Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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143
FXUS63 KFSD 252026
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
326 PM CDT Tue Apr 25 2017

.SHORT TERM...(This evening through Wednesday)
Issued at 324 PM CDT Tue Apr 25 2017

Dry air in the mid levels has had an effect on rainfall today,
mainly in forcing development to be a little slower and also in
reducing overall rainfall amounts. The warm advective band of
precipitation this morning and early afternoon has not been very
impressive, only dropping a tenth of an inch or less through 2 pm
in most locations. The dry air really had an effect on central SD
with light precipitation only now starting to fall as the upper
level cold pool moves into the area.

This upper level cold air should be the main driver through the
evening as this colder air aloft spills into the area. However,
precipitation amounts will be a bit limited as the mid level
boundary is just simply not as impressive as was expected, so went
ahead and lowered amounts. With the colder air aloft moving in some
of the rain will likely mix with or change to snow around
Chamberlain, Huron and possibly De Smet, but at this time
accumulations would be minor.

The dry slot aloft will move across eastern SD into southwest MN and
northwest IA late tonight into Wednesday morning. Lowered chances
for rain in many locations during this time. However, the low level
should remain saturated so cloudy conditions are still expected
through the day Wednesday, with maybe a little sunshine from the
James Valley west.

Increased lows just a touch and kept highs about the same as
stronger winds and cloudy conditions will support a small diurnal
range.


.LONG TERM...(Wednesday night through Tuesday)
Issued at 324 PM CDT Tue Apr 25 2017

Main feature in the long term period is the stretch of below normal
temps. Colder air moves in on Wed night as the H5 trough slowly
moves into northern Minnesota by late Wed night/Thurs morning.
This is expected to be the coldest night through the extended cold
period with all sites below freezing. Cloudy skies and wind
around 10 mph should preclude widespread frost development, so
have left a mention out.

Thurs/Fri will be dry and cool for most areas as the next long wave
trof deepens and moves south into the southern plains by Saturday.
This feature continues to deepen to a closed low and will bring
showers back to the area this weekend.  As the h5 low moves
east/northeast to KS/MO, rain will spread from south to north
Saturday afternoon.  This low slowly moves to near IA/IL by Mon
afternoon, which will keep a lingering chance of rain from Saturday
to Monday.  The bulk of the precip will fall east of the James and
may briefly mix with snow on Sunday night.

As the aforementioned low finally exits the area Monday night, there
is a chance that Tuesday temperatures will return to normal in the
lower to mid 60s.


&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1153 AM CDT Tue Apr 25 2017

Widespread IFR and occasional MVFR ceilings are expected through
tomorrow morning. There will be some improvement tomorrow morning
from west to east from central into eastern SD. Rain will also be
likely across much of the area through the evening hours with some
mix of snow or sleet possible around KHON.


&&

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

$$

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



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