Alert archive / Illinois / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 364
The Storm Prediction Center issued this severe thunderstorm watch at Jul 10, 2021, 1:36 AM CDT for 16 counties in Illinois; 9 counties in Missouri. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 10, 2021, 1:36 AM CDT (06:36 UTC)
- Expired
- Jul 10, 2021, 6:00 AM CDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 60 kt
All 25 counties
Alexander County, IL, Edwards County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Jackson County, IL, Jefferson County, IL, Johnson County, IL, Perry County, IL, Pulaski County, IL, Saline County, IL, Union County, IL, Wabash County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Bollinger County, MO, Butler County, MO, Cape Girardeau County, MO, Carter County, MO, Perry County, MO, Ripley County, MO, Scott County, MO, Stoddard County, MO, Wayne County, MO
The radar
The Paducah radar (KPAH), 105 km from the middle of the area, began a volume at 06:36 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
- 10%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 50%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
1 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 10, 2:36 AM CDT | Severe Thunderstorm Warning | PAH | Bollinger, Cape Girardeau, Perry | 14 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
Little Rock, AR (KLZK), launched 00:00Z, 6.6 hours before the alert went out and 297 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
- 1372 J/kg
- Mixed-layer CIN
- -30 J/kg
- Mixed-layer LCL
- 1621 m above ground
- 0-6 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- -19 m²/s²
- 0-3 km storm-relative helicity
- 7 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.8
The text
As transmitted.
546 WWUS20 KWNS 100633 SEL4 SPC WW 100633 ILZ000-MOZ000-101100- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 364 NWS Storm Prediction Center Norman OK 135 AM CDT Sat Jul 10 2021 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southern Illinois Southeast Missouri * Effective this Saturday morning from 135 AM until 600 AM CDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Scattered large hail events to 1 inch in diameter possible SUMMARY...A line of intense thunderstorms over east-central Missouri and central Illinois will push southward through the watch area overnight. Locally damaging wind gusts will be possible with these storms. The severe thunderstorm watch area is approximately along and 40 statute miles north and south of a line from 20 miles west of Poplar Bluff MO to 30 miles east of Mount Vernon IL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU4). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for 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. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 359...WW 360...WW 361...WW 362...WW 363... AVIATION...A few severe thunderstorms with hail surface and aloft to 1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 31035. ...Hart
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 9, 7:08 PM CDT | Severe Thunderstorm Watch | SPC | Hancock, Henderson, McDonough, Warren | 3 hr |
| Jul 9, 7:54 PM CDT | Mesoscale Discussion | SPC | Adams, Brown, Calhoun, Cass, Greene, Jersey and 9 more | 36 min |
| Jul 9, 8:18 PM CDT | Tornado Watch | SPC | Adams, Brown, Calhoun, Cass, Greene, Jersey and 9 more | 6 hr |
| Jul 9, 10:26 PM CDT | Mesoscale Discussion | SPC | Adams, Brown, Calhoun, Cass, Greene, Jersey and 7 more | 64 min |
| Jul 10, 1:01 AM CDT | Mesoscale Discussion | SPC | Clinton, Jackson, Monroe, Perry, Randolph, Saint Clair and 3 more | 59 min |
| Jul 10, 3:09 AM CDT | Mesoscale Discussion | SPC | Alexander, Franklin, Jackson, Johnson, Pulaski, Saline and 2 more | 2 hr |
| Jul 10, 1:25 PM CDT | Mesoscale Discussion | SPC | Alexander, Clay, Clinton, Edwards, Franklin, Gallatin and 22 more | 2 hr |
| Jul 10, 2:01 PM CDT | Severe Thunderstorm Watch | SPC | Alexander, Bond, Clay, Clinton, Crawford, Edwards and 28 more | 8 hr |
| Jul 10, 3:09 PM CDT | Mesoscale Discussion | SPC | Cass, Champaign, DeWitt, Douglas, Ford, Logan and 8 more | 96 min |
| Jul 10, 5:33 PM CDT | Mesoscale Discussion | SPC | Clay, Edwards, Franklin, Gallatin, Hamilton, Hardin and 10 more | 87 min |
| Jul 9, 9:12 PM CDT | Mesoscale Discussion | SPC | Andrew, Atchison, Buchanan, Caldwell, Clay, Clinton and 8 more | 2 hr |
| Jul 9, 9:58 PM CDT | Severe Thunderstorm Watch | SPC | Andrew, Atchison, Buchanan, Caldwell, Carroll, Chariton and 22 more | 7 hr |
| Jul 10, 1:21 AM CDT | Mesoscale Discussion | SPC | Andrew, Atchison, Buchanan, Caldwell, Clay, Clinton and 11 more | 84 min |
| Jul 10, 2:57 AM CDT | Mesoscale Discussion | SPC | Bates, Caldwell, Carroll, Cass, Chariton, Clay and 20 more | 93 min |
| Jul 10, 5:04 AM CDT | Mesoscale Discussion | SPC | Butler, Carter, Ripley, Stoddard | 56 min |
| Jul 10, 11:37 AM CDT | Mesoscale Discussion | SPC | Barry, Christian, Douglas, Howell, Laclede, McDonald and 9 more | 83 min |
| Jul 10, 1:20 PM CDT | Mesoscale Discussion | SPC | Andrew, Atchison, Holt, Nodaway | 115 min |
| Jul 10, 2:17 PM CDT | Mesoscale Discussion | SPC | Barry, Barton, Jasper, McDonald, Newton, Vernon | 118 min |
| Jul 10, 2:18 PM CDT | Severe Thunderstorm Watch | SPC | Andrew, Atchison, Buchanan, Clay, Clinton, DeKalb and 6 more | 7 hr |
| Jul 10, 3:02 PM CDT | Severe Thunderstorm Watch | SPC | Barry, Barton, Camden, Cedar, Christian, Dade and 26 more | 8 hr |
| Jul 10, 3:44 PM CDT | Mesoscale Discussion | SPC | Atchison, Holt | 91 min |
| Jul 10, 5:27 PM CDT | Mesoscale Discussion | SPC | Andrew, Buchanan, Caldwell, Carroll, Clay, Clinton and 13 more | 2 hr |
Nearby
Severe Thunderstorm Watches in Illinois, 2021Severe Thunderstorm Watches in Missouri, 2021Every severe thunderstorm 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.