Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 252317

Area Forecast Discussion
National Weather Service Sioux Falls SD
617 PM CDT Thu May 25 2017

.SHORT TERM...(This evening through Friday)
Issued at 309 PM CDT Thu May 25 2017

Isolated light rain showers associated with the passage of a cold
front across the area, will gradually taper off this evening. Cloud
cover is considerably increasing, but in terms of precipitation,
light rain or even sprinkles are expected with these showers due to
limited low-level moisture and more stable air as it moves eastward.
In fact, surface observations have been reporting none to a trace of
precipitation with these passing showers. It has been a windy day!
Tight pressure gradients associated with the surface low centered
over north central SD are producing brisk southerly winds gusting
from 30 to 35 mph. Winds are expected to wane down by around sunset.

At upper levels, while the ridge continues to slide east of the FA,
a shortwave will begin to shift northeast, increasing the chance of
precipitation during the nighttime. Low PoP chances are again
expected, but isolated thunderstorms will be possible given a steep
lapse rate and decent CAPE. This will mainly affect our extreme
southern portions of the forecast area through around 13Z.

A mostly dry and warmer Friday is on tap as a surface high pressure
builds in across the region early in the morning. With mostly sunny
skies and breezy northwesterly winds, highs will be in the 70s.
Portions of northwest Iowa could see temperatures in the upper 70s
to near 80.

.LONG TERM...(Friday night through Thursday)
Issued at 309 PM CDT Thu May 25 2017

Relatively quiet medium and extended forecasts continue, with
minimal change needed to the ongoing forecast.  Shortwave energy
pivoting around the base of an central Canadian trough combined with
increased support from brief right entrance region of an upper jet
will bring a risk for scattered showers to the area on Saturday.
Best focus for convection will stay south of the area, but
anticipate a day very similar to Thursday with scattered light
showers moving through by mid-day.

This upper trough brings cooler weather to finish the weekend and
begin next week.  Another favorable setup for afternoon instability
showers presents itself on Sunday and with trough hanging around the
eastern half of the CONUS on Monday, even further instability
showers may develop east of I-29 on Monday.

This upper low isn`t expected to dislodge from the eastern CONUS for
much of the week, which will keep the forecast area under the spell
of cooler and dry high pressure, keeping rain chances minimal and
keeping temperatures cooler than normal to start June.


.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 613 PM CDT Thu May 25 2017

Primarily VFR conditions expected through the TAF period. There
will be the possibility of a brief period of MVFR ceilings around
KSUX toward 12Z on Friday morning with the possibility of a spotty
shower. This will be short lived however with skies clearing out
by mid morning.




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