Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 101130

Area Forecast Discussion
National Weather Service Sioux Falls SD
530 AM CST Sat Mar 10 2018

.SHORT TERM...(Today and Tonight)
Issued at 307 AM CST Sat Mar 10 2018

Fairly messy system, currently evident on water vapor imagery over
southwest MT, will slide southeast into the region today. Ahead of
it, an initial shortwave and push of warm air advection has led to a
line of showers on radar across south central SD early this morning.
A dry layer near 850 mb has tempered this precipitation but with
pockets of favorable elevated lapse rates could see enough localized
enhancement to get something to the ground and thus will leave
chance POPs in this morning.

By late afternoon/early evening, the upper level closed low should
make its way into south central South Dakota and eventually slide
southeastward through Nebraska. This will push a second, and
somewhat more widespread, round of precipitation thru the region
thru the evening and overnight hours. Will likely be somewhat
fractured areas of precipitation, but nonethelesss, good chances of
seeing something at some point during this time frame. Forecast
soundings and temperatures profiles suggest that anything that falls
during the afternoon hours would generally be rain or a rain/snow
mix. The rain/snow line will again crash southward thru the evening
with just plain snow by mid evening region-wide. Fairly quick
hitting and fractured nature of precipitation should keep snow
amounts light for most. Amounts will likely vary quite a bit from
location to location dependant on where different precipitation
bands sit for longer durations of time. This quasi-fractured and
varying nature of the precipitation and resultant rain/snow amounts
should be stressed again when trying to convey how the sensible
weather will play out over the next 36 hours. Unlike the system from
a few days ago, winds will not be a significant factor, although
could gusts up near 30 mph during the evening and overnight hours
west of I-29. The general winter threats will exists with the
potential for slick and snow covered roads, along with periods of
reduced visibility when snow is falling.

As the main wave pulls away Saturday night, another weaker PV
anomoly drops south and, combined with a continued saturated
dentritic layer, will keep a chance of snow going into Sunday
morning. Any lingering precipitation should come to an end thru the
afternoon hours. Winds will remain somewhat breezy Sunday,
particularly west of I-29.

.LONG TERM...(Sunday through Friday)
Issued at 307 AM CST Sat Mar 10 2018

Still looks like a period of tranquil weather and gradual warming
into the next work week. Monday and Tuesday we sit squarly in
northerly flow aloft which will continue to usher in cooler than
normal temperatures. Highs Monday and Tuesday will generally be in
the 30s to perhaps nearing 40 across our far south. Wednesday and
Thursday, the upper level ridge nudges into the region with
southerly surface winds ushering in warmer temeperatures. With 925
mb temperatures anywhere from 7 to 14 C across our region, could be
looking at upper 40s to 50s by Thursday. Friday could be even warmer
with dare I say 60s possible per the ECMWF and Canadian. Meanwhile,
the GFS hints at another wave thus making the details in the far
extended on the murkey side.


.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 523 AM CST Sat Mar 10 2018

Narrow band of wintry mix stretches from near KPIR to KMHE to KSUX
as of 1130z this morning. Surface observations and cameras show
this precipitation has generally been light and brief but
nonetheless, with temperatures hovering near freezing, could be
of note. Once this band moves east of our TAF sites later this
morning, mid level clouds and mostly VFR conditions should prevail
thru the afternoon. KHON will be the exception where MVFR
conditions could spread back in by as early as mid afternoon with
MVFR/IFR conditions impacting all TAF sites by this evening. Light
snow is also expected by during the evening and overnight hours.




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