091 
FXUS63 KFSD 052007
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
307 PM CDT Tue Sep 5 2017

.SHORT TERM...(This evening through Wednesday)
Issued at 307 PM CDT Tue Sep 5 2017

A strong northerly upper level jet will gradually shift east and 
allow a cool surface high pressure to spread across the area. With 
dew points in the mid 30s to lower 40s over northern SD and central 
ND lows tonight will be on the cool side. While some brief frost 
might be possible in low lying areas, most locations are not 
expected to see any frost. Lows will range from the upper 30s in the 
mid James Valley to 40 to 45 elsewhere.

The surface high pressure will be overhead on Wednesday leading to a 
cool, but pleasant day. Winds will be light but late morning and 
afternoon could see some gusts around 15 to 20 mph east of Interstate 
29 due to mixing where winds aloft are a bit stronger. Expect 
afternoon cumulus development again tomorrow but the coverage should 
be a little less than today. Highs will be limited to mid 60s to 
lower 70s in most locations again.


.LONG TERM...(Wednesday night through Tuesday)
Issued at 307 PM CDT Tue Sep 5 2017

On Wednesday night the surface ridge sags only slowly southward. 
This will bring a transition to southerly winds overnight, though 
the gradient remains weak enough that winds will become nearly calm. 
Low lying areas will feel the affect of that with lows dipping into 
the lower 40s, with mid to upper 40s elsewhere.

On Thursday the eastern CONUS trough nudges eastward as rising upper 
level heights build over our area. In a southerly low level flow, 
temperatures will respond with highs into the mid 70s to lower 80s.

On Thursday night and Friday models continue to be split on a 
backdoor cold front which may or may not slide through our area. 
Does not look to have much of an impact on our area either way, 
though temperatures could be slightly cooler than currently 
forecasted over southwestern MN on Friday afternoon if this system 
were to push through. At this point, looking at highs again mid 70s 
to lower 80s.

Upper level ridging builds into our area for the weekend as strong 
surface high pressure builds into the Great Lakes region. This will 
bring about slowly warming temperatures with highs into the upper 
70s to mid 80s by Sunday. With a fairly tight gradient over our 
area, it will be breezy both days, and again had to boost winds a 
bit on those days with Superblend guidance coming in too low.

Models are still in disagreement with regard to a cold frontal 
passage for the beginning of next week, with the GFS now the only 
one actually bringing it through our area. Because of that, still 
looking at warm temperatures with readings in the upper 70s to mid 
80s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1239 PM CDT Tue Sep 5 2017

VFR through the period. Periods of broken ceilings around 6000
feet are likely through about 0z. An isolated shower may also
develop but coverage should be low.


&&

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

$$

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