Alert archive / Illinois / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 15, NWS St. Louis, MO

March 27, 20214 counties in Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Mar 27, 2021, 6:56 PM CDT for 4 counties in Illinois. It was in force for 49 min. 18 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Mar 27, 2021, 6:56 PM CDT (23:56 UTC)
Expired: Mar 27, 2021, 7:45 PM CDT
In force: 49 min
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Bond County, IL, Clinton County, IL, Madison County, IL, Saint Clair County, IL

The radar

The St Louis radar (KLSX), 95 km from the middle of the area, began a volume at 23:56 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 was reported inside it

Time	Report	Where	Remark
Mar 27, 7:00 PM CDT	TSTM WND DMG	2 S Troy, IL	SMALL PIECE OF SIDING RIPPED FROM HOME, FENCE BLOWN DOWN.
Mar 27, 7:00 PM CDT	TSTM WND DMG	3 Se Maryville, IL	LARGE TREES DOWN AND UTILITIES DAMAGED.
Mar 27, 7:00 PM CDT	HAIL 1	Maryville, IL
Mar 27, 7:01 PM CDT	TSTM WND DMG	2 Sse Troy, IL	* 1 INJ * A DELIVERY TRUCK WAS BLOWN INTO ANOTHER CAR ON THE OTHER SIDE OF THE ROAD CAUSING A COLLISION. THE DELIVERY TRUCK DRIVER WAS TAKEN TO THE HOSPITAL FOR MINOR INJURIES. DELAYED REPORT.
Mar 27, 7:03 PM CDT	TSTM WND DMG	Troy, IL	FENCE AND DECK DAMAGE TO A HOME.
Mar 27, 7:05 PM CDT	TSTM WND DMG	2 Ese Troy, IL	DRYWALL RIPPED FROM A HOME, ROOF RIPPED ALL OFF A POLE BARN.
Mar 27, 7:05 PM CDT	HAIL 0.7	2 Ese Edwardsville, IL
Mar 27, 7:08 PM CDT	TSTM WND DMG	3 W Saint Jacob, IL	FENCE DAMAGE WITH OUTBUILDING DESTROYED.
Mar 27, 7:08 PM CDT	HAIL 0.25	Edwardsville, IL
Mar 27, 7:08 PM CDT	TORNADO	1 N Saint Jacob, IL	NWS OFFICIAL STORM SURVEY FOUND AN EF-1 TORNADO OCCURRED ALONG AN INTERMITTENT PATH OF NEARLY 5 MILES FROM NORTH OF ST. JACOB EAST INTO HIGHLAND. THE MOST SIGNIFICANT DAMAGE OCCURRED JUST WEST OF HIGHLAND, WHERE A LARGE, WELL-BUILT SHED WAS DESTROYED WITH DEBR
Mar 27, 7:15 PM CDT	TSTM WND DMG	Highland, IL	HEAVY DAMAGE TO SEVERAL BUILDINGS, MULTIPLE TREES UPROOTED.
Mar 27, 7:15 PM CDT	HAIL 0.75	Edwardsville, IL
Mar 27, 7:17 PM CDT	TSTM WND DMG	1 W Highland, IL	REPORT FROM MPING: TREES UPROOTED OR SNAPPED; ROOF BLOWN OFF.
Mar 27, 7:17 PM CDT	TSTM WND GST 62	1 Ene Highland, IL
Mar 27, 7:18 PM CDT	TSTM WND DMG	Saint Jacob, IL	FLAG POLE SNAPPED IN HALF.
Mar 27, 7:20 PM CDT	HAIL 0.75	1 S Marine, IL
Mar 27, 7:37 PM CDT	TSTM WND DMG	4 W Beaver Creek, IL	TREES AND POWER LINES DOWN ALONG MILLERSBURG ROAD.
Mar 27, 7:54 PM CDT	TSTM WND DMG	2 Ssw Marine, IL	DOWNED TREE BRANCHES AND OTHER DEBRIS, REPORTED VIA TWITTER.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Mar 27, 4:44 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 11.9 hours before the alert went out and 176 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: 1078 m above ground
0-6 km bulk shear: 78 kt
0-1 km storm-relative helicity: 369 m²/s²
0-3 km storm-relative helicity: 384 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

