Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 182043

Area Forecast Discussion
National Weather Service Sioux Falls SD
343 PM CDT WED MAY 18 2016

.SHORT TERM...(This evening through Thursday)
Issued at 342 PM CDT Wed May 18 2016

Mild, quiet weather the next 24 hours with only a small chance for
isolated showers on thursday afternoon. High pressure will slowly
drift east tonight, with southerly flow gradually increasing. This
should allow for the mildest lows in central south dakota and the
coolest lows in northwest iowa where winds are lightest. Lows should
range from near 50 in central South Dakota to the mid 40s in
northwest Iowa.

Southerly flow will bring breezier conditions to the area on
Thursday and temperatures likely about 1 to 3 degrees warmer than
today. With weak upper level support near and just north of the area
as well as model soundings hinting at the potential for some weak
uncapped surface based cape thursday afternoon, suspect that there
will be a few showers, especially in and around southwest Minnesota.
Highs mainly upper 60s to lower 70s.

.LONG TERM...(Thursday night through Wednesday)
Issued at 342 PM CDT Wed May 18 2016

Ridging continues to build over the High Plains on Friday,
pushing the southern stream wave off to the southeast. Meanwhile a
northern stream wave hangs up over northeast SD and southwest MN.
With southerly winds tapping into a very slight increase in
moisture, we could have enough support for scattered to broken
diurnal cumulus and isolated thunderstorms in the heat of the
afternoon. Without any lift or convergence, and some capping seen on
forecast soundings, think this activity will be non severe and quite
spotty. Highs will reach 70 to 75. South-southeast winds will
be breezy at around 15 to 25 mph with some higher gusts in the west.

Upper ridge axis gradually shifts eastward across the Plains over
the weekend as a broad trough digs through the Intermountain West.
With warm air advection, southerly winds, and subsidence, the
forecast will be largely dry Saturday and Sunday, with temperatures
improving a few degrees each day. Did side with the warmer guidance
which produces highs in the upper 70s and lower 80s by Sunday.

The aforementioned trough to our west lifts northeast through the
region through the first half of the week. With flow finally tapping
into gulf moisture by Sunday night, showers and thunderstorms will
become like out ahead of as associated front arriving in central SD.
The main wave lifts northeast and kicks out of the region late
Monday night. Scattered showers and thunderstorm chances continue
into Monday evening with the boundary weakening as it moves east.
Temperatures remain warm during this period, with highs in the 70s
to lower 80s. Conditional instability is fairly high on Sunday
afternoon and evening, with capping in place. Meanwhile shear is
rather marginal across much of the forecast area. The best potential
for severe weather concerns will be in south central SD where the
the cap looks weaker and shear is greatest, however as mentioned,
this is conditional and could easily change in the next few days.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1144 AM CDT Wed May 18 2016

VFR conditions through the period.


.FSD Watches/Warnings/Advisories...


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