Winter Storm Warning 4, NWS Aberdeen, SD

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1131 PM CST Tue Feb 19 2019

.UPDATE...
Issued at 1128 PM CST Tue Feb 19 2019

See the updated aviation discussion below.

UPDATE Issued at 912 PM CST Tue Feb 19 2019

One area of light snow has now tracked northward through a good
portion of the area. Most locations will see a couple hour break
before a more widespread area of light to moderate snow moves in,
and then looks to continue over all but the far western CWA
through the day Wednesday. No significant changes made to POPs,
and no changes made to winds or temperatures at this time.

&&

.SHORT TERM...(This Evening through Wednesday Night)
Issued at 312 PM CST Tue Feb 19 2019

Lead impulse of light snow continues to work northward across the
CWA, and have increased POPs a bit for this initial event, with more
snow expected to spread northward across central SD later this
afternoon and into the early evening. Still anticipate the main snow
event to move in later tonight as larger scale lift/forcing sets up
over the region. Still targeting the eastern CWA for highest snow
accums, which look to generally be in the 3 to 6 inch range, with
lesser amounts west of the James River. Added a row of counties to
the Winter Weather Advisory based on latest snowfall forecast. Winds
will not be an issue with this system, so no impacts from blowing or
drifting snow. Light to moderate snow looks to continue into
Wednesday, eventually winding down from west to east throughout the
day.

As for temperatures, don't really expect much of a drop off tonight.
In fact, temps may be fairly steady overnight as we see clouds,
southeast winds, and very weak warm air advection.

.LONG TERM...(Thursday through Tuesday)
Issued at 312 PM CST Tue Feb 19 2019

The picture at 500mb at 12Z Thursday will be similar to what we've
been dealing with for a while, a large trough over the western U.S.,
with southwesterly flow across much of the east. We'll start out
with dry weather Thursday, as southwesterly flow to slight ridging
is overhead at 500mb which will remain into Friday morning as the
apex of the 500mb trough sets up from eastern MN through the
CA/NV border. A weak elongated area of high pressure at the
surface will be stretched from southeastern Alberta through our
forecast area to the mid MS Valley. An inverted trough stretching
from CO will move across central NE and into southeastern SD
Thursday night, and strengthen its hold on the area Friday, before
shifting into MN Saturday as the parent low becomes more
organized over KS/OK. The best chance for snow over mainly the
southeastern half of SD will be Friday afternoon. Exact snow to
liquid ratios and snow amounts become more problematic as we lose
the DGZ during the day Friday. NAM solution is a little warmer and
drier, with a small potential for mixed precipitation. Have opted
to go closer to the GFS/Canadian solution at this point, with all
snow.

If there is a break from the snow, it will be short lived for our
southeastern counties, as the 500mb trough slides east over the
Northern and Central Plains Saturday, and the surface low rapidly
deepens over northern MO. The track over Lake Michigan by daybreak
Sunday will leave us on the back side of the low, with increased
northerly to northwesterly winds Sunday. A lingering trough will
make it difficult for snow to exit before Sunday afternoon.

Zonal flow slides into the region Sunday into Tuesday. Additional
snow will be possible Monday as a wave in the mainly zonal pushes
in.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
Issued at 1128 PM CST Tue Feb 19 2019

Light to moderate snow will affect the majority of the area
overnight into the day Wednesday, ending from west to east
Wednesday afternoon and evening. MVFR cigs and vsbys can be
expected with the snow. Periods of IFR cigs are possible across
the far eastern part of the area, including KATY, late tonight
into Wednesday morning.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Winter Weather Advisory until 6 PM CST Wednesday for SDZ008-
     020>023.

MN...Winter Weather Advisory until 6 PM CST Wednesday for MNZ039-046.

&&

UPDATE...Parkin
SHORT TERM...TMT
LONG TERM...KF
AVIATION...Parkin

Hazardous Weather Outlook...UPDATED
National Weather Service Aberdeen SD
245 PM CST Tue Feb 19 2019

MNZ039-046-SDZ008-020>023-202045-
Traverse-Big Stone-Roberts-Codington-Grant-Hamlin-Deuel-
245 PM CST Tue Feb 19 2019

This Hazardous Weather Outlook is for west central Minnesota and
northeast South Dakota.

.DAY ONE...This afternoon and tonight.

Snow will spread northward across the area tonight, with light
accumulations by sunrise Wednesday.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Snow will continue on Wednesday, with 3 to 6 inches total
accumulation by the end of the day. Winds are not expected to cause
issues with blowing or drifting snow.

Another storm system will affect the region Friday into Saturday,
with light to moderate snow accumulations once again.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

SDZ003-004-009-015-016-033>035-045-202045-
Corson-Campbell-Walworth-Dewey-Potter-Stanley-Sully-Hughes-Jones-
245 PM CST Tue Feb 19 2019 /145 PM MST Tue Feb 19 2019/

This Hazardous Weather Outlook is for central South Dakota and
north central South Dakota.

.DAY ONE...This afternoon and tonight.

Light snow will spread northward across the area this afternoon and
into the evening hours. Generally, accumulations will remain around
an inch or less.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Another storm system will affect the region Friday into Saturday,
with light to moderate snow accumulations once again.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

SDZ005>007-010-011-017>019-036-037-048-051-202045-
McPherson-Brown-Marshall-Edmunds-Day-Faulk-Spink-Clark-Hyde-Hand-
Lyman-Buffalo-
245 PM CST Tue Feb 19 2019

This Hazardous Weather Outlook is for central South Dakota, north
central South Dakota and northeast South Dakota.

.DAY ONE...This afternoon and tonight.

Light snow will spread northward across the area this evening and
through the overnight hours. Light accumulations are expected by
sunrise Wednesday.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Light snow will continue on Wednesday, with 1 to 3 inches expected by
the end of the day. Winds are not expected to cause issues with
blowing or drifting snow.

Another storm system will affect the region Friday into Saturday,
with light to moderate snow accumulations once again.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

TMT