Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 101747 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1147 AM CST Sat Dec 10 2016

.UPDATE...
Issued at 1147 AM CST Sat Dec 10 2016

18z aviation discussion updated below.

UPDATE Issued at 903 AM CST Sat Dec 10 2016

First wave of light snowfall continues to advect across the
forecast area. Have adjusted pops/QPF/snow amounts in the wake of
this feature, which is currently weakening as it encounters a dry
northeast fetch. Snow amounts have been limited to south of Onida
with 1-2.5 inches accumulation from Sully county down to the I90
corridor, and from there little additional accumulation is
expected. The focus shifts to later this afternoon/evening as the
next surge of warm advection ahead of a subtle 700mb wave develops
across the FSD and southern ABR CWA`s. This is well represented in
the previous forecasters pops/QPF and snow amounts on the order
of 2-3 inches. Did create a better distinction within this
mornings update between this feature and another shot at snow
which is going to be generated by jet placement and shows up in Q
vectors. This will generally track across the northern tier of the
CWA for an additional 1-3 inches. There may be some overlap
between all three systems but generally still not high enough
amounts or a broad enough area to warrant headlines with this
update.

&&

.SHORT TERM...(Today through Monday Afternoon)
Issued at 404 AM CST Sat Dec 10 2016

Broad lift is spreading across western and southern SD with moderate
warm air advection pattern having begun. Large area of light to
moderate snow has developed over the past several hours and
continues to move east, just having recently moved into the
southwest CWA. Have adjusted wx/POP grids a bit to account for this.
Models are showing minor changes with this weekend`s system, with
the 00Z EC interestingly showing an enhancement in forcing/snow
accums along the Hwy 12 corridor of northeast SD. Still expecting a
general 1 to 5 inches across the CWA, ranging from the low end
amounts near the Missouri River, to the high end totals across
northeast/east central SD into west central MN. It would still
appear that the bulk of today`s activity will be across the southern
half of SD into the southern fringes of the CWA. Will have to await
round two for tonight when upper level shortwave energy and upper
jet support move into the area. This is when additional development
of light to moderate snow will occur over a larger portion of the
region. Most of the activity looks to be out of here by Sunday
afternoon.

Will then be watching the frontal passage on Monday which will be
the next surge of arctic air moving in. Increased winds a bit on
Monday above that of SuperBlend.

.LONG TERM...(Monday Evening through Friday)
Issued at 404 AM CST Sat Dec 10 2016

Arctic high pressure at the surface and an upper low nudging down
from Canada will combine to bring very cold temps to the region at
the start of the extended. Little relief is expected by the end of
the period as another, reinforcing shot of cold air plunges H85
temps into the -20s Celsius. At the surface, highs will be in the
single digits with lows of -5 to -15 through the week.

The first half of the extended will be dry. On Friday, energy will
be ejected out of an upper trough and may bring some snow to the
region.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1147 AM CST Sat Dec 10 2016

Snow will move from west to east across the region through the
night into Sunday morning as a couple short wave troughs move
over the region. All locations are expected to be affected with
IFR/MVFR ceilings and vsbys. PIR is expected to be the least
affected by snow. Several inches of accumulation are expected by
the time the snow ends late tonight into Sunday morning.

&&

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

$$

UPDATE...Mohr
SHORT TERM...TMT
LONG TERM...Wise
AVIATION...Mohr


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