325 
WUUS53 KLSX 272356
SVRLSX
ILC005-027-119-163-280045-
/O.NEW.KLSX.SV.W.0015.210327T2356Z-210328T0045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
656 PM CDT Sat Mar 27 2021

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Northern Clinton County in south central Illinois...
  Bond County in south central Illinois...
  Madison County in southwestern Illinois...
  Northeastern St. Clair County in southwestern Illinois...

* Until 745 PM CDT.

* At 655 PM CDT, a severe thunderstorm was located over Maryville,
  moving east at 45 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Belleville, Granite City, O'Fallon, East St. Louis, Collinsville,
  Edwardsville, Fairview Heights, Swansea, Glen Carbon, Shiloh, Wood
  River, Highland, Troy, Bethalto, Maryville, Greenville, Pontoon
  Beach, Centreville, Breese and Lebanon.

This includes the following highways...
 Interstate 70 in Illinois between exits 21 and 45.
 Interstate 55 in Illinois between exits 23 and 30.
 Interstate 64 in Illinois between exits 9 and 19.

This also includes Carlyle Lake Recreational Area and Horseshoe Lake
State Park.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3864 8920 3855 9007 3879 9013 3884 9011
      3886 9014 3903 8933 3881 8925 3874 8925
      3874 8923
TIME...MOT...LOC 2355Z 256DEG 39KT 3872 8999 

HAIL...1.00IN
WIND...60MPH
 
$$

BRC

1 follow-up statement

610 
WWUS53 KLSX 280017
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
717 PM CDT Sat Mar 27 2021

ILC005-027-119-163-280045-
/O.CON.KLSX.SV.W.0015.000000T0000Z-210328T0045Z/
Clinton IL-Bond IL-Madison IL-St. Clair IL-
717 PM CDT Sat Mar 27 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 745 PM CDT
FOR NORTHERN CLINTON AND BOND COUNTIES IN SOUTH CENTRAL ILLINOIS...
EASTERN MADISON AND NORTHEASTERN ST. CLAIR COUNTIES IN SOUTHWESTERN
ILLINOIS...

At 717 PM CDT, a severe thunderstorm was located over Highland,
moving east at 45 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

Locations impacted include...
O'Fallon, Edwardsville, Glen Carbon, Shiloh, Highland, Troy,
Maryville, Greenville, Breese, Lebanon, Carlyle, Trenton, Aviston,
St. Rose, St. Jacob, Marine, Pocahontas, Alhambra, Tamalco and Beaver
Creek.

This also includes Carlyle Lake Recreational Area.
 
This includes the following highways...
 Interstate 70 in Illinois between exits 21 and 45.
 Interstate 55 in Illinois between exits 23 and 30.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3864 8920 3857 8992 3879 8998 3890 8993
      3903 8933 3881 8925 3874 8925 3874 8923
TIME...MOT...LOC 0017Z 256DEG 39KT 3878 8968 

TORNADO...POSSIBLE
HAIL...1.00IN
WIND...60MPH
 
$$

BRC

The office that day

Everything else NWS St. Louis, MO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 27, 4:23 PM CDT	Severe Thunderstorm Warning	LSX	Calhoun, Greene, Pike	52 min
Mar 27, 4:47 PM CDT	Severe Thunderstorm Warning	LSX	Greene, Macoupin	43 min
Mar 27, 4:52 PM CDT	Severe Thunderstorm Warning	LSX	Jersey, Madison	38 min
Mar 27, 5:18 PM CDT	Severe Thunderstorm Warning	LSX	Macoupin, Montgomery	42 min
Mar 27, 5:26 PM CDT	Severe Thunderstorm Warning	LSX	Madison	38 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2021 Every severe thunderstorm warning in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.