Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 122050

Area Forecast Discussion
National Weather Service Duluth MN
250 PM CST Fri Jan 12 2018

.SHORT TERM...(This evening through Saturday)
Issued at 250 PM CST Fri Jan 12 2018

Main short term focus is on wind chill headlines again tonight into
Saturday morning. Enough of a pressure gradient tonight with the
arrival of the high pressure, combined with the clear skies, and
cold min temps, expect wind chill values to warning criteria over
the northern half of the forecast area. Advisory values over the
southern half. Duluth may touch warning criteria for an hour or two,
but not enough for a warning.

An upper level short wave trof will drop southward through the
forecast area tonight and Saturday morning before departing. At the
surface, the high pressure over the Northern Plains late this
afternoon will move over the region by Saturday afternoon. There is
virtually no moisture for this trof to work with and no
precipitation is expected. Even along the south shore of Lake
Superior, there is a dearth of moisture to work with. The wind is
becoming less favorable with time and only expect some occasional
flurries over the higher terrain tonight.

.LONG TERM...(Saturday night through Friday)
Issued at 250 PM CST Fri Jan 12 2018

The main areas of focus in the long-term are frigid temperatures
through the early part of next week, with another round of light,
widespread snow for Sunday.

Surface high pressure will be situated over southeast Minnesota
Saturday evening, with the high pressure ridge right over the
Northland. This, along with light winds, should support a period of
enhanced radiational cooling over the region. Some mid to high
clouds should move in from the west around midnight, ahead of the
next weather system to impact the area Sunday. Temperatures over the
west should be a bit warmer due to this cloud cover. Overnight lows
should range from the middle teens below zero over the west to near
20 below zero over the east. Looks like another night of wind chill
headlines will be in order.

Sunday will feature the aforementioned system that will bring a
round of light snow to nearly all of the Northland. A mid-level
shortwave trough will dive southeastward from the
Saskatchewan/Manitoba region. GFS/NAM model soundings both indicate
a fairly deep saturation within the dendritic snow growth zone of
around 6 to 7 kft. The GFS is showing a bit better isentropic lift
within this layer than previous GFS runs were showing, so increased
PoPs a bit over the consensus blends. This shortwave still looks to
be transient enough to limit the snow amounts, but still thinking
around 1 to 3" of new snow will be possible. The attention then
turns to a prolonged period of lake effect snow chances Monday
through Tuesday evening over the Lake Superior snowbelt. 1000-850 mb
layer winds look to remain from the north, providing a favorable
fetch for lake enhancement.

Temperatures look to gradually warm up for the second half of the
upcoming week as another surface high pressure system will build
into the region. Southerly return flow will help to increase our
temperatures. High temperatures look to possibly return into the
middle 20s to near 30 Thursday and Friday.


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1127 AM CST Fri Jan 12 2018

VFR conditions through the TAF period as high pressure situated
over North Dakota should remain in control through Saturday. The
main focus for this set of TAFs is the potential for MVFR and
possibly IFR ceilings and visibilities at KHIB due to upstream
anthropogenic sources. Current GOES East satellite imagery shows
the plume of clouds from these sources inching towards KHIB, so
maintained the TEMPO group from the previous KHIB TAF for the
next few hours.


DLH -19   1 -13   7 /   0   0   0 100
INL -28  -2 -18   7 /   0   0  10  80
BRD -23   2 -13  10 /   0   0   0  90
HYR -20   2 -18   8 /   0   0   0 100
ASX -12   4 -14  10 /  10   0   0  90


WI...Wind Chill Advisory from 9 PM this evening to 9 AM CST Saturday
     for WIZ001>004-006>009.

MN...Wind Chill Warning from 9 PM this evening to 9 AM CST Saturday
     for MNZ010>012-018>021-025-026.

     Wind Chill Advisory from 9 PM this evening to 9 AM CST Saturday
     for MNZ033>038.

LS...Small Craft Advisory from 8 PM this evening to 4 AM CST Saturday
     for LSZ143-144.

     Small Craft Advisory from 6 PM this evening to 4 AM CST Saturday
     for LSZ140>142.



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