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Area forecast discussion
National Weather Service Sioux Falls South Dakota
1145 am CST Thu Nov 21 2019

Short term...(today and tonight)
issued at 333 am CST Thu Nov 21 2019

Mid-upper wave spinning northeast into northwest Iowa early this
morning, and will continue to progress toward southern Wisconsin by
midday, as a northern stream trough drops southeast across the
Dakotas and Minnesota. Thus far, the bulk of precipitation with the
southern wave has remained near/south of a line from Platte to just
northwest of Sioux Falls, to Marshall, with little if anything to
the northwest of this line, though starting to see indications of
light snow developing on radar in Central/Northeast South Dakota in
response to the northern trough. As temperatures continue to cool
from the northwest through mid morning, could still see some very
light snowfall accumulations across our western/northern counties,
but amounts should be limited to less than a half inch for most, as
weakening lift and overall drying of air mass behind the departing
southern wave will limit precipitation amounts to a few hundredths
at best after 12z.

Expect to see very little movement in temperatures after sunrise,
with continued weak cold advection counteracting any increase in
sunshine as the stratus diminishes this afternoon. Thus looking for
highs within a few degrees of our daybreak readings, from the lower
30s north to around 40 southeast. Clear skies and light winds will
allow for good radiational cooling tonight. Lack of snow cover will
save temperatures from bottoming out as indicated in the coldest
guidance, but still expect lows to dip below the blended guidance,
mainly mid to upper teens for our forecast area.

Long term...(friday through wednesday)
issued at 333 am CST Thu Nov 21 2019

Fairly quiet from Friday through the weekend and into early next
week. Wave develops out of the southern stream over the Central
Plains late Friday, but this expected to remain too far south of our
area to have any impact, except perhaps some increase in clouds in
our far south. This quickly followed by a northern stream clipper
dropping southeast into the northern plains Friday night/Saturday.
Any precipitation potential with this expected to remain well north,
but could see some increase in winds behind the attendant cold front
as it moves through the area on Saturday.

Temperatures moderate through the weekend, with Sunday expected to
be the warmest day of the next several, as 850mb temperatures warm
into the mid-single digits above zero, and westerly flow aids in
mixing the warmer air to the surface. Readings should climb into the
40s Saturday, with highs Sunday from the mid 40s in southwest Minnesota, to
upper 50s in south central South Dakota.

The Holiday travel period leading up to Thanksgiving continues to
show very little agreement among the models. Latest operational
solutions have trended a bit weaker/more open with any waves sliding
through the plains, but several GFS ensemble solutions hold on to a
stronger/closed system somewhere in the plains, sometime in the
Tuesday-Wednesday time frame. With the high degree of variability in
the current solutions, and from run-to-run, will stick with low-mid
chance range pops for Tuesday. Precipitation type just as uncertain
as occurrence, but at this point even the coldest solutions indicate
high temperatures in the mid-upper 30s for our forecast area, so
rain/snow mix wording seems reasonable at this point. Main message
would be to just monitor forecast trends over the next several days,
as much will change as we move through the weekend and early next
week.

&&

Aviation...(for the 18z tafs through 18z Friday afternoon)
issued at 1142 am CST Thu Nov 21 2019

Breezy north winds will gust 25 to 35 mph this afternoon. No
precipitation is expected. Low to mid-level cloud decks will
begin to thin by late afternoon, lingering longest in the east.
Winds decrease overnight, with high cloud cover increasing into
Friday morning.

&&

Fsd watches/warnings/advisories...
South Dakota...none.
Minnesota...none.
Iowa...none.
NE...none.
&&

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