Severe Thunderstorm Warning 98, NWS Aberdeen, SD

Area Forecast Discussion
National Weather Service Aberdeen SD
339 PM CDT Mon Jul 17 2017

.SHORT TERM...(This Evening through Tuesday Afternoon)
Issued at 333 PM CDT Mon Jul 17 2017

The threat for severe storms this afternoon and again late tonight
through Tuesday morning are the forecast concerns.

As of 20Z, a frontal boundary is currently located over northern
Marshall CO, southwestward to Pierre. This boundary will be the
focus for convection through this evening. With high values of
DCAPE, damaging winds will be the main threat. Steep lapse rates,
along with some shear could produce an isolated hail threat as
well. This convection should progress eastward through this
evening with a period of dry conditions expected tonight.

An upper level shortwave, currently over WY and MT will cross the
region late tonight and through the morning hours on Tuesday. While
instability is lacking, isolated severe storms will be possible due
to good 0-6 km bulk shear and upper level jet support. There have
been two events this year when the best MU-cape was south of this
cwa, but we still received severe weather with overnight
convection. The setup tonight looks similar to those two events.

The second around of convection should progress into MN by 21Z
Tuesday. With mostly cloudy skies, highs on Tuesday will be much
cooler than today.

.LONG TERM...(Tuesday Evening through Monday)
Issued at 333 PM CDT Mon Jul 17 2017

Sprawling mid level high pressure over the Southern Plains will
continue through much of the period. Meanwhile, sporadic s/w
activity within the flow aloft over the Northern Plains will
continue to promote periodic mcs activity. The focus Tuesday night
looks to be mainly south of the cwa. However, on Wednesday there is
some consistency with a system moving southeast out of ND and across
the eastern cwa. This could end up being a half way decent severe
weather day given progged moderate mlcapes/strong deep layer shear
leading to some fairly stout supercell composite values by
afternoon. The remainder of the work week looks somewhat active too
given continued moderate to high amounts of deep layer shear and
mlcape values. Plus a mean sfc frontal boundary will exist over the
region until late in the weekend when it will drift south of the
area. Temperatures overall should average out near to perhaps
slightly above normal for most of the period.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon)
Issued at 1236 PM CDT Mon Jul 17 2017

A frontal boundary will cross the region today with winds shifting
from the south, to the north behind the front. Thunderstorms are
possible along the front later this afternoon. Some storms may
impact the terminals of KABR and KATY. Damaging winds will be the
main threat.

&&

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

SHORT TERM...SD
LONG TERM...TDK
AVIATION...SD

Hazardous Weather Outlook
National Weather Service Aberdeen SD
337 AM CDT Mon Jul 17 2017

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-
337 AM CDT Mon Jul 17 2017 /237 AM MDT Mon Jul 17 2017/

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

.DAY ONE...Today and Tonight

Hot air across the area will allow for temperatures to top out in
the upper 90s to over 100 degrees. There is also a touch of
humidity to the air and heat index values may also top 100
degrees for an hour or two this afternoon.

We will also see breezy conditions, mainly east of the Missouri
river. Wind gusts between 20 and 30mph, when combined with the hot
temperatures and drought conditions will also result in High to
Very High grassland fire danger today.

Additionally, A front moving across the area will generate
thunderstorms capable of producing strong winds and large hail.
The threat will be focused mainly across eastern and central South
Dakota today, moving east this evening and during the early
overnight hours.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

An active weather pattern is expected for the area through most of
the work week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be requested late this afternoon and
through the evening.

Connelly

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ABERDEEN SD
525 PM CDT MON JUL 17 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0503 PM     HAIL             5 S GARDEN CITY         44.89N 97.58W
07/17/2017  E0.88 INCH       CLARK              SD   CO-OP OBSERVER

            NICKEL AND DIME SIZED HAIL WITH ESTIMATED
            WINDS OF 40-45 MPH.

&&

JT

Special Weather Statement
National Weather Service Aberdeen SD
545 PM CDT MON JUL 17 2017

SDZ018-172330-
Spink SD-
545 PM CDT MON JUL 17 2017

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN SPINK COUNTY UNTIL
630 PM CDT...

At 545 PM CDT, Doppler radar was tracking a strong thunderstorm near
Hillside Colony, or 19 miles west of Clark, moving east at 25 mph.

Nickel size hail and winds in excess of 30 mph will be possible with
this storm.

Locations impacted include...
Clark Colony.

LAT...LON 4476 9815 4481 9819 4496 9799 4476 9798
TIME...MOT...LOC 2245Z 248DEG 23KT 4481 9812

TDK