Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 221736

Area Forecast Discussion
National Weather Service Aberdeen SD
1136 AM CST Sun Jan 22 2017

Issued at 1018 AM CST Sun Jan 22 2017

Update includes the addition of freezing drizzle moving into north
central SD later this morning/early this afternoon, from BIS.
Increased patchy fog coverage area as a result of several area web
camps and observation platforms. Otherwise, few changes were

UPDATE Issued at 554 AM CST Sun Jan 22 2017

12z aviation discussion updated below.


.SHORT TERM...(Today through Tuesday Afternoon)
Issued at 337 AM CST Sun Jan 22 2017

An area of low pressure over North Dakota will bring westerly
winds and somewhat drier air into the CWA today. While fog and low
stratus may dissipate some by this afternoon, believe most of the
CWA will still see cloudy skies. Will the low clouds and fog come
back again tonight? A majority of the models suggest the fog will
finally leave the CWA as much drier air moves into the region from
the west. Confidence on the return of low stratus tonight is low at
this time.

A deep trough currently off the west coast will send upper level
energy into the Central Rockies by tonight. The upper level jet
support will cause the development of a lee side trough over the
front range of the Rockies by Monday. Some models, like the NAM and
SREF generate a narrow band of heavy snow developing Monday
afternoon over the western portion of SD. This is where upslope flow
and an inverted surface trough will be located. It will be
interesting to see if the band becomes as robust as the NAM
indicates or nearly non-existent as the GFS suggests. The surface
low will cross the Central Plains Monday night through Tuesday with
accumulating snowfall likely over much of this CWA. As of now, the
heaviest snowfall in excess of 3 inches looks best between Highway
212 and I-90. While this system will have significant moisture to
work with, a low SLR may limit extreme snowfall amounts. While
confidence is low with the overall placement of the heaviest snow,
there is enough confidence to increase QPF amounts and thus snowfall
amounts from Superblend. QPF should be increase more based on the
GEFS mean QPF, which is a tenth of an inch more than the current

.LONG TERM...(Tuesday Evening through Saturday)
Issued at 337 AM CST Sun Jan 22 2017

The models all show a strong surface low pressure area over
northwest Missouri moving northeast Tuesday night and Wednesday. As
a result, the ongoing snowfall over our region will also move east
and end into Wednesday afternoon across our eastern CWA. Otherwise,
the models show very good agreement with the rest of the long term
into Saturday with a large surface high pressure area setting up
across the western U.S. while a surface low pressure area develops
over the far northeast U.S./southeast Canada. This will put our
region in persistent northwest flow at the surface with cooler
Canadian air coming across the region. This air will not be
particularly cold with highs across the cwa mainly in the 20s and
lower 30s from Wednesday through Saturday. The time period from
Thursday through Saturday also looks to be dry.


.AVIATION...(For the 18Z TAFS through 18Z Monday Afternoon)
Issued at 1126 AM CST Sun Jan 22 2017

While PIR has been enjoying a clear sky since 20Z yesterday
afternoon, the stratus deck is quickly closing in from the north,
with ceilings under 1K feet. As a result, expect LIFR to IFR
ceilings/vis at most sites through the period. Temporary MVFR
conditions will be possible, especially at PIR initially. Winds
hovering near 10kts this afternoon will diminish to around 5kts
tonight. Expecting some improvement tomorrow by around flight
category by late morning.


SD...Dense Fog Advisory until noon CST today for SDZ007-008-011-

MN...Dense Fog Advisory until noon CST today for MNZ039-046.



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