Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 242327

Area Forecast Discussion
National Weather Service Sioux Falls SD
627 PM CDT Sat Mar 24 2018

.SHORT TERM...(This evening through Sunday)
Issued at 427 PM CDT Sat Mar 24 2018

Brief quiet period this evening, before warm advection ahead of a
subtle mid-level wave starts generating light precipitation in
central South Dakota. This will gradually work eastward through the
day, but is expected to diminish as it progresses east through the
early afternoon. Limited mid-level moisture and generally weak lift
should lead to primarily freezing drizzle or drizzle late tonight
into Sunday. Could see some light icing in areas west of I-29 prior
to temperatures warming up tomorrow morning, but given an expected
scattered nature to the precipitation and light amounts, opting to
cover this potential in the HWO and via social media and not issue
any winter weather headlines at this time. Expecting temperatures in
our west to only dip to a degree or two below freezing tonight in
these areas, and with daytime road surface temperatures warming well
above freezing, impacts may also be confined to elevated/untreated
surfaces, even during the early morning.

.LONG TERM...(Sunday night through Saturday)
Issued at 427 PM CDT Sat Mar 24 2018

Stronger trough will impact the region Sunday night through Monday,
and again (possibly even more-so), precipitation type will be highly
uncertain. Part of the difficulty is variance among the models in
the available moisture below -10C, and thus the potential for
freezing drizzle or drizzle as opposed to rain/snow. With this in
mind, QPF may be a little too high, but confidence in any one
solution is too low to make adjustments to the blended forecast at
this time.

Given the above-mentioned lack of mid-level moisture, and thermal
profiles which nudge above zero across a good portion of the area,
periods of freezing drizzle/rain and associated icing are certainly
possible. However, as mentioned in the short-term section, any icing
impacts, especially during the day, may be limited due to warming
road temps. Will try to hone in on the area of greatest icing risk
over the next couple of forecast cycles, but for now, will focus on
the HWO and social media to heighten awareness of the potential.

Beyond Monday night, we get back into a more tranquil pattern. Not
completely dry as a cool, broad trough settles over the Plains for
midweek, but it appears that any precipitation chances will be
scattered and light.


.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 626 PM CDT Sat Mar 24 2018

Overall, MVFR is expected for the 00Z TAF period. However with an
easterly to southeast fetch of air continuing, it is possible that
a little VFR could sneak into KFSD between 06Z and 12Z Sunday. But
with warm air advection moving in on Sunday, MVFR ceilings will
move back in at KFSD.




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