River Flood Warning 316, NWS Sioux Falls, SD

AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
1040 PM CDT Fri Sep 13 2019

.SHORT TERM...(This Evening through Saturday)
Issued at 223 PM CDT Fri Sep 13 2019

Strato-cu field continues to pivot around the upper low this
afternoon as rather gusty northwest winds slowly subside.  Surface
winds will turn variable later this evening before surface ridging
moves through and a more prevailing southwesterly flow returns.
Closer to daybreak, weak low level warm advection intensifies in the
mid-Missouri River valley. While there is some uncertainty on
moisture availability, a few scattered showers may develop near
Sioux City and Storm Lake near or after daybreak Saturday.

Speaking of Saturday, low level flow remains veered through the day,
focusing the greatest concentration of moisture advection across NW
Iowa and south central Minnesota during the day. With temperatures
rising into the 80s, scattered surface based convection may
redevelop very late in the afternoon and evening along the
moisture gradient as weak but subtle mid-lvl lift moves overhead.
Soundings show an increasing instability gradient developing, with
MLCAPE nearing 2000 J/KG, with effective shear a bit more
marginal around 30 knots. The area with the greatest concerns for
a few strong to severe storms would be along and southeast of a
line from Windom to Beresford and Yankton.  Any activity that
develops should move away fairly quickly.

.LONG TERM...(Saturday Night through Friday)
Issued at 223 PM CDT Fri Sep 13 2019

High pressure moves in again Saturday night, and weak winds, cool
temperatures, and saturated grounds may lead to fog development by
Sunday morning.

The start to next week remains dry and features above normal
temperatures. Southerly flow will draw warmer and more humid air
northward, inducing a longer stretch of 80 degree temperatures
into mid-week. Winds may become a bit breezy, especially during
the afternoon hours of Monday and Tuesday.

Rain chances begin to increase Tuesday night thorough Wednesday
as a stronger wave enters the Northern Rockies. An increasing low
level jet may induce elevated convection into Wednesday morning
with an additional risk for convection along an advancing frontal
boundary Wednesday afternoon and evening.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1039 PM CDT Fri Sep 13 2019

Low level wind shear will develop at KSUX late tonight into early
Saturday morning. While there will be a possibility of
showers/thunderstorms around KSUX both tomorrow morning and
tomorrow afternoon, confidence is too low to include in TAF.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&

SHORT TERM...Dux
LONG TERM...Dux
AVIATION...JM

Hazardous Weather Outlook
National Weather Service Sioux Falls SD
507 PM CDT Fri Sep 13 2019

IAZ001>003-012>014-020>022-031-032-MNZ071-072-080-081-089-090-097-
098-NEZ013-014-SDZ038>040-050-052>071-142215-
Lyon-Osceola-Dickinson-Sioux-O'Brien-Clay-Plymouth-Cherokee-
Buena Vista-Woodbury-Ida-Lincoln-Murray-Cottonwood-Nobles-Jackson-
Pipestone-Rock-Dixon-Dakota-Beadle-Kingsbury-Brookings-Gregory-
Jerauld-Sanborn-Miner-Lake-Moody-Brule-Aurora-Davison-Hanson-McCook-
Minnehaha-Charles Mix-Douglas-Hutchinson-Turner-Bon Homme-Yankton-
Union-
507 PM CDT Fri Sep 13 2019

This Hazardous Weather Outlook is for northwest Iowa, west central
Iowa, southwest Minnesota, northeast Nebraska, central South
Dakota, east central South Dakota, south central South Dakota and
southeast South Dakota.

.DAY ONE...Tonight.

Flooding resulting from heavy rainfall over the past days will
continue to be an ongoing concern. Low-lying and poor drainage
areas, as well as small creeks and streams will continue to exhibit
flooding. Moderate to major river flooding will continue in the
James, Vermillion, Big Sioux, Rock and Redwood rivers.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Isolated thunderstorms are possible Saturday afternoon and evening,
generally east of I-29. A couple of these storms could become severe
with large hail and damaging winds.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.