Alert archive / Illinois / Severe Thunderstorm Watches in 2022

Severe Thunderstorm Watch 430

July 4, 202213 counties in Illinois; Benton County, Jasper County, Newton County, Indiana

The Storm Prediction Center issued this severe thunderstorm watch at Jul 4, 2022, 3:51 PM CDT for 13 counties in Illinois; Benton County, Jasper County, Newton County, Indiana. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Jul 4, 2022, 3:51 PM CDT (20:51 UTC)
Expired
Jul 4, 2022, 7:00 PM CDT
In force
3 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
55 kt

Counties Boone County, IL, DeKalb County, IL, Ford County, IL, Grundy County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Ogle County, IL, Will County, IL, Benton County, IN, Jasper County, IN, Newton County, IN

The radar

The Chicago radar (KLOT), 29 km from the middle of the area, began a volume at 20:54 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
20%
One or more EF2 to EF5 tornadoes
10%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
10%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
50%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jul 4, 4:07 PM CDTSevere Thunderstorm WarningLOTDeKalb, Ogle52 min
Jul 4, 4:16 PM CDTSevere Thunderstorm WarningLOTFord, Iroquois74 min
Jul 4, 4:32 PM CDTSevere Thunderstorm WarningLOTFord, Livingston28 min
Jul 4, 4:34 PM CDTSevere Thunderstorm WarningLOTLivingston41 min
Jul 4, 4:49 PM CDTSevere Thunderstorm WarningLOTFord60 min
Jul 4, 5:44 PM CDTSevere Thunderstorm WarningLOTCook, DuPage, Kane, Kendall, Will46 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, 8.9 hours before the alert went out and 143 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 2022-07-04Temperature 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 2022-07-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 77 square meters per square second.193958Sfc1 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
1113 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
77 m²/s²
0-3 km storm-relative helicity
113 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

917 
WWUS20 KWNS 042047
SEL0  
SPC WW 042047
ILZ000-INZ000-050000-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 430
NWS Storm Prediction Center Norman OK
350 PM CDT Mon Jul 4 2022

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Northeast Illinois
  Northwest Indiana

* Effective this Monday afternoon and evening from 350 PM until
  700 PM CDT.

* Primary threats include...
  Isolated damaging wind gusts to 65 mph possible
  A tornado or two possible

SUMMARY...Two clusters should slowly progress east-southeast across
a portion of northeast Illinois into northwest Indiana with a threat
for damaging winds and a brief/weak tornado, before likely weakening
in a few hours.

The severe thunderstorm watch area is approximately along and 40
statute miles east and west of a line from 45 miles north northwest
of Marseilles IL to 75 miles southeast of Marseilles IL. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU0).

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
1 inch. Extreme turbulence and surface wind gusts to 55 knots. A few
cumulonimbi with maximum tops to 550. Mean storm motion vector
30020.

...Grams

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 4, 1:40 PM CDTMesoscale DiscussionSPCBureau, Ford, Grundy, Iroquois, Kankakee, Kendall and 8 more2 hr
Jul 4, 2:22 PM CDTMesoscale DiscussionSPCBoone, McHenry, Ogle, Stephenson, Winnebago113 min
Jul 4, 3:50 PM CDTMesoscale DiscussionSPCFord, Grundy, Iroquois, Kankakee, Livingston, Vermilion115 min
Jul 4, 5:40 PM CDTMesoscale DiscussionSPCChampaign, Douglas, Edgar, Ford, Iroquois, Vermilion95 min
Jul 4, 6:33 PM CDTMesoscale DiscussionSPCBoone, Jo Daviess, McHenry, Stephenson, Winnebago117 min

Nearby

Severe Thunderstorm Watches in Illinois, 2022Severe Thunderstorm Watches in Indiana, 2022Every severe thunderstorm watch in 2022

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.