briefly for Thursday as high pressure
drifts over the region. Temperatures will trend a little warmer
although remain below normal.

A fast-moving clipper system remains in the picture for Friday
and Saturday. That system will progress eastward from the
northern Plains across the Upper Midwest and into the Great
Lakes during that time. Precipitation chances over the Northland
ramp up Friday afternoon and decrease Saturday morning. Most of
the Northland will see at least a little snow. Some areas could
pick up several inches. The compact nature of the low, timing
of the arrival of precipitable water ahead of the system, and
various forcing mechanisms make it difficult to pinpoint the
most likely areas for shovelable or plowable snow. Some of the
00Z guidance this morning produces the heaviest precipitation
east of our area in northeastern Wisconsin and Upper Michigan.
In addition to the uncertainty of the placement of the heaviest
snow, there is also a small potential for freezing rain or sleet
to the southeast of the low center as it passes over the area.
As of this morning northwest Wisconsin has the best chance of
less than a tenth of an inch of ice accumulation Friday evening.
The freezing rain potential and placement are both likely to
change, so please keep up with the latest forecast over the next
few days.

Looking ahead into next week, there remains a potential for
another round of precipitation during the early part of the
week. While deterministic and ensemble guidance appears to have
shifted the focus of accumulating snow farther south with the
00Z suite, it`s not far enough south to expect it won`t impact
our area. Another several inches of snow are possible Sunday
night through Monday evening.

Temperatures Friday and Saturday will trend a little warmer
while remaining below normal for late March. Temperatures will
likely cool down by several degrees in the wake of the Sunday
night/Monday system.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1251 PM CDT Wed Mar 27 2024

Conditions range from MVFR to IFR across much of the region with
some VFR conditions in western areas as some clearing is seen on
the edge of the expansive cloud deck from the low pressure on
the west side of James Bay. Snow showers underneath the cloud
deck have been on the vigorous side with VSBY reductions down to
around 1SM or less at times. These IFR to LIFR VSBYs have been
pretty short in duration, so have treated with TEMPO groups to
cover this threat with prevailing conditions holding at MVFR to
IFR. Some snow squalls will be possible at times this afternoon
which may reduce VSBYs to nearly zero for brief periods. Snow
showers are expected to taper off after sunset for the most part
with VSBYs returning to VFR this evening. Ceilings will be a
bit slower to rise over parts of the region tonight, but most
areas are expected to be VFR by daybreak, although some pockets
of MVFR may linger into the mid to late morning hours. Winds
will remain breezy from the west into tonight with gusts to 20
to 25 knots.

&&

.MARINE...
Issued at 436 AM CDT Wed Mar 27 2024

Cold air pouring southeastward across western Lake Superior
will continue through Thursday. Gusty northwest winds this
morning will back westerly this morning and may continue to back
southwesterly by this evening. Sustained winds of 10 to 25
knots with gusts to 30 knots are expected through Thursday. We
have extended the Small Craft Advisories for all of the
nearshore waters until 7 PM Thursday. In addition to the gusty
winds, light snow will change to snow showers this afternoon.
Visibility in the showers will dip below 1 mile at times.
Another low pressure system is forecast to traverse the region
from west to east between Friday and Saturday evening. Wind and
waves will likely become hazardous for smaller vessels Friday
afternoon through Saturday morning.

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Winter Weather Advisory until 7 PM CDT this evening for MNZ010-
     011-018-019.
     Winter Weather Advisory until 10 PM CDT this evening for
     MNZ012.
WI...None.
MARINE...Small Craft Advisory until 7 PM CDT Thursday for LSZ121-
     140>148-150.

&&

$$

DISCUSSION...Huyck
AVIATION...BJH
MARINE...Huyck


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