Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 270802

Area Forecast Discussion
National Weather Service Sioux Falls SD
302 AM CDT SAT AUG 27 2016

.SHORT TERM...(Today and Tonight)
Issued at 301 AM CDT Sat Aug 27 2016

A shortwave is sliding across the region very early this morning and
seeing scattered showers developing through the eastern two thirds
of our CWA at this time. This wave will slide into south central
MN/Central IA by mid morning with any shower activity coming to an
end over our area. Anticipate the remainder of the day to be dry
with showers associated with the main upper level low over North
Dakota now looking to remain to our north. A surface warm front does
lift into the Missouri River Valley late this afternoon, and a
couple of CAMs try spit out some convective development over south
central SD during this time frame. In the absence of any real
trigger, elected to keep it dry for now. In a warm air advection
regime, temperatures will be on the increase today with highs mid
70s east of Interstate 29 to lower 80s through the James River and
Missouri River Valleys.

The warm front continues to lift northward tonight, and it will be a
milder night with lows in the lower to mid 60s. Did throw in some
slight pops over the eastern Highway 14 corridor and southwestern MN
later tonight with some models pointing toward convective
development over that area on the nose of a low level
jet/instability gradient.

.LONG TERM...(Sunday through Friday)
Issued at 301 AM CDT Sat Aug 27 2016

For the medium and extended portions of the forecast, favored
guidance from the ECMWF and GFS ensembles. Early in the forecast,
broad mid-lvl ridging continues to dominate the central US. A few
showers or thunderstorms may linger in SW Minnesota early Sunday. In
the afternoon, there is an outside chance for a diurnal thunderstorm
or two south of I-90. Have not included attm, but we`ll need to
monitor trends.

By the start of next week, we`ll be monitoring a weak disturbance
that drifts northward out of the four corners region. This subtle
wave of energy may drift towards the MO river valley on Monday and
Monday Night before settling southward by Tuesday.

From Tuesday-Friday, have adjusted blended model PoPs downward with
more emphasis from the ECMWF and GEFS precipitation probabilities.
Broad mid-lvl ridging becomes more established by mid-week, and
high pressure over the Great Lakes should push meaningful moisture
west of the CWA.

Have trended PoPs upwards by the end of the week and next weekend,
as a transition to southwesterly flow aloft begins. A weak boundary
may push through the area late Friday, with thunderstorms focused
along the frontal boundary.

As far as temperatures are concerned, near to above normal
temperatures in the lower 80s appear likely each day.  The warmest
days of the week will be Monday/Tuesday, with a slightly drop near
80 in the mid-week due to the influence of sfc high pressures, and a
rise back above normal into next weekend as sfc flow turns


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1036 PM CDT Fri Aug 26 2016

The 06Z TAF set reflects some deteriorating conditions through
mid morning Saturday. It appears too stable to mention any chance
for TSRA, so therefore only opted to include a period of showers
for KFSD and KSUX toward daybreak. However thoughts are that
potential fog formation may be a bigger issue for the TAFs later
tonight then any rainfall. Looking at upstream observations, KSUX
could certainly drop into IFR and LIFR in the pre dawn hours
Saturday, lasting until mid morning Saturday. KFSD should see some
widespread MVFR conditions late tonight and Saturday morning and
even some possible IFR shortly after sunrise. At this time, it
appears KHON may stay VFR, except for a brief period of upper end
MVFR between 06Z and 12Z possible. By late morning and midday and
Saturday, all sites should be VFR again.


.FSD Watches/Warnings/Advisories...


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