Alert archive / Missouri / Tornado Watches in 2021

Tornado Watch 553

December 10, 202124 counties in Illinois; 45 counties in Missouri

The Storm Prediction Center issued this tornado watch at Dec 10, 2021, 5:17 PM CST for 24 counties in Illinois; 45 counties in Missouri. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Dec 10, 2021, 5:17 PM CST (23:17 UTC)
Expired: Dec 10, 2021, 11:00 PM CST
In force: 6 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 65 kt

All 69 counties

Adams County, IL, Bond County, IL, Brown County, IL, Calhoun County, IL, Cass County, IL, Christian County, IL, Clinton County, IL, Fayette County, IL, Fulton County, IL, Greene County, IL, Hancock County, IL, Jersey County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Mason County, IL, McDonough County, IL, Menard County, IL, Montgomery County, IL, Morgan County, IL, Pike County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Audrain County, MO, Barry County, MO, Boone County, MO, Callaway County, MO, Camden County, MO, Christian County, MO, City of Saint Louis, MO, Clark County, MO, Cole County, MO, Dade County, MO, Dallas County, MO, Douglas County, MO, Franklin County, MO, Gasconade County, MO, Greene County, MO, Jasper County, MO, Knox County, MO, Laclede County, MO, Lawrence County, MO, Lewis County, MO, Lincoln County, MO, Maries County, MO, Marion County, MO, McDonald County, MO, Miller County, MO, Moniteau County, MO, Monroe County, MO, Montgomery County, MO, Morgan County, MO, Newton County, MO, Osage County, MO, Ozark County, MO, Phelps County, MO, Pike County, MO, Polk County, MO, Pulaski County, MO, Ralls County, MO, Saint Charles County, MO, Saint Louis County, MO, Shelby County, MO, Stone County, MO, Taney County, MO, Warren County, MO, Webster County, MO, Wright County, MO

