207 
FXUS63 KFSD 221132
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
532 AM CST Tue Jan 22 2019

.SHORT TERM...(Today and Tonight)
Issued at 238 AM CST Tue Jan 22 2019

Early this morning, widespread freezing drizzle and very light snows 
continue across the forecast area as an embedded 700 mb shortwave 
moves across the FA. One of the more impactful freezing drizzle 
events in awhile, most areas have experienced a heavy glaze to a 
tenth of an inch of ice through daybreak and we're expecting rather 
hazardous travel through the morning. Minor snow accumulations up
to an inch have also taken place, especially near Huron, where 
the area was clipped by a second embedded shortwave moving into NE
South Dakota this morning. 

Looking ahead through today, considerable changes have been made to 
the forecast. Model consensus in general has shifted to the ideas 
first advertised by the NAM yesterday, shifting deepening 
shortwave energy ejecting out of Colorado further south in the 
Plains, leaving less potential for mesoscale banding and further 
organization in the local area. That said, we'll still be square 
in the middle of the more broad and stretched out 500 mb trough 
through the day so our snow chances aren't expected to be zero. 

An elongated inverted trough will slowly shift southeast this 
morning, and the more pronounced influx of northwest air should 
scour out freezing drizzle from West to Southeast through mid-
morning.  High-resolution guidance continues to suggest that we may 
see a few mid-level snow bands developing by mid-afternoon, but 
generally amounts are going to be much lower, likely a dusting to an 
inch in most areas. Regarding QPF, tossed out Superblend and 
utilized a blend of CONSShort and HREF which seems to capture the
more limited aspect of this event. 

HAZARDS:  Will leave current advisories in place as the freezing 
drizzle impacts will be rather significant through mid-morning. It's 
possible that much of the advisory could be trimmed back or canceled 
prior to expiration today. 

.LONG TERM...(Wednesday through Monday)
Issued at 238 AM CST Tue Jan 22 2019

Wednesday: Rather quiet conditions are expected as winds turn 
westerly.  Temperatures may rise into the upper teens to upper 20s 
in the MO river valley. 

Wednesday night-Thursday: Continuing to watch the potential for an 
arctic front to move through prior to daybreak Thursday. Flurries or 
very light snow will accompany this front, but the biggest concerns 
will be with strong winds.  Models continue to suggest gusts over 30 
knots through the morning and over 20 through the day.   Blended in 
CONSMOS guidance for winds, and stronger NBM guidance for gusts. 
Blowing snow and drifting may be an issue, although we'll see what 
impacts the freezing drizzle tonight has, since there is now a bit 
of a crust on top of the powder.

Thursday night: In addition to the arctic front, temperatures will 
fall through much of the day on Thursday, falling below zero 
Thursday night.  Right now, anticipating advisory level wind chills 
with the coldest temperatures east of the James River valley 
Friday morning. 

Friday-Monday: Sharp northwest flow will make forecasting difficult 
through the weekend.  Numerous mid-level waves will move through the 
region, but confidence in specific timing is low.  Each of these 
waves will bring the potential for a dusting to couple inches of 
snow.  Right now, weaker waves will be focused around Friday and 
Saturday, with the potential of a stronger Alberta clipper Sunday 
night into Monday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 526 AM CST Tue Jan 22 2019

Aviation may remain a bit of a mess today, as ceilings are 
starting to bounce around from low MVFR to IFR to LIFR. Sioux City
will continue to see light freezing drizzle or perhaps even a few
drops of freezing rain through mid-morning as a weak elevated 
band may initiate a bit of a seeder feeder process. Further north,
light snows, flurries or light haze will continue through the 
morning. 

Generally, snow chances have lowered significantly over the area
for today, but will continue to provide some nuisance visibility 
restrictions through mid-afternoon. 

Ceilings will rise slowly tonight. 

 
&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Winter Weather Advisory until 6 PM CST this evening for SDZ050-
     063>071.

     Winter Weather Advisory until 9 AM CST this morning for 
     SDZ054>056-059>062.

MN...Winter Weather Advisory until 6 PM CST this evening for MNZ081-
     089-090.

     Winter Weather Advisory until 9 AM CST this morning for MNZ080-
     097-098.

IA...Winter Weather Advisory until 6 PM CST this evening for IAZ001-
     002-012.

     Winter Weather Advisory until midnight CST tonight for IAZ003-
     013-014-020>022-031-032.

NE...Winter Weather Advisory until 6 PM CST this evening for NEZ013.

     Winter Weather Advisory until midnight CST tonight for NEZ014.

&&

$$

SHORT TERM...Dux
LONG TERM...Dux
AVIATION...Dux