Alert archive / Minnesota / Mesoscale Discussions in 2012

Mesoscale Discussion 1313

June 29, 2012Dickinson County, Lyon County, Osceola County, Iowa; 11 counties in Minnesota; 4 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jun 29, 2012, 5:35 PM CDT for Dickinson County, Lyon County, Osceola County, Iowa; 11 counties in Minnesota; 4 counties in South Dakota. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued: Jun 29, 2012, 5:35 PM CDT (22:35 UTC)
Expired: Jun 29, 2012, 6:30 PM CDT
In force: 55 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Dickinson County, IA, Lyon County, IA, Osceola County, IA, Brown County, MN, Cottonwood County, MN, Jackson County, MN, Lincoln County, MN, Lyon County, MN, Murray County, MN, Nobles County, MN, Pipestone County, MN, Redwood County, MN, Rock County, MN, Watonwan County, MN, Lake County, SD, Lincoln County, SD, Minnehaha County, SD, Moody County, SD

The radar

The Sioux Falls radar (KFSD), 67 km from the middle of the area, began a volume at 22:36 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 nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 10.6 hours before the alert went out and 220 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: 2323 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 15 m²/s²
0-3 km storm-relative helicity: 89 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.

208 
ACUS11 KWNS 292235
SWOMCD
SPC MCD 292235 
MNZ000-IAZ000-SDZ000-292330-

MESOSCALE DISCUSSION 1313
NWS STORM PREDICTION CENTER NORMAN OK
0535 PM CDT FRI JUN 29 2012

AREAS AFFECTED...PORTIONS OF ERN SD...SWRN MN...NWRN IA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 292235Z - 292330Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...AN ISOLATED SVR THREAT MAY CONTINUE INTO THE EVENING.
WHILE CONVECTIVE TRENDS ACROSS THE AREA WILL CONTINUE TO BE
MONITORED...THE NEED FOR A WW CURRENTLY APPEARS UNLIKELY.

DISCUSSION...CONVECTION CONTINUES TO INITIATE ALONG A DIFFUSE
STATIONARY FRONT THAT EXTENDS FROM S-CNTRL SD ENEWD TO E-CNTRL MN
WITHIN A FAIRLY NARROW CORRIDOR WHERE PRECIPITATION/OVERTURNING HAS
BEEN MINIMAL THROUGH THE DIURNAL HEATING CYCLE. THIS HAS CONTRIBUTED
TO THE DEVELOPMENT OF MODERATE INSTABILITY -- MLCAPE VALUES OF 1000
TO 2000 J/KG -- WHICH MAY SUPPORT OCCASIONALLY ROBUST CONVECTIVE
UPDRAFTS. SIOUX FALLS VWP DATA INDICATE 44 KT OF 0-6 KM BULK
SHEAR...WHICH WILL SUPPORT OCCASIONALLY ORGANIZED
CONVECTION...INCLUDING PERHAPS BRIEF/TRANSIENT SUPERCELL STRUCTURES.
HOWEVER...WITH VISIBLE SATELLITE IMAGERY DEPICTING A LACK OF
BOUNDARY-LAYER CU ACROSS THE AREA...INHIBITION MAY GREATLY LIMIT THE
SPATIAL EXTENT OF ANY SVR THREAT IF A LARGER COLD POOL DOES NOT
MATERIALIZE. AND...IN THE ABSENCE OF STRONGER LARGE-SCALE FORCING
FOR ASCENT...STORM COVERAGE MAY BE LIMITED...THUS BREEDING LOW
CONFIDENCE IN THE OPPORTUNITY FOR UPSCALE CONVECTIVE GROWTH. WHILE
THE AREA WILL CONTINUE TO BE MONITORED...THE ANTICIPATED ISOLATED
NATURE OF THE SVR THREAT OVER A FAIRLY NARROW CORRIDOR WILL LIKELY
PRECLUDE THE NEED FOR WW ISSUANCE.

..COHEN/HART.. 06/29/2012

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

ATTN...WFO...MPX...DMX...FSD...

LAT...LON   43629460 43209548 43139656 43269700 43609735 44129733
            44429668 44659536 44379449 43629460

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 29, 7:59 AM CDT	Mesoscale Discussion	SPC	Lyon, Plymouth, Sioux	91 min
Jun 29, 2:43 PM CDT	Mesoscale Discussion	SPC	Adair, Appanoose, Benton, Black Hawk, Boone, Buchanan and 31 more	3 hr
Jun 29, 3:49 PM CDT	Severe Thunderstorm Watch	SPC	Benton, Cedar, Clinton, Des Moines, Henry, Iowa and 19 more	5 hr
Jun 29, 5:04 PM CDT	Mesoscale Discussion	SPC	Iowa, Johnson, Poweshiek	26 min

Nearby

Mesoscale Discussions in Minnesota, 2012 Mesoscale Discussions in South Dakota, 2012 Mesoscale Discussions in Iowa, 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.