Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 101817
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1217 PM CST Wed Jan 10 2018

.SHORT TERM...(Today and Tonight)
Issued at 302 AM CST Wed Jan 10 2018

The final warm day before much colder air settles into the region
tonight. An upper level jet to the north will gradually drift east
through the day, keeping southerly flow in place well into the
afternoon. This will allow for widespread highs in the upper 30s to
mid 40s.

A cold front will start to leak into central SD by mid afternoon as
mid and upper level frontal forcing also increases. This will bring
a chance for rain and snow into central SD late afternoon and
evening. The chance for precipitation will shift east through the
evening, but by mid evening a southern jet will likely interact with
the mid level boundary and possibly a little instability to bring
about the development of a second band of precipitation. This band
has the potential to bring a little bit heavier precipitation and
will focus the higher threat for greater than 3 to 5 inches in
northwest IA. Throughout the late afternoon and evening there will
be a threat for a brief period of sleet or freezing rain but without
and warm air wrapping back over the cold low level air not concerned
about any widespread icing problems at this time.

Will go ahead and transition the watch to an advisory for all areas
except a small area from around the Iowa Great Lakes to Storm Lake.
The heavier snow will not begin in this area until late tonight and
there are still some hints of heavier snow amounts near by, so any
shift in the models north and west by a few miles would bring a
higher snow potential.

.LONG TERM...(Thursday through Tuesday)
Issued at 302 AM CST Wed Jan 10 2018

The snow will continue into Thursday morning, then diminish from
west to east from late morning into Thursday afternoon. Storm
total snowfall will likely be about 1-3 inches in central SD and 2
to 5 inches in northwest IA. There are still hints that near and
just west of Interstate 29 in SD could be a bit of a low spot in
between the two bands of precipitation. Along with the snow will
be strong northwest winds of 20 to 35 mph which will likely cause
a little blowing and drifting, especially in areas where 3 inches
or more of fresh snow falls.

Another system will move through on Friday with decent warm air
advection and fairly deep dendritic temperatures. Not expecting any
real high amounts at this time, mainly 1 to 4 inches.

Otherwise Sunday may be another shot of snow as warm advection
builds across the Plains as a wave drops south into the area.

Temperatures Thursday through next Tuesday will be well below normal
with Saturday and Monday the two coldest days.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1109 AM CST Wed Jan 10 2018

IFR ceilings and MVFR visibility will continue for areas along and
east of I-29 through this evening. A brief improvement may occur
with the arrival of a cold front, however ceilings and
visibilities will very quickly drop back to IFR and even
occasional LIFR as snow and winds spread across the region behind
the front. Winds will average 20 to 35 kt while the snow is
falling, and into much of Thursday, causing blowing snow concerns.
MVFR and IFR ceilings and visibility will persist into the daytime
Thursday.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Winter Weather Advisory from midnight tonight to 6 PM CST
     Thursday for SDZ067-070-071.

     Winter Weather Advisory from 5 PM this afternoon to 8 AM CST
     Thursday for SDZ038-050-052-053-057>059-063-064.

     Winter Weather Advisory from 9 PM this evening to noon CST
     Thursday for SDZ039-040-054>056-060>062-065-066-068-069.

MN...Winter Weather Advisory from midnight tonight to 6 PM CST
     Thursday for MNZ071-072-080-081-089-097-098.

     Winter Storm Watch from late tonight through Thursday afternoon
     for MNZ090.

IA...Winter Weather Advisory from midnight tonight to 6 PM CST
     Thursday for IAZ001-012-020-031.

     Winter Storm Watch from late tonight through Thursday afternoon
     for IAZ002-003-013-014-021-022-032.

NE...Winter Weather Advisory from midnight tonight to 6 PM CST
     Thursday for NEZ013-014.

&&

$$

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



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