Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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140
FXUS63 KFSD 261116
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
616 AM CDT Sun Mar 26 2017

.UPDATE...
Issued at 612 AM CDT Sun Mar 26 2017

Winds have turned light and stratus has slowly settled this
morning in areas along and just west of the Buffalo Ridge. Will go
ahead and issue a short duration dense fog advisory. Elsewhere,
fairly widespread fog continues, but the reductions in visibility
are much more sporadic. Conditions will slowly improve mid-
morning, with fog hanging around the higher elevation areas
through noon.


&&

.SHORT TERM...(Today and Tonight)
Issued at 317 AM CDT Sun Mar 26 2017

Another cloudy day is expected over the region. Only concerns today
are pointed towards light rain chances, along with redevelopment of
fog overnight.

This morning: A narrow corridor of light rain persists across parts
of Southwest Minnesota, tied to vorticity axis on the northwestern
quadrant of larger upper low centered over western Illinois.  Short
term model data suggests a bit of intensification of this narrow
band through mid-morning as mid-level moisture increases overhead
before sliding eastward by mid-day.  Elsewhere, stratus will remain,
with visibilities dipping below one mile at times along the Buffalo
Ridge into mid morning. Visibilities may bounce around enough to
avoid an advisory, but will continue to monitor.

This afternoon: Outside of the aforementioned rain chance in the
east, We`ll also keep an eye on a subtle shortwave moving into the
MO river valley later this afternoon.  Couldn`t discount a scattered
light shower west of the MO river.  Stratus will fail to really
dissipate or advect anywhere today, and will lower high temperatures
in most areas.

Tonight: Again, another night with low stratus, visibilities remain
more uncertain, and will cover most of the area with at least some
fog mention into Monday morning.

.LONG TERM...(Monday through Saturday)
Issued at 317 AM CDT Sun Mar 26 2017

Models continue to advertise a deepening trough Monday into Tuesday
across the western half of the US working into the plains Tuesday
night into Thursday.  There continues to be  a variety of model
solutions, with the GFS favoring a southern track, while the
Canadian and ECMWF are further north.  Have maintained chance pops
through the latter portion of the week.  Biggest change made to the
forecast was to cool temperatures on Thursday.  GFS solution much
warmer (by 4-7 degrees C) than the ECMWF or Canadian.  Blended the
ECMWF solution into Superblend, but may need to cool things even
further.  If this is the case, may at least have a mix of rain and
snow across eastern portions of the forecast area Thursday night
into Friday morning.

Models continue to suggest a second system working into the plains
next weekend.  Like the first system, this system is fairly wound up
and slow moving, with the bulk of the precipitation focused south of
the forecast area.  Models hint this system may have some connection
to a northern stream wave, though the northern stream wave appears
to be moisture starved. With details still to be worked out with the
second system, left guidance pops in the chance range for now.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 612 AM CDT Sun Mar 26 2017

Widespread low ceilings and fog continues this morning. Expect
only slow improvement through the daytime hours once again. Like
Saturday, Huron may break free of the stratus briefly, however
flow is fairly weak today, and that break may be short lived.

Near Sioux City, a narrow corridor of very light rain showers has
developed at 6am. As expected, this rain band will just graze the
airport, and should begin to pivot North and northeast through
mid morning.

Expect stratus to again build down tonight into Monday morning.
Coverage of fog is a little less certain, but later tafs can begin
to address this issue.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Dense Fog Advisory until 10 AM CDT this morning for SDZ040-055-
     056.

MN...Dense Fog Advisory until 10 AM CDT this morning for MNZ071-080-
     089-097-098.

IA...None.
NE...None.
&&

$$

UPDATE...Dux
SHORT TERM...Dux
LONG TERM...BT
AVIATION...Dux



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