Alert archive / Illinois / Tornado Watches in 2020

Tornado Watch 376

July 15, 202026 counties in Illinois

The Storm Prediction Center issued this tornado watch at Jul 15, 2020, 6:12 PM CDT for 26 counties in Illinois. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Jul 15, 2020, 6:12 PM CDT (23:12 UTC)
Expired
Jul 15, 2020, 11:00 PM CDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt
All 26 counties

Champaign County, IL, Clark County, IL, Clay County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, Douglas County, IL, Edgar County, IL, Edwards County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Jackson County, IL, Jasper County, IL, Jefferson County, IL, Johnson County, IL, Lawrence County, IL, Perry County, IL, Richland County, IL, Saline County, IL, Union County, IL, Vermilion County, IL, Wabash County, IL, Wayne County, IL, White County, IL, Williamson County, IL

The radar

The Evansville,IN radar (KVWX), 95 km from the middle of the area, began a volume at 23:14 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
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
50%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jul 15, 6:17 PM CDTSevere Thunderstorm WarningILXColes, Cumberland, Douglas, Moultrie, Shelby43 min
Jul 15, 6:31 PM CDTSevere Thunderstorm WarningILXClay, Cumberland, Effingham, Shelby44 min
Jul 15, 7:04 PM CDTSevere Thunderstorm WarningILXClark, Clay, Crawford, Cumberland, Effingham, Jasper and 2 more56 min
Jul 15, 7:19 PM CDTSevere Thunderstorm WarningPAHJackson, Perry41 min
Jul 15, 7:40 PM CDTSevere Thunderstorm WarningPAHJackson50 min
Jul 15, 7:52 PM CDTFlash Flood WarningPAHPerry6 hr
Jul 15, 8:00 PM CDTTornado WarningPAHJackson30 min
Jul 15, 8:01 PM CDTSevere Thunderstorm WarningILXClay, Richland44 min
Jul 15, 8:52 PM CDTSevere Thunderstorm WarningPAHJackson, Union38 min
Jul 15, 9:26 PM CDTSevere Thunderstorm WarningILXClay, Richland49 min
Jul 15, 10:20 PM CDTFlash Flood WarningPAHWayne4 hr

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, 11.2 hours before the alert went out and 136 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 12:00Z on 2020-07-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 12:00Z on 2020-07-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 30 square meters per square second.1939Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1529 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
30 m²/s²
0-3 km storm-relative helicity
32 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

116 
WWUS20 KWNS 152308
SEL6  
SPC WW 152308
ILZ000-160400-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 376
NWS Storm Prediction Center Norman OK
610 PM CDT Wed Jul 15 2020

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Eastern and southern Illinois

* Effective this Wednesday evening from 610 PM until 1100 PM CDT.

* Primary threats include...
  A couple tornadoes possible
  Scattered damaging wind gusts to 70 mph possible
  Isolated large hail events to 1.5 inches in diameter possible

SUMMARY...Severe thunderstorms currently over portions of central
and southwestern Illinois may continue to pose a threat for damaging
wind, isolated hail and a couple of tornadoes, before weakening in
more-stable air near the Indiana line.

The tornado watch area is approximately along and 30 statute miles
east and west of a line from 30 miles south southeast of Mount
Vernon IL to 20 miles north northwest of Danville IL. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU6).

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 373...WW 374...WW 375...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1.5 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 26025.

...Edwards

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 15, 1:10 PM CDTMesoscale DiscussionSPCBond, Calhoun, Cass, Christian, Clinton, Fayette and 17 more2 hr
Jul 15, 2:10 PM CDTTornado WatchSPCBond, Brown, Calhoun, Cass, Christian, Clinton and 30 more7 hr
Jul 15, 2:13 PM CDTMesoscale DiscussionSPCBrown, Fulton, Livingston, McDonough, McLean, Marshall and 5 more62 min
Jul 15, 3:14 PM CDTTornado WatchSPCFord, Grundy, Iroquois, Kankakee, Livingston6 hr
Jul 15, 5:35 PM CDTMesoscale DiscussionSPCBond, Champaign, Christian, Clark, Clay, Clinton and 35 more85 min

Nearby

Tornado Watches in Illinois, 2020Every tornado watch in 2020

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.