Alert archive / South Dakota / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 108, NWS Aberdeen, SD

July 21, 20114 counties in South Dakota

NWS Aberdeen, SD issued this severe thunderstorm warning at Jul 21, 2011, 9:33 PM CDT for 4 counties in South Dakota. It was in force for 42 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: Jul 21, 2011, 9:33 PM CDT (02:33 UTC)
Expired: Jul 21, 2011, 10:15 PM CDT
In force: 42 min
Issued by: NWS Aberdeen, SD
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Hughes County, SD, Jones County, SD, Stanley County, SD, Sully County, SD

The radar

The Rapid City radar (KUDX), 196 km from the middle of the area, began a volume at 02:35 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 nearest sounding before it

Rapid City, SD (KUNR), launched 00:00Z, 2.6 hours before the alert went out and 201 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 420 J/kg
Mixed-layer CIN: -158 J/kg
Mixed-layer LCL: 2686 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: 34 m²/s²
0-3 km storm-relative helicity: 244 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.0

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 Jul 21, 8:06 PM CDT, 1 hour 27 minutes earlier.

Area forecast discussion, Jul 21, 8:06 PM CDT, 1 hour 27 minutes before

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Hazardous weather outlook, Jul 21, 5:42 AM CDT, 15 hours 51 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE ABERDEEN SD
542 AM CDT THU JUL 21 2011

MNZ039-046-SDZ003>011-015>023-033>037-045-048-051-221045-
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-
542 AM CDT THU JUL 21 2011 /442 AM MDT THU JUL 21 2011/

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

ISOLATED TO SCATTERED THUNDERSTORMS WILL DEVELOP AND MOVE ACROSS
PORTIONS OF NORTH CENTRAL AND NORTHEAST SOUTH DAKOTA EARLY THIS
MORNING. NO SEVERE THUNDERSTORMS ARE ANTICIPATED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THUNDERSTORMS ARE POSSIBLE ACROSS THE AREA FROM LATE THURSDAY
NIGHT THROUGH SATURDAY NIGHT...WITH THE BEST CHANCES BEING FRIDAY
AFTERNOON AND NIGHT. SEVERE STORMS ARE POSSIBLE WITH LARGE HAIL.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY OR TONIGHT.

In the hours before

Special weather statement, Jul 21, 8:39 PM CDT, 54 minutes before

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Local storm report, Jul 21, 9:18 PM CDT, 15 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 8:49 PM CDT	Severe Thunderstorm Warning	ABR	Jones	26 min
Jul 21, 10:13 PM CDT	Severe Thunderstorm Warning	ABR	Lyman	32 min
Jul 21, 10:17 PM CDT	Severe Thunderstorm Warning	ABR	Hughes, Sully	43 min
Jul 22, 2:31 AM CDT	Areal Flood Warning	ABR	Buffalo, Campbell, Corson, Dewey, Hughes, Hyde and 5 more	7 days
Jul 22, 5:10 AM CDT	Severe Thunderstorm Warning	ABR	Jones	37 min
Jul 22, 5:45 AM CDT	Severe Thunderstorm Warning	ABR	Jones, Lyman	30 min
Jul 22, 5:25 PM CDT	Severe Thunderstorm Warning	ABR	Codington, Grant, Roberts	50 min
Jul 22, 6:43 PM CDT	Flash Flood Warning	ABR	Codington, Grant	6 hr

Nearby

Severe Thunderstorm Warnings in South Dakota, 2011 Every severe thunderstorm warning in 2011

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.