Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 180552
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1152 PM CST Sun Dec 17 2017

.SHORT TERM...(This evening through Monday night)
Issued at 307 PM CST Sun Dec 17 2017

Warm, southeast flow across the Northland will help maintain some
low-level stratus and misty conditions through tonight. There
could be some pockets of clearer skies in the evening, but more
moisture will move into the region later tonight, helping to fill
in the gaps. This new forecast is cloudier than the previous
forecast, and the cloud cover will bolster the overnight
temperatures. The new forecast is therefore a bit warmer than
before. Low temperatures should be in the lower 20s.

There will be increasing southwest flow Monday in advance of an
approaching cold front and mid-level trough. This will help to
lift the mist and low-level stratus. While it will remain cloudy,
temperatures will climb to near or little above the freezing mark.
Although, melting on the roads will be limited by the lack of
sun.

Snow will spread into northern Minnesota during the afternoon
and evening thanks to moderate/strong large- scale forcing for
ascent. A strong jet will move into the Northern Plains as a cold
front and mid- level trough move into the Northland. Northern
Minnesota will get about 1 to 2 inches, but some areas could get
up to 3 inches. The 12Z European came in with much more
precipitation than its previous run, and we might need to increase
the snowfall forecast a bit more if more models trend this way.

.LONG TERM...(Monday night through Sunday)
Issued at 307 PM CST Sun Dec 17 2017

Two main stories in the long term period.
1) Potential for heavy snow
2) Bitter cold temperatures

A weak system will pass by on Monday night bringing light
snowfall with northwesterly flow continuing after it passes. The
next system begins to nudge in on Wednesday afternoon draping a
frontogenetic band of snowfall across the region for a couple of
inches of snow meanwhile the parent low to this snowfall is still
way back in Colorado. As an upper trough moves eastward, this low
deepens and eventually slides through southern WI wrapping around
the beginnings of a comma head over nw WI. This feature will
provide a prolonged period of snow with over 6" of snow currently
forecast for NW WI. Now, depending on the track a lot of scenarios
could take place - a more northerly track would bring that snow
into the Arrowhead while a more southerly track would diminish
snowfall amounts. Models are beginning to come into fair agreement
on the track and intensity of this system, so confidence is
definitely increasing, but the details still need to be ironed
out.

After the larger snow system exits the region, it pulls down a
very cold air mass from Canada with 850 mb temps down into the -20
to -30 C range which translates to temperatures dropping to -10 to
-20 F. Most certainly wind chill advisories will be needed. This
 air mass looks to linger for a long time, so brace for a bitter
 stretch of cold.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1148 PM CST Sun Dec 17 2017

Widespread IFR & LIFR conditions in stratus as of issuance time
to continue through approximately 15z Monday. Fog/drizzle
expected to develop as well, and should affect the terminals
through 16z time range, with visibilities as low as LIFR as well.
Some improvement is expected to MVFR ceilings with VFR visibilities
in the 16z-18z time range. The next round of snow to begin moving
into the terminals after 20z. KINL and KHIB to be most affected,
with MVFR/IFR visibilities and IFR/LIFR ceilings in -sn. Snow to
end from west to east beginning around 03z.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  22  33  23  28 /   0  60  20   0
INL  21  33  21  23 /   0  80  60  20
BRD  24  35  23  30 /   0  20  10   0
HYR  20  34  25  32 /  10  20  10   0
ASX  21  35  27  32 /   0  40  30  10

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Small Craft Advisory until 10 PM CST Tuesday for LSZ140-146-147.

     Small Craft Advisory from 4 AM Monday to 10 PM CST Tuesday for
     LSZ141>143.

&&

$$

SHORT TERM...Grochocinski
LONG TERM...Wolfe
AVIATION...LE



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