Alert archive / Illinois / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 308, NWS St. Louis, MO

September 25, 2012Clinton County, Saint Clair County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Sep 25, 2012, 4:39 PM CDT for Clinton County, Saint Clair County, Illinois. It was in force for 51 min. 8 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: Sep 25, 2012, 4:39 PM CDT (21:39 UTC)
Expired: Sep 25, 2012, 5:30 PM CDT
In force: 51 min
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Hail: 1.25 in
Wind: 60.0 mph

Counties Clinton County, IL, Saint Clair County, IL

The radar

The St Louis radar (KLSX), 87 km from the middle of the area, began a volume at 21:40 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
Sep 25, 4:48 PM CDT	HAIL 0.75	New Baden, IL	ONE HALF TO THREE QUARTER INCH HAIL
Sep 25, 4:50 PM CDT	HAIL 1	New Baden, IL	A FEW STONES AT 1.00 INCH DIAMETER
Sep 25, 4:50 PM CDT	HAIL 3	New Baden, IL	TIME ESTIMATED FROM RADAR.
Sep 25, 4:55 PM CDT	HAIL 3	Trenton, IL	TIME ESTIMATED FROM RADAR.
Sep 25, 4:56 PM CDT	HAIL 1.5	Trenton, IL	JUST BELOW GOLF BALL SIZE HAIL.
Sep 25, 5:07 PM CDT	HAIL 1.5	Aviston, IL	PING PONG BALL SIZE HAIL COVERING THE GROUND AT AVISTON.
Sep 25, 5:07 PM CDT	HAIL 2.75	Aviston, IL	PING PONG BALL SIZE HAIL COVERING THE GROUND AT AVISTON.
Sep 25, 5:11 PM CDT	HAIL 2.5	Aviston, IL	DAMAGING SHINGLES

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

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 9.7 hours before the alert went out and 197 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: 221 J/kg
Mixed-layer CIN: -192 J/kg
Mixed-layer LCL: 560 m above ground
0-6 km bulk shear: 53 kt
0-1 km storm-relative helicity: 108 m²/s²
0-3 km storm-relative helicity: 134 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.7

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

685 
WUUS53 KLSX 252139
SVRLSX
ILC027-163-252230-
/O.NEW.KLSX.SV.W.0308.120925T2139Z-120925T2230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
439 PM CDT TUE SEP 25 2012

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  WEST CENTRAL CLINTON COUNTY IN SOUTH CENTRAL ILLINOIS...
  EAST CENTRAL ST. CLAIR COUNTY IN SOUTHWEST ILLINOIS...

* UNTIL 530 PM CDT

* AT 435 PM CDT...A SEVERE THUNDERSTORM WAS LOCATED NEAR MASCOUTAH...
  AND MOVING NORTHEAST AT 30 MPH.

  HAZARD...HALF DOLLAR SIZE HAIL AND 60 MPH WIND GUSTS.

  SOURCE...RADAR INDICATED.

  IMPACT...MINOR DAMAGE TO VEHICLES...ROOFS AND WINDOWS. MINOR TREE
           DAMAGE...WITH LIMBS UP TO ONE INCH IN DIAMETER BROKEN.

* LOCATIONS IMPACTED INCLUDE...
  NEW BADEN...BREESE...TRENTON...AVISTON AND SUMMERFIELD.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
BUILDING.

TO REPORT SEVERE WEATHER CONTACT YOUR NEAREST LAW ENFORCEMENT AGENCY.
THEY WILL SEND YOUR REPORT TO THE NATIONAL WEATHER SERVICE IN ST
LOUIS.

&&

LAT...LON 3863 8973 3863 8941 3850 8975 3856 8981
TIME...MOT...LOC 2140Z 233DEG 25KT 3856 8974

HAIL...1.25IN
WIND...60 MPH

$$

TES

1 follow-up statement

218 
WWUS53 KLSX 252156
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
456 PM CDT TUE SEP 25 2012

ILC163-252205-
/O.CAN.KLSX.SV.W.0308.000000T0000Z-120925T2230Z/
ST. CLAIR IL-
456 PM CDT TUE SEP 25 2012

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN ST. CLAIR COUNTY
IS CANCELLED...

