Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 192327

Area Forecast Discussion
National Weather Service Sioux Falls SD
627 PM CDT Thu Oct 19 2017

.SHORT TERM...(This evening through Friday)
Issued at 257 PM CDT Thu Oct 19 2017

Upper level ridging will spread across the area tonight as troughing
deepens over the Rockies. This will bring a strengthening southerly
flow which will lead to mild temperatures. Lows tonight will be in
the mid to upper 50s with highs on Friday in the mid to upper 70s.
While winds will support a fire weather concern Friday, afternoon
humidity values will still be in the 40 to 50 percent range so not
anticipating any fire weather headlines. Right now now going to
issue a wind advisory but there will be a chance for near advisory
criteria through Friday.

.LONG TERM...(Friday night through Thursday)
Issued at 257 PM CDT Thu Oct 19 2017

Friday night into Saturday still the best chance for precipitation
through the period. Broad southwest flow aloft will be in place with
a shortwave expected to eject from the Rockies onto the Plains
Friday night. This should help focus the warm air advection a bit
and when couple with marginal instability bring a chance for showers
and thunderstorms to the area. The best chance should be from about
3 am Saturday to noon Saturday and east of the James River. At this
time not anticipating any severe weather.

Saturday night into Sunday looks quiet as westerly flow develops.
This should allow for good mixing and decent warming. Morning lows
will be in the 30s to lower 40s with highs on Sunday in the 60s.

In the outer periods(Monday through Thursday) looks like a good
potential for some roller coaster temperatures. One fairly strong
dip in the jet stream will exit Tuesday night which will allow a
brief, shortwave ridge to build across the area on Wednesday. This
will be followed by another fairly stout dip in the jet stream with
more cooler temperatures Thursday, likely continuing into Friday. If
this pattern evolves close to what is expected temperatures Tuesday,
Thursday and Friday will below normal and Wednesday will be above
normal. The chances for precipitation will be low through the period
and expect mainly dry conditions.


.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 621 PM CDT Thu Oct 19 2017

VFR conditions expected through the TAF period. Low level wind
shear in the surface to 1000 foot layer will be predominant this
evening through early Friday morning, only abating due to the
gusty southerly winds picking up at the surface by mid morning
Friday. Mid level clouds associated with the trough swinging
through KS/NE tomorrow will overspread the region late in the TAF
period. Consensus blend of short term guidance resulted in
unrealistic ceiling heights, so leaned heavily on the GFS output.
Any ceilings that do develop may approach the low end of VFR but
are not expected to result in any restrictions.




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