Alert archive / Illinois / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 21, NWS Chicago, IL

May 11, 20114 counties in Illinois

NWS Chicago, IL issued this severe thunderstorm warning at May 11, 2011, 4:39 PM CDT for 4 counties in Illinois. It was in force for 36 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: May 11, 2011, 4:39 PM CDT (21:39 UTC)
Expired: May 11, 2011, 5:15 PM CDT
In force: 36 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Cook County, IL, DuPage County, IL, Kane County, IL, Lake County, IL

The radar

The Chicago radar (KLOT), 59 km from the middle of the area, began a volume at 21:41 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
May 11, 1:23 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 9.7 hours before the alert went out and 199 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: 2842 J/kg
Mixed-layer CIN: -105 J/kg
Mixed-layer LCL: 931 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: -17 m²/s²
0-3 km storm-relative helicity: 93 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 2.6

Open this sounding in Storm Lab

The text

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

124 
WUUS53 KLOT 112139
SVRLOT
ILC031-043-089-097-112215-
/O.NEW.KLOT.SV.W.0021.110511T2139Z-110511T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
439 PM CDT WED MAY 11 2011

THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHWESTERN COOK COUNTY IN NORTHEAST ILLINOIS...
  NORTHWESTERN DUPAGE COUNTY IN NORTHEAST ILLINOIS...
  KANE COUNTY IN NORTHEAST ILLINOIS...
  SOUTHWESTERN LAKE COUNTY IN NORTHEAST ILLINOIS...

* UNTIL 515 PM CDT

* AT 437 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
  ELGIN...AND MOVING NORTHEAST AT 20 MPH.

  QUARTER SIZE HAIL WAS REPORTED WITH THESE STORMS NEAR ELGIN.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  STREAMWOOD AND HANOVER PARK AROUND 445 PM CDT.
  HOFFMAN ESTATES AROUND 455 PM CDT.
  SCHAUMBURG AROUND 500 PM CDT.
  INVERNESS AND BARRINGTON AROUND 505 PM CDT.
  PALATINE AND ROLLING MEADOWS AROUND 510 PM CDT.
  ARLINGTON HEIGHTS...KILDEER...BUFFALO GROVE AND LONG GROVE AROUND
  515 PM CDT.

OTHER LOCATIONS IMPACTED BY THIS SEVERE THUNDERSTORM INCLUDE
BARRINGTON HILLS...SOUTH BARRINGTON AND DEER PARK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 60 MILES PER
HOUR...LARGE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN. FOR YOUR
PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR HOME
OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE INTO
AREAS WHERE WATER COVERS THE ROAD.

&&

LAT...LON 4234 8804 4208 8779 4180 8845 4190 8860
      4216 8828 4216 8820 4222 8820
TIME...MOT...LOC 2139Z 244DEG 17KT 4205 8824
WIND...HAIL 60MPH 1.00IN

$$

SHEA

2 follow-up statements

534 
WWUS53 KLOT 112206
SVSLOT

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
506 PM CDT WED MAY 11 2011

ILC031-043-089-097-112215-
/O.CON.KLOT.SV.W.0021.000000T0000Z-110511T2215Z/
KANE IL-DUPAGE IL-LAKE IL-COOK IL-
506 PM CDT WED MAY 11 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR NORTHWESTERN
COOK...SOUTHWESTERN LAKE...NORTHWESTERN DUPAGE AND KANE COUNTIES
UNTIL 515 PM CDT...

AT 504 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING HALF DOLLAR SIZE HAIL...AND
DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
INVERNESS...OR NEAR PALATINE...MOVING NORTHEAST AT 20 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  ROLLING MEADOWS AROUND 510 PM CDT.
  PALATINE...ARLINGTON HEIGHTS...KILDEER AND BUFFALO GROVE AROUND 515
  PM CDT.

OTHER LOCATIONS IMPACTED BY THIS SEVERE THUNDERSTORM INCLUDE DEER
PARK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 60 MILES PER
HOUR...LARGE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN. FOR YOUR
PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR HOME
OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE INTO
AREAS WHERE WATER COVERS THE ROAD.

&&

LAT...LON 4234 8804 4208 8779 4180 8845 4190 8860
      4216 8828 4216 8820 4222 8820
TIME...MOT...LOC 2205Z 244DEG 17KT 4210 8809
WIND...HAIL 60MPH 1.25IN

$$

SHEA

082 
WWUS53 KLOT 112216
SVSLOT

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
516 PM CDT WED MAY 11 2011

ILC031-043-089-097-112223-
/O.EXP.KLOT.SV.W.0021.000000T0000Z-110511T2215Z/
KANE IL-DUPAGE IL-LAKE IL-COOK IL-
516 PM CDT WED MAY 11 2011

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN COOK...
SOUTHWESTERN LAKE...NORTHWESTERN DUPAGE AND KANE COUNTIES HAS BEEN 
REISSUED...

PLEASE REFER TO THAT BULLETIN FOR THE LATEST SEVERE WEATHER
INFORMATION.

REMEMBER...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR
PORTIONS OF KANE AND COOK COUNTIES UNTIL 600 PM CDT.

LAT...LON 4234 8804 4208 8779 4180 8845 4190 8860
      4216 8828 4216 8820 4222 8820
TIME...MOT...LOC 2213Z 244DEG 17KT 4212 8804

$$

SHEA

The office that day

Everything else NWS Chicago, IL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 11, 3:19 PM CDT	Severe Thunderstorm Warning	LOT	Lake, McHenry	56 min
May 11, 4:04 PM CDT	Areal Flood Advisory	LOT	McHenry	65 min
May 11, 4:06 PM CDT	Severe Thunderstorm Warning	LOT	Cook, Kane, Lake, McHenry	54 min
May 11, 4:36 PM CDT	Areal Flood Advisory	LOT	Cook, Kane, Lake, McHenry	32 min
May 11, 4:51 PM CDT	Severe Thunderstorm Warning	LOT	Lake, McHenry	54 min
May 11, 5:02 PM CDT	Flash Flood Warning	LOT	Cook, Kane, Lake, McHenry	4 hr
May 11, 5:10 PM CDT	Severe Thunderstorm Warning	LOT	Winnebago	10 min
May 11, 5:11 PM CDT	Severe Thunderstorm Warning	LOT	Cook, Kane, Lake, McHenry	49 min
May 11, 5:21 PM CDT	Special Marine Warning	LOT		114 min
May 11, 5:38 PM CDT	Severe Thunderstorm Warning	LOT	Lake, McHenry	33 min
May 11, 5:43 PM CDT	Severe Thunderstorm Warning	LOT	Grundy, Kendall, LaSalle, Livingston	62 min
May 11, 5:52 PM CDT	Severe Thunderstorm Warning	LOT	Cook, Lake	27 min
May 11, 6:08 PM CDT	Special Marine Warning	LOT		90 min
May 11, 6:14 PM CDT	Special Marine Warning	LOT		85 min
May 11, 6:44 PM CDT	Severe Thunderstorm Warning	LOT	Grundy, Kankakee, Kendall, Will	46 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2011 Every severe thunderstorm warning 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.