Alert archive / Illinois / Mesoscale Discussions in 2011

Mesoscale Discussion 877

May 22, 201112 counties in Illinois; Lake County, Indiana

The Storm Prediction Center issued this mesoscale discussion at May 22, 2011, 9:35 PM CDT for 12 counties in Illinois; Lake County, Indiana. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued
May 22, 2011, 9:35 PM CDT (02:35 UTC)
Expired
May 22, 2011, 10:30 PM CDT
In force
55 min
Issued by
the Storm Prediction Center

Counties DeKalb County, IL, DuPage County, IL, Grundy County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, McHenry County, IL, Will County, IL, Lake County, IN

The radar

The Chicago radar (KLOT), 21 km from the middle of the area, began a volume at 02:38 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

Lincoln, IL (KILX), launched 00:00Z, 2.6 hours before the alert went out and 182 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, Lincoln, IL at 00:00Z on 2011-05-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2469 joules per kilogram.LCLLFCEL10008507005003002001001 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, Lincoln, IL at 00:00Z on 2011-05-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 228 square meters per square second.193958Sfc1 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
2469 J/kg
Mixed-layer CIN
-13 J/kg
Mixed-layer LCL
952 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
228 m²/s²
0-3 km storm-relative helicity
319 m²/s²
Significant tornado parameter
3.8
Supercell composite
17.0

Open this sounding in Storm Lab

The text

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

350 
ACUS11 KWNS 230236
SWOMCD
SPC MCD 230235
INZ000-ILZ000-WIZ000-230330-

MESOSCALE DISCUSSION 0877
NWS STORM PREDICTION CENTER NORMAN OK
0935 PM CDT SUN MAY 22 2011

AREAS AFFECTED...EXTREME SERN WI THROUGH NRN IL

CONCERNING...TORNADO WATCH 327...

VALID 230235Z - 230330Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 327 CONTINUES.

SEVERE THREAT MAY PERSIST A COUPLE HOURS BEYOND WW 327 EXPIRATION
TIME OF 03Z ACROSS NRN IL INTO EXTREME SERN WI. PRIMARY THREAT HAS
TRANSITIONED TO DAMAGING WIND AND HAIL...BUT AN ISOLATED TORNADO OR
TWO CANNOT BE RULED OUT. PER COORDINATION WITH WFO CHICAGO...WW 327
WILL BE LOCALLY EXTENDED FOR NRN IL UNTIL AROUND 05Z.

CONVECTIVE OUTFLOW MERGING WITH PACIFIC FRONT HAS RESULTED IN RAPID
UPSCALE LINEAR GROWTH FROM EXTREME SERN WI SWWD THROUGH NWRN IL.
PREVIOUS AND ONGOING CONVECTION AND ONSET OF NOCTURNAL COOLING HAVE
STABILIZED THE BOUNDARY LAYER EAST OF SQUALL LINE AND SHOULD POSE A
LIMITING FACTOR FOR A MORE ROBUST SEVERE/TORNADO THREAT.
NEVERTHELESS...VERTICAL SHEAR AND LOW LEVEL HODOGRAPHS REMAIN
FAVORABLE FOR EMBEDDED ORGANIZED STORM STRUCTURES INCLUDING
SUPERCELLS AND BOWING SEGMENTS AS ACTIVITY CONTINUES EWD NEXT COUPLE
HOURS.

..DIAL.. 05/23/2011

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

ATTN...WFO...LOT...ILX...MKX...DVN...

LAT...LON   42818815 41998781 41428726 40678775 40948891 41678958
            42818815

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 22, 7:52 PM CDTMesoscale DiscussionSPCBond, Calhoun, Clinton, Greene, Jersey, Macoupin and 6 more53 min
May 22, 8:26 PM CDTTornado WatchSPCBond, Calhoun, Cass, Champaign, Christian, Clay and 35 more8 hr
May 22, 10:24 PM CDTMesoscale DiscussionSPCClark, Clay, Coles, Crawford, Cumberland, Edgar and 9 more66 min
May 23, 7:25 AM CDTMesoscale DiscussionSPCEdgar, Vermilion65 min
May 23, 10:55 AM CDTSevere Thunderstorm WatchSPCAlexander, Bond, Calhoun, Clinton, Edwards, Fayette and 27 more7 hr
May 23, 12:37 PM CDTMesoscale DiscussionSPCBond, Christian, Clark, Clay, Clinton, Coles and 34 more83 min
May 23, 12:54 PM CDTSevere Thunderstorm WatchSPCChampaign, Christian, Clark, Clay, Coles, Crawford and 13 more5 hr
May 23, 2:52 PM CDTMesoscale DiscussionSPCClark, Clay, Coles, Crawford, Cumberland, Edgar and 8 more53 min
May 23, 3:58 PM CDTMesoscale DiscussionSPCAlexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 14 more92 min
May 23, 4:24 PM CDTMesoscale DiscussionSPCMassac96 min
May 22, 7:20 PM CDTMesoscale DiscussionSPCAdams, Allen, Benton, Blackford, Boone, Carroll and 33 more115 min
May 22, 9:59 PM CDTMesoscale DiscussionSPCAllen, Carroll, Cass, DeKalb, Elkhart, Fulton and 14 more61 min
May 23, 3:20 AM CDTMesoscale DiscussionSPCClark, Floyd, Harrison, Jefferson, Ohio, Scott and 1 more85 min
May 23, 11:35 AM CDTMesoscale DiscussionSPCAdams, Allen, Blackford, Cass, DeKalb, Elkhart and 13 more85 min
May 23, 1:15 PM CDTSevere Thunderstorm WatchSPCAdams, Allen, Blackford, Cass, DeKalb, Elkhart and 15 more8 hr
May 23, 3:28 PM CDTSevere Thunderstorm WatchSPCClark, Crawford, Dearborn, Dubois, Fayette, Floyd and 12 more6 hr
May 23, 5:20 PM CDTMesoscale DiscussionSPCClark, Crawford, Dearborn, Decatur, Fayette, Floyd and 15 more55 min
May 23, 5:40 PM CDTMesoscale DiscussionSPCAdams, Allen, Blackford, DeKalb, Grant, Howard and 8 more65 min

Nearby

Mesoscale Discussions in Illinois, 2011Mesoscale Discussions in Indiana, 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.