Alert archive / Illinois / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 36, NWS Chicago, IL

June 19, 2018LaSalle County, Livingston County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Jun 19, 2018, 4:20 PM CDT for LaSalle County, Livingston County, Illinois. It was in force for 40 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: Jun 19, 2018, 4:20 PM CDT (21:20 UTC)
Expired: Jun 19, 2018, 5:00 PM CDT
In force: 40 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties LaSalle County, IL, Livingston County, IL

The radar

The Chicago radar (KLOT), 76 km from the middle of the area, began a volume at 21:22 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 12:00Z, 9.3 hours before the alert went out and 108 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: 1016 J/kg
Mixed-layer CIN: -70 J/kg
Mixed-layer LCL: 1106 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: -54 m²/s²
0-3 km storm-relative helicity: -11 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 Jun 19, 3:17 PM CDT, 1 hour 3 minutes earlier.

Area forecast discussion, Jun 19, 3:17 PM CDT, 1 hour 3 minutes before

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Hazardous weather outlook, Jun 19, 4:03 AM CDT, 12 hours 17 minutes before

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In the hours before

Special weather statement, Jun 19, 2:16 PM CDT, 2 hours 4 minutes before

Special Weather Statement
National Weather Service Chicago/Romeoville Il
216 PM CDT TUE JUN 19 2018

INZ002-010-011-192000-
Porter IN-Newton IN-Jasper IN-
216 PM CDT TUE JUN 19 2018

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN NEWTON...
SOUTHEASTERN PORTER AND NORTHERN JASPER COUNTIES UNTIL 300 PM CDT...

At 215 PM CDT, Doppler radar was tracking a strong thunderstorm over
Forest City, moving east at 20 mph.

Half inch hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
De Motte, Forest City, Dunns Bridge, Pembroke, Roselawn and
Wheatfield.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 4112 8731 4120 8731 4120 8730 4129 8693
      4108 8693
TIME...MOT...LOC 1915Z 270DEG 18KT 4117 8724

KREIN

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 18, 9:40 PM CDT	River Flood Advisory	LOT	Boone	66 hr
Jun 18, 9:51 PM CDT	River Flood Advisory	LOT	Kane, McHenry	5 hr
Jun 18, 9:53 PM CDT	River Flood Advisory	LOT	Kane, Kendall	7 days
Jun 18, 10:05 PM CDT	River Flood Advisory	LOT	Lake	11 hr
Jun 18, 10:32 PM CDT	River Flood Advisory	LOT	Winnebago	59 hr
Jun 19, 12:01 AM CDT	Areal Flood Warning	LOT	Boone, Ogle, Winnebago	12 hr
Jun 19, 2:11 AM CDT	River Flood Warning	LOT	Boone	37 hr
Jun 19, 2:11 AM CDT	River Flood Warning	LOT	Winnebago	18 hr
Jun 19, 2:16 AM CDT	River Flood Advisory	LOT	Ogle	42 hr
Jun 19, 2:16 AM CDT	River Flood Advisory	LOT	Lee	13 days
Jun 19, 2:22 AM CDT	River Flood Watch	LOT	Winnebago	7 hr
Jun 19, 2:55 AM CDT	River Flood Warning	LOT	Kane, McHenry	31 hr
Jun 19, 3:05 AM CDT	River Flood Advisory	LOT	Lake	5 days
Jun 19, 3:05 AM CDT	River Flood Advisory	LOT	Cook	17 hr
Jun 19, 9:14 AM CDT	River Flood Warning	LOT	Lake	11 days
Jun 19, 9:17 AM CDT	River Flood Warning	LOT	Winnebago	9 days
Jun 19, 9:32 AM CDT	River Flood Advisory	LOT	Will	11 hr
Jun 19, 9:35 AM CDT	River Flood Advisory	LOT	Winnebago	4 days
Jun 19, 9:35 AM CDT	River Flood Advisory	LOT	Winnebago	4 days
Jun 19, 4:18 PM CDT	Marine Dense Fog Advisory	LOT		17 hr
Jun 19, 4:50 PM CDT	Severe Thunderstorm Warning	LOT	Grundy, LaSalle, Livingston	25 min
Jun 19, 5:25 PM CDT	Special Weather Statement	LOT	Iroquois	35 min
Jun 19, 5:46 PM CDT	Special Weather Statement	LOT	Iroquois	29 min
Jun 19, 6:16 PM CDT	Areal Flood Advisory	LOT	Ford, Iroquois	3 hr
Jun 19, 2:16 PM CDT	Special Weather Statement	LOT	Jasper	44 min
Jun 19, 2:54 PM CDT	Areal Flood Advisory	LOT	Jasper, Lake, Newton, Porter	3 hr

Nearby

Severe Thunderstorm Warnings in Illinois, 2018 Every severe thunderstorm warning in 2018

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.