Alert archive / Illinois / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 56, NWS Chicago, IL
NWS Chicago, IL issued this severe thunderstorm warning at Aug 9, 2021, 3:14 PM CDT for 4 counties in Illinois. It was in force for 61 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
- Aug 9, 2021, 3:14 PM CDT (20:14 UTC)
- Expired
- Aug 9, 2021, 4:15 PM CDT
- In force
- 61 min
- Issued by
- NWS Chicago, IL
- Area
- Storm-based polygon
- Tornado
- Possible
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties Boone County, IL, DeKalb County, IL, Ogle County, IL, Winnebago County, IL
The radar
The Milwaukee radar (KMKX), 86 km from the middle of the area, began a volume at 20:19 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 |
|---|---|---|---|
| Aug 9, 2:43 PM CDT | Tornado Watch | SPC | 9 hr |
The nearest sounding before it
Davenport, (KDVN), launched 12:00Z, 8.2 hours before the alert went out and 151 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.
- Mixed-layer CAPE
- 1676 J/kg
- Mixed-layer CIN
- -63 J/kg
- Mixed-layer LCL
- 705 m above ground
- 0-6 km bulk shear
- 43 kt
- 0-1 km storm-relative helicity
- 171 m²/s²
- 0-3 km storm-relative helicity
- 208 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 2.7
The text
As transmitted.
603
WUUS53 KLOT 092014
SVRLOT
ILC007-037-141-201-092115-
/O.NEW.KLOT.SV.W.0056.210809T2014Z-210809T2115Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Chicago/Romeoville
314 PM CDT Mon Aug 9 2021
The National Weather Service in Chicago has issued a
* Severe Thunderstorm Warning for...
Northeastern Ogle County in north central Illinois...
Northwestern De Kalb County in north central Illinois...
Southeastern Winnebago County in north central Illinois...
Southern Boone County in north central Illinois...
* Until 415 PM CDT.
* At 313 PM CDT, a severe thunderstorm was located over Rockford,
moving east at 30 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
* Locations impacted include...
Rockford, Belvidere, Loves Park, Machesney Park, Roscoe, Poplar
Grove, Rockford Airport, Candlewick Lake, Cherry Valley, Davis
Junction, Kirkland, Timberlane, New Milford, Monroe Center, Garden
Prairie, Caledonia and Fairdale.
Including the following interstates...
I-39 between mile markers 108 and 123.
I-90 between mile markers 9 and 31.
This includes... Boone County Fairgrounds, Rock Cut State Park, Rock
Valley College, Rockford Rivets Baseball, and Rockford Speedway.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A Tornado Watch remains in effect until 1000 PM CDT for north central
Illinois.
For your protection move to an interior room on the lowest floor of a
building.
A Tornado Watch remains in effect until 1000 PM CDT for north central
Illinois.
&&
LAT...LON 4233 8871 4216 8871 4215 8872 4200 8895
4223 8926 4239 8902
TIME...MOT...LOC 2013Z 282DEG 24KT 4225 8907
TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Carlaw3 follow-up statements
094
WWUS53 KLOT 092033
SVSLOT
Severe Weather Statement
National Weather Service Chicago/Romeoville
333 PM CDT Mon Aug 9 2021
ILC007-037-141-201-092115-
/O.CON.KLOT.SV.W.0056.000000T0000Z-210809T2115Z/
Ogle IL-De Kalb IL-Winnebago IL-Boone IL-
333 PM CDT Mon Aug 9 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM CDT
FOR NORTHEASTERN OGLE...NORTHWESTERN DE KALB...SOUTHEASTERN WINNEBAGO
AND SOUTHERN BOONE COUNTIES...
At 332 PM CDT, a severe thunderstorm was located near Cherry Valley,
or near Belvidere, moving east at 25 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
Locations impacted include...
Rockford, Belvidere, Loves Park, Machesney Park, Roscoe, Poplar
Grove, Rockford Airport, Candlewick Lake, Cherry Valley, Davis
Junction, Kirkland, Timberlane, New Milford, Monroe Center, Garden
Prairie, Caledonia and Fairdale.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A Tornado Watch remains in effect until 1000 PM CDT for north central
Illinois.
