Alert archive / South Dakota / Mesoscale Discussions in 2004

Mesoscale Discussion 660

May 11, 200424 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at May 11, 2004, 6:53 PM CDT for 24 counties in South Dakota. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: May 11, 2004, 6:53 PM CDT (23:53 UTC)
Expired: May 11, 2004, 9:00 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 24 counties

Aurora County, SD, Beadle County, SD, Brule County, SD, Buffalo County, SD, Charles Mix County, SD, Clark County, SD, Codington County, SD, Davison County, SD, Day County, SD, Douglas County, SD, Faulk County, SD, Gregory County, SD, Hamlin County, SD, Hand County, SD, Hanson County, SD, Hyde County, SD, Jerauld County, SD, Kingsbury County, SD, Lyman County, SD, Marshall County, SD, Miner County, SD, Sanborn County, SD, Spink County, SD, Tripp County, SD

The radar

The Aberdeen radar (KABR), 130 km from the middle of the area, began a volume at 23:55 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.

Severe Thunderstorm Watch 191May 11, 8:45 PM CDT

The nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 11.9 hours before the alert went out and 71 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: 48 J/kg
Mixed-layer CIN: -312 J/kg
Mixed-layer LCL: 1079 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 355 m²/s²
0-3 km storm-relative helicity: 454 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.9

Open this sounding in Storm Lab

The text

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

443 
ACUS11 KWNS 112354
SWOMCD
SPC MCD 112353 
SDZ000-NEZ000-120200-

MESOSCALE DISCUSSION 0660
NWS STORM PREDICTION CENTER NORMAN OK
0653 PM CDT TUE MAY 11 2004

AREAS AFFECTED...N CNTRL NEB...CNTRL/ERN SD

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 112353Z - 120200Z

CONTINUE REMAINING VALID PORTION OF WW 187...AND NEW WW 189.
THREAT FOR STRONG...POTENTIALLY DAMAGING WINDS APPEARS TO BE
INCREASING ACROSS PARTS OF CENTRAL/EASTERN SOUTH DAKOTA THROUGH
12/03-04Z.

UPSCALE EVOLUTION OF CONVECTIVE ACTIVITY INTO MORE ORGANIZED
MESOSCALE SCALE CONVECTIVE SYSTEM APPEARS UNDERWAY IN
MOIST...POTENTIALLY UNSTABLE ENVIRONMENT SOUTH/EAST OF DEEP SURFACE
LOW NEAR PIERRE.  WARM SECTOR SURFACE TEMPERATURES ARE STILL IN THE
MID/UPPER 80S...CONTRIBUTING TO SURFACE BASED CAPE UP TO 2000 J/KG. 
THIS WILL REMAIN SUPPORTIVE OF INTENSE UPDRAFTS WITH LARGE
HAIL...WHILE DAMAGING DOWNBURSTS BECOME AN INCREASING THREAT WITHIN
THE NEXT HOUR OR TWO.

EVAPORATIVE COOLING NEAR HEAVY PRECIPITATION APPEARS LIKELY TO
SUPPORT SUBSTANTIAL SURFACE MESO HIGH/COLD POOL ACROSS THE
CHAMBERLAIN/WINNER AREAS OF SOUTH CENTRAL SOUTH DAKOTA THROUGH
AROUND 12/01Z. THIS SHOULD SUBSEQUENTLY BEGIN TO SURGE
NORTHEASTWARD TOWARD THE INTERSTATE 29 CORRIDOR...AS 40+ KT
SOUTHERLY LOW-LEVEL JET VEERS IN RESPONSE TO LOW-LEVEL PRESSURE/
HEIGHT FALL CENTER ALREADY SHIFTING ACROSS NORTHERN MINNESOTA TOWARD
THE UPPER GREAT LAKES REGION.

..KERR.. 05/11/2004

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

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

44749985 45159933 45559846 45819735 45129690 44139712
43429784 43139862 42919927 42810060 44199983

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 10, 8:06 PM CDT	Mesoscale Discussion	SPC	Custer, Fall River, Lawrence	114 min
May 10, 10:19 PM CDT	Mesoscale Discussion	SPC	Butte, Custer, Fall River, Harding, Lawrence	116 min
May 10, 10:45 PM CDT	Severe Thunderstorm Watch	SPC	Fall River	4 hr
May 11, 1:27 AM CDT	Mesoscale Discussion	SPC	Bennett, Haakon, Hughes, Hyde, Jackson, Jones and 9 more	63 min
May 11, 1:32 PM CDT	Mesoscale Discussion	SPC	Bennett, Brown, Campbell, Clark, Codington, Corson and 27 more	118 min
May 11, 1:55 PM CDT	Severe Thunderstorm Watch	SPC	Bennett, Campbell, Corson, Dewey, Haakon, Jackson and 7 more	5 hr
May 11, 3:55 PM CDT	Tornado Watch	SPC	Beadle, Brown, Clark, Codington, Day, Deuel and 10 more	5 hr
May 11, 5:04 PM CDT	Mesoscale Discussion	SPC	Bennett, Brule, Buffalo, Faulk, Hand, Hughes and 8 more	116 min
May 11, 5:37 PM CDT	Mesoscale Discussion	SPC	Brown, Day, Edmunds, McPherson, Marshall, Roberts	113 min
May 11, 6:40 PM CDT	Severe Thunderstorm Watch	SPC	Aurora, Bon Homme, Brule, Buffalo, Charles Mix, Davison and 12 more	6 hr

Nearby

Mesoscale Discussions in South Dakota, 2004 Every mesoscale discussion in 2004

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.