Alert archive / North Dakota / Mesoscale Discussions in 2012

Mesoscale Discussion 1691

August 3, 201222 counties in North Dakota; 16 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Aug 3, 2012, 1:31 PM CDT for 22 counties in North Dakota; 16 counties in South Dakota. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued: Aug 3, 2012, 1:31 PM CDT (18:31 UTC)
Expired: Aug 3, 2012, 2:30 PM CDT
In force: 59 min
Issued by: the Storm Prediction Center
Chance of a watch: 80%

All 38 counties

Barnes County, ND, Cass County, ND, Cavalier County, ND, Dickey County, ND, Eddy County, ND, Emmons County, ND, Foster County, ND, Grand Forks County, ND, Griggs County, ND, Kidder County, ND, LaMoure County, ND, Logan County, ND, McIntosh County, ND, Nelson County, ND, Pembina County, ND, Ramsey County, ND, Ransom County, ND, Sargent County, ND, Steele County, ND, Stutsman County, ND, Traill County, ND, Walsh County, ND, Brown County, SD, Campbell County, SD, Dewey County, SD, Edmunds County, SD, Faulk County, SD, Haakon County, SD, Hand County, SD, Hughes County, SD, Hyde County, SD, Jones County, SD, McPherson County, SD, Potter County, SD, Stanley County, SD, Sully County, SD, Walworth County, SD, Ziebach County, SD

The radar

The Bismarck radar (KBIS), 108 km from the middle of the area, began a volume at 18:32 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 553Aug 3, 2:40 PM CDT

The nearest sounding before it

Bismarck Municip, ND (KBIS), launched 12:00Z, 6.5 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: 331 J/kg
Mixed-layer CIN: -242 J/kg
Mixed-layer LCL: 1310 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 89 m²/s²
0-3 km storm-relative helicity: 99 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.

832 
ACUS11 KWNS 031831
SWOMCD
SPC MCD 031831 
MNZ000-NDZ000-SDZ000-031930-

MESOSCALE DISCUSSION 1691
NWS STORM PREDICTION CENTER NORMAN OK
0131 PM CDT FRI AUG 03 2012

AREAS AFFECTED...ERN ND...N-CNTRL/CNTRL SD

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

VALID 031831Z - 031930Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...SFC-BASED TSTMS ARE EXPECTED TO DEVELOP AHEAD OF A
EWD/SEWD PROGRESSING COLD FRONT ACROSS PORTIONS ERN ND AND
N-CNTRL/CNTRL SD. SEVERE WIND AND HAIL AS WELL AS ISOLATED TORNADOES
APPEAR POSSIBLE WITH THIS ACTIVITY. A WW WILL LIKELY BE REQUIRED FOR
A PORTION OF THE AREA.

DISCUSSION...LATEST SFC ANALYSIS DEPICTS A COLD FRONT EXTENDING SWWD
FROM SRN MB ACROSS CNTRL ND AND INTO NWRN SD. A SFC LOW IS LOCATED
ALONG THIS FRONT APPROXIMATELY 45 MI W OF MBG. THIS LOW APPEARS TO
BE A PSEUDO TRIPLE POINT WITH THE COLD FRONT CONTINUING WSWWD FROM
THIS LOW...A WARM FRONT EXTENDING SEWD ACROSS CNTRL/SERN SD...AND A
WEAK TROUGH AXIS SSWWD THROUGH S-CNTRL SD INTO THE NEB PANHANDLE.
VISIBLE SATELLITE IMAGERY IS BEGINNING TO SHOW A CU FIELD ACROSS
CNTRL SD...IN AN AREA WHERE TEMPS HAVE REACHED THE UPPER 80S AND
MESOANALYSIS INDICATES LITTLE TO NO CINH. ELSEWHERE..SOME CINH STILL
REMAINS /AS INDICATED ON THE 18Z ABR SOUNDING/ BUT CONTINUED
BOUNDARY LAYER HEATING AND LARGE-SCALE LIFT ASSOCIATED WITH THE COLD
FRONT/SHORTWAVE TROUGH WILL AID IN FURTHER DESTABILIZATION. CINH
SHOULD BE ELIMINATED ACROSS MOST OF THE DISCUSSION AREA DURING THE
NEXT HOUR OR SO. MLCAPE A0A 1500 J/KG AND EFFECTIVE BULK SHEAR AOA
30 KTS WILL SUPPORT ORGANIZED TSTM STRUCTURE WITH AN INITIAL
SUPERCELL MODE TRANSITIONING INTO MORE OF A LINEAR MODE. INCREASED
SWLY WINDS ALOFT AND AN ASSOCIATED INCREASE IN LOW-LEVEL SHEAR
ACROSS FAR ERN SD MAY SUPPORT AN ISOLATED TORNADO THREAT WITH ANY
DISCRETE CELLS THAT DEVELOP ACROSS THE AREA. HOWEVER...THIS AREA
WILL LIKELY TAKE LONGER TO DESTABILIZE AND MOST OF THE ACTIVITY IS
EXPECTED TO BE IN A LINEAR MODE BY THE TIME IT/S THAT FAR EAST. AS A
RESULT...A WW WILL LIKELY BE REQUIRED FOR A PORTION OF THE AREA.

..MOSIER/THOMPSON.. 08/03/2012

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

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

LAT...LON   46190077 45540127 44570210 43550052 45119808 46319720
            47649703 48989716 49019835 48039928 46570038 46190077

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 2, 7:10 PM CDT	Mesoscale Discussion	SPC	Adams, Billings, Bowman, Divide, Dunn, Golden Valley and 5 more	95 min
Aug 3, 2:14 PM CDT	Severe Thunderstorm Watch	SPC	Barnes, Cass, Dickey, Eddy, Emmons, Foster and 14 more	7 hr
Aug 3, 6:19 PM CDT	Mesoscale Discussion	SPC	Barnes, Cass, Dickey, Eddy, Foster, Grand Forks and 9 more	86 min
Aug 3, 1:02 AM CDT	Mesoscale Discussion	SPC	Gregory	88 min

Nearby

Mesoscale Discussions in North Dakota, 2012 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.