Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 151704

Area Forecast Discussion
National Weather Service Sioux Falls SD
1204 PM CDT Sun Apr 15 2018

.SHORT TERM...(Today and Tonight)
Issued at 409 AM CDT Sun Apr 15 2018

Powerful late winter storm continues to impact part of the region
today as it slowly translate east-northeast into the Great Lakes/
Ohio Valley region, albeit blizzard conditions are not expected to
continue. As the core of the system slowly swings east, an inverted
trough will be moving over the CWA, keeping moisture and instability
through the day. Latest model runs suggest a strong 700 mb
frontogenesis and DivQ developing along and east of the I-29
corridor through mid morning - early afternoon. Therefore, have
increased PoPs east of the I-29 where periods of light to moderate
snow could continue throughout the day. Snow will slowly taper off
from west to east by the afternoon and evening hours. Additional
snow accumulations of 1 to 3 inches will be possible.

Winds will gradually decrease to 15-25 mph with gusts to 30 mph by
the afternoon hours across South Dakota as the pressure gradient
weakens. Windy conditions will persist in southwest Minnesota and
northwest Iowa through the evening with gusts to 35 mph possible at

In terms of headlines, have issued a winter weather advisory for
light snow and blowing snow through the evening.

Conditions will gradually improve into the overnight hours with
light northwest winds and mostly clear skies. Lows will generally be
in the teens with wind chill values in the single digits above by
early Monday morning.

.LONG TERM...(Monday through Saturday)
Issued at 409 AM CDT Sun Apr 15 2018

Alright, round 1 ending, round 2 ...on the way? More snow and mix
precipitation are possible by mid-week.

An amplified upper ridge builds in across the region Monday through
Tuesday, keeping the region mostly dry with colder than average
temperatures. Highs will mainly be in the 30s and lower 40s.

Several upper-level waves will be ejecting east into the Plains,
bringing the next upper wave and associated surface low across the
area Tuesday night into Wednesday. There are still uncertainty in
timing, intensity and track of this system, but there is a good
consensus that this system will bring rain, snow, and even a mix
of precipitation across the region. The GFS looks a bit
disorganized, but the ECMWF and Canadian bring the system
close/over the area by Tuesday night. The NAM gives us a little
bit of hope, bringing the closed low farther south. Synoptically,
there will be a good setup and potential for freezing rain, then
changing to snow as an inverted trough and warm air advects
northward into the region. Definitely, this is the next period to
keep an eye on. Again, it will all depend on the location and
track of the main upper low.


.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1157 AM CDT Sun Apr 15 2018

A combination of VFR/MVFR conditions and periods of light snow or
flurries will continue through the afternoon and early evening
hours. Expect clearing from west to east this evening and
overnight with VFR conditions for a period thereafter. With light
winds, clearing skies and building surface high pressure, can`t
rule out some fog development early Monday morning. High res
guidance has been rather fleeting with the placement and extent of
any fog and thus will just include mention in KHON and KFSD for
now and let subsequent TAF updates refine up or down from there.


SD...Winter Weather Advisory until 1 PM CDT this afternoon for SDZ040-

MN...Winter Weather Advisory until 1 PM CDT this afternoon for MNZ098.

     Winter Weather Advisory until 7 PM CDT this evening for MNZ071-

IA...Winter Weather Advisory until 1 PM CDT this afternoon for IAZ001-

     Winter Weather Advisory until 7 PM CDT this evening for IAZ002-

NE...Winter Weather Advisory until 1 PM CDT this afternoon for NEZ013-



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