Area Forecast Discussion
Issued by NWS Duluth, MN

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038
FXUS63 KDLH 200254
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
854 PM CST Mon Feb 19 2018

.UPDATE...
Issued at 854 PM CST Mon Feb 19 2018

A lake effect band of snow continues over far northern Douglas
County, including the Superior area, through Fond Du Lac and into
southeast Carlton County. Spotters report snowfall around an inch
per hour in Superior and other observers have reported heavy snow
in parts of Duluth and far northern Wisconsin. We are leaning
toward upgrading the Winter Weather Advisory for Douglas, Southern
Saint Louis, and Carlton Counties to a warning for the heavy snow.
Overall the snow has diminished across these counties but that
band of heavy lake effect snow should continue for several more
hours and may gradually shift north as 850MB winds veer overnight.

UPDATE Issued at 757 PM CST Mon Feb 19 2018

The snow has diminished for now across much of northwest
Wisconsin with observations indicating most of the snow was
light. Snow has increased over northern Minnesota, especially from
the Walker and Longville areas northeast through the Iron Range
into the Arrowhead. This snow has developed quicker than expected
and adjustments to the forecast have been made. We increased snow
amounts some there as well, especially through the evening hours.
A band of heavier snow was also occurring through portions of the
Twin Ports into southeast Carlton County. This was partially
driven by lake processes and we increased snowfall there. We`ll
have to watch that area closely as the low level winds and
temperatures change little into the early morning hours which
could lead to heavy snowfall.

&&

.SHORT TERM...(This evening through Tuesday)
Issued at 322 PM CST Mon Feb 19 2018

The Northland will continue to be affected by snow and areas of
freezing rain through Tuesday morning. An area of low pressure
over eastern Iowa will continue lifting towards southern Michigan
this afternoon and evening. A mid-level frontogenetical band
across northwest Wisconsin and the forcing from the area of low
pressure will continue to produce snow across east-central MN and
northwest WI through at least this evening. Areas of freezing rain
are forecast in northwest Wisconsin through tonight and early
Tuesday because of the lack of cold enough air in the saturated
layer aloft to ensure sufficient ice crystal seeding for snow.
Price County, and areas to the south and east, will be the most
affected by the freezing rain with up to a couple tenths of an
inch of icing. Some of the freezing rain may fall as sleet because
of refreezing potential because of much colder air near the
surface. Another wave of snow will spread into the Northland later
tonight from the southwest due to large-scale forcing from an
approaching from mid/upper trough. This next wave will primarily
bring more snow to central and northern MN, but areas of northwest
WI will get some additional light snow, too. All together, it will
be a snowy or icy stretch of weather for the Northland through
early Tuesday. The snow and freezing rain will diminish from the
south Tuesday. Most of the precipitation should end by the
afternoon, but there could be lingering very light snow across far
northern MN. Colder air will begin to work its way into the
Northland from the northwest Tuesday in the wake of the departing
snow.

Tonight`s lows will range from the low teens in northwest
WI to near 0 degrees across the Canadian border region.
Tomorrow`s highs will be in the middle and lower 20s in northwest
WI and the teens across central and northeast MN.

.LONG TERM...(Tuesday night through Monday)
Issued at 322 PM CST Mon Feb 19 2018

The main concerns for the long term include overnight low
temperatures Tuesday night and Wednesday, along with the potential
for light snow Thursday night and Friday.

By Tuesday evening the mid-level vort max and associated inverted
surface trough will be located over northern Minnesota, northwest
Ontario, and western Upper Michigan. These features will continue
to move toward the northeast overnight with rising heights and
surface high pressure to moving into the region. Skies will
gradually clear from the southwest overnight with wind speeds
diminishing. Think we`ll have efficient radiational cooling and
have lowered min temps below the consensus blends toward the
cooler bias-corrected versions of the SREF and HiResARW. Expect
overnight lows from the low single digits above zero along the
south shore and portions of north-central Wisconsin, to around
15 below zero over portions of central and northeast Minnesota.
Mostly sunny skies are expected for Wednesday with below average
temperatures in the teens to low 20s above zero. Wednesday night
looks cold once again with efficient radiational cooling. Warm air
advection aloft may limit the cooling so opted to carry temps
near zero along the south shore to around -11 for areas in the
Iron Range. Interior portions of northwest Wisconsin will likely
dip to -5 to -10, as well.

As the surface ridge glides farther east Thursday, temperatures
will trend warmer and approach normal readings for most locations.
Highs will top out in the middle to upper 20s. A few low 30s
aren`t out of the question, either. The southerly to southeasterly
winds will also increase moisture across the area ahead of an
approaching shortwave trough for Thursday night and Friday. As the
trough moves through the Northland, look for light snow to
develop and spread northeast across the area during the evening.
The best forcing for ascent will be short-lived with snow tapering
off over central Minnesota early Friday morning and ending during
the afternoon for northwest Wisconsin and northeast Minnesota. A
few inches of accumulation are possible from this fast-moving
system.

Models diverge in their handling of the forecast details after
Friday. Temperatures will continue their warming trend for the
weekend with highs near normal in the upper 20s to low 30s. Clouds
will return by Saturday afternoon, and a few models spit out a
few snow showers Saturday night and Sunday. With the variety of
solutions offered, opted to keep only chance POPs in the picture
Saturday night with lower values on Sunday. None of the guidance
features a well-organized system, so nuisance snow amounts of less
than an inch seem favored.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 545 PM CST Mon Feb 19 2018

An area of low pressure and upper level shortwave will affect the
Northland tonight into Tuesday morning. An area of FGEN forcing is
expected to strengthen as well. These features will continue to
cause light snow with a wintry mix possible over portions of
northwest Wisconsin. Snow will expand in coverage and intensity
over much of northern Minnesota tonight and should decrease for a
time over much of northwest Wisconsin this evening. MVFR and IFR
conditions are expected for most areas through the period with
the visibility dropping to below a mile at times. Areas close to
Lake Superior, including the Twin Ports and Ashland will see
higher winds causing blowing and drifting.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH   9  18  -3  19 / 100  90   0   0
INL   0  11 -11  18 /  90  90  10   0
BRD   9  17  -9  19 /  90  80   0   0
HYR  13  23  -2  21 /  90  80  10   0
ASX  14  22   4  22 /  90  90  10  10

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory until noon CST Tuesday for WIZ001>004-
     006>009.

MN...Winter Weather Advisory until noon CST Tuesday for MNZ010>012-
     018>021-025-026-033>038.

LS...None.
&&

$$

UPDATE...Melde
SHORT TERM...Grochocinski
LONG TERM...Huyck
AVIATION...Melde



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