Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 142125

Area Forecast Discussion
National Weather Service Sioux Falls SD
325 PM CST Tue Nov 14 2017

.SHORT TERM...(This evening through Wednesday)
Issued at 324 PM CST Tue Nov 14 2017

Surface low pressure moving through the area this afternoon which
was bringing warmer readings to the area. As the wind turns to the
southwest and especially west the low stratus is eroding and
temperatures warming. Most locations west of I-29 were in the 50s at
20z and even locations east of I-29 were climbing to around 50s at
that time. As the sun sets a little drizzle will be possible close
to SLB and SPW during the evening but not expecting that to amount
to much. A wave without much to work with will move into central SD
this evening and through the area overnight. A few light showers or
sprinkles will be possible along and north of I-90.

As for temperatures, a somewhat non-diurnal fall is expected tonight
with some mixing behind the initial boundary this evening, then a
more rapid fall late tonight and early Wednesday morning as the
colder air surges into areas north of I-29. This should bring lows
in the mid 30s in northwest IA to closer to 30 along highway 14.

Partly cloudy and a bit breezy on Wednesday with highs from the mid
30s along highway 14 to the upper 40s closer to SUX.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 324 PM CST Tue Nov 14 2017

Wednesday night into Thursday will see an upper level jet max
move through which will drop surface high pressure into the area
Wednesday night. This should allow temperatures to drop back into
the teens to mid 20s, with the colder readings along and east of
I- 29.

As this high pressure shifts east, a very strong southerly gradient
will develop with south winds of 25 to 35 mph and gusts around 40
mph likely. While temperatures will be around normal they will feel
a bit on the cool side with the strong wind.

Friday and Friday night looks like our best chance for precipitation
over the next several days, but even this chance is not all that
great. For now looks like mostly a rain threat although a little
light snow might mix in.

Saturday through Tuesday will see highs right around normal with
little to no chance for precipitation. This is care of northwest flow
aloft. By Wednesday and Thursday next week it the GFS suggests that
there will be a chance for some cooler temperatures but right now
agreement is low with the ECMWF and Canadian indicating mild
conditions continuing.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1148 AM CST Tue Nov 14 2017

Widespread IFR to LIFR ceilings continue at midday from near the
James River valley eastward. Visibility continues to be IFR or
worse from the mid James River valley southeast toward northwest
Iowa and southwest MN. Gradual increase in westerly component to
surface and near-surface flow will likely erode both quantities
from the south and southwest through the afternoon, with the final
flushing of conditions likely to come with frontal passage around
early evening for KFSD/KSUX.

Does appear that as the main cool air push evolves very late
tonight and Wednesday morning, there will be an area of
stratocumulus which develops and swings across at least KHON and
KFSD. Have currently kept this as a scattered coverage of cloud
base near or less than 2 kft, but could easily have an hour or two
during the morning of MVFR ceilings.




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