Alert archive / Illinois / Severe Thunderstorm Watches in 2018
Severe Thunderstorm Watch 253
The Storm Prediction Center issued this severe thunderstorm watch at Jul 1, 2018, 12:58 PM CDT for 55 counties in Illinois; 5 counties in Indiana. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 1, 2018, 12:58 PM CDT (17:58 UTC)
- Expired
- Jul 1, 2018, 8:00 PM CDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 60 counties
Bond County, IL, Boone County, IL, Bureau County, IL, Cass County, IL, Champaign County, IL, Christian County, IL, Clark County, IL, Coles County, IL, Cook County, IL, Cumberland County, IL, DeKalb County, IL, DeWitt County, IL, Douglas County, IL, DuPage County, IL, Edgar County, IL, Effingham County, IL, Fayette County, IL, Ford County, IL, Fulton County, IL, Greene County, IL, Grundy County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Macoupin County, IL, Marshall County, IL, Mason County, IL, McHenry County, IL, McLean County, IL, Menard County, IL, Montgomery County, IL, Morgan County, IL, Moultrie County, IL, Ogle County, IL, Peoria County, IL, Piatt County, IL, Putnam County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Shelby County, IL, Stark County, IL, Tazewell County, IL, Vermilion County, IL, Will County, IL, Winnebago County, IL, Woodford County, IL, Benton County, IN, Jasper County, IN, Lake County, IN, Newton County, IN, Porter County, IN
The radar
The Chicago radar (KLOT), 57 km from the middle of the area, began a volume at 18:00 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
- 5%
- 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
- 30%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
4 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 1, 6:03 PM CDT | Severe Thunderstorm Warning | LSX | Bond, Macoupin, Madison, Montgomery | 42 min |
| Jul 1, 6:04 PM CDT | Flash Flood Warning | ILX | DeWitt, Logan | 3 hr |
| Jul 1, 7:18 PM CDT | Severe Thunderstorm Warning | ILX | Shelby | 57 min |
| Jul 1, 7:37 PM CDT | Flash Flood Warning | LSX | Bond, Fayette, Macoupin, Madison, Montgomery | 6 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, 6.0 hours before the alert went out and 112 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
- 1834 J/kg
- Mixed-layer CIN
- -58 J/kg
- Mixed-layer LCL
- 867 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 123 m²/s²
- 0-3 km storm-relative helicity
- 109 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.5
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 1, 11:37 AM CDT | Mesoscale Discussion | SPC | Boone, Jo Daviess, McHenry, Stephenson, Winnebago | 83 min |
| Jul 1, 12:23 PM CDT | Mesoscale Discussion | SPC | Adams, Bond, Boone, Brown, Bureau, Carroll and 56 more | 97 min |
| Jul 1, 3:37 PM CDT | Mesoscale Discussion | SPC | Bond, Boone, Cass, Champaign, Christian, Clark and 46 more | 83 min |
| Jul 1, 6:51 PM CDT | Mesoscale Discussion | SPC | Bond, Champaign, Christian, Clark, Clay, Clinton and 22 more | 114 min |
Nearby
Severe Thunderstorm Watches in Illinois, 2018Severe Thunderstorm Watches in Indiana, 2018Every severe thunderstorm watch in 2018
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.