Alert archive / Illinois / Tornado Warnings in 2021
Tornado Warning 25, NWS Chicago, IL
NWS Chicago, IL issued this tornado warning at Aug 9, 2021, 3:46 PM CDT for Boone County, Winnebago County, Illinois. It was in force for 26 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, 3:46 PM CDT (20:46 UTC)
- Expired
- Aug 9, 2021, 4:12 PM CDT
- In force
- 26 min
- Issued by
- NWS Chicago, IL
- Area
- Storm-based polygon
- Tornado
- Radar indicated
- Hail
- 0.75 in
Counties Boone County, IL, Winnebago County, IL
The radar
The Milwaukee radar (KMKX), 88 km from the middle of the area, began a volume at 20:50 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, 8.8 hours before the alert went out and 152 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.
020
WFUS53 KLOT 092046
TORLOT
ILC007-201-092130-
/O.NEW.KLOT.TO.W.0025.210809T2046Z-210809T2130Z/
BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Chicago/Romeoville
346 PM CDT Mon Aug 9 2021
The National Weather Service in Chicago has issued a
* Tornado Warning for...
Southeastern Winnebago County in north central Illinois...
Southern Boone County in north central Illinois...
* Until 430 PM CDT.
* At 346 PM CDT, a severe thunderstorm capable of producing a tornado
was located over Cherry Valley, or near Belvidere, moving east at
10 mph.
HAZARD...Tornado.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed.
Damage to roofs, windows, and vehicles will occur. Tree
damage is likely.
* This dangerous storm will be near...
Belvidere around 350 PM CDT.
Including the following interstates...
I-39 between mile markers 121 and 123.
I-90 between mile markers 16 and 29.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
&&
LAT...LON 4223 8874 4215 8875 4215 8888 4220 8901
4228 8896
TIME...MOT...LOC 2046Z 286DEG 10KT 4222 8893
TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
$$
Carlaw2 follow-up statements
514
WWUS53 KLOT 092059
SVSLOT
Severe Weather Statement
National Weather Service Chicago/Romeoville
359 PM CDT Mon Aug 9 2021
ILC201-092109-
/O.CAN.KLOT.TO.W.0025.000000T0000Z-210809T2130Z/
Winnebago IL-
359 PM CDT Mon Aug 9 2021
...THE TORNADO WARNING FOR SOUTHEASTERN WINNEBAGO COUNTY IS
CANCELLED...
The tornadic thunderstorm which prompted the warning has moved out
of the warned area. Therefore, the warning has been cancelled.
A Tornado Watch remains in effect until 1000 PM CDT for north central
Illinois.
LAT...LON 4223 8874 4215 8875 4215 8888 4219 8894
4226 8891
TIME...MOT...LOC 2059Z 284DEG 10KT 4222 8889
$$
ILC007-092130-
/O.CON.KLOT.TO.W.0025.000000T0000Z-210809T2130Z/
Boone IL-
359 PM CDT Mon Aug 9 2021
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 430 PM CDT FOR SOUTHERN
BOONE COUNTY...
At 359 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Belvidere, moving east at 10 mph.
HAZARD...Tornado.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed. Damage
to roofs, windows, and vehicles will occur. Tree damage is
likely.
This dangerous storm will be near...
Belvidere around 405 PM CDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
&&
LAT...LON 4223 8874 4215 8875 4215 8888 4219 8894
4226 8891
TIME...MOT...LOC 2059Z 284DEG 10KT 4222 8889
TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
$$
Carlaw360
WWUS53 KLOT 092112
SVSLOT
Severe Weather Statement
National Weather Service Chicago/Romeoville
412 PM CDT Mon Aug 9 2021
ILC007-092122-
/O.CAN.KLOT.TO.W.0025.000000T0000Z-210809T2130Z/
Boone IL-
412 PM CDT Mon Aug 9 2021
...THE TORNADO WARNING FOR SOUTHERN BOONE COUNTY IS CANCELLED...
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore, the warning has been cancelled.
A Tornado Watch remains in effect until 1000 PM CDT for north central
Illinois.
LAT...LON 4223 8874 4215 8875 4215 8888 4219 8894
4226 8891
TIME...MOT...LOC 2110Z 286DEG 10KT 4221 8884
$$
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, 3:14 PM CDT | Severe Thunderstorm Warning | LOT | Boone, DeKalb, Ogle, Winnebago | 61 min |
| Aug 9, 3:25 PM CDT | Areal Flood Advisory | LOT | Boone, Winnebago | 3 hr |
| 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
Tornado Warnings in Illinois, 2021Every tornado warning in 2021Tornadoes 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.