Alert archive / South Dakota / Mesoscale Discussions in 2005

Mesoscale Discussion 1925

August 3, 200532 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Aug 3, 2005, 12:54 PM CDT for 32 counties in South Dakota. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Aug 3, 2005, 12:54 PM CDT (17:54 UTC)
Expired: Aug 3, 2005, 3:30 PM CDT
In force: 3 hr
Issued by: the Storm Prediction Center

All 32 counties

Aurora County, SD, Beadle County, SD, Brown County, SD, Brule County, SD, Buffalo County, SD, Campbell County, SD, Clark County, SD, Davison County, SD, Dewey County, SD, Edmunds County, SD, Faulk County, SD, Haakon County, SD, Hamlin County, SD, Hand County, SD, Hughes County, SD, Hyde County, SD, Jackson County, SD, Jerauld County, SD, Jones County, SD, Kingsbury County, SD, Lyman County, SD, Mellette County, SD, Miner County, SD, Pennington County, SD, Potter County, SD, Sanborn County, SD, Spink County, SD, Stanley County, SD, Sully County, SD, Todd County, SD, Tripp County, SD, Walworth County, SD

The radar

The Rapid City radar (KUDX), 191 km from the middle of the area, began a volume at 17:53 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 699Aug 3, 3:05 PM CDT

The nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 5.9 hours before the alert went out and 174 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: 346 J/kg
Mixed-layer CIN: -423 J/kg
Mixed-layer LCL: 1753 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: -74 m²/s²
0-3 km storm-relative helicity: -45 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.

000 
ACUS11 KWNS 031754
SWOMCD
SPC MCD 031754 
SDZ000-032030-

MESOSCALE DISCUSSION 1925
NWS STORM PREDICTION CENTER NORMAN OK
1254 PM CDT WED AUG 03 2005

AREAS AFFECTED...SD

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 031754Z - 032030Z

TSTMS WILL INCREASE ACROSS WRN-CNTRL SD THROUGH THIS AFTN WITH
THREATS FOR LARGE HAIL AND DAMAGING WINDS.  PARTS OF THE REGION MAY
NEED A WW.

17Z SFC ANALYSIS PLACES THE SYNOPTIC COLD FRONT FROM SERN ND TO THE
BLACK HILLS AND INTO NERN WY.  MOIST NLY UPSLOPE FLOW WAS DEEPENING
ACROSS WRN SD PER VWP AT RAPID CITY BEHIND THIS FRONT. COMBINATION
OF THE ENHANCED UPSLOPE FLOW AND LARGE SCALE ASCENT ASSOCIATED WITH
A WY SHORTWAVE TROUGH ARE BECOMING FAVORABLE FOR INCREASING
TSTMS...BOTH OVER THE BLACK HILLS AND IN ELEVATED BANDS N OF THE
FRONT. 

MESOANALYSIS INDICATES A THERMAL RIDGE HAS DEVELOPED AHEAD OF THE
FRONT FROM THE BLACK HILLS EWD INTO CNTRL SD.  RUC SOUNDINGS SUGGEST
THAT THE AIR MASS REMAINS CAPPED ON THE PLAINS...BUT AS HEATING
CONTINUES...ELEVATED/HIGHER BASED TSTMS WILL HAVE A GREATER
PROBABILITY IN ROOTING INTO THE VERY UNSTABLE BOUNDARY LAYER. 
EFFECTIVE VERTICAL SHEAR OF 40-45 KTS WILL BE SUFFICIENT FOR
SUPERCELLS WITH LARGE HAIL.  DAMAGING WINDS COULD BECOME A FACTOR
IF/WHEN TSTMS DEVELOP INTO THE BOUNDARY LAYER.

TSTMS SHOULD CONTINUE EVOLVING ALONG/N OF THE FRONT THROUGH
21Z...THEN POSSIBLY EWD INTO THE THERMAL RIDGE AXIS ACROSS CNTRL/SRN
SD LATER THIS AFTN.

..RACY.. 08/03/2005

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

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

44160352 44860170 45850002 45639800 44859708 43789759
43349858 43090109 43550342

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 3, 1:58 AM CDT	Mesoscale Discussion	SPC	Codington, Day, Grant, Marshall, Roberts	92 min
Aug 3, 3:05 PM CDT	Severe Thunderstorm Watch	SPC	Aurora, Beadle, Brookings, Brown, Brule, Buffalo and 33 more	7 hr
Aug 3, 5:45 PM CDT	Mesoscale Discussion	SPC	Aurora, Beadle, Brookings, Brule, Buffalo, Charles Mix and 23 more	90 min

Nearby

Mesoscale Discussions in South Dakota, 2005 Every mesoscale discussion in 2005

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.