Special Weather Statement, NWS Aberdeen, SD

Area Forecast Discussion
National Weather Service Aberdeen SD
219 PM CDT Mon Aug 30 2021

.SHORT TERM...(This Evening through Tuesday Night)
Issued at 218 PM CDT Mon Aug 30 2021

Current flat westerly flow aloft will give way to rising heights as
we head toward mid-week. For tonight, s/w over MT will continue to
advect into and across ND. Thus, WAA pattern will continue with
moderate LLJ up through the central part of SD. Increasing heat and
instability this afternoon will lead to a chance for convection this
evening and overnight, especially west of the James valley. Given
moderate MLCAPE/moderate deep layer shear and steep mid-level lapse
rates, a few severe storms look possible. Unfortunately, the CAMS
are offering various solutions as to the evolution of convection
this evening over the Missouri valley. Thus, PoP confidence isn't
particularly high over this region. Also, during the evening an H5
speed max enters the western border area of NE/SD. This energy may
well lead to an MCS that starts over southern SD, and then cruises
southeast overnight into NE/IA. There is fair agreement among the
CAMS that this will occur, thus leading to higher forecaster
confidence. At this point Tuesday and Tuesday night appear dry as
mid-level ridge builds over the forecast area. Temperatures over the
short range will favor near average for the time of year.

.LONG TERM...(Wednesday through Monday)
Issued at 218 PM CDT Mon Aug 30 2021

The main challenge in this period continues to be storm chances
going into late Wednesday through Thursday. An upper ridge is
expected to still be overhead as we begin on Wednesday. This should
give most of our CWA a dry but warm and humid day. An upper trough
will be digging into the Pac NW during the day. Shortwave trough
energy is progged to ride up the backside of the upper ridge
northeastward into our region by the end of the day. At the sfc, lee
side troughing will be working into the western Dakotas during the
daytime. Sfc Td's are expected to be pushing into the upper 60s to
around 70 degrees by afternoon. With instability increasing by late
in the day, potential for low-level jet development and a resultant
warm-air advection pattern should lead to a good chance for showers
and thunderstorms going into Wednesday night and Thursday. One
limiting factor that will have to be watched could be the strength
of a developing cap over portions of the region. A cold front is
progged to push through the region by the end of the day Thursday
going into Friday. Most of the area should be drier on Friday, but
additional weaker waves moving through the region this upcoming
weekend could lead to additional chances for more shower activity.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon)
Issued at 1218 PM CDT Mon Aug 30 2021

Terminals KABR,KATY,KPIR,KMBG

VFR skies/vsbys are expected regionwide through tonight. Isolated
storms are possible mainly for KMBG/KPIR this evening.

&&

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

SHORT TERM...TDK
LONG TERM...Vipond
AVIATION...TDK

Hazardous Weather Outlook...UPDATED
National Weather Service Aberdeen SD
302 PM CDT Mon Aug 30 2021

MNZ039-046-SDZ006>008-011-018>023-312015-
Traverse-Big Stone-Brown-Marshall-Roberts-Day-Spink-Clark-Codington-
Grant-Hamlin-Deuel-
302 PM CDT Mon Aug 30 2021

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

.DAY ONE...This afternoon and tonight.

Showers and thunderstorms are possible tonight, severe weather is
not expected.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Good chances of thunderstorms are expected Wednesday night into
Thursday night.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

SDZ003>005-009-010-015>017-033>037-045-048-051-312015-
Corson-Campbell-McPherson-Walworth-Edmunds-Dewey-Potter-Faulk-
Stanley-Sully-Hughes-Hyde-Hand-Jones-Lyman-Buffalo-
302 PM CDT Mon Aug 30 2021 /202 PM MDT Mon Aug 30 2021/

This Hazardous Weather Outlook is for central South Dakota and
north central South Dakota.

.DAY ONE...This afternoon and tonight.

Scattered thunderstorms are expected this afternoon and tonight.
There is a slight risk of severe weather with large hail and damaging
winds.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Good chances of thunderstorms are expected Wednesday night into
Thursday night.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be requested. 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.

Special Weather Statement
National Weather Service Aberdeen SD
338 PM MDT Mon Aug 30 2021

SDZ003-302215-
Corson SD-
338 PM MDT Mon Aug 30 2021

...A strong thunderstorm will impact portions of northwestern Corson
County through 415 PM MDT...

At 338 PM MDT, Doppler radar was tracking a strong thunderstorm near
Thunder Hawk, or 12 miles east of Lemmon, moving east at 40 mph.

HAZARD...Winds in excess of 30 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

This strong thunderstorm will be near...
  Keldron around 350 PM MDT.
  Morristown around 355 PM MDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

A Severe Thunderstorm Watch remains in effect until 900 PM MDT for
north central South Dakota.

&&

LAT...LON 4594 10200 4595 10187 4594 10155 4585 10152
      4577 10197 4583 10200
TIME...MOT...LOC 2138Z 250DEG 35KT 4588 10192

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...30 MPH

TDK