Winter Storm Watch 3, NWS Aberdeen, SD

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1112 PM CST Tue Dec 13 2016

.UPDATE...
Issued at 829 PM CST Tue Dec 13 2016

No major changes expected overnight. Temperatures have been
bouncing around a bit due to winds. Those winds should stay up
enough to keep the bottom from falling out.

&&

.SHORT TERM...(This Evening through Wednesday Night)
Issued at 332 PM CST Tue Dec 13 2016

As one area of high pressure departs the region, the next one will
arrive later tonight. With the pressure gradient remaining fairly
tight, the well mixed environment should keep temperatures from
falling too much tonight. Expect low temperatures in the single
digits on either side of zero. This high pressure will be over
southwest SD Wednesday afternoon with colder temps likely over this
CWA. With the tightest pressure gradient over northeast SD, have
removed the mention of blowing snow for most locations except the
Sisseton Hills area. Low temperatures Thursday night are a little
difficult to determine. While diminishing winds should produce
bitter cold readings in the teens below zero, increasing cloud cover
from our next storm could keep temps from free falling.

.LONG TERM...(Thursday through Tuesday)
Issued at 332 PM CST Tue Dec 13 2016

Models and ensembles all agree pretty well through the long term,
especially with the storm system affecting the region late this week
into Saturday morning. After a very cold Wednesday night/Thursday
morning, waa clouds along with the first shot of light snow will be
spreading from southwest to northeast across the region Thursday and
Thursday night. The models had lowered their amount of qpf with this
first push and thus have lowered pops some. Otherwise, the models
all show an upper level low pressure trough off the Pacific moving
quickly east and across our region Thursday night into Friday night.
Good frontogenesis/isentropic lift along with Pacific moisture will
result in quick development of snow from west to east across the
region Thursday night into Friday morning, ending by Saturday
morning. The superblend pops were too low for this event and thus
inserted or went very close to the previous forecast as this event
now looks pretty certain. Although, there may be some difference in
where the heaviest snow falls. The superblend snow ratios were also
too low, especially south in the region. Thus, have increased these
to be more in line with what will likely happen. At this time
snowfall amounts of 4 to 7 inches look like a good starting point
across the cwa. Areas of blowing snow are also possible with
northwest winds of 15 to 25 mph.

As this system moves by, another bitter Arctic high pressure area
will build into the region for Saturday and Saturday night. With
this air along with the additional snow cover, highs on Saturday
will likely not reach zero across the cwa with mainly single digits
below zero. With the high pressure ridge settling over Saturday
night, this will set the stage for a record or near record cold
night with lows mainly in the 20s below zero. Sunday will be mostly
sunny with a very slow rise in temperatures with many locations
still not making it to above zero.

Then the models show some relief for Monday and Tuesday with heights
rising as warmer air moves in. Temperatures will be in the teens on
Monday and 20s and lower 30s on Tuesday with dry conditions
expected.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
Issued at 1111 PM CST Tue Dec 13 2016

VFR conditions are expected through the valid taf period at all
terminals.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

UPDATE...TDK
SHORT TERM...SD
LONG TERM...Mohr
AVIATION...TDK

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE ABERDEEN SD
406 PM CST TUE DEC 13 2016

MNZ039-046-SDZ003>011-015>023-033>037-045-048-051-142215-
TRAVERSE-BIG STONE-CORSON-CAMPBELL-MCPHERSON-BROWN-MARSHALL-
ROBERTS-WALWORTH-EDMUNDS-DAY-DEWEY-POTTER-FAULK-SPINK-CLARK-
CODINGTON-GRANT-HAMLIN-DEUEL-STANLEY-SULLY-HUGHES-HYDE-HAND-JONES-
LYMAN-BUFFALO-
406 PM CST TUE DEC 13 2016 /306 PM MST TUE DEC 13 2016/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WEST CENTRAL
MINNESOTA...CENTRAL SOUTH DAKOTA...NORTH CENTRAL SOUTH DAKOTA AND
NORTHEAST SOUTH DAKOTA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

NO HAZARDOUS WEATHER EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A STORM SYSTEM IS EXPECTED TO AFFECT OUR REGION FRIDAY AND FRIDAY
NIGHT. DECENT SNOWFALL ACCUMULATIONS ARE EXPECTED ACROSS THE
REGION WITH 4 TO 7 INCHES OR MORE POSSIBLE. INCREASING WINDS COULD
ALSO BRING AREAS OF BLOWING SNOW.

BITTERLY COLD TEMPERATURES WILL FOLLOW THIS SYSTEM FOR SATURDAY
INTO SUNDAY MORNING. LOWS SATURDAY NIGHT ARE EXPECTED TO BE IN
THE 20 DEGREES BELOW ZERO RANGE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED.

MOHR