Area Forecast Discussion
Issued by NWS Aberdeen, SD

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000
FXUS63 KABR 110639
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
1239 AM CST Thu Jan 11 2018

.UPDATE...
Issued at 1236 AM CST Thu Jan 11 2018

Switched northwest counties over to a Wind Chill Advisory that
will continue through the morning hours. The southwestern corner
is more difficult. While snow has likely ended for a good portion
of the area, radar returns remain over Lyman County. However, area
web cams show little snow and little visibility reduction. Will
likely need to get rid of this hazard a few hours before 12Z.
Northern tier counties will be flirting with Wind Chill Advisory
criteria through the morning.

UPDATE Issued at 957 PM CST Wed Jan 10 2018

Drastically cut snow accumulations across the region as this snow
has not amounted to much. Visibility reductions are still
occurring as gusty winds blow the falling snow around so will
leave the winter weather advisory in place for the time being.
Also exited the system faster in the morning by a few hours.

UPDATE Issued at 557 PM CST Wed Jan 10 2018

The anticipated freezing drizzle has developed across portions of
the area from Aberdeen to Miller. Only very light misty conditions
are being reported at this time, but radar is indicating some
heavier returns just south of Aberdeen. No major changes to the
current forecast as pops and overall precip trends are holding
steady.

&&

.SHORT TERM...(This Evening through Thursday Afternoon)
Issued at 320 PM CST Wed Jan 10 2018

An area of low pressure and Arctic front will continue tracking
across the region tonight through Thursday morning. With warm air
ahead of this system, precipitation may begin as rain or drizzle. As
the atmosphere cools, the precipitation will become a wintry mix
with minor ice accumulations possible. Snow will become the
dominate p-type tonight, which when combined with gusty
northwesterly winds will cause blowing and drifting snow with
reduction in visibility. The strongest winds should occur along
the I-29 corridor where near white out conditions are possible
tonight. Precipitation should gradually end for west to east
during the morning hours on Thursday.

Timing of this system has continued to slow down, with pcpn now
reaching the Missouri Valley closer to 0Z, and the James Valley
around 3Z. While the start time has changed, the ending time remains
about the same. Snow should exit the Missouri Valley around 12Z and
I-29 corridor by 18Z Thursday. With breezy northerly winds
continuing Thursday afternoon, patchy blowing will be possible,
especially in eastern SD and western MN.

Snowfall amounts have changed some from the previous forecast. Radar
returns in central Nebraska will track northeast tonight with the
upper level trough. The combination of the surface low east of
the region, along with upper level support, a narrow band of
heavier snowfall could occur from Chamberlain to Huron, over to
Watertown tonight. This band will likely produce 2 to 4 inches of
snow with isolated higher amounts.

The combination of gusty winds and bitter cold temperatures will
produce wind chill values of 20 below, to 30 degrees below zero over
northeastern SD and western MN.

.LONG TERM...(Thursday Evening through Wednesday)
Issued at 320 PM CST Wed Jan 10 2018

The period opens with the forecast area in northwest flow aloft. A
low pressure system clipping along in pattern on Friday may bring
some light snow to the area (generally less than an inch is thought
possible at this time). Staying in amplifying flow, another low
pressure system is forecast to sweep southward through the region in
nearly meridional flow aloft and could bring another light dusting
of snow to the cwa on Sunday. Beyond that, dry upper level ridging
begins over the region by Tuesday night and persists into Wednesday.

Much of the forecast period will be dominated by much below normal
temperature as another arctic airmass builds down across the region.
Friday night/Saturday morning lows could be the coldest of the
period as 1045-1050hpa surface high centers overtop of the region.
Current forecast lows for Friday night will need some additional
evaluating in the coming days.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1124 PM CST Wed Jan 10 2018

As snow exits to the east tonight, conditions will improve to VFR.
Northwest winds will remain gusty through Thursday morning at 20
to 35 kts.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Chill Advisory until noon CST /11 AM MST/ today for SDZ003-
     004-009-015-016.

     Winter Weather Advisory until 9 AM CST this morning for
     SDZ005>008-010-011-017>023-036-037-051.

     Winter Weather Advisory until 6 AM CST /5 AM MST/ early this
     morning for SDZ033>035-045-048.

MN...Winter Weather Advisory until 9 AM CST this morning for MNZ039-
     046.

&&

$$

UPDATE...KF
SHORT TERM...SD
LONG TERM...Dorn
AVIATION...Wise



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