Alert archive / Illinois / Severe Thunderstorm Watches in 2016

Severe Thunderstorm Watch 285

June 22, 201621 counties in Illinois

The Storm Prediction Center issued this severe thunderstorm watch at Jun 22, 2016, 4:25 AM CDT for 21 counties in Illinois. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Jun 22, 2016, 4:25 AM CDT (09:25 UTC)
Expired: Jun 22, 2016, 7:08 AM CDT
In force: 3 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 60 kt

All 21 counties

Cass County, IL, Champaign County, IL, Christian County, IL, Coles County, IL, Cumberland County, IL, DeWitt County, IL, Douglas County, IL, Logan County, IL, Macon County, IL, Mason County, IL, McLean County, IL, Menard County, IL, Morgan County, IL, Moultrie County, IL, Peoria County, IL, Piatt County, IL, Sangamon County, IL, Schuyler County, IL, Shelby County, IL, Tazewell County, IL, Woodford County, IL

The radar

The Lincoln radar (KILX), 6 km from the middle of the area, began a volume at 09:28 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: 2%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 20%
Ten or more severe hail reports: 20%
One or more hailstones of 2 inches or more: 10%
Six or more combined severe hail and wind reports: 60%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Jun 22, 5:01 AM CDT	Severe Thunderstorm Warning	ILX	Mason, Menard	44 min
Jun 22, 5:38 AM CDT	Severe Thunderstorm Warning	ILX	DeWitt, Logan, McLean, Macon, Mason, Menard and 1 more	37 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

Mesoscale Discussion 1017Jun 22, 4:00 AM CDT

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 9.4 hours before the alert went out and 67 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1708 m above ground
0-6 km bulk shear: 58 kt
0-1 km storm-relative helicity: 34 m²/s²
0-3 km storm-relative helicity: 148 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

876 
WWUS20 KWNS 220923
SEL5  
SPC WW 220923
ILZ000-221500-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 285
NWS STORM PREDICTION CENTER NORMAN OK
425 AM CDT WED JUN 22 2016

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
  CENTRAL ILLINOIS

* EFFECTIVE THIS WEDNESDAY MORNING FROM 425 AM UNTIL 1000 AM CDT.

* PRIMARY THREATS INCLUDE...
  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE
  ISOLATED LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE

SUMMARY...THUNDERSTORMS WILL MOVE SOUTHEAST ACROSS THE WATCH AREA
THIS MORNING WITH A RISK FOR DAMAGING WINDS AND ISOLATED LARGE HAIL.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 45
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 40 MILES WEST
SOUTHWEST OF PEORIA ILLINOIS TO 20 MILES EAST OF MATTOON
ILLINOIS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU5).

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.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 283...WW 284...

AVIATION...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 450. MEAN STORM
MOTION VECTOR 31030.


...BUNTING

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 21, 10:28 PM CDT	Mesoscale Discussion	SPC	Adams, Brown, Calhoun, Cass, Christian, Fulton and 18 more	2 hr
Jun 21, 11:18 PM CDT	Severe Thunderstorm Watch	SPC	Hancock, Henderson, McDonough, Mercer, Rock Island, Warren	6 hr
Jun 22, 2:31 AM CDT	Mesoscale Discussion	SPC	Mercer	119 min
Jun 22, 4:00 AM CDT	Mesoscale Discussion	SPC	Brown, Cass, Christian, DeWitt, Fulton, Hancock and 14 more	2 hr
Jun 22, 3:38 PM CDT	Mesoscale Discussion	SPC	Boone, Bureau, Carroll, Champaign, Cook, DeKalb and 32 more	97 min
Jun 22, 6:11 PM CDT	Tornado Watch	SPC	Boone, Bureau, Carroll, Champaign, Cook, DeKalb and 28 more	7 hr

Nearby

Severe Thunderstorm Watches in Illinois, 2016 Every severe thunderstorm watch in 2016

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.