For your protection move to an interior room on the lowest floor of a
building.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4233 8871 4216 8871 4215 8872 4200 8895
4223 8926 4239 8902
TIME...MOT...LOC 2032Z 282DEG 24KT 4222 8890
TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Carlaw398
WWUS53 KLOT 092042
SVSLOT
Severe Weather Statement
National Weather Service Chicago/Romeoville
342 PM CDT Mon Aug 9 2021
ILC007-037-141-201-092115-
/O.CON.KLOT.SV.W.0056.000000T0000Z-210809T2115Z/
Ogle IL-De Kalb IL-Winnebago IL-Boone IL-
342 PM CDT Mon Aug 9 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM CDT
FOR NORTHEASTERN OGLE...NORTHWESTERN DE KALB...SOUTHEASTERN WINNEBAGO
AND SOUTHERN BOONE COUNTIES...
At 341 PM CDT, a severe thunderstorm was located over Cherry Valley,
or near Belvidere, moving east at 20 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
Locations impacted include...
Rockford, Belvidere, Poplar Grove, Rockford Airport, Cherry Valley,
Davis Junction, Kirkland, New Milford, Monroe Center, Garden Prairie
and Fairdale.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A Tornado Watch remains in effect until 1000 PM CDT for north central
Illinois.
For your protection move to an interior room on the lowest floor of a
building.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4233 8871 4216 8871 4215 8872 4200 8895
4222 8920 4228 8906
TIME...MOT...LOC 2041Z 285DEG 18KT 4221 8894
TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Carlaw920
WWUS53 KLOT 092115
SVSLOT
Severe Weather Statement
National Weather Service Chicago/Romeoville
415 PM CDT Mon Aug 9 2021
ILC007-037-141-201-092125-
/O.EXP.KLOT.SV.W.0056.000000T0000Z-210809T2115Z/
Ogle IL-De Kalb IL-Winnebago IL-Boone IL-
415 PM CDT Mon Aug 9 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN OGLE...
NORTHWESTERN DE KALB...SOUTHEASTERN WINNEBAGO AND SOUTHERN BOONE
COUNTIES HAS EXPIRED...
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been allowed to expire.
A Tornado Watch remains in effect until 1000 PM CDT for north central
Illinois.
LAT...LON 4233 8871 4216 8871 4215 8872 4200 8895
4222 8920 4228 8906
TIME...MOT...LOC 2115Z 282DEG 24KT 4217 8867
$$
CarlawThe office that day
Everything else NWS Chicago, IL issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 9, 6:52 AM CDT | Special Weather Statement | LOT | Winnebago | 23 min |
| Aug 9, 11:49 AM CDT | Areal Flood Advisory | LOT | Boone, DeKalb, Kane, McHenry, Ogle, Winnebago | 3 hr |
| Aug 9, 2:46 PM CDT | Heat Advisory | LOT | Boone, Cook, DeKalb, DuPage, Ford, Grundy and 12 more | 28 hr |
| Aug 9, 3:25 PM CDT | Areal Flood Advisory | LOT | Boone, Winnebago | 3 hr |
| Aug 9, 3:46 PM CDT | Tornado Warning | LOT | Boone, Winnebago | 26 min |
| Aug 9, 4:12 PM CDT | Areal Flood Advisory | LOT | Boone, McHenry | 3 hr |
| Aug 9, 4:34 PM CDT | Tornado Warning | LOT | DeKalb | 41 min |
| Aug 9, 4:39 PM CDT | Tornado Warning | LOT | DeKalb, Ogle | 51 min |
| Aug 9, 5:11 PM CDT | Tornado Warning | LOT | Lee | 49 min |
| Aug 9, 5:15 PM CDT | Tornado Warning | LOT | DeKalb, Kane | 60 min |
| Aug 9, 5:32 PM CDT | Tornado Warning | LOT | DeKalb, Ogle | 43 min |
| Aug 9, 5:42 PM CDT | Tornado Warning | LOT | Kane | 48 min |
| Aug 9, 6:00 PM CDT | Tornado Warning | LOT | DeKalb, Lee | 26 min |
| Aug 9, 6:09 PM CDT | Tornado Warning | LOT | DeKalb, Kane | 51 min |
| Aug 9, 6:24 PM CDT | Tornado Warning | LOT | DuPage, Kane | 66 min |
| Aug 9, 6:45 PM CDT | Special Marine Warning | LOT | 90 min | |
| Aug 9, 6:50 PM CDT | Tornado Warning | LOT | Kane | 40 min |
Nearby
Severe Thunderstorm Warnings in Illinois, 2021Every severe thunderstorm warning in 2021
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.