Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 240901
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
301 AM CST Wed Jan 24 2018

.SHORT TERM...(Today through Thursday)
Issued at 301 AM CST Wed Jan 24 2018

A digging upper level shortwave trof will move from eastern Manitoba
to the southwest corner of northwest Ontario through the day, then
diminish by 00Z Thursday. An elongated area of vorticity will also
move across the forecast area during the day. At the surface, a warm
front was found moving into the western third of the region at 0830Z.
This warm front will move in conjunction with the elongated
vorticity. The best moisture will be found over the north portion of
the forecast area, but is relatively sparse as the mean RH will be
less than 70 percent. Have placed a mention of flurries as a result.
As the surface flow becomes southeasterly before 12Z, still
expecting some lake effect snow to develop and move along the north
shore from near Silver Bay, and up the north shore to near Tofte.
The short term models all show some disorganization to any lake snow
bands, but still expect them to move farther up the north shore to
Grand Maris and possibly Hovland by noon, then to Grand Portage in
the afternoon. Up to an inch of snow is possible from Lutsen to
Grand Marais, with lighter amounts elsewhere.

As the aforementioned vorticity moves northeast over northern
Minnesota, a second channeled area of vorticity follows. The best
moisture remains over the northern portion of the forecast area,
however sparse. Have small pops for some light snow from Crane Lake
east southeast to Lake Superior. Behind these upper level features,
ridging begins to arrive from the west and covers the region for
Thursday.

By late morning Thursday, warm air advection begins as the mid level
flow turns southerly. 850mb temps warm to either side of 0C by 00Z
Friday. No weather is expected, but max temps will be milder and
reach the upper 20s over the Arrowhead, to the 30s elsewhere.


.LONG TERM...(Thursday night through Tuesday)
Issued at 301 AM CST Wed Jan 24 2018

The extended period will start out with temperatures much above
normal, then cool through the weekend before another warmup Tuesday.
There will be periodic chances for precipitation, with a wintry mix
possible in northern Minnesota Friday/Friday evening. The models are
in decent agreement through the period.

The upper ridge will be over the central part of the CONUS extending
north in Canada early Thursday evening. The ridge will pass east of
the Northland Thursday night as a shortwave approaches. A broad area
of low pressure over the Northern Plains and Canadian Prairies
Thursday evening will deepen as it lifts into Ontario Friday
afternoon. There may be some light precipitation, drizzle, freezing
drizzle, or snow Friday into Friday evening over portions of
northern Minnesota before changing to all snow overnight as colder
temperatures move in and saturation deepens. Precipitation should be
light Friday but as the colder air continues to move in Friday night
into Saturday, some light snow accumulation will be possible over
northern Minnesota with light snow or flurries developing further
south across the Northland. Highs Friday will be in the mid thirties
to lower forties then cool into the lower twenties over the
Borderland to around 30 in northwest Wisconsin on Saturday. High
pressure will build into the region Saturday night into Sunday
shutting down any lingering light snow or flurries for most areas.
As the high moves in, low level winds will become northerly Saturday
night into Sunday which will cause lake effect snow to develop in
the snowbelt of the South Shore, especially over eastern Ashland and
Iron Counties. Lake effect snow will be possible Saturday night into
Monday with the best chance for snow accumulation late Saturday
night into Sunday night. Several inches look possible during this
time. Temperatures will continue to cool through the weekend with
highs Sunday in the teens to lower twenties.

The models remain in reasonable agreement into early next week
moving another ridge into the Four Corners region north into
Saskatchewan/Alberta by 00Z Tuesday with warm air advection
developing across the Northland. As the ridge continues east, warm
air advection will strengthen Monday night into Tuesday, and an area
of snow and a possible mix will move across the Northland. Light
accumulation will be possible. Highs Tuesday will be in the upper
twenties to middle thirties.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1141 PM CST Tue Jan 23 2018

An approaching upper level shortwave and weak frontal boundary
will bring gradually deteriorating conditions to the Northland TAF
sites through the night. There have been some reports of patchy
freezing drizzle just west of KBRD, and we do expect that some
patchy freezing drizzle will move into the KBRD vicinity during
the early morning hours. Some of this may even spread into KINL
and KHIB overnight as well. Otherwise, we expect conditions to
become largely MVFR to IFR, and then remain moreso in the MVFR
range for Wednesday and Wednesday evening. Some visibility
restrictions are possible, but generally in the MVFR range.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  24  14  29  25 /  10  10   0   0
INL  24  10  29  24 /  10  10  10  10
BRD  28  16  32  26 /   0   0   0   0
HYR  26  12  33  26 /  10  10   0   0
ASX  26  13  32  25 /  10  10   0   0

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.

&&

$$

SHORT TERM...GSF
LONG TERM...Melde
AVIATION...DAP



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