Alert archive / Indiana / Tornado Watches in 2021

Tornado Watch 557

December 10, 202127 counties in Illinois; 30 counties in Indiana

The Storm Prediction Center issued this tornado watch at Dec 10, 2021, 7:47 PM CST for 27 counties in Illinois; 30 counties in Indiana. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
Dec 10, 2021, 7:47 PM CST (01:47 UTC)
Expired
Dec 11, 2021, 3:44 AM CST
In force
8 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
70 kt
All 57 counties

Champaign County, IL, Clark County, IL, Clay County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, DeWitt County, IL, Douglas County, IL, Edgar County, IL, Effingham County, IL, Ford County, IL, Iroquois County, IL, Jasper County, IL, Kankakee County, IL, Lawrence County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, McLean County, IL, Moultrie County, IL, Peoria County, IL, Piatt County, IL, Richland County, IL, Shelby County, IL, Tazewell County, IL, Vermilion County, IL, Woodford County, IL, Bartholomew County, IN, Benton County, IN, Boone County, IN, Brown County, IN, Clay County, IN, Clinton County, IN, Daviess County, IN, Fountain County, IN, Greene County, IN, Hendricks County, IN, Jackson County, IN, Jasper County, IN, Jennings County, IN, Johnson County, IN, Knox County, IN, Lawrence County, IN, Marion County, IN, Martin County, IN, Monroe County, IN, Montgomery County, IN, Morgan County, IN, Newton County, IN, Owen County, IN, Parke County, IN, Putnam County, IN, Sullivan County, IN, Tippecanoe County, IN, Vermillion County, IN, Vigo County, IN, Warren County, IN

The radar

The Lincoln radar (KILX), 116 km from the middle of the area, began a volume at 01:48 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 SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
60%
One or more EF2 to EF5 tornadoes
40%
Ten or more severe wind reports
60%
One or more gusts of 65 knots or more
40%
Ten or more severe hail reports
10%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

36 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Dec 10, 8:05 PM CSTTornado WarningILXMason, Tazewell40 min
Dec 10, 8:28 PM CSTTornado WarningILXLogan, Mason, Tazewell32 min
Dec 10, 8:32 PM CSTSevere Thunderstorm WarningILXLogan, Sangamon28 min
Dec 10, 8:38 PM CSTTornado WarningILXMcLean, Woodford22 min
Dec 10, 8:38 PM CSTSevere Thunderstorm WarningINDBartholomew, Brown, Johnson, Shelby25 min
Dec 10, 8:50 PM CSTTornado WarningILXMcLean12 min
Dec 10, 8:58 PM CSTSevere Thunderstorm WarningILXDeWitt, McLean, Macon, Moultrie, Piatt, Sangamon47 min
Dec 10, 9:09 PM CSTSevere Thunderstorm WarningILXChristian, Macon, Moultrie, Piatt, Shelby66 min
Dec 10, 9:23 PM CSTTornado Warning Tornado observedILXShelby36 min
Dec 10, 9:27 PM CSTSevere Thunderstorm WarningLOTFord, Iroquois, Livingston48 min
Dec 10, 9:33 PM CSTSevere Thunderstorm WarningILXChampaign, Piatt, Vermilion42 min
Dec 10, 9:46 PM CSTSevere Thunderstorm WarningLOTKankakee, Will44 min
Dec 10, 9:51 PM CSTSevere Thunderstorm WarningILXChampaign, Coles, Cumberland, Douglas, Moultrie, Piatt and 1 more54 min
Dec 10, 9:55 PM CSTTornado WarningILXColes, Douglas, Moultrie19 min
Dec 10, 9:58 PM CSTTornado Warning Tornado observedILXColes, Douglas, Moultrie32 min
Dec 10, 10:04 PM CSTTornado WarningLOTJasper, Porter26 min
Dec 10, 10:22 PM CSTSevere Thunderstorm WarningLOTBenton, Jasper, Newton38 min
Dec 10, 10:24 PM CSTSevere Thunderstorm WarningILXChampaign, Clark, Coles, Douglas, Edgar, Vermilion35 min
Dec 10, 10:26 PM CSTTornado Warning Tornado observedILXColes, Douglas, Edgar, Vermilion19 min
Dec 10, 10:32 PM CSTSevere Thunderstorm WarningINDFountain, Vermillion, Warren28 min
Dec 10, 10:42 PM CSTSevere Thunderstorm Warning Considerable damage threatINDDaviess, Greene, Knox, Martin, Monroe, Owen33 min
Dec 10, 10:45 PM CSTTornado WarningINDFountain, Parke, Vermillion30 min
Dec 10, 10:55 PM CSTSevere Thunderstorm Warning Considerable damage threatINDDaviess, Greene, Knox, Sullivan35 min
Dec 10, 10:55 PM CSTSevere Thunderstorm WarningINDFountain, Montgomery, Parke, Tippecanoe, Vermillion, Vigo and 1 more35 min
Dec 10, 10:56 PM CSTSevere Thunderstorm WarningILXColes, Cumberland, Effingham, Jasper, Moultrie, Shelby49 min
Dec 10, 11:10 PM CSTTornado WarningINDDaviess, Greene, Knox, Sullivan22 min
Dec 10, 11:16 PM CSTSevere Thunderstorm WarningINDCarroll, Clinton, Montgomery, Parke, Putnam, Tippecanoe29 min
Dec 10, 11:36 PM CSTSevere Thunderstorm WarningINDBoone, Carroll, Clinton, Hamilton, Howard, Montgomery and 1 more24 min
Dec 10, 11:40 PM CSTSevere Thunderstorm WarningILXClark, Coles, Crawford, Cumberland, Edgar, Effingham and 2 more65 min
Dec 10, 11:58 PM CSTSevere Thunderstorm WarningINDBoone, Clinton, Hamilton, Hendricks, Howard, Madison and 4 more32 min
Dec 11, 12:05 AM CSTSevere Thunderstorm WarningINDParke, Vermillion, Vigo25 min
Dec 11, 12:28 AM CSTSevere Thunderstorm WarningINDClay, Parke, Putnam, Vigo32 min
Dec 11, 12:49 AM CSTSevere Thunderstorm WarningINDHendricks, Putnam26 min
Dec 11, 12:59 AM CSTSevere Thunderstorm WarningINDHendricks, Putnam21 min
Dec 11, 1:15 AM CSTSevere Thunderstorm WarningINDHamilton, Marion30 min
Dec 11, 1:56 AM CSTSevere Thunderstorm WarningINDBartholomew, Brown, Johnson, Monroe, Morgan, Shelby34 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 1.8 hours before the alert went out and 54 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-pSkew-T log-p diagram, Lincoln, IL at 00:00Z on 2021-12-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 119 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 00:00Z on 2021-12-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 341 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
119 J/kg
Mixed-layer CIN
-33 J/kg
Mixed-layer LCL
662 m above ground
0-6 km bulk shear
73 kt
0-1 km storm-relative helicity
341 m²/s²
0-3 km storm-relative helicity
357 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

