Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 280809

Area Forecast Discussion
National Weather Service Sioux Falls SD
309 AM CDT Tue Mar 28 2017

.SHORT TERM...(Today and Tonight)
Issued at 309 AM CDT Tue Mar 28 2017

Rather quiet weather continues through the short term portions of
the forecast.  Mid and upper level clouds continue to stream
northward over the CWA in response to a number of mid-level
shortwaves moving through. While stratus has shifted south and
southeast of the CWA, temporary clearing has allowed fog to begin
to develop over NW Iowa.  The concentration of fog will likely be
highest across northern Iowa, but as thin patches of upper clouds
move through, could see patchy development northward along the I-29
corridor.  Will continue to monitor for the need of any dense fog

Today itself should be a very pleasant day. Outside of dodging mid-
level clouds, an occasionally breezy easterly wind should continue
to allow temperatures into the 50s. Thicker mid-lvl clouds may limit
temperatures over south central SD.

Tonight: Deeper moisture contained over western NE/KS will begin to
advect eastward overnight. A stronger shortwave pivoting northward
will try to push very light rain northward by Wednesday morning. The
influence of dry low-level flow from the northeast could really keep
PoPs low for areas northeast of a Huron to Sioux Falls and
Worthington line. With the increased cloud cover, temperatures
should remain well in the 30s.

.LONG TERM...(Wednesday through Monday)
Issued at 309 AM CDT Tue Mar 28 2017

Active medium range with several chances of precipitation.  Fairly
deep saturation is expected on Wednesday as deep trough churns
across the central plains. Warm air advection and frontogenetic
forcing increases throughout the day on Wednesday, and have raised
pops into the categorical range across northwest Iowa on Wednesday
afternoon. Weak forcing lingers Wednesday night into Thursday across
northwest Iowa, and have kept chance pops lingering through the
better part of the day. Lingering low clouds will likely keep
temperatures below normal east of I-29.

Second system moving across the central and southern Plains will
create the chance for light rain south of I-90. Any precipitation
that ventures this far north appears to be fairly light.

Temperatures should be fairly mild through the weekend into early
next week ahead of a cold front that works through the area on
Tuesday.  Kept the chance pops associated with the frontal passage,
which appears to be mildly unstable.  Considered adding a mention of
thunder next Tuesday, but through collaboration decided to leave it
out for now.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1031 PM CDT Mon Mar 27 2017

A few areas of concern tonight. MVFR stratus in northwest Iowa
continues to retreat. Models suggest that this will largely remain
south of the Highway 20 corridor tonight into much of Tuesday,
then lift northward after 00z Tuesday evening with the approach of
the next weather system. Will leave out of the KSUX TAF through
04z. With the light winds and low level moisture in place, expect
areas of fog to develop in the early morning hours for most areas,
with the exception of the James Valley area. Visibility will drop
as low as 1 to 4 miles. South central SD may also see some fog
develop, but this will likely be more spotty. Fog will lift by




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