The radar

The St Louis radar (KLSX), 57 km from the middle of the area, began a volume at 23:21 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: 70%
One or more EF2 to EF5 tornadoes: 50%
Ten or more severe wind reports: 50%
One or more gusts of 65 knots or more: 30%
Ten or more severe hail reports: 30%
One or more hailstones of 2 inches or more: 20%
Six or more combined severe hail and wind reports: 70%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Dec 10, 5:33 PM CST	Severe Thunderstorm Warning	SGF	Greene, Webster	42 min
Dec 10, 5:44 PM CST	Severe Thunderstorm Warning	SGF	Camden, Dallas, Laclede, Miller	46 min
Dec 10, 5:49 PM CST	Severe Thunderstorm Warning	SGF	Camden, Laclede, Pulaski	41 min
Dec 10, 5:59 PM CST	Tornado Warning	SGF	Laclede, Webster, Wright	31 min
Dec 10, 6:10 PM CST	Severe Thunderstorm Warning	SGF	Maries, Miller	35 min
Dec 10, 6:13 PM CST	Severe Thunderstorm Warning	LSX	Boone, Callaway, Cole, Moniteau	47 min
Dec 10, 6:18 PM CST	Severe Thunderstorm Warning	LSX	Cole, Osage	42 min
Dec 10, 6:19 PM CST	Severe Thunderstorm Warning	SGF	Maries, Miller	26 min
Dec 10, 6:21 PM CST	Tornado Warning	SGF	Laclede, Pulaski, Texas, Wright	39 min
Dec 10, 6:22 PM CST	Severe Thunderstorm Warning	SGF	Maries, Phelps, Pulaski	38 min
Dec 10, 6:25 PM CST	Tornado Warning	SGF	Maries, Phelps, Pulaski	35 min
Dec 10, 6:27 PM CST	Tornado Warning	LSX	Audrain, Callaway	34 min
Dec 10, 6:27 PM CST	Severe Thunderstorm Warning	SGF	Barton, Dade, Jasper, Lawrence	26 min
Dec 10, 6:30 PM CST	Tornado Warning	LSX	Callaway, Cole, Gasconade, Montgomery, Osage	45 min
Dec 10, 6:42 PM CST	Tornado Warning	LSX	Pike	48 min
Dec 10, 6:42 PM CST	Severe Thunderstorm Warning	LSX	Crawford, Franklin, Gasconade, Osage	48 min
Dec 10, 6:44 PM CST	Severe Thunderstorm Warning Considerable damage threat	SGF	Cedar, Dade, Greene, Lawrence, Polk	46 min
Dec 10, 6:48 PM CST	Tornado Warning	SGF	Maries, Phelps	15 min
Dec 10, 6:49 PM CST	Tornado Warning	LSX	Franklin, Gasconade, Osage, Warren	41 min
Dec 10, 6:49 PM CST	Severe Thunderstorm Warning	SGF	Dent, Phelps, Pulaski	56 min
Dec 10, 6:50 PM CST	Tornado Warning	LSX	Audrain, Callaway, Montgomery, Pike, Ralls	40 min
Dec 10, 7:00 PM CST	Tornado Warning	LSX	Gasconade, Lincoln, Montgomery, Pike, Warren	45 min
Dec 10, 7:02 PM CST	Tornado Warning	LSX	Crawford, Franklin, Gasconade	43 min
Dec 10, 7:04 PM CST	Severe Thunderstorm Warning	SGF	Barry, Stone	41 min
Dec 10, 7:11 PM CST	Tornado Warning	LSX	Pike	49 min
Dec 10, 7:11 PM CST	Severe Thunderstorm Warning Considerable damage threat	SGF	Dallas, Polk, Webster	49 min
Dec 10, 7:14 PM CST	Severe Thunderstorm Warning	SGF	Dent, Phelps, Texas	46 min
Dec 10, 7:15 PM CST	Tornado Warning	ILX	Cass, Morgan, Scott	45 min
Dec 10, 7:16 PM CST	Tornado Warning	LSX	Pike	14 min
Dec 10, 7:16 PM CST	Tornado Warning	LSX	Franklin, Lincoln, Saint Charles, Warren	44 min
Dec 10, 7:26 PM CST	Tornado Warning	SGF	Barry, Christian, Stone	34 min
Dec 10, 7:30 PM CST	Tornado Warning	LSX	Calhoun, Greene, Jersey	45 min
Dec 10, 7:35 PM CST	Tornado Warning Tornado observed	LSX	Calhoun, Jersey	40 min
Dec 10, 7:36 PM CST	Tornado Warning	LSX	Pike	21 min
Dec 10, 7:37 PM CST	Severe Thunderstorm Warning	SGF	Barry, Christian, Stone, Taney	38 min
Dec 10, 7:37 PM CST	Severe Thunderstorm Warning Considerable damage threat	SGF	Camden, Dallas, Laclede, Miller, Polk, Pulaski	53 min
Dec 10, 7:39 PM CST	Tornado Warning	SGF	Christian, Stone, Taney	36 min
Dec 10, 7:45 PM CST	Severe Thunderstorm Warning	SGF	Christian, Douglas, Greene, Webster	45 min
Dec 10, 7:54 PM CST	Tornado Warning Tornado observed	ILX	Cass, Mason, Menard	40 min
Dec 10, 7:54 PM CST	Severe Thunderstorm Warning	SGF	Dallas, Greene, Laclede, Webster	36 min
Dec 10, 7:58 PM CST	Tornado Warning Tornado observed	SGF	Christian, Douglas, Ozark, Taney	47 min
Dec 10, 8:05 PM CST	Tornado Warning	ILX	Mason, Tazewell	40 min
Dec 10, 8:06 PM CST	Tornado Warning Tornado observed	LSX	Jersey, Macoupin, Madison	39 min
Dec 10, 8:07 PM CST	Severe Thunderstorm Warning	SGF	Camden, Laclede, Maries, Miller, Phelps, Pulaski	47 min
Dec 10, 8:10 PM CST	Severe Thunderstorm Warning	LSX	Franklin	35 min
Dec 10, 8:20 PM CST	Severe Thunderstorm Warning	ILX	Christian, Sangamon	40 min
Dec 10, 8:24 PM CST	Tornado Warning	SGF	Douglas, Texas, Wright	18 min
Dec 10, 8:28 PM CST	Tornado Warning	ILX	Logan, Mason, Tazewell	32 min
Dec 10, 8:29 PM CST	Severe Thunderstorm Warning	LSX	Franklin, Jefferson, Saint Louis, City of Saint Louis	30 min
Dec 10, 8:32 PM CST	Severe Thunderstorm Warning	ILX	Logan, Sangamon	28 min
Dec 10, 8:33 PM CST	Tornado Warning Tornado observedConsiderable damage threat	LSX	Bond, Madison	42 min
Dec 10, 8:34 PM CST	Severe Thunderstorm Warning	LSX	Crawford, Franklin, Gasconade, Osage	41 min
Dec 10, 8:37 PM CST	Tornado Warning	LSX	Macoupin, Madison	17 min
Dec 10, 8:41 PM CST	Severe Thunderstorm Warning	SGF	Douglas, Howell, Texas, Wright	34 min
Dec 10, 8:44 PM CST	Tornado Warning Tornado observed	LSX	Fayette, Macoupin, Madison, Montgomery	46 min
Dec 10, 8:47 PM CST	Tornado Warning	LSX	Franklin, Gasconade, Warren	43 min
Dec 10, 8:56 PM CST	Tornado Warning	LSX	Bond, Fayette, Montgomery	34 min
Dec 10, 8:58 PM CST	Severe Thunderstorm Warning	ILX	DeWitt, McLean, Macon, Moultrie, Piatt, Sangamon	47 min
Dec 10, 9:07 PM CST	Severe Thunderstorm Warning	LSX	Calhoun	38 min
Dec 10, 9:09 PM CST	Severe Thunderstorm Warning	ILX	Christian, Macon, Moultrie, Piatt, Shelby	66 min
Dec 10, 9:39 PM CST	Tornado Warning	LSX	Macoupin, Madison	51 min
Dec 10, 10:05 PM CST	Severe Thunderstorm Warning	LSX	Madison, Saint Clair	25 min
Dec 10, 10:18 PM CST	Severe Thunderstorm Warning	LSX	Bond, Fayette, Macoupin, Madison, Montgomery	57 min
Dec 10, 10:26 PM CST	Tornado Warning	LSX	Bond, Fayette, Montgomery	49 min
Dec 10, 10:51 PM CST	Severe Thunderstorm Warning	LSX	Clinton, Saint Clair, Washington	39 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 12:00Z, 11.3 hours before the alert went out and 224 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 925 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: 160 m²/s²
0-3 km storm-relative helicity: 233 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

