Alert archive / Illinois / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 152
The Storm Prediction Center issued this severe thunderstorm watch at May 6, 2021, 12:38 PM CDT for 6 states. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- May 6, 2021, 12:38 PM CDT (17:38 UTC)
- Expired
- May 6, 2021, 6:00 PM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 65 kt
All 76 counties
Clay County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Greene County, AR, Jackson County, AR, Lawrence County, AR, Mississippi County, AR, Poinsett County, AR, Randolph County, AR, Alexander County, IL, Edwards County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Hardin County, IL, Jackson County, IL, Jefferson County, IL, Johnson County, IL, Massac County, IL, Perry County, IL, Pope County, IL, Pulaski County, IL, Saline County, IL, Union County, IL, Wabash County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Gibson County, IN, Posey County, IN, Vanderburgh County, IN, Ballard County, KY, Caldwell County, KY, Calloway County, KY, Carlisle County, KY, Crittenden County, KY, Fulton County, KY, Graves County, KY, Henderson County, KY, Hickman County, KY, Livingston County, KY, Lyon County, KY, Marshall County, KY, McCracken County, KY, Trigg County, KY, Union County, KY, Webster County, KY, Bollinger County, MO, Butler County, MO, Cape Girardeau County, MO, Carter County, MO, Dunklin County, MO, Mississippi County, MO, New Madrid County, MO, Pemiscot County, MO, Perry County, MO, Ripley County, MO, Scott County, MO, Stoddard County, MO, Wayne County, MO, Carroll County, TN, Crockett County, TN, Dyer County, TN, Fayette County, TN, Gibson County, TN, Hardeman County, TN, Haywood County, TN, Henry County, TN, Lake County, TN, Lauderdale County, TN, Madison County, TN, Obion County, TN, Shelby County, TN, Tipton County, TN, Weakley County, TN
The radar
The Paducah radar (KPAH), 34 km from the middle of the area, began a volume at 17:41 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
- 5%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 50%
- One or more hailstones of 2 inches or more
- 40%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
12 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 6, 12:53 PM CDT | Severe Thunderstorm Warning | PAH | Bollinger, Butler, Carter, Ripley, Stoddard, Wayne | 37 min |
| May 6, 1:03 PM CDT | Severe Thunderstorm Warning | LZK | Lawrence, Randolph | 57 min |
| May 6, 1:13 PM CDT | Severe Thunderstorm Warning | PAH | Alexander | 47 min |
| May 6, 1:24 PM CDT | Tornado Warning | PAH | Cape Girardeau, Scott | 31 min |
| May 6, 1:43 PM CDT | Severe Thunderstorm Warning | MEG | Greene | 47 min |
| May 6, 2:17 PM CDT | Severe Thunderstorm Warning | MEG | Craighead, Mississippi, Poinsett | 43 min |
| May 6, 3:03 PM CDT | Severe Thunderstorm Warning | MEG | Crittenden, Mississippi, Poinsett | 42 min |
| May 6, 3:22 PM CDT | Severe Thunderstorm Warning | PAH | Calloway | 38 min |
| May 6, 3:52 PM CDT | Severe Thunderstorm Warning | PAH | Jefferson, Wayne | 38 min |
| May 6, 4:54 PM CDT | Tornado Warning | PAH | Wayne | 36 min |
| May 6, 5:27 PM CDT | Severe Thunderstorm Warning | PAH | Johnson, Pope, Saline, Williamson | 38 min |
| May 6, 5:57 PM CDT | Severe Thunderstorm Warning | PAH | Johnson, Massac | 33 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
Nashville Metro, TN (KBNA), launched 12:00Z, 5.6 hours before the alert went out and 234 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1719 m above ground
- 0-6 km bulk shear
- 65 kt
- 0-1 km storm-relative helicity
- -90 m²/s²
- 0-3 km storm-relative helicity
- -71 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
774
WWUS20 KWNS 061735
SEL2
SPC WW 061735
ARZ000-ILZ000-INZ000-KYZ000-MOZ000-TNZ000-062300-
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 152
NWS Storm Prediction Center Norman OK
1235 PM CDT Thu May 6 2021
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Northeast Arkansas
Southern Illinois
Far southwest Indiana
Western Kentucky
Southeast Missouri
Western Tennessee
* Effective this Thursday afternoon and evening from 1235 PM
until 600 PM CDT.
* Primary threats include...
Scattered damaging winds and isolated significant gusts to 75
mph possible
Scattered large hail and isolated very large hail events to 2
inches in diameter possible
SUMMARY...Multiple lower-topped supercells should develop within a
cluster of thunderstorms spreading east-southeast across the
Mid-Mississippi into the Lower Ohio Valleys. Large hail and damaging
winds should be the primary hazards.
The severe thunderstorm watch area is approximately along and 60
statute miles east and west of a line from 40 miles east northeast
of Mount Vernon IL to 35 miles east southeast of Jonesboro AR. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU2).
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.
&&
AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 65 knots. A
few cumulonimbi with maximum tops to 400. Mean storm motion vector
29035.
...GramsSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 6, 10:05 AM CDT | Mesoscale Discussion | SPC | Clay, Crittenden, Mississippi | 85 min |
| May 6, 12:02 PM CDT | Mesoscale Discussion | SPC | Clay, Craighead, Greene, Lawrence, Mississippi, Randolph | 118 min |
| May 6, 2:45 PM CDT | Mesoscale Discussion | SPC | Clay, Craighead, Crittenden, Cross, Greene, Mississippi and 1 more | 90 min |
| May 6, 9:52 AM CDT | Mesoscale Discussion | SPC | Bond, Calhoun, Clinton, Greene, Jersey, Macoupin and 7 more | 83 min |
| May 6, 1:10 PM CDT | Mesoscale Discussion | SPC | Champaign, Christian, Coles, Cumberland, DeWitt, Douglas and 10 more | 2 hr |
| May 6, 5:11 PM CDT | Mesoscale Discussion | SPC | Bedford, Cannon, Cheatham, Coffee, Davidson, Franklin and 18 more | 94 min |
Nearby
Severe Thunderstorm Watches in Illinois, 2021Severe Thunderstorm Watches in Kentucky, 2021Severe Thunderstorm Watches in Tennessee, 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.