Alert archive / Illinois / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 82, NWS Quad Cities, IA

August 11, 2021Bureau County, Putnam County, Whiteside County, Illinois

NWS Quad Cities, IA issued this severe thunderstorm warning at Aug 11, 2021, 8:33 AM CDT for Bureau County, Putnam County, Whiteside County, Illinois. It was in force for 57 min. 4 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Aug 11, 2021, 8:33 AM CDT (13:33 UTC)
Expired: Aug 11, 2021, 9:30 AM CDT
In force: 57 min
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Damage threat: Considerable
Hail: 1.0 in
Wind: 70.0 mph

Counties Bureau County, IL, Putnam County, IL, Whiteside County, IL

The radar

The Quad Cities radar (KDVN), 93 km from the middle of the area, began a volume at 13:33 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.

What was reported inside it

Time	Report	Where	Remark
Aug 11, 8:35 AM CDT	TSTM WND DMG	Ohio, IL	POLE BARN DESTROYED FROM THE STRAIGHT LINE WINDS, WITH POSTS RIPPED OUT OF THE GROUND.
Aug 11, 8:40 AM CDT	TSTM WND DMG	Ohio, IL	TREE DOWN AND CORN FLATTENED. 2-4 INCH BRANCHES ALSO DOWN. ESTIMATED 60 MPH OR GREATER.
Aug 11, 8:50 AM CDT	TSTM WND DMG	La Moille, IL	VERY HIGH WINDS LEAD TO MANY 2 TO 6 INCH LIMBS DOWN.
Aug 11, 9:16 AM CDT	TSTM WND DMG	La Moille, IL	SEVERAL TREES DOWN IN TOWN. ONE FELL ON A SPOTTERS HOUSE, LEADING TO WATER LEAKING IN. POWER LINES DOWN THROUGHOUT TOWN AS WELL, WITH POWER OUT.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 1.6 hours before the alert went out and 87 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: 2852 J/kg
Mixed-layer CIN: -107 J/kg
Mixed-layer LCL: 1040 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 170 m²/s²
0-3 km storm-relative helicity: 193 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.7

Open this sounding in Storm Lab

The text

As transmitted.

247 
WUUS53 KDVN 111333
SVRDVN
ILC011-155-195-111430-
/O.NEW.KDVN.SV.W.0082.210811T1333Z-210811T1430Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Quad Cities IA/IL
833 AM CDT Wed Aug 11 2021

The National Weather Service in the Quad Cities has issued a

* Severe Thunderstorm Warning for...
  Putnam County in north central Illinois...
  Eastern Whiteside County in northwestern Illinois...
  Bureau County in north central Illinois...

* Until 930 AM CDT.

* At 832 AM CDT, severe thunderstorms were located along a line
  extending from near Rock Falls to near Castleton, moving east at 
  50 mph. An area of strong winds will continue behind the storms, 
  with an extended period of near 60 mph winds expected to last up 
  to 2 hours.

  HAZARD...70 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect considerable 
           tree damage. Wind damage is also likely to mobile homes, 
           roofs, and outbuildings.

* These severe thunderstorms will remain over mainly rural areas of
  Putnam, eastern Whiteside and Bureau Counties, including the
  following locations... Seatonville, Spring Valley Airport, Cherry,
  Penrose, Round Grove, Mark, Standard, Coal Hollow, Como and
  Ottville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4110 8934 4115 8933 4115 8964 4123 8964
      4123 8985 4189 8987 4191 8963 4159 8963
      4158 8917 4110 8916
TIME...MOT...LOC 1332Z 281DEG 43KT 4175 8973 4114 8975 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

Ervin

5 follow-up statements

182 
WWUS53 KDVN 111341
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
841 AM CDT Wed Aug 11 2021

ILC011-155-195-111430-
/O.CON.KDVN.SV.W.0082.000000T0000Z-210811T1430Z/
Putnam IL-Whiteside IL-Bureau IL-
841 AM CDT Wed Aug 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 930 AM CDT
FOR PUTNAM...EASTERN WHITESIDE AND BUREAU COUNTIES...

