Alert archive / South Dakota / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 207, NWS Aberdeen, SD

August 26, 2018Brown County, McPherson County, South Dakota

NWS Aberdeen, SD issued this severe thunderstorm warning at Aug 26, 2018, 8:20 PM CDT for Brown County, McPherson County, South Dakota. It was in force for 40 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 26, 2018, 8:20 PM CDT (01:20 UTC)
Expired
Aug 26, 2018, 9:00 PM CDT
In force
40 min
Issued by
NWS Aberdeen, SD
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Brown County, SD, McPherson County, SD

The radar

The Aberdeen radar (KABR), 38 km from the middle of the area, began a volume at 01:23 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Aug 26, 7:37 PM CDTTornado WatchSPC5 hr

The nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 1.3 hours before the alert went out and 92 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Aberdeen, SD at 00:00Z on 2018-08-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2190 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Aberdeen, SD at 00:00Z on 2018-08-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 164 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
2190 J/kg
Mixed-layer CIN
-121 J/kg
Mixed-layer LCL
1710 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
164 m²/s²
0-3 km storm-relative helicity
254 m²/s²
Significant tornado parameter
0.3
Supercell composite
16.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Aberdeen, SD wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 26, 6:46 PM CDT, 1 hour 34 minutes earlier.

Area forecast discussion, Aug 26, 6:46 PM CDT, 1 hour 34 minutes before
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
646 PM CDT Sun Aug 26 2018

.UPDATE...
Issued at 645 PM CDT Sun Aug 26 2018

00z aviation discussion updated below.

&&

.SHORT TERM...(This Evening through Monday Afternoon)
Issued at 321 PM CDT Sun Aug 26 2018

Rather complex scenario this afternoon in regards to convection.
Still watching band of weak showers and storms moving eastward into
the James River valley, but still a pretty large cap in place based
on the 19Z ABR sounding. Cap is a bit weaker down towards the
Watertown region, so perhaps when this mid-level impulse makes its
way further east we will see more robust development. Still lots of
uncertainty though in regards to overall evolution/timing and areal
coverage of any thunderstorms this afternoon/evening. Best bulk
shear is along and north of Highway 12, with plenty of instability
to work with as well. Will stress though a low confidence in overall
areal coverage and timing of storms - mainly due to capping issues.
If something were to manage to break through the cap in the weaker
CIN environment across the southeast CWA, it would likely go severe
quickly based on the parameters, especially further north closer to
the better bulk shear values. May have to look further west as well
over the next couple hours as the main mid-level wave/forcing
approaches. CAMs are trying to latch on to this a bit, with
convection across western/central SD by 00Z this evening. Will
continue to monitor.

Looking at tomorrow, will be watching another area of low pressure
and mid-level wave move through the region. Looking at decent
chances for showers and storms across at least the northern CWA by
the late afternoon hours.

.LONG TERM...(Monday Evening through Sunday)
Issued at 321 PM CDT Sun Aug 26 2018

Sfc low pressure will continue to affect the region Monday night.
Showers and thunderstorms, some of which may be strong to severe
across northern SD and west central MN on Monday evening, will
gradually exit. An upper trough will then usher in considerably
cooler air for Tuesday as H85 temps plunge into the single digits.
Highs may struggle to get into the upper 60s by Tuesday afternoon.
Nudged winds a bit higher than Superblend with the low and in the
caa regime, as well.

Also dropped temperatures a couple of degrees lower than blends on
Tuesday night. While some clouds may linger, it will not be a far
fall into the lower 40s across the east. Warm air advection across
the west will help moderate temps. Zonal flow aloft for the end of
the week will provide a bump in temps, as well. There will also be
increased mixing in southerly surface flow ahead of a lee side front
on the Rockies. As the front progresses east on Thurs and Fri,
showers and thunderstorms will again develop across the region.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
Issued at 645 PM CDT Sun Aug 26 2018

Scattered showers and thunderstorms will move across the region
through this evening as a cold front and upper level short wave
trough moves through the region. These could affect the airports at
or in the vicinity. Otherwise, mainly VFR conditions are expected
through tonight and Monday.

&&

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

UPDATE...Mohr
SHORT TERM...TMT
LONG TERM...Wise
AVIATION...Mohr
Hazardous weather outlook, Aug 26, 5:10 AM CDT, 15 hours 10 minutes before
Hazardous Weather Outlook
National Weather Service Aberdeen SD
510 AM CDT Sun Aug 26 2018

MNZ039-046-SDZ003>011-015>023-033>037-045-048-051-271015-
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-
510 AM CDT Sun Aug 26 2018 /410 AM MDT Sun Aug 26 2018/

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.

Throughout the day today and tonight, isolated to scattered strong to
severe thunderstorms are possible. The main severe weather threats
include large hail, damaging winds and torrential rainfall.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

Thunderstorms are possible Monday afternoon through Monday night, and
then again, at times, late in the week and over the weekend.

.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.

Dorn

In the hours before

Local storm report, Aug 26, 7:47 PM CDT, 33 minutes before
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Local storm report, Aug 26, 8:05 PM CDT, 15 minutes before
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Local storm report, Aug 26, 8:07 PM CDT, 13 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ABERDEEN SD
807 PM CDT SUN AUG 26 2018

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

0805 PM     HAIL             4 N CANNING             44.45N 100.03W
08/26/2018  E1.75 INCH       HUGHES             SD   PUBLIC

            LOTS OF NICKEL TO GOLF BALL SIZED HAIL.

&&

JT
Local storm report, Aug 26, 8:11 PM CDT, 9 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ABERDEEN SD
811 PM CDT SUN AUG 26 2018

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

0802 PM     HAIL             5 N BLUNT               44.59N 99.99W
08/26/2018  M1.50 INCH       SULLY              SD   FIRE DEPT/RESCUE

&&

JT

The office that day

Everything else NWS Aberdeen, SD issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 26, 7:18 PM CDTSevere Thunderstorm WarningABRDewey, Hughes, Stanley, Sully42 min
Aug 26, 7:39 PM CDTSevere Thunderstorm WarningABRHughes, Stanley, Sully51 min
Aug 26, 8:14 PM CDTSevere Thunderstorm WarningABRHughes, Hyde, Sully61 min
Aug 26, 8:48 PM CDTSevere Thunderstorm WarningABRHand, Hyde42 min
Aug 26, 9:58 PM CDTSevere Thunderstorm WarningABRHand32 min
Aug 26, 11:19 PM CDTSevere Thunderstorm WarningABRClark, Hamlin41 min
Aug 27, 12:07 AM CDTSpecial Weather StatementABRDeuel, Hamlin38 min
Aug 27, 12:17 AM CDTSevere Thunderstorm WarningABRDeuel, Hamlin43 min
Aug 27, 6:27 PM CDTSevere Thunderstorm WarningABRStanley48 min
Aug 27, 6:54 PM CDTSevere Thunderstorm WarningABRJones36 min

Nearby

Severe Thunderstorm Warnings in South Dakota, 2018Every severe thunderstorm warning in 2018

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.