Lake Vermilion Area Weather – February 3-5

KEY MESSAGES

– Cold and breezy tonight. A Cold Weather Advisory is in effect for the Arrowhead with wind chills as low as -30 expected.
– Light snow is expected Wednesday night with a 40-90% chance for 3 inches of snow (or more).
– Another system could bring light snow to parts of the region around Saturday. The best chances for accumulating snow are south of the Twin Ports (~60% chance).

DISCUSSION

Issued at 243 PM CST Mon Feb 3 2025

A weak upper level trough and cold air advection are promoting
an area of light snow this afternoon across northeast Minnesota.
Visibilities down to around a mile have been reported at times
north of the Iron Range. Additional localized accumulations up
to half an inch may be possible this afternoon, but for most
places it should be less. Dry air will creep its way in this
evening, ending the light snow broadly, though strong cold air
advection could kick off a few flurries or light snow showers
along the South Shore tonight with strong over-lake instability
(850 hPa temps dropping to the -25 to nearly -30 range). Not
expecting much for accumulation since we will lose most moisture
and synoptic support.

The other story for tonight, and really the main story, is some
cold temperatures. The cold air mass moving in will lead to
temperatures falling into the single digits to teens below zero
(coldest in northeast Minnesota). With high pressure still well
to the northwest, a tight pressure gradient will remain and wind
gusts to 20 mph will be common (up to 25 to nearly 30 mph at
times in the Arrowhead due to downsloping along the North
Shore). Wind chills around -20 to -25 are expected nearly
everywhere. Some places in northeast Minnesota may drop down to
-30. We issued a Cold Weather Advisory for the Arrowhead, where
confidence is highest in the combination of winds and cold
temperatures leading to the lowest wind chills tonight. It is
possible that some other places in northeast Minnesota could
see some brief -30 wind chills as well, though they should be
more spotty.

High pressure gradually swings east across the region Tuesday
into early Wednesday, leading to some quiet but also somewhat
chilly weather. Another night with lows falling below zero is
expected Tuesday night, though winds should be much lighter,
keeping wind chill values closer to the air temperature.

The next eventful weather arrives Wednesday afternoon in the
form of a somewhat hybrid storm system, with a clipper skirting
across the Canadian Border and another low across the central
Plains. Widespread warm air advection out ahead of these lows
will promote an area of widespread light snow across the region.
Confidence continues to be high with around a 40-90% chance for
3″ or more. Models are generally in good agreement with timing
and QPF, with QPF around a quarter of an inch. That said, there
is still some wiggle room for things to change. The main thing
will be timing where the snow develops with the warm air
advection. If it starts a little later than models currently
suggest (i.e. further northeast), some parts of the region (e.g.
west and south) could see lower-end snow totals. Colder
temperatures should support a thermal profile settled closely
within the DGZ to the northeast, which gives places like the
Arrowhead the best chance of seeing the 5 or 6 inch amounts. As
was mentioned in the previous discussion, Extreme Forecast Index
is approaching 1 in QPF (suggesting anomalously high values for
this time of year), but Shift of Tails is low, which suggests
that very high snowfall amounts over what is currently forecast
are not likely. It wouldn`t be surprising to see some ~6″
amounts, especially in the Arrowhead, depending on what snowfall
ratios end up being. But, at this time, amounts much higher than
that don`t appear likely.

Temperatures will support snowfall ratios that will generally be
in the 10-18:1 or so (higher to the north). This snow will be
able to be blown around, and while winds are not expected to be
terribly gusty Wednesday night when the snow is falling, it will
quickly increase from the west as cold air starts to filter back
in. So, some breezy conditions as the snow is winding down
Thursday morning, leading to a bit of blowing snow, then
increasing winds gusting to 30 to perhaps 35 mph Thursday
afternoon which should lead to some more blowing and drifting
snow after it generally stops falling. There is a possibility
for some lingering snow showers and perhaps a few snow squalls
(10-20% chance) Thursday afternoon as steep lapse rates develop
in the post-cold frontal air. The strong winds and some
frontogenesis will be there, but dry air may be the limiting
factor in snow squall potential, so we will have to continue
monitoring that possibility. If any snow showers do develop, the
combination of gusty winds with them could lead to some low
visibilities and hazardous driving conditions.

We will be in-between systems on Friday, so generally quiet
weather is expected then. But, another low pressure system is
looking likely going into Saturday that may impact a good
portion of the region. There are still plenty of storm track
differences with this one, so low to medium confidence at this
time on where accumulating snow is most likely. Most models
bring the main band of frontogenetically-induced snow through
central Minnesota, but that could certainly change. QPF and
snowfall amounts could change too, but in general, it looks like
another potentially advisory-level event for the places that see
the heaviest snowfall amounts.

AVIATION

Issued at 538 PM CST Mon Feb 3 2025

Northwest winds with areas of MVFR stratocumulus are spread
across the area this evening. colder and drier air moving in
from the west will help dissipate the MVFR clouds, gradually
returning all terminals to VFR conditions by 06z. Overnight, the
northwest flow will help generate MVFR stratus along the south
shore, but for now the ceilings appear to stay northeast of
KHYR. Winds will decrease overnight to less than 10kts by 09z,
the remain light with VFR conditions through the end of the TAF
period.

MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR

Issued at 243 PM CST Mon Feb 3 2025

Gusty northwest winds are expected tonight through early Tuesday
morning. Gusts up to 25 to nearly 30 knots are expected along
the nearshore zones tonight, strongest along the Outer Apostle
Islands. Wave heights rising to around 6 ft there will also
promote the possibility for some heavy freezing spray. Small
Craft Advisories have been issued starting this afternoon and
lingering through early Tuesday morning for all nearshore zones
and a Heavy Freezing Spray Warning is in effect as well for the
Outer Apostle Islands. Winds become much lighter Tuesday through
Wednesday. Gusty westerly winds develop again Thursday with
another snowy system moving through. Widespread wind gusts to
around 25 to 30 knots are likely (80-90% chance), and some gales
to around 35 knots are possible as well (~50-60% chance).

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

WATCHES/WARNINGS/ADVISORIES

MN…Cold Weather Advisory from midnight tonight to 9 AM CST
Tuesday for MNZ012-021.
WI…None.
MARINE…Small Craft Advisory until 7 AM CST Tuesday for LSZ140>142-150.
Small Craft Advisory until 4 AM CST Tuesday for LSZ143>148.
Heavy Freezing Spray Warning from 10 PM this evening to 6 AM
CST Tuesday for LSZ150.