Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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871
FXUS63 KFSD 121104
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
504 AM CST Fri Jan 12 2018

.SHORT TERM...(Today and Tonight)
Issued at 329 AM CST Fri Jan 12 2018

A surface high pressure currently over North Dakota and the Canadian
Plains will continue to push south this morning and through the
day. This will keep steady north winds and bitter wind chills
across the region. By mid-day, temperatures will moderate
slightly, but only get a few degrees above zero, leading to wind
chills staying in the negative single digits and teens even during
the afternoon. Winds chills drop again tonight into Saturday
morning, with widespread values in the negative 15 to 25 range.

The other feature of interest in the near term is an area of modest
moisture advection ahead of a weak shortwave trough. This system
will bring light snow to areas along and southwest of the James
River Valley this afternoon. Those in south central South Dakota
near Gregory have the best chance of seeing up to an inch of new
snow, with lighter amounts as one heads north and east. Those
along the I-29 corridor may see flurries, but very little
accumulation is expected here, as the weak dynamics struggle to
overcome the dry air near the surface. Snow and flurries quickly
diminish after nightfall.

.LONG TERM...(Saturday through Thursday)
Issued at 329 AM CST Fri Jan 12 2018

Another quick moving shortwave trough looks to bring snow to the
region early Sunday morning. This system currently looks to have a
bit more moisture and warm air to work with, so snow totals of an
inch or two are possible around Yankton, SD and far northeast NE.
Overall coverage of these higher amounts will be minimal though,
with most only seeing a dusting to half an inch.

The warmer air that this system brings into the area will be very
short-lived. By Sunday night, an arm of the Hudson Bay Low will
usher in another arctic airmass. The mild 20s of Sunday will
quickly be replaced with high temperatures Monday that struggle to
get into the positive single digits. Wind chills will drop into
the negative 20s and 30s for Monday morning. Additionally, the
cold front associated with this push of frigid air will likely
bring brief snowfall area-wide Monday morning, but amounts again
look light, with under an inch of new snow.

Dangerously cold temperatures with breezy winds persist into
Tuesday, but by Wednesday temperatures look to moderate back into
the teens and 20s for highs as the longwave trough migrates east and
a ridge of high pressure builds over the region. Temperatures become
even more mild for the end of the work week, perhaps slightly above
normals, with widespread highs in the 30s by Friday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 503 AM CST Fri Jan 12 2018

VFR through the period. An area of light snow will work into south
central SD late this morning and continue into the afternoon from
there into parts of Nebraska.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Wind Chill Advisory until 10 AM CST this morning for SDZ038>040-
     052>056-058>062-066-067.

MN...Wind Chill Advisory until 10 AM CST this morning for MNZ071-072-
     080-081-089-090-097-098.

IA...Wind Chill Advisory until 10 AM CST this morning for IAZ001>003-
     012>014-021-022.

NE...None.
&&

$$

SHORT TERM...VandenBoogart
LONG TERM...VandenBoogart
AVIATION...08



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