Alert archive / South Dakota / Mesoscale Discussions in 2012

Mesoscale Discussion 710

May 5, 201215 counties in South Dakota; Weston County, Wyoming

The Storm Prediction Center issued this mesoscale discussion at May 5, 2012, 2:06 AM MDT for 15 counties in South Dakota; Weston County, Wyoming. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued: May 5, 2012, 2:06 AM MDT (08:06 UTC)
Expired: May 5, 2012, 3:30 AM MDT
In force: 84 min
Issued by: the Storm Prediction Center
Chance of a watch: 95%

Counties Custer County, SD, Fall River County, SD, Haakon County, SD, Hughes County, SD, Hyde County, SD, Jackson County, SD, Jones County, SD, Lawrence County, SD, Lyman County, SD, Meade County, SD, Mellette County, SD, Oglala Lakota County, SD, Pennington County, SD, Stanley County, SD, Sully County, SD, Weston County, WY

The radar

The Rapid City radar (KUDX), 58 km from the middle of the area, began a volume at 08:05 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, 8.1 hours before the alert went out and 57 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: 1750 m above ground
0-6 km bulk shear: 67 kt
0-1 km storm-relative helicity: 34 m²/s²
0-3 km storm-relative helicity: 155 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.

975 
ACUS11 KWNS 050806
SWOMCD
SPC MCD 050806 
SDZ000-WYZ000-050930-

MESOSCALE DISCUSSION 0710
NWS STORM PREDICTION CENTER NORMAN OK
0306 AM CDT SAT MAY 05 2012

AREAS AFFECTED...WRN SD

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

VALID 050806Z - 050930Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...ELEVATED HAIL STORMS ARE DEVELOPING AND WILL LIKELY
PERSIST FOR SEVERAL HOURS.

DISCUSSION...STORMS HAVE FORMED RAPIDLY OVER NERN WY AND WRN SD AS
COOLING WITH THE UPPER TROUGH OVERSPREADS AN INCREASINGLY MOIST AIR
MASS ABOVE A SURFACE STABLE LAYER. MUCH OF THE MOISTENING IS AROUND
700 MB WHERE FLOW IS OUT OF THE S. FORECAST SOUNDINGS INDICATE 2-3
KM OF A WEAK LOW LEVEL LAPSE RATES BUT STEEP LAPSE RATES ABOVE. VERY
STRONG DEEP LAYER EFFECTIVE SHEAR WILL PROVE FAVORABLE FOR HAIL
STORMS.

..JEWELL.. 05/05/2012

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

ATTN...WFO...ABR...UNR...CYS...

LAT...LON   43040375 43070434 43230479 43750478 44750335 45080053
            44749939 44219917 43599969 43200168 43100300 43040375

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 4, 8:54 PM MDT	Mesoscale Discussion	SPC	Union	96 min
May 5, 2:19 AM MDT	Severe Thunderstorm Watch	SPC	Bennett, Buffalo, Butte, Custer, Dewey, Fall River and 17 more	9 hr
May 5, 5:49 AM MDT	Severe Thunderstorm Watch	SPC	Aurora, Beadle, Bon Homme, Brookings, Brule, Charles Mix and 18 more	7 hr
May 5, 8:50 AM MDT	Mesoscale Discussion	SPC	Aurora, Beadle, Brookings, Brule, Buffalo, Davison and 13 more	55 min
May 5, 1:09 PM MDT	Mesoscale Discussion	SPC	Union	96 min
May 5, 2:52 PM MDT	Mesoscale Discussion	SPC	Clay, Lincoln, Union, Yankton	83 min
May 5, 4:31 PM MDT	Tornado Watch	SPC	Bon Homme, Clay, Union, Yankton	5 hr
May 5, 5:21 PM MDT	Mesoscale Discussion	SPC	Aurora, Beadle, Bon Homme, Brule, Charles Mix, Davison and 15 more	84 min
May 5, 5:46 PM MDT	Severe Thunderstorm Watch	SPC	Aurora, Beadle, Brookings, Brule, Charles Mix, Davison and 14 more	6 hr

Nearby

Mesoscale Discussions in South Dakota, 2012 Mesoscale Discussions in Wyoming, 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.