Hail and Damaging Winds in South Dakota, August 17, 2019

Area Forecast Discussion
National Weather Service Aberdeen SD
312 PM CDT Sat Aug 17 2019

.SHORT TERM...(This Evening through Sunday Night)
Issued at 312 PM CDT Sat Aug 17 2019

Storm development is starting out west this afternoon along a cold
front as large scale lift and cooling from an upper level low
pressure trough was approaching from the west. Mixed layer capes to
the east of the front will increase to 2000-3000 J/KG as deep layer
shear increases from the northwest through the afternoon and
evening. Deep layer shear will be from 30 to 45 knots by early
evening. Therefore, expect storms to increase in coverage through
the late afternoon and evening with some severe storms expected.
Large hail is the main threat at first with the storms developing
into a line with damaging winds being more of a threat later on. All
ops and hi-res models show widespread development into the evening
hours. Therefore, have high pops in the forecast along with mention
of severe. Heavy rain could also occur. Some of the models also show
a lot of post-frontal/elevated showers/storms tonight. Therefore,
expect this to all move east with cooler and drier high pressure
following in behind tonight into Sunday. Sunday will be sunny with
light winds with highs in the 70s.

.LONG TERM...(Monday through Saturday)
Issued at 312 PM CDT Sat Aug 17 2019

There will be a brief period of upper ridging but that becomes more
zonal aloft across the area initially, with surface high pressure
across the east weakening and retreating. A wave across North
Dakota, along with the remnants of a pseudo-monsoon wave will
provide lift across the northern plains/Nebraska, though it does
appear best forcing may be both north and south of the CWA, and
maybe the better environment will occur Monday night. Upstream
ridging will follow with a deepening eastern CONUS trough. That will
deflect high pressure overhead Tuesday and into Wednesday. Models
diverge on how to handle the upper flow thereafter with a series of
waves crossing the northern tier of the country, but it does look
like a return for milder conditions for the latter half of the work
week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1259 PM CDT Sat Aug 17 2019

A cold front sliding across the region through this evening will
bring numerous thunderstorms with it. All airports are expected to
be affected with IFR/MVFR ceilings and/or vsbys. The storms may also
be severe with large hail and damaging winds. This will all move
east by late evening with low VFR/MVFR ceilings for a time behind
the storms. Otherwise, expect conditions to become VFR for later
tonight and Sunday morning.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

SHORT TERM...Mohr
LONG TERM...Connelly
AVIATION...Mohr

Hazardous Weather Outlook
National Weather Service Aberdeen SD
333 AM CDT Sat Aug 17 2019

MNZ039-046-SDZ003>011-015>023-033>037-045-048-051-180845-
Traverse-Big Stone-Corson-Campbell-McPherson-Brown-Marshall-Roberts-
Walworth-Edmunds-Day-Dewey-Potter-Faulk-Spink-Clark-Codington-Grant-
Hamlin-Deuel-Stanley-Sully-Hughes-Hyde-Hand-Jones-Lyman-Buffalo-
333 AM CDT Sat Aug 17 2019 /233 AM MDT Sat Aug 17 2019/

This Hazardous Weather Outlook is for west central Minnesota,
central South Dakota, north central South Dakota and northeast
South Dakota.

.DAY ONE...Today and tonight.

A cold front will sweep through the region this afternoon and evening
bringing strong to severe storms. Large hail, damaging winds, and
even a tornado or two will be possible.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Strong to severe storms are possible Monday evening, mainly east of
the Missouri River.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will likely be needed later today. Weather
spotters are encouraged to submit reports to the National Weather
Service in Aberdeen. The public can submit reports on our web page,
Facebook page, or our Twitter feed.