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Area forecast discussion
National Weather Service Duluth Minnesota
539 PM CST sun Dec 15 2019

Short term...(this evening through Monday night)
issued at 250 PM CST sun Dec 15 2019

An upper level short wave trof was moving through Minnesota
accompanied by a vorticity maxima and warm air advection. This
combination was generating some snow showers. This wave will
continue to move through the forecast area this afternoon, but the
snow will diminish from west to east with its departure. Some snow
showers/flurries will still be found along the shore of Lake
Superior due to some lake effect processes.

Another short wave trof follows behind the aforementioned trof
tonight and will produce a few more snow showers/flurries. Greatest
potential for this activity will be along the Borderland, and near
Lake Superior. Snow accumulations will be minor.

The parade of short waves in the northwest flow aloft, will continue
to affect the area on Monday. However, dry air will be in place
ahead of this next wave and the majority of the day will be dry. By
late afternoon, enough moisture arrives from the west for an
opportunity for additional snow showers/flurries along the
Borderland.

Another wave crosses the area Monday night accompanied by a cold
front. Moisture is limited for these features to work with, but
additional snow showers/flurries will dot the landscape as forcing
will be sufficient.

Long term...(tuesday through sunday)
issued at 250 PM CST sun Dec 15 2019

Cold start to the long term with snow showers and cold wind
chills expected. Temperatures begin to warm Wednesday night and
will trending above normal Friday and Saturday.

In the wake of an Arctic cold front Tuesday, strong northwest
winds will bring another shot of cold air into the region. There
will be a chance of snow showers, mainly over far northern
Minnesota, and into the northwest Wisconsin snowbelt areas. Winds
subside and skies clear as surface high pressure moves overhead
Tuesday night and Wednesday. Look for efficient radiational which
will yield low temps in the single digits and teens below zero. A
few spots may dip into the -20s Wednesday morning. Wednesday will
remain cold with highs in the single digits above zero.

An upper-level ridge will build over the northern plains and will
shift the flow aloft into a more zonal configuration. The
westerly winds will bring warmer temperatures for the remainder
of the week. A weak impulse will move through the Minnesota
arrowhead Wednesday afternoon and evening and may squeeze out a
few snow showers. Another chance of light snow is in the picture
for Saturday into Saturday night, but models diverge on the
evolution of the upper wave. For now have downplayed precip
chances during that period.

&&

Aviation...(for the 00z tafs through 00z Monday evening)
issued at 538 PM CST sun Dec 15 2019

A trough of low pressure, cold front, and shortwave aloft will all
affect the Northland tonight at varying times. MVFR ceilings and
areas of light snow or flurries will occur through much of the
night across the region...and into Monday morning over far
eastern Minnesota into northern Wisconsin. The ceilings will lift
or become scattered through the day Monday to VFR conditions.

&&

Marine...
issued at 250 PM CST sun Dec 15 2019

Southwest winds over Western Lake Superior continue tonight and
wind speeds will increase as the pressure gradient tightens this
evening. Sustained winds of 10 to 20 knots are expected and a few
gusts to 25 knots are possible tonight, mainly for waters on the
northern and northwestern portions of the Bayfield peninsula. A
Small Craft Advisory is in effect from 10 PM until 10 am. Winds
will subside Monday morning.

Attention then shifts to a cold front and a period of strong
northwest winds Tuesday and Tuesday night. Winds will start from
the west and will veer northwesterly by late Tuesday morning.
Wind speeds increase to 10 to 20 knots with gusts 25 to 30 knots
possible. Occasional gale-force gusts to 35 knots are possible.
The strongest winds will be along the South Shore. The wind
speeds will decrease late Tuesday night and winds will back
southwesterly by late Wednesday morning.

&&

Preliminary point temps/pops...
dlh 0 11 -2 10 / 40 0 10 0
inl -1 7 -2 5 / 30 10 20 0
brd 1 12 0 13 / 0 0 10 0
hyr 1 15 -2 14 / 10 0 10 10
asx 4 15 2 15 / 20 0 10 10

&&

Dlh watches/warnings/advisories...
WI...none.
Minnesota...none.
Ls...Small Craft Advisory from 10 PM this evening to 10 am CST Monday
for lsz146-147.

&&

$$

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