Alert archive / Illinois / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 21, NWS Chicago, IL

February 28, 20176 counties in Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Feb 28, 2017, 10:18 PM CST for 6 counties in Illinois. It was in force for 27 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: Feb 28, 2017, 10:18 PM CST (04:18 UTC)
Expired: Feb 28, 2017, 10:45 PM CST
In force: 27 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties DeKalb County, IL, DuPage County, IL, Grundy County, IL, Kane County, IL, Kendall County, IL, Will County, IL

The watch it was issued in

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

Issued	Product	Office	Lasted
Feb 28, 9:51 PM CST	Tornado Watch	SPC	6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 4.3 hours before the alert went out and 168 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: 687 J/kg
Mixed-layer CIN: -73 J/kg
Mixed-layer LCL: 887 m above ground
0-6 km bulk shear: 72 kt
0-1 km storm-relative helicity: 395 m²/s²
0-3 km storm-relative helicity: 431 m²/s²
Significant tornado parameter: 1.6
Supercell composite: 6.7

Open this sounding in Storm Lab

The text

As transmitted.

315 
WUUS53 KLOT 010418
SVRLOT
ILC037-043-063-089-093-197-010445-
/O.NEW.KLOT.SV.W.0021.170301T0418Z-170301T0445Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Chicago/Romeoville Il
1018 PM CST TUE FEB 28 2017

The National Weather Service in Chicago has issued a

* Severe Thunderstorm Warning for...
  Kendall County in northeastern Illinois...
  Northwestern Will County in northeastern Illinois...
  Southeastern De Kalb County in north central Illinois...
  Northern Grundy County in northeastern Illinois...
  Southern Kane County in northeastern Illinois...
  Southwestern DuPage County in northeastern Illinois...

* Until 1045 PM CST

* At 1017 PM CST, severe thunderstorms were located along a line
  extending from near Little Rock to near Yorkville to near Morris,
  moving northeast at 65 mph.

  HAZARD...60 mph wind gusts and quarter size hail. 

  SOURCE...Radar indicated. 

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees. 

* Severe thunderstorms will be near, 
  Oswego around 1025 PM CST. 
  Aurora, Naperville, Minooka, Montgomery and Sugar Grove around 
  1030 PM CST. 
  Joliet, Plainfield, Channahon, North Aurora and Shorewood around 
  1035 PM CST. 
  Bolingbrook, Romeoville, West Chicago, Batavia, Warrenville and 
  Rockdale around 1040 PM CST. 
  Wheaton, Lockport and Winfield around 1045 PM CST. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

A tornado watch remains in effect until 400 AM CST for north central
and northeastern Illinois.

LAT...LON 4188 8814 4148 8805 4136 8859 4163 8860
      4163 8864 4172 8868
TIME...MOT...LOC 0417Z 242DEG 56KT 4171 8866 4156 8844 4141 8853 

HAIL...1.00IN
WIND...60MPH
 
$$

IZZI

2 follow-up statements

744 
WWUS53 KLOT 010431
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville Il
1031 PM CST TUE FEB 28 2017

ILC037-010440-
/O.CAN.KLOT.SV.W.0021.000000T0000Z-170301T0445Z/
De Kalb IL-
1031 PM CST TUE FEB 28 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN DE KALB COUNTY IS
CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

A tornado watch remains in effect until 400 AM CST for northeastern
Illinois.

LAT...LON 4188 8814 4148 8805 4136 8859 4163 8860
      4167 8856 4175 8854
TIME...MOT...LOC 0430Z 243DEG 52KT 4180 8844 4165 8822 4150 8831 

$$

ILC043-063-089-093-197-010445-
/O.CON.KLOT.SV.W.0021.000000T0000Z-170301T0445Z/
Kendall IL-Will IL-Grundy IL-Kane IL-DuPage IL-
1031 PM CST TUE FEB 28 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1045 PM CST
FOR KENDALL...NORTHWESTERN WILL...NORTHERN GRUNDY...SOUTHEASTERN KANE
AND SOUTHWESTERN DUPAGE COUNTIES...

At 1030 PM CST, severe thunderstorms were located along a line
extending from near Sugar Grove to near Plainfield to near Minooka,
moving northeast at 60 mph.

HAZARD...60 mph wind gusts and penny size hail. 

SOURCE...Radar indicated. 

IMPACT...Expect damage to roofs, siding, and trees. 

These severe storms will be near...
  Joliet and Naperville around 1035 PM CST. 
  Bolingbrook, Romeoville, Batavia, Warrenville and Rockdale around 
  1040 PM CST. 
  Wheaton, Lockport and Winfield around 1045 PM CST. 