At 841 AM CDT, severe thunderstorms were located along a line
extending from near Rock Falls to near Castleton, moving east at 50 
mph. An area of strong winds will continue behind the storms, with 
an extended period of near 60 mph winds expected to last up to 2 
hours.

HAZARD...75 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings.

Locations impacted include...
Sterling, Rock Falls, Princeton, Hennepin, Spring Valley, DePue,
Granville, Walnut, Ladd, Wyanet, Sheffield, Tiskilwa, Tampico, La
Moille, Dalzell, Buda, Bureau Junction, McNabb, Deer Grove and
Emerson.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

These are potentially deadly storms. Seek shelter in an interior room
on the lowest floor of a well-built structure. Abandon vehicles in
search of a more substantial permanent structure. Stay away from
windows.

&&

LAT...LON 4110 8934 4115 8933 4115 8964 4123 8964
      4123 8985 4189 8987 4191 8963 4159 8963
      4158 8917 4110 8916
TIME...MOT...LOC 1341Z 281DEG 43KT 4173 8963 4112 8965 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

Ervin

107 
WWUS53 KDVN 111350
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
850 AM CDT Wed Aug 11 2021

ILC011-155-195-111430-
/O.CON.KDVN.SV.W.0082.000000T0000Z-210811T1430Z/
Putnam IL-Whiteside IL-Bureau IL-
850 AM CDT Wed Aug 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 930 AM CDT
FOR PUTNAM...EASTERN WHITESIDE AND BUREAU COUNTIES...

At 850 AM CDT, severe thunderstorms were located along a line
extending from near Amboy to near Henry, moving east at 60 mph.
An area of strong winds will continue behind the storms, with an 
extended period of near 60 mph winds expected to last up to 2 hours.

HAZARD...75 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings.

Locations impacted include...
Sterling, Rock Falls, Princeton, Hennepin, Spring Valley, DePue,
Granville, Walnut, Ladd, Wyanet, Sheffield, Tiskilwa, Tampico, La
Moille, Dalzell, Buda, Bureau Junction, McNabb, Deer Grove and
Emerson.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

These are potentially deadly storms. Seek shelter in an interior room
on the lowest floor of a well-built structure. Abandon vehicles in
search of a more substantial permanent structure. Stay away from
windows.

&&

LAT...LON 4110 8934 4115 8933 4115 8964 4123 8964
      4123 8985 4189 8987 4191 8963 4159 8963
      4158 8917 4110 8916
TIME...MOT...LOC 1350Z 280DEG 52KT 4169 8935 4108 8937 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

Ervin

939 
WWUS53 KDVN 111402
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
902 AM CDT Wed Aug 11 2021

ILC011-155-195-111430-
/O.CON.KDVN.SV.W.0082.000000T0000Z-210811T1430Z/
Putnam IL-Whiteside IL-Bureau IL-
902 AM CDT Wed Aug 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 930 AM CDT
FOR PUTNAM...EASTERN WHITESIDE AND BUREAU COUNTIES...

At 901 AM CDT, severe thunderstorms were located along a line
extending from 7 miles southeast of Amboy to Varna, moving east at 50
mph.

An area of strong winds will continue behind the storms, with an 
extended period of near 60 mph winds expected to last up to one 
hour.  A High Wind Warning continues through 10 AM for winds up to 
60 MPH. 

HAZARD...70 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings.

Locations impacted include...
Sterling, Rock Falls, Princeton, Hennepin, Spring Valley, DePue,
Granville, Walnut, Ladd, Wyanet, Sheffield, Tiskilwa, Tampico, La
Moille, Dalzell, Buda, Bureau Junction, McNabb, Deer Grove and
Emerson.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

These are potentially deadly storms. Seek shelter in an interior room
on the lowest floor of a well-built structure. Abandon vehicles in
search of a more substantial permanent structure. Stay away from
windows.

&&

LAT...LON 4110 8934 4115 8933 4115 8964 4123 8964
      4123 8985 4189 8987 4191 8963 4159 8963
      4158 8917 4110 8916
TIME...MOT...LOC 1401Z 281DEG 43KT 4167 8921 4106 8923 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

Ervin

512 
WWUS53 KDVN 111411
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
911 AM CDT Wed Aug 11 2021

ILC011-155-195-111430-
/O.CON.KDVN.SV.W.0082.000000T0000Z-210811T1430Z/
Putnam IL-Whiteside IL-Bureau IL-
911 AM CDT Wed Aug 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 930 AM CDT
FOR PUTNAM...EASTERN WHITESIDE AND BUREAU COUNTIES...

