Alert archive / Illinois / Tornado Watches in 2020

Tornado Watch 374

July 15, 20205 counties in Illinois

The Storm Prediction Center issued this tornado watch at Jul 15, 2020, 3:14 PM CDT for 5 counties in Illinois. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Jul 15, 2020, 3:14 PM CDT (20:14 UTC)
Expired
Jul 15, 2020, 9:00 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt

Counties Ford County, IL, Grundy County, IL, Iroquois County, IL, Kankakee County, IL, Livingston County, IL

The radar

The Chicago radar (KLOT), 53 km from the middle of the area, began a volume at 20:13 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
30%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
20%
One or more gusts of 65 knots or more
5%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jul 15, 3:28 PM CDTSevere Thunderstorm WarningLOTLivingston62 min
Jul 15, 4:10 PM CDTTornado Warning Tornado observedLOTLivingston35 min
Jul 15, 4:27 PM CDTTornado Warning Tornado observedLOTLivingston63 min
Jul 15, 5:11 PM CDTTornado WarningLOTFord, Iroquois45 min
Jul 15, 7:19 PM CDTFlash Flood WarningLOTLivingston3 hr
Jul 15, 8:04 PM CDTSevere Thunderstorm WarningLOTFord29 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, 8.2 hours before the alert went out and 119 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

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, 5:35 PM CDTMesoscale DiscussionSPCBond, Champaign, Christian, Clark, Clay, Clinton and 35 more85 min
Jul 15, 6:12 PM CDTTornado WatchSPCChampaign, Clark, Clay, Coles, Crawford, Cumberland and 20 more5 hr

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.