300 
WWUS20 KWNS 110144
SEL7  
SPC WW 110144
ILZ000-INZ000-110800-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 557
NWS Storm Prediction Center Norman OK
745 PM CST Fri Dec 10 2021

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Central and eastern Illinois
  Western to southern Indiana

* Effective this Friday night and Saturday morning from 745 PM
  until 200 AM CST.

* Primary threats include...
  A few tornadoes likely with a couple intense tornadoes possible
  Scattered damaging winds likely with isolated significant gusts
    to 80 mph possible

SUMMARY...A fast-moving linear cluster with embedded supercells will
spread east from western Illinois into Indiana tonight.

The tornado watch area is approximately along and 60 statute miles
east and west of a line from 45 miles northeast of Peoria IL to 40
miles south southwest of Bloomington IN. For a complete depiction of
the watch see the associated watch outline update (WOUS64 KWNS
WOU7).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 552...WW 553...WW
554...WW 555...WW 556...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1 inch. Extreme turbulence and surface wind
gusts to 70 knots. A few cumulonimbi with maximum tops to 400. Mean
storm motion vector 24045.

...Grams

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 10, 7:02 PM CSTMesoscale DiscussionSPCCalhoun, Greene, Jersey, Macoupin, Madison, Monroe and 4 more58 min
Dec 10, 7:18 PM CSTMesoscale DiscussionSPCChampaign, Christian, Clark, Clay, Coles, Crawford and 18 more87 min
Dec 10, 8:53 PM CSTMesoscale DiscussionSPCBond, Champaign, Christian, Clark, Clay, Coles and 21 more97 min
Dec 10, 9:36 PM CSTMesoscale DiscussionSPCClark, Coles, Cumberland, Edgar, Effingham, Shelby54 min
Dec 10, 10:09 PM CSTMesoscale DiscussionSPCMassac96 min
Dec 10, 11:03 PM CSTTornado WatchSPCAlexander, Clinton, Edwards, Fayette, Franklin, Gallatin and 17 more5 hr
Dec 10, 11:28 PM CSTMesoscale DiscussionSPCAlexander, Clark, Clay, Coles, Crawford, Cumberland and 24 more92 min
Dec 10, 6:21 PM CSTTornado WatchSPCClark, Crawford, Dubois, Floyd, Harrison, Jefferson and 4 more10 hr
Dec 10, 8:35 PM CSTMesoscale DiscussionSPCHarrison85 min
Dec 10, 10:25 PM CSTMesoscale DiscussionSPCBartholomew, Benton, Blackford, Boone, Brown, Carroll and 50 more95 min
Dec 10, 11:08 PM CSTMesoscale DiscussionSPCDearborn, Decatur, Delaware, Fayette, Franklin, Hamilton and 16 more67 min
Dec 10, 11:20 PM CSTTornado WatchSPCAdams, Allen, Blackford, Carroll, Cass, Dearborn and 27 more6 hr
Dec 11, 1:46 AM CSTMesoscale DiscussionSPCBartholomew, Brown, Daviess, Dearborn, Decatur, Delaware and 21 more59 min

Nearby

Tornado Watches in Indiana, 2021Tornado Watches in Illinois, 2021Every tornado watch 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.