Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 150201

Area Forecast Discussion
National Weather Service Duluth MN
801 PM CST Tue Nov 14 2017

Issued at 759 PM CST Tue Nov 14 2017

Dense fog continued to develop across much of the Northland,
particularly across northeast Minnesota. Have issued a Dense Fog
Advisory. With a cold front moving in overnight, we should
gradually see improvement in the west during the early morning
hours, and across the rest of northeast Minnesota during the
remainder of the night. Will need to watch northwest Wisconsin for
the possibility of dense fog as well, although so far, it is not
too bad across that area.


.SHORT TERM...(This evening through Wednesday)
Issued at 311 PM CST Tue Nov 14 2017

A baggy area of low pressure currently over the eastern Dakotas will
slowly move east tonight. Meanwhile, a mid level trof will accompany
a slow cold front that will reach the western half of the forecast
area by midnight. The airmass will change little ahead of these
features and expect fog to prevail tonight. Rain will develop just
ahead of the front with the highest likelihood over northwest
Wisconsin. This is where the best upward vertical motion will be
found in response to an upper level impulse, and upper level
divergence from an approaching jet. Surface temps will be warm
enough for the ptype to be rain, although some light snow may mix in
over the higher terrain of Cook County late tonight. The baggy low
and the mid level trof reach the eastern edge of the region by
Wednesday morning. The favored location for rain will continue to be
along and ahead of the front. Strong cold air advection begins late
tonight over western Koochiching County where 850mb temps will go
from the single digits celsius to near -6C by 12Z Wednesday. The
ptype becomes all snow over Koochiching and begins to mix in over
inland Cook County.

With the arrival of the cold air behind the front, which is east of
the area by 9am, the fog will diminish quickly behind the cold
front. Before the rest of the warm air is eroded Wednesday morning,
some rain/rain snow mix is expected over the eastern edge of the
region. All snow elsewhere, especially in the afternoon. The cold
air surges over the rest of the area with 850mb temps dropping to
near -10C. Up to one half inch of snow accumulation is possible by
the end of the day over the higher terrain of northern St. Louis,
Lake and Cook counties. Lake effect snow processes begin late in the
afternoon over the Gogebic Range. A quick burst of accumulating snow
is possible and may see an inch by the end of the day.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 311 PM CST Tue Nov 14 2017

Near-seasonable temperatures for the rest of the work week before
another arctic blast Friday night through Sunday leading to well
below normal temperatures, though at this point conditions do not
appear favorable to break any low temperature records or record low
max temps. It will feel very cold due to strong winds Saturday,
though, with wind chill values in the single digits through the
afternoon. After lingering south-shore lake effect snow Wednesday
night skies will briefly clear out Thursday before increasing
towards Thursday night as warm air moves into the region ahead of a
cold front. A wintry mix is expected to begin in the evening hours
of Thursday night, changing to mainly rain through the day Friday,
then ending as snow Friday night as colder air moves in. Snowfall
accumulation is looking light due to the warm air that will advect
in, limited to just a few inches for the higher terrain of the MN
Arrowhead and little elsewhere. Lake effect snow lingers across the
south shore through Saturday night. Skies clear out Sunday with
highs in the 20s, then "warmer" with increasing clouds on Monday
with highs in the upper 20s to mid 30s. Beyond Monday yet another
push of colder air will move in from the north as a broad area of
high pressure builds in towards the Thanksgiving holiday.


.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 544 PM CST Tue Nov 14 2017

The widespread low clouds, fog and drizzle will continue across
the Northland tonight, but an improvement is in the offing for
Wednesday. Widespread IFR to LIFR conditions will prevail
overnight at the TAF sites, with fog, drizzle and low clouds. A
cold front moving through on Wednesday will bring in gradually
dryer air, along with some gusty northwest winds during the day.
Some lingering snow showers will be possible in the northern TAF
sites, especially at KINL. We should see a general improvement to
MVFR for most areas on Wednesday.


DLH  33  33  19  31 /  50  20   0   0
INL  30  30  14  29 /  30  60  10   0
BRD  31  31  19  34 /  30  10   0   0
HYR  35  36  22  33 /  60  30  10   0
ASX  36  38  25  33 /  60  30  30  10


MN...Dense Fog Advisory until 4 AM CST Wednesday for MNZ011-012-

     Dense Fog Advisory until midnight CST tonight for MNZ010-018-025-

LS...Small Craft Advisory until 10 PM CST this evening for LSZ140.



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