Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 090530

Area Forecast Discussion
National Weather Service Duluth MN
1130 PM CST Thu Dec 8 2016

Issued at 1023 PM CST Thu Dec 8 2016

We updated to increase POPs and snow amounts along the South
Shore, especially in northern Bayfield and far northeast Douglas
Counties. We received a report 4 miles east of Iron River of 9.2
inches as of 945 pm. 3.5 inches of that fell since 4 pm. There has
been heavier snow showers that continue to impact that area,
although they are not quite as widespread as earlier this evening.
Both the RAP and NAM shows the low level winds backing slightly
overnight which should shift the snow showers further east.

UPDATE Issued at 546 PM CST Thu Dec 8 2016

Snow showers continued over portions of the Northland this evening
with them most numerous along the South Shore and over parts of
the Iron Range/Arrowhead. We made some minor adjustments to the
forecast early this evening to account for the latest
radar/observation trends.


.SHORT TERM...(This evening through Friday)
Issued at 315 PM CST Thu Dec 8 2016

Lake effect snow gradually winds down through the rest of the work
week as temperatures continue to fall. An additional 4-8" are
possible for parts of Iron county tonight into Friday, but elsewhere
snow will start to wind down tonight as high pressure builds in from
the west. Occasional flurries as well as lake-effect snow off some
of the larger inland lakes (such as Lake of the Woods and Leech
Lake), but for the most part accumulating snowfall will come to an
end tonight.

On the synoptic scale a the upper low which brought much of the snow
that`s on the ground across the Northland is well off tot he
northeast while a mid-level shortwave ridge moves across the upper
Great Lakes region tonight into Friday. An associated area of high
pressure will build in from the west through Friday. As this ridging
builds in mid-level moisture will continue to decrease as depicted
by the clear skies across much of the Dakotas on visible satellite
this afternoon, with breaks in the clouds also visible in parts of
the Upper Midwest. Tonight into tomorrow this mid and high level
clouds will exit the region but at least some broken low-level
stratus clouds will continue to persist across the region.

At this point based on the latest guidance it seems like the Lake
Effect Snow Advisory and Warning are a bit too aggressive with their
length, and given current trends the Advisory for at least Bayfield
county may be able to be cancelled early tonight. As this mid-level
ridging builds in some low level winds will turn more west-
northwesterly leading to low level wind shear which, combined with
the ever-decreasing column moisture, may lead to lake effect snow
processes diminishing over the very short fetch available for
Bayfield county. This will also impact the lake effect snow
processes impacting the Gogebic Range as fetch becomes more west-
northwesterly by Friday afternoon, which could cause snow showers to
gradually come to an end on the Wisconsin side of the range. It`s a
complicated scenario, and since the Advisory and Warning already go
out pretty far decided just to leave them be for now and let later
shifts evaluate the situation.

.LONG TERM...(Friday night through Thursday)
Issued at 315 PM CST Thu Dec 8 2016

The extended begins with a shortwave skirting through Ontario. Will
see the 1000-850 hPa winds shift to a westerly direction Saturday
morning. This will bring lake effect snow to an end across the South
Shore of Lake Superior. Winds will shift to a more easterly
direction late on Saturday into early Sunday, which may bring lake
effect snow showers to the North Shore of Lake Superior. The main
concern is the amount of moisture available, but still think there
is enough moisture to warrant low precipitation chances at this
point in time.

The main focus in the long term is the wave ejecting through the
Pacific Northwest into the Northern Plains on Saturday. This wave
will quickly move southeastward into the Central Great Lakes by
early Sunday morning. The latest forecast guidance is still in
disagreement with the strength of the wave and the attendant surface
low. The NAM has continued its trend of a stronger system moving
through, however the ECMWF/GFS/CMC continue show a weaker and faster
wave move through. Leaned on a blend of the GFS/ECMWF/CMC which
brings the Northland light snow accumulations from the Brainerd
Lakes region to the Park Falls area. The wave still remains
offshore, so will need to keep a close eye on this system.

Broad troughing will continue across the CONUS through next week.
Will see a cutoff system move into northern Saskatchewan/Manitoba
and slowly rotate southeastward into Ontario/Hudson Bay by mid week
depending on the long term forecast guidance used. Expect lake
effect snow shower chances across the South Shore of Lake Superior
from Tuesday to Thursday due to northwest flow. Expect some of the
coldest temperatures of the season mid to late next week with highs
in the single digits below and above zero. In addition, wind chills
will be a concern with values in the teens and 20`s below zero.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1130 PM CST Thu Dec 8 2016

A mix of MVFR and VFR ceilings continued over the Northland this
evening and that will continue for several more hours but MVFR
ceilings are expected to become prevalent later tonight into
Friday morning. Snow showers continued over portions of the Iron
Range into northern Wisconsin, with flurries elsewhere. We expect
flurries or light snow showers to continue over much of the
Northland tonight with heavier lake effect snow showers along the
South Shore tonight into at least early Friday morning. Low level
winds will back which should cause the snow showers to become
lighter and less numerous. Mainly MVFR ceilings will gradually
lift from west to east late in the period.


DLH   9  13   0   9 /  50  10   0   0
INL   7   9  -5   6 /  30  30  20  10
BRD   7  10  -3  10 /  20  10   0  20
HYR  12  16   3  13 /  20  10  10  10
ASX  16  18   7  14 /  70  40  20  10


WI...Lake Effect Snow Warning until 6 AM CST Saturday for WIZ004.

     Lake Effect Snow Advisory until 3 PM CST Friday for WIZ002-003.

LS...Small Craft Advisory until 6 AM CST Friday for LSZ121-140>142-



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