Alert archive / Wisconsin / Mesoscale Discussions in 2011

Mesoscale Discussion 2197

September 20, 20114 counties in Minnesota; 20 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Sep 20, 2011, 3:45 PM CDT for 4 counties in Minnesota; 20 counties in Wisconsin. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Sep 20, 2011, 3:45 PM CDT (20:45 UTC)
Expired
Sep 20, 2011, 5:45 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 24 counties

Carlton County, MN, Itasca County, MN, Lake County, MN, Saint Louis County, MN, Ashland County, WI, Barron County, WI, Bayfield County, WI, Buffalo County, WI, Chippewa County, WI, Clark County, WI, Douglas County, WI, Dunn County, WI, Eau Claire County, WI, Iron County, WI, Jackson County, WI, Marathon County, WI, Pepin County, WI, Price County, WI, Rusk County, WI, Sawyer County, WI, Taylor County, WI, Trempealeau County, WI, Washburn County, WI, Wood County, WI

The radar

The Duluth radar (KDLH), 52 km from the middle of the area, began a volume at 20:47 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, 8.8 hours before the alert went out and 204 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-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 2011-09-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 12:00Z on 2011-09-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 94 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
1233 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
94 m²/s²
0-3 km storm-relative helicity
173 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.

920 
ACUS11 KWNS 202045
SWOMCD
SPC MCD 202045 
WIZ000-MIZ000-MNZ000-202245-

MESOSCALE DISCUSSION 2197
NWS STORM PREDICTION CENTER NORMAN OK
0345 PM CDT TUE SEP 20 2011

AREAS AFFECTED...NORTHERN MN/WESTERN WI

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 202045Z - 202245Z

AN ISOLATED SEVERE THREAT...IN THE FORM OF WIND/HAIL AND/OR A BRIEF
TORNADO...MAY BE POSSIBLE LATE THIS AFTERNOON ACROSS NORTHEAST
MN/WESTERN WI.

WATER VAPOR IMAGERY REFLECTS A NEARLY STACKED CYCLONE CENTERED NEAR
THE ND/MN BORDER AT MID-AFTERNOON...WITH SURFACE ANALYSIS INDICATIVE
OF AN ARCING CONFLUENCE ZONE ACROSS NORTHERN MN SOUTHWARD TO
NEAR/WEST OF THE MS RIVER. THE PREVALENCE OF CLOUD COVER AND A
RELATIVELY COOL/MODESTLY MOIST AIRMASS IS EXPECTED TO LIMIT THE
OVERALL EXTENT/LIKELIHOOD OF SEVERE POTENTIAL. THAT SAID...POCKETS
OF MODEST CLEARING ARE OCCURRING /SUCH AS CURRENTLY NOTED ACROSS
NORTHEAST MN/ ALONG THE EAST-NORTHEAST ADVANCING SURFACE
BOUNDARY...AND SOME ADDITIONAL LOW-LEVEL HEATING IN THE PRESENCE OF
LOWER TO MIDDLE 50S F SURFACE DEWPOINTS MAY PROVE SUFFICIENT FOR
SUSTAINED/LIGHTNING-PRODUCING UPDRAFTS LATE THIS AFTERNOON/EARLY
EVENING. IN THE PRESENCE OF AMPLE AMBIENT VERTICAL
VORTICITY/RELATIVELY STRONG VERTICAL SHEAR/SRH AS OBSERVED PER
REGIONAL WSR-88D VWPS...A BRIEF TORNADO AND/OR STRONG WIND GUSTS
COULD OCCUR ASIDE FROM SMALL HAIL. ANY SUCH SEVERE THREAT IS
CURRENTLY EXPECTED TO BE MARGINAL/LOCALIZED IN NATURE...BUT
CONVECTIVE TRENDS WILL CONTINUE TO BE MONITORED.

..GUYER.. 09/20/2011

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

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

LAT...LON   47389392 48269386 47539140 46548994 44468969 44009183
            45369209 46429257 47389392

Nearby

Mesoscale Discussions in Wisconsin, 2011Mesoscale Discussions in Minnesota, 2011Every 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.