Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 132112

Area Forecast Discussion
National Weather Service Duluth MN
312 PM CST Sat Jan 13 2018

.SHORT TERM...(This evening through Sunday)
Issued at 312 PM CST Sat Jan 13 2018

It will be another very cold night. The surface high pressure
ridge over the region will shift east through the Northland
tonight, at least providing clear skies and very light winds this
evening. Temperatures will drop quickly to well below zero. Light
southerly winds will develop later tonight in the wake of the
passing high pressure, and there will be increasing cloud cover
from the northwest due to an approaching Canadian Clipper. The
winds and cloud cover are expected to start increasing
temperatures later tonight into Sunday morning, so the coldest
temperatures tonight will likely be around midnight or so. Expect
lows of about 10 to 20 below zero, and a little warmer along the
North Shore. There will not be much wind tonight, but "wind"
chills may flirt with 25 below zero at times overnight into Sunday
morning. Decided these borderline very cold wind chills did not
warrant a wind chill headline for tonight.

A quick-moving Canadian Clipper will be dropping south out of
Manitoba into the Northern Plains and western Great Lakes region
Sunday. This Clipper will spread snow into the region with its
period of moderate to strong large-scale forcing for ascent.
Overall, snowfall with this passing Clipper will be relatively
light, about 1 to 3 inches for much of the Northland late Sunday
morning through Sunday evening. However, the far North Shore will
see about 3 to 5 inches thanks to some lake and terrain
enhancement. Have issued a Winter Weather Advisory for the North
Shore area of Cook County.

.LONG TERM...(Sunday night through Saturday)
Issued at 312 PM CST Sat Jan 13 2018

A closed upper low, with its associated surface low, will affect
the forecast area Sunday night through Monday as it moves south
southeast. Will have the highest pops Sunday evening, over the
eastern third of the region, which is on the northwest side of the
low center. This is where the best forcing will be found. Have
pops decreasing farther away from the low. This trend of
decreasing pops continues overnight. Pieces of embedded energy
rotating around the closed low will work in concert with an
inverted trof from the tip of the Arrowhead into the eastern
Wisconsin portion of the region. Have the highest pops in this
neighborhood late Sunday night. Another surge of Arctic air
arrives on the back side of this system with 850mb temps dropping
into the -20 to -25C range. It will be brisk with a tight pressure
gradient and the cold air advection occurring. The aforementioned
system moves into lower Lake Michigan Monday night. This will
gradually bring and end to the synoptic snow, but will crank up
the lake effect snow machine for the higher terrain areas of the
south shore of Lake Superior. Have the highest pops over Iron
county as they are traditionally the most likely to get decent
lake effect snow. This situation continues through Tuesday before
diminishing Tuesday night as high pressure takes control and the
low level flow turns to the west. Even though the upper flow
remains northwest, the mid level/surface flow turn to the west
with dry warm air advection Wednesday. The upper flow eventually
transitions to a more westerly direction, the mid and low level
flow maintains its westerly direction Thursday afternoon. This
trend continues through Friday morning with a dry forecast.


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 312 PM CST Sat Jan 13 2018

Widespread VFR conditions are expected through tonight thanks to
clear skies with passing high pressure. There will be increasing
cloud cover late tonight and Sunday from the northwest with an
approaching Canadian Clipper. This Clipper will spread snow and
widespread MVFR/IFR conditions into the region Sunday morning and


DLH -13   7  -6   2 /   0  90  50  10
INL -16   6 -13  -4 /   0  80  20  10
BRD -11  10 -13  -4 /   0  90  20  10
HYR -17   9  -1   7 /   0 100  70  20
ASX -14  11   4  11 /   0  90  70  50


MN...Winter Weather Advisory from 10 AM Sunday to midnight CST Sunday
     night for MNZ021.



SHORT TERM...Grochocinski
AVIATION...Grochocinski is the U.S. government's official web portal to all federal, state and local government web resources and services.