Alert archive / Minnesota / Mesoscale Discussions in 2012

Mesoscale Discussion 670

May 2, 201223 counties in Minnesota; 4 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at May 2, 2012, 11:06 PM CDT for 23 counties in Minnesota; 4 counties in South Dakota. It was in force for 24 min.

The area

The outline as issued.

The facts

Issued: May 2, 2012, 11:06 PM CDT (04:06 UTC)
Expired: May 2, 2012, 11:30 PM CDT
In force: 24 min
Issued by: the Storm Prediction Center
Chance of a watch: 60%

All 27 counties

Anoka County, MN, Big Stone County, MN, Carver County, MN, Chippewa County, MN, Dakota County, MN, Hennepin County, MN, Kandiyohi County, MN, Lac qui Parle County, MN, McLeod County, MN, Meeker County, MN, Pope County, MN, Ramsey County, MN, Renville County, MN, Scott County, MN, Sherburne County, MN, Sibley County, MN, Stearns County, MN, Stevens County, MN, Swift County, MN, Traverse County, MN, Washington County, MN, Wright County, MN, Yellow Medicine County, MN, Codington County, SD, Day County, SD, Grant County, SD, Roberts County, SD

The radar

The Minneapolis radar (KMPX), 140 km from the middle of the area, began a volume at 04:08 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 00:00Z, 4.1 hours before the alert went out and 137 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: 84 J/kg
Mixed-layer CIN: -59 J/kg
Mixed-layer LCL: 1937 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: 21 m²/s²
0-3 km storm-relative helicity: 134 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

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

384 
ACUS11 KWNS 030406
SWOMCD
SPC MCD 030406 
WIZ000-MNZ000-SDZ000-NDZ000-030430-

MESOSCALE DISCUSSION 0670
NWS STORM PREDICTION CENTER NORMAN OK
1106 PM CDT WED MAY 02 2012

AREAS AFFECTED...PARTS OF CENTRAL MN AND NERN SD

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 030406Z - 030430Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...WW WILL BE COORDINATED FOR POTENTIAL ISSUANCE ACROSS PARTS
OF CENTRAL MN INTO NERN SD.

DISCUSSION...AT 04Z...A SURFACE FRONT EXTENDED FROM NERN SD ESEWD
THROUGH CENTRAL MN TO THE TWIN CITIES METRO INTO CENTRAL WI.  A
MODERATELY UNSTABLE AIR MASS RESIDING ALONG AND S OF THIS BOUNDARY
WITH A FEED OF LOW LEVEL MOISTURE EXTENDING NWD ACROSS SERN SD/SWRN
MN APPEARS TO BE SUPPORTING THE ONGOING STRONG TO SEVERE STORMS OVER
WEST CENTRAL MN AND NERN SD.  THE NRN CHIPPEWA STORM IS LIKELY
LOCATED ON OR VERY CLOSE TO THE WNW-ESE ORIENTED BOUNDARY...AND THUS
MAY BE SURFACE BASED.  WATER VAPOR IMAGERY AND OBJECTIVE ANALYSES
SUGGESTED A FEW PERTURBATIONS/JET MAXES MOVING THROUGH THE ERN
DAKOTAS TO CENTRAL MN WHICH SHOULD SUSTAIN THE ONGOING ACTIVITY AND
SUPPORT NEW TSTM DEVELOPMENT. EFFECTIVE BULK SHEAR OF UP TO 50 KT
WILL MAINTAIN THE LIKELIHOOD FOR ROTATING UPDRAFTS AND THE ATTENDANT
THREAT FOR LARGE HAIL AND DAMAGING WINDS.

..PETERS/THOMPSON.. 05/03/2012

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

ATTN...WFO...MPX...FGF...ABR...

LAT...LON   44939781 45939736 45939594 45819532 45359299 45119274
            44469292 44539448 44939781

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 2, 7:20 PM CDT	Mesoscale Discussion	SPC	Big Stone, Clay, Grant, Traverse, Wilkin	55 min
May 2, 7:38 PM CDT	Mesoscale Discussion	SPC	Blue Earth, Brown, Cottonwood, Dodge, Faribault, Fillmore and 16 more	37 min
May 2, 7:47 PM CDT	Severe Thunderstorm Watch	SPC	Dodge, Fillmore, Houston, Mower, Olmsted, Wabasha and 1 more	5 hr
May 2, 9:18 PM CDT	Mesoscale Discussion	SPC	Blue Earth, Brown, Cottonwood, Faribault, Freeborn, Goodhue and 10 more	27 min
May 3, 8:43 AM CDT	Mesoscale Discussion	SPC	Dakota, Dodge, Goodhue, Olmsted, Rice, Steele and 2 more	92 min
May 2, 10:43 PM CDT	Mesoscale Discussion	SPC	Clay, Union	62 min

Nearby

Mesoscale Discussions in Minnesota, 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.