Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 230943
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
343 AM CST Thu Feb 23 2017

.SHORT TERM...(Today through Friday night)
Issued at 308 AM CST Thu Feb 23 2017

A winter storm is still on track to affect portions of the
Northland, especially northwest Wisconsin. The models have come
into better agreement with this model suite and adjustments were
made to expected snowfall.

Water vapor imagery showed an upper trough over the western CONUS
with shortwave energy just coming onshore. Another shortwave was
exiting the region and the Northland will see a mostly dry day
today. There may be some early morning light snow over
Ashland/Iron Counties. Skies will be partly to mostly cloudy and
highs today will range from the 25 to 30 over far northern
Minnesota to the mid to upper thirties over much of northern
Wisconsin.

The western trough will move east today into tonight causing a
surface low to deepen and move toward the Iowa/Missouri/Illinois
border by 12Z Friday. Most of the models are in agreement on this.
An area of strong warm air advection and FGEN forcing will lift
north tonight into portions of northern Wisconsin bringing an
increasing chance for snow. The low will then move toward southern
Lake Michigan by 00Z Saturday with the Canadian a bit further
south. The last few runs of the NAM has been to shift the track
further south toward most of the other solutions. The low will
continue northeast Friday night to just north of Michigan by 12Z
Saturday. Snow will develop later tonight over northwest Wisconsin
then increase to the west and north Friday into Friday evening.
Heavy snow is still expected over portions of the Northland but
we did diminish snowfall amounts over far northeast Minnesota into
far northwest Wisconsin. Consensus is that the heaviest snow will
fall over Price/Iron/Ashland and portions of Sawyer Counties,
then diminish to the west/north of there. We did keep the Winter
Storm Watch area the same but did push it back to start at 06Z. We
left Douglas/Burnett/Bayfield/Pine Counties in the watch despite
cutting the snow amounts there the most. Although not likely, it
is possible the track of the low may shift further north bringing
higher snowfall there. There will likely be a lake contribution to
the snow over portions of the South Shore as well, especially
Friday into Friday night leading to heavy snow there. Continue to
monitor the latest forecast as this storm system is still
developing and some changes to expected snowfall is likely.

.LONG TERM...(Saturday through Wednesday)
Issued at 308 AM CST Thu Feb 23 2017

Summary: Lake effect snow showers continue Saturday for portions of
northwest Wisconsin, then another chance of light snow arrives with
a weak upper-level trough Sunday. A more potent storm system appears
on the horizon in the Monday night through Wednesday morning
timeframe.

The lingering affects of the departing storm system will continue on
Saturday and Saturday night. Cool cyclonic flow across western Lake
Superior will support lake effect snow showers for northern Bayfield
and northern Iron Counties. Temperatures across the Northland will
trend slightly cooler, near normal for Saturday and Saturday night.
Another upper-level trough will push southeastward out of the
Canadian Prairies late Saturday night and across the Northland on
Sunday. This disturbance will bring a bit of Pacific moisture with
it and a chance of light snow. As of this morning accumulations
appear low, less than an inch. Lake effect snow showers are
possible once again over snowbelt areas of northwest Wisconsin
in the wake of the Sunday system. High temperatures Sunday will
trend a degree or two warmer.

A deeper trough of low pressure will move across the western United
States Monday afternoon and cross into the Plains on Tuesday.
Deterministic guidance features three distinct solutions for
handling this system, so confidence is low this morning, and
ensemble members feature a wide envelope of solutions. There is a
general trend toward developing a storm system in the Plains and
lifting it into the Mississippi River Valley by midweek. The
location, timing, and type of precipitation with this system is
quite uncertain. The GFS is slowest and driest with low pressure
taking shape in southern Montana and quickly scooting east into the
western Great Lakes. There are timing differences between the ECMWF
and GEM solutions, but both models bring some fashion of a Colorado
Low into the region. Meanwhile the GEFS mean is farther south from
the ECMWF solution. Each of these solutions brings precipitation to
the Northland, but amounts and types vary widely. Maintained a
consensus approach which yields chance POPs and a rain/snow mix for
the Northland beginning late Monday and winding down Tuesday
afternoon or early Wednesday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1124 PM CST Wed Feb 22 2017

There will be lingering IFR/MVFR ceilings across portions of
northeast Minnesota and northwest Wisconsin through the wee hours
of this morning, but overall there should be a transition to
primarily VFR conditions overnight into Thursday morning. Then
expect VFR to continue through Thursday. There will be lower
ceilings Thursday evening as a winter storm approaches the region,
but conditions will likely remain VFR until about midnight or
later.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  32  18  24  11 /   0  30  40  40
INL  26  10  22   7 /   0   0  10  10
BRD  34  20  27  13 /   0  20  20  10
HYR  38  24  28  15 /  10  60  80  70
ASX  36  23  28  16 /  10  50  70  80

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...Winter Storm Watch from late tonight through Saturday morning
     for WIZ001>004-006>009.

MN...Winter Storm Watch from late tonight through Saturday morning
     for MNZ038.

LS...None.
&&

$$

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


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