Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 211157

National Weather Service Sioux Falls SD
657 AM CDT Sun Apr 21 2019

.SHORT TERM...(Today through Monday Afternoon)
Issued at 326 AM CDT Sun Apr 21 2019

Sporadic and isolated showers forming in northwest Iowa into
southwest Minnesota early this morning as warm air advection
leads to very elevated showers. Very dry air in the subcloud
layer, so don`t expect much in the way of accumulation.

Today, a boundary will sag southward throughout the day.  Ahead of
the front, very mild airmass will result in one final day across the
southeastern half of the forecast area.  00Z models continued with
the trend of slowing the boundary ever so slightly, and raised
forecast highs along and south of a line from Yankton to Windom.

Atmosphere ahead of the boundary is capped, but north of the
boundary, there is the potential for a shower or thunderstorm. As
the boundary continues to work south this evening, could see a
marginal risk for an elevated storm if atmosphere can saturate in
the 6000-8000 foot agl level. Elevated directional shear is fairly
limited, but there is very marginal speed shear. Am thinking
early in convective life cycle, a storm may be able to produce
some small hail, possibly up to the size of quarters briefly.

Expect storms to become more widespread tonight as shortwave lifts
northeast into the region.  Secondary wave follows on its heals
leading to additional showers throughout the day on Monday.  In
general, have 0.5-1" forecast across the region, but wouldn`t be
surprised if there are some locations that pick up more than an
inch, with the greatest likelihood east of I-29.  The clouds,
showers, and brisk northeast winds will keep temperatures below
normal on Monday.

.LONG TERM...(Monday Evening through Saturday)
Issued at 326 AM CDT Sun Apr 21 2019

A warming trend is expected Tuesday into Wednesday ahead of a front
that moves through the region Wednesday night.  The front appears to
move through the region mainly dry.

The weekend appears to be potentially active next weekend as a
series of waves move through the region under the guidance of the
northern branch of the jet. Potentially, fairly strong low level
jet may develop across the western plains next weekend, leading to
a nocturnal focus to convective chances.


.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 657 AM CDT Sun Apr 21 2019

Areas to the cold side of a surface boundary will first experience
gusty northeast wind reaching 25 to 30 mph at times, but also
should see development of areas of MVFR stratus during the
afternoon and evening hours, which will expand southeast and
blossom as elevated convection becomes more widespread overnight.
There could be some areas of IFR ceilings by later in the night
around KHON and KFSD.




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