Lake Vermilion Area Weather – WEEKEND – Dec. 20-22

–

KEY MESSAGES

– Lingering lake-effect snow on the South Shore will taper off this morning.

– Chilly weather tonight with lows falling to the single digits to teens below zero, coldest in northeast Minnesota.

– A clipper may bring a few inches of snow Sunday night into early Monday morning.

– Generally quiet and mild weather for Christmas Eve and Christmas Day.

AREA FORECAST DISCUSSION

Issued at 308 AM CST Fri Dec 20 2024

Dry and cold air is quickly filtering in with north to northwest
flow across northeast Minnesota early this morning, while lake-
effect snow persists across the South Shore. As winds continue
transitioning to northwesterly, the lake-effect snow will pivot
east towards Iron County by sunrise, then taper off to just
clouds or flurries this afternoon as drier air moves in.

Sunshine is expected to be plentiful today for the most part,
but there may be just enough low-level moisture and mixing to
produce some scattered stratocumulus in places. A jet max over
the Dakotas/Montana will slowly slide east today into Saturday,
and an attendant series of weak upper-level waves will likely
bring some broken to overcast clouds over the western and
central parts of Minnesota, and perhaps a little light snow
around Saturday into Saturday evening (accumulations less than
half an inch).

For tonight, surface high pressure centered just north of Lake
Superior is expected to keep skies mostly clear and winds light
with a cold air mass in place. Temperatures are expected to fall
into the single digits to teens below zero, with the coldest
lows around the Arrowhead where the chances for clouds is
lowest. Wind chills are not expected to be much of a factor with
the high pressure nearby keeping winds light. While chances are
low (10% or less), it wouldn`t be too surprising to see some
lake-effect flurries around western Lake Superior tonight with
the cold air mass in place. But, confidence is not high enough
to include any PoPs at this point.

Warm air advection develops Saturday with an aforementioned weak
trough passing by, which could produce a little light snow.
Winds pick up from the south Sunday night, and we`ll look for
highs in the 20s on Sunday with increasing clouds due to an
approaching clipper system from the west. This clipper may have
some decent moisture to work with (PWATs 0.4″-0.6″), but it
should be passing through pretty quickly. We`ll have to keep an
eye out for some fgen banding that could produce some advisory-
level snows locally, but otherwise, it looks like a fairly
typical and not-too-threatening clipper that could bring the
usual 1-3 inches for some parts of the region sometime around
Sunday night into Monday morning.

Broad ridging is looking most likely on Christmas Eve and
Christmas day, keeping the weather generally quiet and mild
(highs in the low to mid 30s).

The ridging may break down going into Thursday, and there are
hints at a deeper upper-level troughing pattern setting up over
the Midwest. This could lead to some more active weather to end
the week into next weekend.

AVIATION

Issued at 544 AM CST Fri Dec 20 2024

All Minnesota terminals have cleared to VFR and are expected to
remain VFR through today. The only slight caveat may be the
eventual development of some stratocumulus clouds today, but
with such a dry air mass moving in, coverage is expected to be
scattered at the most. At HYR, MVFR ceilings persist the next
couple hours or so with lake-effect clouds and light snow
showers. As winds continue to become northwesterly, these clouds
are expected to move off to the east, and HYR will see VFR
conditions. After sunset, there could be some fog development
that could persist much of tonight. Added in some MVFR
visibilities to most Minnesota terminals tonight to account for
this possibility, but confidence is only around 50% that it will
happen since the air mass should be dry and perhaps result in
more frost than fog.

MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR

Issued at 308 AM CST Fri Dec 20 2024

Gusty north to northwest winds are expected to persist through
mid-morning, then lighten up through mid-day and this
afternoon. Wave heights up to 5 ft persist around the Bayfield
Peninsula and Outer Apostle Islands through this morning as
well. Small Craft Advisories are in effect through this morning.
Wind speeds remain light with gusts less than 20 kt through
Saturday. Winds become southerly going into Saturday, and some
wind gusts to 20 to 25 kt and waves up to around 4 ft (20-30%
chance) are possible Saturday night into Sunday.

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