Area Forecast Discussion
Issued by NWS Duluth, MN

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042
FXUS63 KDLH 210540
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1140 PM CST Fri Jan 20 2017

.SHORT TERM...(This evening through Saturday)
Issued at 356 PM CST Fri Jan 20 2017

Summary: The Northland will be socked in with low cloud cover, as
well as periods of a wintry mixture of precipitation and
misty/foggy conditions, through Saturday.

An negatively tilted upper-trough will continue lifting north
through the Northern Plains and western Great Lakes region through
tonight. Synoptic lift ahead of the trough will produce an area of
rain and snow across parts of the Northland, primarily northern
Minnesota through this evening. There is just enough warm air in
the lower levels to help melt some of that snow, hence the mix of
rain and snow. The relatively warm temperatures, and progressive
movement of the precipitation, will likely result in little if any
accumulation. There could be light freezing rain in some areas
across northern Minnesota, such as the higher terrain of the North
Shore, this evening when temperatures fall and possibly approach
the freezing mark. Little if any icing accumulation is expected,
but roads could nonetheless be slick in some spots.

A thick layer of lower-level stratus will linger across the
Northland, in the wake of the passing upper trough and area of
rain/snow the rest of today and into Saturday. This saturated
layer may be thick enough to squeeze out drizzle at times, which
may be freezing drizzle in spots tonight and early Saturday where
the air and road surface temperatures get cold enough. For the
most part, though, not expecting much icing with air temperatures
staying slightly above the freezing mark for most areas.

Tonight will certainly be a misty one given the drizzle and
abundant moisture in the air. Areas of fog, true visibility
reductions for motorists, are possible, but not expected to be
dense...more in the 1/2 mile to 1 mile visibility range at times.

A somewhat stacked low will lift north from northern Iowa to
northwest Wisconsin through the course of Saturday. It will bring
another period of deeper moisture and synoptic lift to produce
some light rain, and at times a wintry mixture of rain and snow,
primarily across northwest Wisconsin, the Interstate 35 corridor
in east central to northeast Minnesota, and along the North Shore.
Little if any snow accumulation is forecast. The morning mist/fog
visibility reductions will likely improve by the afternoon,
except east flow from Lake Superior will likely maintain some fog
along the higher terrain near the Twin Ports and up the North
Shore.

.LONG TERM...(Saturday night through Friday)
Issued at 356 PM CST Fri Jan 20 2017

Wintry precipitation is expected Saturday night through Monday
with another system moving into the region around midweek.

A distorted Omega Block pattern will continue over the Plains and
Upper Midwest Saturday evening through Tuesday. A trough of low
pressure extending from the Canadian Prairies southeast into the
central Great Lakes will slowly weaken with several lobes of
vorticity gradually retreating northwestward. A wintry mix of
drizzle, freezing drizzle, and snow is likely Saturday night
through Sunday. There is still a possibility some areas along the
North Shore may receive around one-tenth of an inch of ice
accumulation during the period. However, surface and ground
temperatures will be the main driving factor at that time, so will
continue to mention that potential in the HWO and forecast rather
than hoisting headlines this afternoon. Drizzle, freezing drizzle,
and fog will continue on Monday as precipitation slowly ends from
south to north during the afternoon. Temperatures will remain
quite mild for late January.

A deep shortwave trough will move through the Southeast Monday
and Tuesday, finally breaking down the blocking pattern and
transitioning to a more progressive flow regime. A deep
positively-tilted longwave trough will move across the CONUS
Tuesday through the end of the week, with several shortwave
troughs and lobes of vorticity rotating through the Upper Midwest
and western Great Lakes. Precipitation chances will increase once
again Tuesday night and Wednesday beginning in our southern zones
and lifting northeastward by Wednesday afternoon. At this point a
rain/snow mix seems favored for most areas, with all snow in the
far northwest. Several inches of accumulation are possible.
Precipitation types change to all snow by Wednesday evening with
snow chances continuing through Thursday night with another couple
of inches possible. Temperatures will remain much above normal for
the remainder of the week, with a cooling trend moving highs and
lows a little closer to average Friday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1138 PM CST Fri Jan 20 2017

Widespread VLIFR to IFR conditions will continue across the
Northland TAF sites throughout the period, as an area of low
pressure lingers across the region. We will see areas of light
rain, freezing drizzle and snow across the Northland tonight and
on Saturday. This will cause some surface icing. CIG`s and VSBY`s
are expected to improve only slightly on Saturday, but probably
remaining in at least the IFR category.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  33  36  33  37 /  70  70  60  30
INL  32  37  30  37 /  90  40  50  40
BRD  33  36  31  38 /  30  50  40  20
HYR  33  38  33  40 /  40  70  50  20
ASX  33  38  33  40 /  80  60  70  30

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory until 10 AM CST Saturday for WIZ001>004-
     006>009.

MN...Winter Weather Advisory until 10 AM CST Saturday for MNZ010>012-
     018>021-025-026-033>038.

LS...None.
&&

$$

SHORT TERM...Grochocinski
LONG TERM...Huyck
AVIATION...DAP



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