Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 170334

Area Forecast Discussion
National Weather Service Sioux Falls SD
1034 PM CDT Wed May 16 2018

.SHORT TERM...(This evening through Thursday)
Issued at 313 PM CDT Wed May 16 2018

A warm afternoon with just a touch of humidity, dew points in the
upper 50s to lower 60s. Cumulus developing in most locations with a
deeper slightly more organized cumulus field in central SD. A look
at the soundings for late afternoon and early evening hints that
areas west of the James River will see the best chance to become
uncapped. However with minimal shear and CAPE values around 500-1000
J/kg severe weather is not expected. With little in the way of mid
and upper level support any showers or thunderstorms that do develop
will diminish quickly after sunset. A ridge of cooler high pressure
will nose into the area from the east and keep winds fairly light
tonight, except for central SD. Lows should range from the mid 50s
in northwest IA to around 60 in central SD.

Thursday should prove to be a fairly quiet day as high pressure in
the low levels keeps the wind direction from the south or southeast.
With more stable air to the southeast this hints that any storms
that can develop in central SD will likely remain fairly closely
tied to the axis of instability. So will not have any pops until
after 7 pm for central SD, and even then will have the pops confined
to locations west of Interstate 29.

.LONG TERM...(Thursday night through Wednesday)
Issued at 313 PM CDT Wed May 16 2018

As the mid level winds turn just a bit to the southwest on Thursday
night scattered showers and thunderstorms could push into the James
Valley. Right now not anticipating any severe weather. With some
wind and clouds lows will be warmer in the upper 50s to lower 60s.

Friday into Friday night the right entrance region of the upper
level jet becomes a bit more organized to the north so expect to see
a better chance for showers and thunderstorms into eastern SD as
cooler low and mid level temperatures work southeast. Instability
and shear not overly impressive so not anticipating very much severe
weather. The better instability continues to remain west of
Interstate 29.

Friday night into Saturday upper level low pressure should lift
northeast and bring a better chance for showers and thunderstorms.
Again, the instability and shear are not very impressive so the only
real threats will be lightning and spotty heavy rainfall.

The upper level low will be slow to exit so chances will linger into
Monday morning. An abundance of clouds along with the rainfall
chance will keep temperatures fairly low. Highs on Saturday and
Sunday will mainly be in the 60s.

Monday into Wednesday broad upper level high pressure will spread
across the area and bring afternoon temperatures in the 70s back
into the area with much smaller chances for showers and


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1027 PM CDT Wed May 16 2018

VFR conditions should continue through most of the period. Some
high res guidance tries to renew some shower activity later
tonight west of the James River but appears too remote of a
possibility to include mention. Southerly winds will be breezier
on Thursday, gusting in the 15-25 kt range at times during the
afternoon and evening. Shower and thunderstorm activity will begin
to approach KHON from the west very late and just beyond the
current TAF period Thursday night.




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