Alert archive / Minnesota / Mesoscale Discussions in 2011

Mesoscale Discussion 1815

August 1, 201114 counties in Minnesota; 11 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Aug 1, 2011, 11:29 AM CDT for 14 counties in Minnesota; 11 counties in Wisconsin. It was in force for 31 min.

The area

The outline as issued.

The facts

Issued: Aug 1, 2011, 11:29 AM CDT (16:29 UTC)
Expired: Aug 1, 2011, 12:00 PM CDT
In force: 31 min
Issued by: the Storm Prediction Center

All 25 counties

Anoka County, MN, Benton County, MN, Carver County, MN, Chisago County, MN, Dakota County, MN, Hennepin County, MN, Isanti County, MN, McLeod County, MN, Meeker County, MN, Ramsey County, MN, Sherburne County, MN, Stearns County, MN, Washington County, MN, Wright County, MN, Barron 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, Taylor County, WI

The radar

The Minneapolis radar (KMPX), 78 km from the middle of the area, began a volume at 16:29 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.

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 4.5 hours before the alert went out and 80 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: 2974 J/kg
Mixed-layer CIN: -122 J/kg
Mixed-layer LCL: 898 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 10 m²/s²
0-3 km storm-relative helicity: 59 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

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

835 
ACUS11 KWNS 011629
SWOMCD
SPC MCD 011629 
WIZ000-MNZ000-011700-

MESOSCALE DISCUSSION 1815
NWS STORM PREDICTION CENTER NORMAN OK
1129 AM CDT MON AUG 01 2011

AREAS AFFECTED...CENTRAL/EAST CENTRAL MN INTO WEST CENTRAL WI

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 011629Z - 011700Z

WW MAY BE NEEDED BY 17Z FOR PARTS OF EAST CENTRAL MN /TWIN CITIES
METRO/ INTO WEST CENTRAL WI.

TRENDS IN REGIONAL RADAR IMAGERY SHOWED A RECENTLY FORMED LINE OF
STORMS EXTENDING FROM STEARNS COUNTY TO KANDIYOHI COUNTY IN CENTRAL
MN...WITH THIS ACTIVITY MOVING ESE AT 30-35 KT.  PER MESOSCALE
DETAILS PROVIDED IN SPC MESOSCALE DISCUSSION #1813...THIS LINE OF
STORMS WAS LIKELY ELEVATED AND BEING SUPPORTED BY A FEED OF VERY
MOIST AND MODERATELY UNSTABLE AIR PER SWLY LLJ.  WHILE THIS ACTIVITY
HAS BEEN ELEVATED THUS FAR...SURFACE ANALYSES DO INDICATE A FRONT
EXTENDING FROM THE TWIN CITIES METRO ESEWD THROUGH CENTRAL WI.  THIS
BOUNDARY ALSO TENDS TO MARK THE SRN EXTENT OF A CLOUD SHIELD
ASSOCIATED WITH THE MN MCS.

IF THE LINE OF STORMS CONTINUES TO SHOW SIGNS OF BEING
MAINTAINED...THEN A NEW WW WILL BE NEEDED FROM THE TWIN CITIES METRO
INTO WEST CENTRAL WI...WHERE MODERATE INSTABILITY AND EFFECTIVE BULK
SHEAR OF 40-45 KT WILL SUPPORT A SEVERE WEATHER THREAT.

..PETERS.. 08/01/2011

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

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

LAT...LON   44759397 44939487 45349486 45929430 45899361 45709254
            45539127 45469069 45079030 44449048 44379121 44569249
            44759397

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 31, 10:26 PM CDT	Severe Thunderstorm Watch	SPC	Becker, Clay, Clearwater, Grant, Kittson, Mahnomen and 8 more	8 hr
Aug 1, 12:35 AM CDT	Mesoscale Discussion	SPC	Clay, Norman, Polk	85 min
Aug 1, 2:31 AM CDT	Mesoscale Discussion	SPC	Becker, Cass, Clay, Clearwater, Crow Wing, Douglas and 11 more	89 min
Aug 1, 4:57 AM CDT	Severe Thunderstorm Watch	SPC	Becker, Benton, Big Stone, Brown, Cass, Chippewa and 28 more	7 hr
Aug 1, 7:31 AM CDT	Mesoscale Discussion	SPC	Anoka, Benton, Blue Earth, Brown, Carver, Chippewa and 33 more	89 min
Aug 1, 10:42 AM CDT	Mesoscale Discussion	SPC	Benton, Kandiyohi, Meeker, Mille Lacs, Morrison, Pope and 5 more	63 min
Aug 1, 11:52 AM CDT	Severe Thunderstorm Watch	SPC	Anoka, Becker, Benton, Big Stone, Blue Earth, Brown and 43 more	7 hr
Aug 1, 1:50 PM CDT	Mesoscale Discussion	SPC	Blue Earth, Dakota, Dodge, Fillmore, Freeborn, Goodhue and 12 more	25 min
Aug 1, 2:04 PM CDT	Severe Thunderstorm Watch	SPC	Dodge, Fillmore, Houston, Mower, Olmsted, Wabasha and 1 more	5 hr
Aug 1, 3:53 PM CDT	Mesoscale Discussion	SPC	Anoka, Becker, Benton, Blue Earth, Carver, Chippewa and 47 more	67 min

Nearby

Mesoscale Discussions in Minnesota, 2011 Mesoscale Discussions in Wisconsin, 2011 Every mesoscale discussion in 2011

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.