Alert archive / South Dakota / Mesoscale Discussions in 2012

Mesoscale Discussion 875

May 22, 201222 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at May 22, 2012, 7:30 PM CDT for 22 counties in South Dakota. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued: May 22, 2012, 7:30 PM CDT (00:30 UTC)
Expired: May 22, 2012, 9:00 PM CDT
In force: 90 min
Issued by: the Storm Prediction Center

All 22 counties

Beadle County, SD, Brown County, SD, Brule County, SD, Buffalo County, SD, Campbell County, SD, Edmunds County, SD, Faulk County, SD, Hand County, SD, Hughes County, SD, Hyde County, SD, Jerauld County, SD, Jones County, SD, Lyman County, SD, McPherson County, SD, Mellette County, SD, Potter County, SD, Spink County, SD, Stanley County, SD, Sully County, SD, Todd County, SD, Tripp County, SD, Walworth County, SD

The radar

The Aberdeen radar (KABR), 127 km from the middle of the area, began a volume at 00:33 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

Aberdeen, SD (KABR), launched 00:00Z, 0.5 hours before the alert went out and 104 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: 1261 J/kg
Mixed-layer CIN: -279 J/kg
Mixed-layer LCL: 2310 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 99 m²/s²
0-3 km storm-relative helicity: 228 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

154 
ACUS11 KWNS 230030
SWOMCD
SPC MCD 230030 
SDZ000-NEZ000-230200-

MESOSCALE DISCUSSION 0875
NWS STORM PREDICTION CENTER NORMAN OK
0730 PM CDT TUE MAY 22 2012

AREAS AFFECTED...PARTS OF CNTRL/ERN SOUTH DAKOTA

CONCERNING...SEVERE THUNDERSTORM WATCH 291...

VALID 230030Z - 230200Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 291
CONTINUES.

SUMMARY...SCATTERED STORM DEVELOPMENT IS UNDERWAY...WITH FURTHER
DEVELOPMENT STILL POSSIBLE THIS EVENING.

DISCUSSION...SCATTERED STORM DEVELOPMENT IS ONGOING ALONG AND JUST
EAST OF A NARROW PRE-FRONTAL CORRIDOR OF STRONGER SURFACE HEATING
ACROSS CENTRAL SOUTH DAKOTA.  ACTIVITY HAS GENERALLY BEEN SLOWLY
INTENSIFYING...BUT APPEARS TO BE STRUGGLING GIVEN THE STRENGTH OF
STRONG MID-LEVEL INHIBITION STILL PRESENT...PARTICULARLY SOUTH OF
THE NORTH DAKOTA/SOUTH DAKOTA BORDER AREA.  STRONGER MID-LEVEL
FORCING FOR UPWARD VERTICAL MOTION APPEARS LIKELY TO REMAIN NORTH OF
THE STATE BORDER THIS EVENING...BUT THE EASTWARD ADVECTION OF THE
LEADING EDGE OF COOLER MID-LEVEL AIR COULD STILL WEAKEN INHIBITION
ALONG/AHEAD OF THE COLD FRONT ACROSS CENTRAL INTO EASTERN SOUTH
DAKOTA LATER THIS EVENING.  IF THIS OCCURS..IT WILL COINCIDE WITH
PRE-FRONTAL SOUTHERLY LOW-LEVEL JET INTENSIFICATION IN EXCESS OF
40-50 KT...WHICH MAY CONTRIBUTE TO POTENTIAL FOR STRONG CONVECTIVE
SURFACE GUSTS.

..KERR.. 05/23/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...FSD...ABR...LBF...UNR...

LAT...LON   43580156 44950037 45820004 45780004 45929953 45939847
            45689795 44789782 43519895 42920048 43580156

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 22, 8:41 PM CDT	Mesoscale Discussion	SPC	Marshall, Roberts	64 min
May 23, 2:04 PM CDT	Mesoscale Discussion	SPC	Brookings, Deuel, Grant, Hamlin, Lake, McCook and 3 more	86 min
May 23, 2:56 PM CDT	Mesoscale Discussion	SPC	Union	94 min
May 23, 4:07 PM CDT	Severe Thunderstorm Watch	SPC	Union	7 hr

Nearby

Mesoscale Discussions in South Dakota, 2012 Every mesoscale discussion in 2012

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.