Alert archive / South Dakota / Mesoscale Discussions in 2012

Mesoscale Discussion 1108

June 9, 201223 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jun 9, 2012, 9:08 PM MDT for 23 counties in South Dakota. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued: Jun 9, 2012, 9:08 PM MDT (03:08 UTC)
Expired: Jun 9, 2012, 10:15 PM MDT
In force: 67 min
Issued by: the Storm Prediction Center
Chance of a watch: 80%

All 23 counties

Bennett County, SD, Brown County, SD, Buffalo County, SD, Campbell County, SD, Edmunds County, SD, Faulk County, SD, Haakon County, SD, Hand County, SD, Hughes County, SD, Hyde County, SD, Jackson County, SD, Jones County, SD, Lyman County, SD, Marshall County, SD, McPherson County, SD, Mellette County, SD, Oglala Lakota County, SD, Potter County, SD, Spink County, SD, Stanley County, SD, Sully County, SD, Todd County, SD, Walworth County, SD

The radar

The Rapid City radar (KUDX), 177 km from the middle of the area, began a volume at 03:09 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Rapid City, SD (KUNR), launched 00:00Z, 3.1 hours before the alert went out and 181 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2489 m above ground
0-6 km bulk shear: 69 kt
0-1 km storm-relative helicity: 24 m²/s²
0-3 km storm-relative helicity: 312 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

873 
ACUS11 KWNS 100309
SWOMCD
SPC MCD 100308
SDZ000-NDZ000-100415-

MESOSCALE DISCUSSION 1108
NWS STORM PREDICTION CENTER NORMAN OK
1008 PM CDT SAT JUN 09 2012

AREAS AFFECTED...PARTS OF SWRN...CENTRAL AND NERN SD

CONCERNING...SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY

VALID 100308Z - 100415Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...POTENTIAL EXISTS FOR A FURTHER INCREASE IN TSTM COVERAGE
AND INTENSITY AS A COLD FRONT...NOW MOVING THROUGH WRN
SD...PROGRESSES EWD LATE THIS EVENING AND OVERNIGHT THROUGH
CENTRAL/ERN SD.  LINE SEGMENTS AND SUPERCELLS WILL BE THE PRIMARY
STORM MODES WITH A THREAT FOR HAIL AND DAMAGING WIND GUSTS.

DISCUSSION...MESOSCALE AND OBJECTIVE ANALYSES INDICATED A COLD FRONT
ATTENDANT TO THE MID-UPPER LEVEL TROUGH MOVING INTO THE NRN HIGH
PLAINS EXTENDED FROM CENTRAL ND SWWD INTO WRN/SWRN SD...GENERALLY
JUST TO THE EAST OF RAPID CITY.  THIS DATA ALSO SUGGESTS THE ONGOING
CONVECTION/EMBEDDED TSTMS OVER WRN SD/ERN WY IN THE POST-FRONTAL
ENVIRONMENT AND THE MORE RECENT STORMS FORMING JUST EAST OF RAP ON
THE FRONT ARE BEING AIDED PRIMARILY BY LOW-LEVEL FRONTOGENETICAL
FORCING.

AN INCREASE IN TSTM DEVELOPMENT IS EXPECTED DURING THE NEXT FEW
HOURS AS THIS FORCING ENCOUNTERS HIGHER MOISTURE AND STRONGER
INSTABILITY LOCATED SW-NE OVER CENTRAL TO NERN SD.  EFFECTIVE BULK
SHEAR OF 40-60 KT ORIENTED PARALLEL TO THE FRONT WILL FAVOR LINE
SEGMENTS AND SUPERCELLS PRODUCING A THREAT FOR HAIL AND STRONG WIND
GUSTS.

..PETERS/THOMPSON.. 06/10/2012

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

ATTN...WFO...FGF...FSD...ABR...BIS...UNR...

LAT...LON   43190277 43860205 44430155 45929985 45949737 44909812
            43629965 43100013 43020188 43190277

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 9, 9:23 PM MDT	Severe Thunderstorm Watch	SPC	Bennett, Buffalo, Campbell, Dewey, Edmunds, Faulk and 17 more	5 hr
Jun 9, 11:45 PM MDT	Mesoscale Discussion	SPC	Brown, Campbell, Day, Edmunds, Faulk, Hand and 7 more	60 min
Jun 10, 12:07 AM MDT	Severe Thunderstorm Watch	SPC	Beadle, Brown, Clark, Codington, Day, Grant and 3 more	6 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.