Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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649
FXUS63 KFSD 160859
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
259 AM CST Fri Feb 16 2018

.SHORT TERM...(Today and Tonight)
Issued at 259 AM CST Fri Feb 16 2018

A cold start to the day as north winds have brought in much drier
and colder air. The combination of wind and cold temperatures will
keep wind chills in the 10 below to 15 below range through mid
morning. As cold high pressure drifts south of the area southerly
flow will develop and temperatures will try to recover. It will be a
little too late along and east of Interstate 29, but central SD will
see temperatures climb into the 30s. Parts of northwest IA and
southwest MN will only warm into the lower 20s.

By tonight clouds will increase as a weak wave moves through.
Precipitation chances will be scant but parts of northwest IA will
get into a warm advective area and some light snow will be possible.
Only going to go with a 20 percent chance as confidence marginal and
low level dry air will likely fight any measurable snow. With clouds
and somewhat strong south winds lows will be on the less cold side
in the mid teens to lower 20s.

.LONG TERM...(Saturday through Thursday)
Issued at 259 AM CST Fri Feb 16 2018

On Saturday a trough of low pressure will swing through and bring
a small chance for a little light snow. Once again, accumulations
should be light, but a little better chance for a half an inch or
so in east central SD. As the trough passes a mixy environment
will develop and temperatures will climb to around or a little
above normal, with highs from 30 to 40.

Saturday night into Sunday a strong jet will develop to the north
with the right entrance region fairly well forecast to move onto the
northern and central Plains Sunday afternoon and night. This will
allow low pressure to develop with southerly flow ahead of it,
bringing another mild day to the area, with highs from the lower 30s
near Huron and upper 40s in parts of northwest IA.

Sunday night into Monday night will see some big changes as cold air
in the low levels spills into the Plains as the jet to the north
remains fairly stationary. This stationary jet will support keeping
the lower to mid level front in place and possibly drift northwest a
bit, which should bring some overrunning to the low level cold pool.
Unfortunately this may mean some mixed precipitation or freezing rain
to some locations, with the better chances in northwest IA late
Sunday night into Monday morning. Still a lot up in the air as mid
level dry air may not allow any snow or freezing rain to develop and
much of far southeast SD, southwest MN and northwest IA could see
freezing drizzle. A tough call as mid level frontal forcing is
fairly strong late Sunday night in northwest IA, but moisture is a
little sparse. Farther to the north the dendritic layer should be
saturated a deeper and snow is expected north of Interstate 90. How
this band behaves from Monday night into Tuesday not an easy call so
will just have a broad area of snow Monday night into Tuesday.

Wednesday into Friday looks quiet with a recovering cold air mass.
Temperatures will be somewhat dependent upon any fresh snow cover
but for now does not look excessively cold, except possibly
Wednesday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1039 PM CST Thu Feb 15 2018

VFR conditions are expected through the TAF period.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&

$$

SHORT TERM...08
LONG TERM...08
AVIATION...JM



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