862 
WWUS20 KWNS 102315
SEL3  
SPC WW 102315
ILZ000-MOZ000-110500-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 553
NWS Storm Prediction Center Norman OK
520 PM CST Fri Dec 10 2021

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Western and central Illinois
  Southwest to northeast Missouri

* Effective this Friday afternoon and evening from 520 PM until
  1100 PM CST.

* Primary threats include...
  A few tornadoes likely with a couple intense tornadoes possible
  Scattered damaging winds and isolated significant gusts to 75
    mph possible
  Isolated large hail events to 1.5 inches in diameter possible

SUMMARY...Additional supercells should develop from southwest to
northeast Missouri and spread rapidly northeast this evening.

The tornado watch area is approximately along and 80 statute miles
east and west of a line from 30 miles west northwest of Peoria IL to
45 miles west of West Plains MO. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU3).

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...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1.5 inches. Extreme turbulence and surface wind
gusts to 65 knots. A few cumulonimbi with maximum tops to 400. Mean
storm motion vector 23045.

...Grams

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 10, 1:35 PM CST	Mesoscale Discussion	SPC	Alexander, Pulaski, Union	2 hr
Dec 10, 3:07 PM CST	Tornado Watch	SPC	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 17 more	11 hr
Dec 10, 4:45 PM CST	Mesoscale Discussion	SPC	Alexander, Hardin, Jackson, Johnson, Massac, Pope and 3 more	90 min
Dec 10, 5:27 PM CST	Mesoscale Discussion	SPC	Calhoun, Jersey	3 hr
Dec 10, 12:27 PM CST	Mesoscale Discussion	SPC	Clay, Dickinson, Emmet, Lyon, O'Brien, Osceola and 1 more	4 hr
Dec 10, 3:31 PM CST	Mesoscale Discussion	SPC	Clay, Dickinson, Emmet, Kossuth, Lyon, Osceola and 2 more	4 hr
Dec 10, 2:44 PM CST	Mesoscale Discussion	SPC	Audrain, Boone, Carroll, Chariton, Clark, Cooper and 13 more	2 hr

Nearby

Tornado Watches in Missouri, 2021 Tornado Watches in Illinois, 2021 Every 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.