THE STORM WHICH PROMPTED THE WARNING HAS MOVED OUT OF THE WARNED 
AREA.

LAT...LON 3863 8941 3853 8970 3863 8971
TIME...MOT...LOC 2155Z 239DEG 16KT 3859 8968

$$

ILC027-252230-
/O.CON.KLSX.SV.W.0308.000000T0000Z-120925T2230Z/
CLINTON IL-
456 PM CDT TUE SEP 25 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR WEST CENTRAL
CLINTON COUNTY UNTIL 530 PM CDT...

AT 454 PM CDT...A SEVERE THUNDERSTORM WAS LOCATED NEAR TRENTON...AND
MOVING NORTHEAST AT 20 MPH.

HAZARD...PING PONG BALL SIZE HAIL AND 60 MPH WIND GUSTS.

SOURCE...TRAINED WEATHER SPOTTERS REPORTED QUARTER SIZED HAIL AT 450 
         PM AT NEW BADEN.

IMPACT...DAMAGE TO VEHICLES...ROOFS AND WINDOWS. MINOR TREE DAMAGE...
         WITH LIMBS UP TO ONE INCH IN DIAMETER BROKEN.

LOCATIONS IMPACTED INCLUDE...
BREESE...TRENTON AND AVISTON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
BUILDING.

TO REPORT SEVERE WEATHER CONTACT YOUR NEAREST LAW ENFORCEMENT AGENCY.
THEY WILL SEND YOUR REPORT TO THE NATIONAL WEATHER SERVICE IN ST
LOUIS.

&&

LAT...LON 3863 8941 3853 8970 3863 8971
TIME...MOT...LOC 2155Z 239DEG 16KT 3859 8968

HAIL...1.50IN
WIND...60 MPH

$$

TES

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 25, 3:38 AM CDT	Severe Thunderstorm Warning	LSX	Bond, Clinton, Fayette, Marion	22 min
Sep 25, 4:36 AM CDT	Areal Flood Advisory	LSX	Pike	5 hr
Sep 25, 4:29 PM CDT	Severe Thunderstorm Warning	LSX	Clinton, Madison, Saint Clair	46 min
Sep 25, 5:05 PM CDT	Severe Thunderstorm Warning	LSX	Clinton	55 min
Sep 25, 5:07 PM CDT	Tornado Warning	LSX	Clinton	23 min
Sep 25, 5:09 PM CDT	Severe Thunderstorm Warning	LSX	Calhoun, Jersey, Madison	51 min
Sep 25, 5:12 PM CDT	Severe Thunderstorm Warning	LSX	Clinton, Saint Clair	18 min
Sep 25, 5:19 PM CDT	Tornado Warning	LSX	Washington	26 min
Sep 25, 5:28 PM CDT	Severe Thunderstorm Warning	LSX	Marion	47 min
Sep 25, 5:34 PM CDT	Tornado Warning Tornado observed	LSX	Washington	41 min
Sep 25, 5:43 PM CDT	Severe Thunderstorm Warning	LSX	Clinton, Washington	62 min
Sep 25, 6:08 PM CDT	Severe Thunderstorm Warning	LSX	Madison, Monroe, Saint Clair	52 min
Sep 25, 6:14 PM CDT	Severe Thunderstorm Warning	LSX	Washington	46 min
Sep 25, 6:19 PM CDT	Areal Flood Advisory	LSX	Clinton, Marion, Washington	6 hr
Sep 25, 6:30 PM CDT	Severe Thunderstorm Warning	LSX	Marion	26 min
Sep 25, 6:45 PM CDT	Severe Thunderstorm Warning	LSX	Clinton, Madison, Marion, Washington	45 min
Sep 25, 6:50 PM CDT	Severe Thunderstorm Warning	LSX	Monroe, Saint Clair	46 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2012 Every severe thunderstorm warning in 2012

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.