Alert archive / Minnesota / Mesoscale Discussions in 2012

Mesoscale Discussion 1371

July 3, 201217 counties in Minnesota; 14 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Jul 3, 2012, 2:00 AM CDT for 17 counties in Minnesota; 14 counties in Wisconsin. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued: Jul 3, 2012, 2:00 AM CDT (07:00 UTC)
Expired: Jul 3, 2012, 3:30 AM CDT
In force: 90 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 31 counties

Anoka County, MN, Benton County, MN, Carver County, MN, Chisago County, MN, Dakota County, MN, Hennepin County, MN, Isanti County, MN, Kanabec County, MN, McLeod County, MN, Meeker County, MN, Mille Lacs County, MN, Pine County, MN, Ramsey County, MN, Scott County, MN, Sherburne County, MN, Washington County, MN, Wright County, MN, Barron County, WI, Burnett County, WI, Chippewa County, WI, Clark County, WI, Dunn County, WI, Eau Claire County, WI, Pepin County, WI, Pierce County, WI, Polk County, WI, Rusk County, WI, Saint Croix County, WI, Sawyer County, WI, Taylor County, WI, Washburn County, WI

The radar

The Minneapolis radar (KMPX), 81 km from the middle of the area, began a volume at 07:00 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, 7.0 hours before the alert went out and 83 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: 2216 J/kg
Mixed-layer CIN: -59 J/kg
Mixed-layer LCL: 2064 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 41 m²/s²
0-3 km storm-relative helicity: 116 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 5.5

Open this sounding in Storm Lab

The text

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

480 
ACUS11 KWNS 030701
SWOMCD
SPC MCD 030700
WIZ000-MNZ000-030830-

MESOSCALE DISCUSSION 1371
NWS STORM PREDICTION CENTER NORMAN OK
0200 AM CDT TUE JUL 03 2012

AREAS AFFECTED...EAST-CENTRAL/SOUTH-CENTRAL MN TO NORTHWEST/CENTRAL
WI

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 030700Z - 030830Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...AT LEAST LOCALLY DAMAGING WINDS/SEVERE HAIL...ALONG WITH
HEAVY RAINFALL...WILL REMAIN A CONCERN OVERNIGHT FROM EAST-CENTRAL
AND PERHAPS SOUTH-CENTRAL/SOUTHEAST MN INTO PORTIONS OF
NORTHWEST/CENTRAL WI. MONITORING CONVECTIVE TRENDS FOR A POSSIBLE
SEVERE TSTM WATCH.

DISCUSSION...ON THE HEELS OF AN INITIAL MCS /NOW ACROSS NORTHEAST WI
AND UPPER MI/...A SECONDARY QUASI-LINEAR MCS HAS EVOLVED ACROSS
EAST-CENTRAL MN EARLY IN THE OVERNIGHT /AROUND 70 MILES NORTH OF THE
TWIN CITIES AS OF 0645Z/. IT IS LIKELY THAT THIS QLCS IS BEING FED
FROM THE SOUTHWEST BY VIRTUE OF A MODERATE /30+ KT/ SOUTHWESTERLY
LOW LEVEL JET AS PER RECENT WSR-88D VWP DATA FROM MINNEAPOLIS AND
GIVEN THE EARLIER 00Z OBSERVED MSP SOUNDING. THIS MCS HAS SHOWN SOME
RECENT SIGNS OF ADDITIONAL FORWARD PROPAGATION/SOUTHEASTWARD
ACCELERATION ACROSS EAST-CENTRAL MN WITH A FORWARD MOTION OF AROUND
40 KT...AND THIS INCIPIENT BOWING OF THE QLCS APPEARS TO BE FAVORING
THE NORTHEAST EDGE OF AN EARLIER OUTFLOW BOUNDARY WHERE SURFACE
WINDS ARE BACKED TO SOUTHEASTERLY. IT IS POSSIBLE THAT THIS
ACCELERATION TREND WILL CONTINUE...ESPECIALLY GIVEN THE POSSIBILITY
OF ADDITIONAL CELL MERGERS VIA RECENT ADDITIONAL DEVELOPMENT ACROSS
SOUTH-CENTRAL MN. WHILE MUCH OF THE MCS IS COINCIDENT WITH A SHALLOW
NEAR-SURFACE STABLE LAYER...WHICH WILL GENERALLY HINDER DOWNDRAFT
INTENSITY TO THE SURFACE...THE DISTINCT POSSIBILITY OF ADDITIONAL
FORWARD/SOUTHEASTWARD ACCELERATION OVER THE NEXT 1-2 HR COULD
CONTRIBUTE TO ADDITIONAL BOUTS OF AT LEAST NEAR-SEVERE WIND GUSTS
FROM EAST-CENTRAL MN INTO PORTIONS OF NORTHWEST/CENTRAL WI.

..GUYER/MEAD.. 07/03/2012

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

ATTN...WFO...GRB...DLH...ARX...MPX...

LAT...LON   44859467 45859439 46229264 45809083 45169003 44529061
            44569205 44569382 44859467

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 2, 9:17 PM CDT	Mesoscale Discussion	SPC	Aitkin, Carlton, Cook, Crow Wing, Kanabec, Lake and 4 more	118 min
Jul 2, 11:17 PM CDT	Mesoscale Discussion	SPC	Aitkin, Carlton, Crow Wing, Pine, Wadena	88 min
Jul 2, 7:23 PM CDT	Mesoscale Discussion	SPC	Brown, Calumet, Columbia, Dane, Dodge, Florence and 18 more	2 hr
Jul 2, 10:13 PM CDT	Severe Thunderstorm Watch	SPC	Florence, Forest, Langlade, Lincoln, Marinette, Oconto and 2 more	4 hr

Nearby

Mesoscale Discussions in Minnesota, 2012 Mesoscale Discussions in Wisconsin, 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.