936
FXUS63 KDLH 232339
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
539 PM CST Sat Nov 23 2024

.KEY MESSAGES...

- Generally quiet weather for most tonight into Sunday.

- Chances for light snow Sunday night into Monday night have
  increased. Amounts have risen, with at least a 60% chance for
  1"+ for the Arrowhead and along the snow belt of the South
  Shore. The chance for 4"+ is less than 25 percent for all but
  some isolated areas of northern Minnesota.

- No large storm systems currently expected in the extended
  period and temperatures will cool after Sunday with much
  colder air arriving late week. Highs by Friday will be 5 to
  15 degrees below normal.

- Lake effects are likely to bring an extended period of light
  snow to the South Shore Wednesday through next weekend.

&&

.DISCUSSION...
Issued at 416 PM CST Sat Nov 23 2024

Things have been relatively quiet today, with stratus lingering
over far northern MN and higher clouds to the south as a
surface low developing over eastern WY pushes warm air in our
direction. Have kept temperatures on the warmer end of guidance
tonight and Sunday with that warm air advection going on. The
surface low slides southeast across Kansas on Sunday, then to
Illinois by Monday, and southern Ontario Tuesday. An inverted
trough extends from this surface low north to across the
Northland, and simply changes orientation as the low moves east.
An upper level shortwave over southern Saskatchewan moves from
southern Saskatchewan Sunday to southern Alberta Monday, then
finally to Lake Superior Tuesday. These features combined should
help to produce snow over the Northland beginning sometime late
Sunday, continuing through Sunday night into Monday before
tapering off to flurries by Tuesday. A lot of the recent model
runs have come in noticeably wetter than the previous run, but
seems to be reasonably well supported by the short range
ensembles, with the WPC plumes showing the current forecast
right in the middle of the operational model plumes. However,
between the change in this set of models and the large spread in
the QPF, have decided to hold off on issuing any winter
headline, though the current forecast would produce enough
accumulating snow to warrant a Winter Weather Advisory. Will let
the 00z set of models come in before making that call. The
heaviest snowfall accumulations should be late Sunday night
into Monday morning for the Arrowhead, with lake effect snow
showers lingering into Tuesday at a steadier, slower rate. While
I have some decent total accumulations along the South Shore,
the rates should be low enough that we will not need an advisory
there.

The extended part of the forecast is generally quiet with no
large storm systems to contend with. Our Sunday into Monday
system will slowly exit off to the east, with the inverted
trough extending back over the Lake Superior gradually breaking
down Tuesday into Tuesday night. A weak surface ridge will slide
into the area for Wednesday. An upper level trough with an
embedded shortwave will cross the Rockies Wednesday, causing a
surface low to develop over SE Colorado, which will then slide
east and move up the Ohio river valley, leaving the Northland in
northwest flow through next weekend with colder air slowly
moving into the area. This will leave us with a good pattern for
lake effect snow, especially from Wednesday night through
Saturday. Have boosted pops along the South Shore through the
extended.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 539 PM CST Sat Nov 23 2024

MVFR stratus has been more persistent in lingering across
northern Minnesota and both observational and model trends show
this stratus slowly expanding southward this evening and
tonight. Therefore, I bring MVFR ceilings back into KDLH this
evening and have it persist at KDLH/KHIB/KINL through Sunday
morning. Confidence is lower in this stratus reaching KBRD or
KHYR, so have kept those TAF sites VFR through the TAF period.
There may be a brief window of time Sunday afternoon when
northeastern Minnesota terminals see ceilings improve to VFR in
a warm advection regime, but this would be short-lived as a
clipper system scooting east out of the Canadian prairies brings
a return of light snow/wintry mix to the Northland starting on
Sunday evening and increasing in coverage into Sunday night and
early Monday. Expect ceilings and visibilities to rapidly
deteriorate after the current TAF period as this precipitation
moves through.

Light northerly winds this evening veer to easterly tonight and
Sunday. Daytime wind gusts could reach to around 14-18 knots,
locally highest for KDLH and locations along the North Shore of
Lake Superior.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 416 PM CST Sat Nov 23 2024

Northwest winds of less than 15 kts to gradually diminish and
back into the northeast tonight. Winds will increase out of the
northeast to east on Sunday at 10 to 20 knots with gusts up to
25 knots Sunday afternoon and evening. Conditions will become
hazardous for smaller vessels for much of the nearshore waters
with the highest wind/wave combination occurring from Two
Harbors to Duluth to Port Wing. Small Craft Advisories will
likely be needed for portions of the area. The wind will back to
north to northwest Monday with speeds remaining 10 to 20 knots
with higher gusts. Winds will increase a bit more Monday night
before decreasing Tuesday.

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...None.

&&

$$

DISCUSSION...LE
AVIATION...Rothstein
MARINE...LE