Alert archive / South Dakota / Mesoscale Discussions in 2012

Mesoscale Discussion 1545

July 22, 201215 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 22, 2012, 4:38 PM CDT for 15 counties in South Dakota. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Jul 22, 2012, 4:38 PM CDT (21:38 UTC)
Expired: Jul 22, 2012, 6:15 PM CDT
In force: 97 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Brown County, SD, Campbell County, SD, Clark County, SD, Codington County, SD, Day County, SD, Dewey County, SD, Edmunds County, SD, Faulk County, SD, Marshall County, SD, McPherson County, SD, Potter County, SD, Roberts County, SD, Spink County, SD, Sully County, SD, Walworth County, SD

The radar

The Aberdeen radar (KABR), 56 km from the middle of the area, began a volume at 21:41 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 503Jul 22, 5:45 PM CDT

The nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 9.6 hours before the alert went out and 79 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: 2180 J/kg
Mixed-layer CIN: -207 J/kg
Mixed-layer LCL: 1248 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 5 m²/s²
0-3 km storm-relative helicity: 33 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

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

119 
ACUS11 KWNS 222138
SWOMCD
SPC MCD 222138 
MNZ000-SDZ000-NDZ000-222315-

MESOSCALE DISCUSSION 1545
NWS STORM PREDICTION CENTER NORMAN OK
0438 PM CDT SUN JUL 22 2012

AREAS AFFECTED...NORTHEAST SD AND PORTIONS OF EXTREME SRN ND

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 222138Z - 222315Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...THUNDERSTORMS WILL CONTINUE AHEAD OF APPROACHING COLD
FRONT INTO THIS EVENING. LOCALLY STRONG WINDS/MARGINALLY SEVERE HAIL
ARE POSSIBLE WITH STRONGER STORMS BUT WIDESPREAD/ORGANIZED SEVERE
WEATHER IS NOT ANTICIPATED AT THIS TIME. THEREFORE A WW IS NOT
EXPECTED AS STORMS CONTINUE E/SEWD.

DISCUSSION...THUNDERSTORMS HAVE DEVELOPED THIS AFTERNOON AHEAD OF
APPROACHING COLD FRONT WHICH IS LOCATED FROM SRN ND INTO NW SD.
WHILE THIS COLD FRONT WILL BE A FOCUS FOR CONTINUED ACTIVITY/FURTHER
DEVELOPMENT...EXPECT CONVECTION TO REMAIN RATHER UNORGANIZED. WHILE
THE DOWNSTREAM AIR MASS IS CHARACTERIZED BY STRONG INSTABILITY/WEAK
REMAINING CAP AND AMPLE MOISTURE...WEAK UPPER FORCING AND DEEP LAYER
SHEAR SHOULD LIMIT SEVERE POTENTIAL.  THAT BEING SAID...ISOLATED
STRONG WIND GUSTS/MARGINALLY SEVERE HAIL WILL BE POSSIBLE WITH ANY
STRONGER CELLS THAT DEVELOP. A WW IS NOT EXPECTED AT THIS TIME BUT
TRENDS WILL CONTINUE TO BE MONITORED.

..LEITMAN/CARBIN.. 07/22/2012

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

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

LAT...LON   45860026 45440094 45010101 44570027 44559874 44729747
            45259680 45879668 46059850 46089948 45860026

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 21, 9:27 PM CDT	Mesoscale Discussion	SPC	Corson, Dewey, Haakon, Harding, Meade, Pennington and 2 more	63 min
Jul 21, 10:51 PM CDT	Mesoscale Discussion	SPC	Aurora, Beadle, Brookings, Brule, Buffalo, Charles Mix and 24 more	54 min
Jul 22, 5:45 PM CDT	Severe Thunderstorm Watch	SPC	Brown, Campbell, Clark, Codington, Corson, Day and 10 more	4 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.