Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 262044

Area Forecast Discussion
National Weather Service Sioux Falls SD
344 PM CDT Fri May 26 2017

.SHORT TERM...(This evening through Saturday)
Issued at 343 PM CDT Fri May 26 2017

A very pleasant start to the holiday weekend as breezy northwest
winds have pushed temperatures into the 70s. The biggest concerns in
the short term portions of the forecast deal with rain chances on

Later tonight, strong warm advection associated with an upper trough
crossing the Northern Rockies will begin to initiate convection over
the western High Plains.  This convection will likely form into one
or more clusters of and slowly push eastward into Saturday morning.
Further north in the western Dakotas, increased frontogenesis with
support from broad divergence in the right entrance region of an
upper jet, will develop a linear band of showers from the Black
Hills into central SD by daybreak.

The developing MCS over southern Nebraska will likely be the
dominating feature on Saturday, with very light rain and relatively
high based showers spreading eastward along a surface boundary by
mid-day and into the afternoon. Soundings again, showing a fairly
dry pre-storm environment, so not anticipating widespread or heavy
rain.  However we will be dealing with considerable virga and
scattered showers  from mid-morning through mid-afternoon. Depending
on the speed of this shortwave, temperatures will remain a bit
cooler than today.  There is potential that temperatures may need to
be further lowered based on clouds.

.LONG TERM...(Saturday night through Friday)
Issued at 343 PM CDT Fri May 26 2017

Saturday evening, a short wave moving down the northern stream flow
on the southwest side of a large upper low centered in south central
Canada, will phase with a short wave exiting the central plains.
This will create some shower activity which will linger through the
evening hours, most pronounced in our northern zones along the
northern short wave, and in our extreme southeast near Storm Lake
and Spencer IA closer to the departing central plains wave.
Otherwise after midnight there will be a general clearing trend.

Sunday through Tuesday next week, our weather will be largely
influenced by the aforementioned upper low as it drifts slowly
southeastward through the Great Lakes region. Temperatures will
hover close to normal with deep mixing creating breezy conditions,
especially on Sunday and Monday. A weak TSRA is possible around
Marshall MN Sunday afternoon on the nose of a jet streak which is
moving southeastward. A few light showers are also possible in
southwest MN Monday afternoon along a weak short wave.

For Wednesday through Friday, the upper air pattern is not conducive
for any widespread rainfall at all. Winds look lighter, and
temperatures will still be pretty close to normal.


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1236 PM CDT Fri May 26 2017

VFR conditions expected into Saturday morning. Will be watching
for an increasing risk of showers by late morning and into the
mid-day hours, just at the end of this valid TAF.




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