At 910 AM CDT, severe thunderstorms were located along a line
extending from near Paw Paw to near Wenona, moving east at 50 mph.

HAZARD...60 mph wind gusts will continue. An area of strong winds 
         will continue behind the storms, with an extended period of 
         near 60 mph winds expected to last up to one hour.  A High 
         Wind Warning continues through 10 AM for winds up to 60 
         MPH. 

SOURCE...Radar indicated.

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

Locations impacted include...
Sterling, Rock Falls, Princeton, Hennepin, Spring Valley, DePue,
Granville, Walnut, Ladd, Wyanet, Sheffield, Tiskilwa, Tampico, La
Moille, Dalzell, Buda, Bureau Junction, McNabb, Deer Grove and
Emerson.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Widespread wind damage is expected behind the storms. Continue to 
seek shelter NOW inside a sturdy structure and stay away from 
windows.

&&

LAT...LON 4110 8934 4115 8933 4115 8964 4123 8964
      4123 8985 4189 8987 4191 8963 4159 8963
      4158 8917 4110 8916
TIME...MOT...LOC 1410Z 281DEG 43KT 4164 8904 4103 8906 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Ervin

541 
WWUS53 KDVN 111421
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
921 AM CDT Wed Aug 11 2021

ILC011-155-195-111430-
/O.EXP.KDVN.SV.W.0082.000000T0000Z-210811T1430Z/
Putnam IL-Whiteside IL-Bureau IL-
921 AM CDT Wed Aug 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR PUTNAM...EASTERN WHITESIDE AND
BUREAU COUNTIES WILL EXPIRE AT 930 AM CDT...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning will be allowed to expire.
However very gusty winds still expected behind the storms. 

An area of strong winds will continue behind the storms, with an 
extended period of near 60 mph winds expected to last up to one 
hour.  A High Wind Warning continues through 10 AM for winds up to 
60 MPH. 

LAT...LON 4110 8934 4115 8933 4115 8964 4123 8964
      4123 8985 4189 8987 4191 8963 4159 8963
      4158 8917 4110 8916
TIME...MOT...LOC 1420Z 281DEG 43KT 4162 8891 4101 8893 

$$

Ervin

The office that day

Everything else NWS Quad Cities, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 11, 5:56 AM CDT	Severe Thunderstorm Warning	DVN	Hancock	19 min
Aug 11, 6:24 AM CDT	Special Weather Statement	DVN	McDonough	36 min
Aug 11, 6:24 AM CDT	Severe Thunderstorm Warning	DVN	Henderson, Warren	22 min
Aug 11, 6:38 AM CDT	Severe Thunderstorm Warning	DVN	Henderson, Mercer, Warren	37 min
Aug 11, 6:59 AM CDT	Flash Flood Warning	DVN	Hancock, Henderson	3 hr
Aug 11, 7:32 AM CDT	Special Weather Statement	DVN	Rock Island	28 min
Aug 11, 7:55 AM CDT	Special Weather Statement	DVN	Bureau, Henry, Whiteside	65 min
Aug 11, 8:07 AM CDT	Severe Thunderstorm Warning	DVN	Bureau, Henry, Rock Island, Whiteside	53 min
Aug 11, 8:16 AM CDT	High Wind Warning	DVN	Henderson, Henry, Mercer, Rock Island, Warren, Whiteside	104 min
Aug 11, 9:46 AM CDT	Areal Flood Warning	DVN	Henderson	3 hr
Aug 11, 9:59 AM CDT	Special Weather Statement	DVN	McDonough	31 min
Aug 11, 10:45 AM CDT	Special Weather Statement	DVN	Henderson, Warren	30 min
Aug 11, 10:57 AM CDT	Severe Thunderstorm Warning	DVN	Henderson, McDonough, Warren	33 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2021 Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.