Lake Vermilion Area Weather – Dec. 7-9

KEY MESSAGES

– A messy winter system will move in tomorrow producing heavy

  wet snow across northern MN. Areas further south will see a

  mixed bag of precipitation with some ice accumulations

  possible

– Lingering snow chances for Monday as the Clipper moves into Lake

  Superior.

– A blast of arctic air midweek will see temperatures rapidly

  dropping Wednesday.

DISCUSSION

Issued at 402 PM CST Sat Dec 7 2024
Current Conditions/Tonight:
A weak clipper is exiting to our east across northern Lake Superior
this afternoon with west to southwesterly winds filtering in behind
the system. Skies have rapidly cleared faster then previously
forecasted allowing for temperatures to over achieve this afternoon
with highs in the 40s across much of the region. Cloud cover is
expected to return tonight ahead of an approaching system which
should help to insulate some of these temperatures with overnight
lows staying in the 20s. We may also see some advection fog come
into play briefly across north central MN before day break.
Sunday Next Wintry System Setup:
Sunday a pair of lows will bring a mix of rain and snow back to the
Northland. The primary low is of the clipper variety traversing
across Saskatchewan Sunday and entering MN on Monday. The secondary
Low is set to move into southern MN Sunday afternoon before
weakening on Monday and rejoining the parent circulation over Lake
Superior. Looking at the ALPW we can see a plume of moisture
extending from the Cascades and across southern Canada. This added
moisture pushes our PWATs to around 0.70 inches which is over
the 95th the percentile of climatology.
Mixed Bag of Precipitation (Sunday morning/afternoon):
These higher PWATs and ample forcing would normally translate into a
simple snow forecast but we can`t get that lucky. For this upcoming
set up we have several wrenches being thrown into the forecast.
Above freezing surface temperatures with a warm nose aloft will lead
to some mixed precipitation issues. There is also a dry slot
forecasted to move in Sunday evening which could eat away at
overall precip totals or lead to some widespread freezing
drizzle. Factoring in the over achieving temperatures today we
have seen quite a reduction in ice accumulations for tomorrow
based on surface temperature alone. The latest high res guidance
suggests having the rain snow line stretching from Cass down
through Burnett. Within this sector stands our best chance of
seeing some freezing rain and ice accumulations. While the
overall total ice has been reduced it seems Cass County could
see a tenth of an inch of ice and has been added to a Winter
Weather Advisory.
Snow (Sunday):
As mentioned previously the warmer temperatures throw numerous
problems into the snowfall forecast but for the most part northern
MN is favored to see mostly snow. Our SLRs are going to be on the
low side leading to more of a wet concrete type of snow that tends
to stick to trees and powerlines. A tight temperature gradient
over the region will also lead to strong FGEN bands. Some banded
snow segments will also be possible in northern MN as the
parent surface low moves across the International Border through
Monday. The current forecast package captures the initial push
of snow well with the highest rates coming in Sunday afternoon
and evening. Snowfall rates largely drop as we head into Monday
but this may be slightly underdone as favorable mid level lapse
rates coincide with a band of FGEN at 925mb across northern MN.
Winter Weather Headlines:
Overall, wet heavy snow is expected across northern MN with some
mixed bag precipitation across north central MN into NW WI. Terrain
and lake effect boost for the North Shore will lead to the highest
snowfall totals in excess of 6 inches along the elevated terrain of
Cook county. The preponderance of warm air at play associated
with this system will lead to a sharp gradient in snowfall
totals across northern MN. A Winter Warning has been issued for
southern Cook County and Winter Weather Advisories have been
issued for northern MN and Cass County.
More snow chances (Monday):
Monday will see the clipper system moving over Lake Superior with a
cold front sweeping in from the west. Gusty winds and wrap around
moisture will be falling as snow through the day. As mentioned above
there is some concern for some over achieving snow showers as
steeper mid level lapse rates interact with a FGEN band around 925mb
across northern MN. Temperatures will be flirting around freezing
for the day before tanking with the passage of the cold front.
Blast of Arctic Air (Wednesday):
Through the remainder of the week we will maintain our NW flow
with embedded moisture in the pattern. Off and on light snow and
flurries will be abound. Warm Lake Superior will be producing
ongoing snow chances for the South Shore once again. A blast of
arctic air is expected to barge in from the north on Wednesday
with highs in the single digits across most of the Northland.
This may lead to a Cold Weather Advisory on Thursday morning.

AVIATION

Issued at 515 PM CST Sat Dec 7 2024
MVFR conditions were spreading south through far northern
Minnesota this evening and that trend will continue with ceiling
lowering further overnight to low MVFR into IFR. Fog will also
be possible with a IFR/MVFR visibility. There will also be low
level wind shear in spots this evening.
A low pressure system will bring precipitation to the region
Sunday into Monday. Warmer air over southern portions of the
Northland will lead to mixed precipitation from freezing rain to
light snow to just rain. Far northern Minnesota will see mainly
snow. The snow could be heavy at times over mainly the North
Shore.

MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR

Issued at 402 PM CST Sat Dec 7 2024
Westerly winds are expected to taper off this evening with a breif
lull in Marine headlines through tomorrow morning. Another clipper
system entering from the west will lead to an enhancement of NW
winds and additional hazards for small vessels. Expect a
prolonged period of enhanced winds once again through Thursday.
For the open water discussion, refer to the NWS Marquette Area
Forecast Discussion at weather.gov/mqt.