Other locations impacted by these severe thunderstorms include
Preston Heights, Crystal Lawns, Lisbon, Crest Hill, Boulder Hill,
Millington and Fairmont.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

A tornado watch remains in effect until 400 AM CST for northeastern
Illinois.

LAT...LON 4188 8814 4148 8805 4136 8859 4163 8860
      4167 8856 4175 8854
TIME...MOT...LOC 0430Z 243DEG 52KT 4180 8844 4165 8822 4150 8831 

HAIL...0.75IN
WIND...60MPH
 
$$

BIRK

273 
WWUS53 KLOT 010445
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville Il
1045 PM CST TUE FEB 28 2017

ILC043-063-089-093-197-010455-
/O.EXP.KLOT.SV.W.0021.000000T0000Z-170301T0445Z/
Kendall IL-Will IL-Grundy IL-Kane IL-DuPage IL-
1045 PM CST TUE FEB 28 2017

...THE SEVERE THUNDERSTORM WARNING FOR KENDALL...NORTHWESTERN WILL...
NORTHERN GRUNDY...SOUTHEASTERN KANE AND SOUTHWESTERN DUPAGE COUNTIES
HAS EXPIRED...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore the warning has been allowed to expire.  However gusty
winds and heavy rain are still possible with these thunderstorms.

A tornado watch remains in effect until 400 AM CST for northeastern
Illinois.

LAT...LON 4188 8814 4148 8805 4136 8859 4163 8860
      4167 8856 4175 8854
TIME...MOT...LOC 0445Z 242DEG 56KT 4190 8819 4175 8797 4160 8806 

$$

BIRK

The office that day

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

Issued	Product	Office	Counties	Lasted
Feb 28, 6:00 PM CST	Severe Thunderstorm Warning	LOT	Cook, Grundy, Kendall, Will	45 min
Feb 28, 6:13 PM CST	Tornado Warning	LOT	Grundy, LaSalle, Livingston	32 min
Feb 28, 6:24 PM CST	Severe Thunderstorm Warning	LOT	LaSalle	51 min
Feb 28, 6:26 PM CST	Areal Flood Advisory	LOT	Cook, Grundy, Kendall, LaSalle, Livingston, Will	3 hr
Feb 28, 6:44 PM CST	Severe Thunderstorm Warning	LOT	Kankakee, Will	46 min
Feb 28, 6:44 PM CST	Severe Thunderstorm Warning	LOT	Cook, Will	46 min
Feb 28, 7:04 PM CST	Severe Thunderstorm Warning	LOT	Grundy, Kendall, Will	41 min
Feb 28, 7:41 PM CST	Severe Thunderstorm Warning	LOT	LaSalle	34 min
Feb 28, 7:45 PM CST	Severe Thunderstorm Warning	LOT	Cook, Kankakee, Will	45 min
Feb 28, 8:04 PM CST	Severe Thunderstorm Warning	LOT	Grundy, LaSalle, Will	26 min
Feb 28, 8:24 PM CST	Special Marine Warning	LOT		96 min
Feb 28, 8:35 PM CST	Severe Thunderstorm Warning	LOT	DeKalb, Kendall, LaSalle, Lee	40 min
Feb 28, 8:51 PM CST	Areal Flood Advisory	LOT	Cook, DeKalb, DuPage, Grundy, Kane, Kankakee and 4 more	6 hr
Feb 28, 8:57 PM CST	Severe Thunderstorm Warning	LOT	Cook, Will	37 min
Feb 28, 9:09 PM CST	Areal Flood Warning	LOT	Cook, Grundy, Kendall, Will	6 hr
Feb 28, 9:34 PM CST	Severe Thunderstorm Warning	LOT	LaSalle	56 min
Feb 28, 9:57 PM CST	Special Weather Statement	LOT	Cook	33 min
Feb 28, 10:56 PM CST	Special Marine Warning	LOT		64 min
Feb 28, 11:20 PM CST	Special Weather Statement	LOT	Ford, Iroquois	25 min
Feb 28, 11:27 PM CST	River Flood Warning	LOT	Lake	5 days
Feb 28, 11:28 PM CST	River Flood Warning	LOT	Cook	31 hr
Feb 28, 11:34 PM CST	River Flood Advisory	LOT	Kane, Kendall	7 days
Feb 28, 11:38 PM CST	River Flood Advisory	LOT	Cook	36 hr
Mar 1, 12:21 AM CST	River Flood Warning	LOT	Will	27 hr
Mar 1, 12:21 AM CST	River Flood Warning	LOT	Bureau, LaSalle, Putnam	72 hr

Nearby

Severe Thunderstorm Warnings in Illinois, 2017 Every severe thunderstorm warning in 2017

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.