Alert archive / Illinois / Severe Thunderstorm Warnings in 2013

Severe Thunderstorm Warning 28, NWS Chicago, IL

May 30, 2013Grundy County, LaSalle County, Livingston County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at May 30, 2013, 3:34 PM CDT for Grundy County, LaSalle County, Livingston County, Illinois. It was in force for 56 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: May 30, 2013, 3:34 PM CDT (20:34 UTC)
Expired: May 30, 2013, 4:30 PM CDT
In force: 56 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Grundy County, IL, LaSalle County, IL, Livingston County, IL

The radar

The Chicago radar (KLOT), 66 km from the middle of the area, began a volume at 20:35 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 30, 12:32 PM CDT	Tornado Watch	SPC	7 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 8.6 hours before the alert went out and 114 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: 1076 J/kg
Mixed-layer CIN: -48 J/kg
Mixed-layer LCL: 826 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 218 m²/s²
0-3 km storm-relative helicity: 221 m²/s²
Significant tornado parameter: 1.1
Supercell composite: 6.2

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Chicago, IL wrote its last area forecast discussion before this severe thunderstorm warning went out at May 30, 3:29 PM CDT, 5 minutes earlier.

Area forecast discussion, May 30, 3:29 PM CDT, 5 minutes before

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Hazardous weather outlook, May 30, 12:34 PM CDT, 3 hours before

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In the hours before

Special weather statement, May 30, 2:28 PM CDT, 1 hour 6 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
228 PM CDT THU MAY 30 2013

ILZ014-022-023-INZ001-302015-
COOK IL-KANKAKEE IL-LAKE IN-WILL IL-
228 PM CDT THU MAY 30 2013

...SPECIAL WEATHER STATEMENT...

AT 228 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR PEOTONE...MOVING NORTH AT 45 MPH.

NICKEL SIZE HAIL AND WINDS TO 50 MPH...ARE POSSIBLE WITH THIS STORM.

CITIES AND TOWNS AFFECTED...
  PEOTONE...            GRANT PARK...         MANTENO...
  MONEE...              BEECHER...            UNIVERSITY PARK...
  CRETE...              FRANKFORT...          CHICAGO HEIGHTS...

OTHER LOCATIONS AFFECTED...
FIRST MIDWEST BANK AMPHITHEATRE...GOVERNORS STATE UNIVERSITY...
PRAIRIE STATE COLLEGE...PURDUE UNIVERSITY CALUMET...SOUTH SUBURBAN
COLLEGE...WILL COUNTY FAIRGROUNDS...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

GUSTY WINDS MAY CAUSE SMALL BRANCHES TO BE BLOWN DOWN...AND LOOSE
OBJECTS TO BLOW AROUND.  SEEK SHELTER IN A STURDY STRUCTURE UNTIL
THIS STORM HAS PASSED.

&&

LAT...LON 4116 8770 4121 8786 4175 8783 4166 8742
      4165 8742 4163 8732
TIME...MOT...LOC 1928Z 194DEG 39KT 4132 8772

BMD

Local storm report, May 30, 2:53 PM CDT, 41 minutes before

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Local storm report, May 30, 3:12 PM CDT, 22 minutes before

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Local storm report, May 30, 3:14 PM CDT, 20 minutes before

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Local storm report, May 30, 3:15 PM CDT, 19 minutes before

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Local storm report, May 30, 3:33 PM CDT, 1 minute before

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The office that day

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

Issued	Product	Office	Counties	Lasted
May 29, 8:55 PM CDT	Small Craft Advisory	LOT		24 hr
May 30, 4:09 AM CDT	Flash Flood Watch	LOT	Boone, DeKalb, DuPage, Ford, Grundy, Iroquois and 10 more	66 hr
May 30, 2:00 PM CDT	Severe Thunderstorm Warning	LOT	Lee	60 min
May 30, 2:35 PM CDT	Special Marine Warning	LOT		85 min
May 30, 2:55 PM CDT	Severe Thunderstorm Warning	LOT	Grundy, LaSalle, Livingston, Will	65 min
May 30, 2:56 PM CDT	Severe Thunderstorm Warning	LOT	Cook, Will	34 min
May 30, 3:08 PM CDT	Special Marine Warning	LOT		97 min
May 30, 3:59 PM CDT	Special Marine Warning	LOT		2 hr
May 30, 4:16 PM CDT	Severe Thunderstorm Warning	LOT	DeKalb, Grundy, Kane, Kendall, LaSalle, Will	59 min
May 30, 4:22 PM CDT	Areal Flood Advisory	LOT	Cook, DuPage, Will	3 hr
May 30, 4:28 PM CDT	Severe Thunderstorm Warning	LOT	Cook, Will	47 min
May 30, 5:13 PM CDT	Areal Flood Advisory	LOT	Cook, Will	3 hr
May 30, 5:50 PM CDT	Severe Thunderstorm Warning	LOT	LaSalle, Lee, Ogle, Winnebago	70 min
May 30, 5:56 PM CDT	Special Weather Statement	LOT	Ford, Iroquois	64 min
May 30, 6:09 PM CDT	Special Marine Warning	LOT		51 min
May 30, 6:42 PM CDT	Severe Thunderstorm Warning	LOT	Boone, DeKalb, Lee, McHenry, Ogle, Winnebago	78 min
May 30, 2:28 PM CDT	Special Weather Statement	LOT	Lake	47 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2013 Every severe thunderstorm warning in 2013

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.