Alert archive / Wisconsin / Mesoscale Discussions in 2011

Mesoscale Discussion 855

May 22, 201116 counties in Illinois; 32 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at May 22, 2011, 1:49 PM CDT for 16 counties in Illinois; 32 counties in Wisconsin. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued: May 22, 2011, 1:49 PM CDT (18:49 UTC)
Expired: May 22, 2011, 2:45 PM CDT
In force: 56 min
Issued by: the Storm Prediction Center

All 48 counties

Boone County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Grundy County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, McHenry County, IL, Ogle County, IL, Putnam County, IL, Will County, IL, Winnebago County, IL, Adams County, WI, Brown County, WI, Calumet County, WI, Columbia County, WI, Dane County, WI, Dodge County, WI, Fond du Lac County, WI, Green Lake County, WI, Jefferson County, WI, Kenosha County, WI, Langlade County, WI, Lincoln County, WI, Manitowoc County, WI, Marathon County, WI, Marquette County, WI, Menominee County, WI, Milwaukee County, WI, Oconto County, WI, Outagamie County, WI, Ozaukee County, WI, Portage County, WI, Racine County, WI, Rock County, WI, Shawano County, WI, Sheboygan County, WI, Taylor County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI, Waupaca County, WI, Waushara County, WI, Winnebago County, WI

The radar

The Milwaukee radar (KMKX), 56 km from the middle of the area, began a volume at 18:52 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

Green Bay/Straub, WI (KGRB), launched 12:00Z, 6.8 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: 351 J/kg
Mixed-layer CIN: -121 J/kg
Mixed-layer LCL: 1006 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: -1 m²/s²
0-3 km storm-relative helicity: -1 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.4

Open this sounding in Storm Lab

The text

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

573 
ACUS11 KWNS 221849
SWOMCD
SPC MCD 221849 
WIZ000-MIZ000-ILZ000-221945-

MESOSCALE DISCUSSION 0855
NWS STORM PREDICTION CENTER NORMAN OK
0149 PM CDT SUN MAY 22 2011

AREAS AFFECTED...ERN WI...NRN IL

CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY 

VALID 221849Z - 221945Z

CONDITIONS WILL CONTINUE TO RAPIDLY EVOLVE THIS AFTERNOON AND A
TORNADO WATCH WILL LIKELY BE NEEDED FROM ERN WI INTO NRN IL.

SURFACE MAP SHOWS RELATIVELY DRY AIR IN PLACE OVER ERN WI/NRN IL
WITH DEWPOINTS ONLY IN THE 50S F. HOWEVER...MID 60S TO NEAR 70S F
BOUNDARY LAYER DEWPOINTS ARE LURKING UPSTREAM OVER SERN IA AND CNTRL
IL...AND WILL MOVE INTO THE AREA BY EVENING. ALSO AT THAT
TIME...WIND PROFILES WILL HAVE BECOME MORE FAVORABLE FOR SUPERCELLS
WITH A THREAT OF TORNADOES.  THE 18Z DVN SOUNDING SHOWS VERY STEEP
LAPSE RATES ALOFT WITH MINIMAL CAPPING...ALONG WITH AMPLE DEEP LAYER
WIND FIELDS FOR ORGANIZED SEVERE. 

ACTIVITY HAS FORMED ALONG THE GRAVITY WAVE OVER CNTRL IL...AND THEY
MAY BECOME BETTER ORGANIZED WITH TIME. FARTHER N... A LEAD BAND OF
CONVECTION WILL TRAVERSE WI WITH PERHAPS A MARGINAL HAIL THREAT.
HOWEVER...THE GREATEST SEVERE THREAT WILL EVOLVE OUT OF THE DRYLINE
STORMS OVER E CNTRL IA AND NRN MO...WITH TORNADOES AND VERY LARGE
HAIL AS THEY CROSS THE MS INTO WI AND IL.

..JEWELL.. 05/22/2011

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

ATTN...WFO...MQT...GRB...LOT...ILX...MKX...DVN...ARX...

LAT...LON   41068933 42688945 44458993 45259071 45518888 45128755
            44268741 41148764 41068933

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 22, 4:41 AM CDT	Mesoscale Discussion	SPC	Adams, Boone, Brown, Bureau, Carroll, Cass and 37 more	2 hr
May 22, 10:53 AM CDT	Mesoscale Discussion	SPC	Adams, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	2 hr
May 22, 12:51 PM CDT	Tornado Watch	SPC	Adams, Bond, Brown, Bureau, Calhoun, Carroll and 42 more	10 hr
May 22, 2:04 PM CDT	Tornado Watch	SPC	Boone, Cook, DeKalb, DuPage, Ford, Grundy and 12 more	9 hr
May 22, 2:59 PM CDT	Mesoscale Discussion	SPC	Jo Daviess	2 hr
May 22, 4:16 PM CDT	Mesoscale Discussion	SPC	Champaign, Douglas, Edgar, Ford, Iroquois, Kankakee and 2 more	119 min
May 22, 5:47 PM CDT	Mesoscale Discussion	SPC	Boone, Bureau, Carroll, DeKalb, DuPage, Grundy and 23 more	88 min
May 22, 12:07 PM CDT	Tornado Watch	SPC	Adams, Barron, Buffalo, Chippewa, Clark, Crawford and 16 more	7 hr
May 22, 3:43 PM CDT	Tornado Watch	SPC	Ashland, Bayfield, Burnett, Douglas, Iron, Price and 2 more	5 hr

Nearby

Mesoscale Discussions in Wisconsin, 2011 Mesoscale Discussions in Illinois, 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.