Alert archive / Illinois / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 262, NWS St. Louis, MO

September 5, 2012Monroe County, Saint Clair County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Sep 5, 2012, 10:23 AM CDT for Monroe County, Saint Clair County, Illinois. It was in force for 32 min. 1 report 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 5, 2012, 10:23 AM CDT (15:23 UTC)
Expired: Sep 5, 2012, 10:55 AM CDT
In force: 32 min
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

Counties Monroe County, IL, Saint Clair County, IL

The radar

The St Louis radar (KLSX), 60 km from the middle of the area, began a volume at 15:26 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 5, 10:30 AM CDT	TSTM WND DMG	Columbia, IL	8-10 INCH DIAMETER TREE LIMBS DOWN.

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
Sep 5, 9:37 AM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 3.4 hours before the alert went out and 225 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: 1271 J/kg
Mixed-layer CIN: -188 J/kg
Mixed-layer LCL: 1037 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 107 m²/s²
0-3 km storm-relative helicity: 138 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.6

Open this sounding in Storm Lab

The text

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

685 
WUUS53 KLSX 051523
SVRLSX
ILC133-163-051615-
/O.NEW.KLSX.SV.W.0262.120905T1523Z-120905T1615Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
1023 AM CDT WED SEP 5 2012

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTH CENTRAL MONROE COUNTY IN SOUTHWEST ILLINOIS...
  ST. CLAIR COUNTY IN SOUTHWEST ILLINOIS...

* UNTIL 1115 AM CDT

* AT 1021 AM CDT...A SEVERE THUNDERSTORM WAS LOCATED NEAR
  MILLSTADT...AND MOVING EAST AT 40 MPH.

  HAZARD...QUARTER SIZE HAIL.

  SOURCE...RADAR INDICATED.

  IMPACT...MINOR DAMAGE TO VEHICLES...ROOFS AND WINDOWS.

* LOCATIONS IMPACTED INCLUDE...
  CENTREVILLE...MILLSTADT...FAIRVIEW HEIGHTS...BELLEVILLE...
  SWANSEA...O'FALLON...SHILOH...FREEBURG...SCOTT AFB...LEBANON...
  MASCOUTAH...SMITHTON...BARR...FLORAVILLE...FAYETTEVILLE AND
  SUMMERFIELD.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3834 8972 3839 9033 3845 9028 3848 9028
      3855 9024 3862 9018 3863 8971
TIME...MOT...LOC 1523Z 272DEG 34KT 3848 9013

HAIL...1.00IN
WIND...<50 MPH

$$

TILLY

1 follow-up statement

479 
WWUS53 KLSX 051555
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
1055 AM CDT WED SEP 5 2012

ILC133-163-051605-
/O.CAN.KLSX.SV.W.0262.000000T0000Z-120905T1615Z/
MONROE IL-ST. CLAIR IL-
1055 AM CDT WED SEP 5 2012

...THE SEVERE THUNDERSTORM WARNING FOR ST. CLAIR AND NORTH CENTRAL
MONROE COUNTIES IS CANCELLED...

THE STORM WHICH PROMPTED THE WARNING HAS MOVED OUT OF THE WARNED
AREA.  HOWEVER GUSTY WINDS ARE STILL POSSIBLE WITH THIS THUNDERSTORM.

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

LAT...LON 3834 8972 3839 9033 3845 9028 3848 9028
      3855 9024 3862 9018 3863 8971
TIME...MOT...LOC 1555Z 283DEG 25KT 3842 8992

$$

TILLY

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 5, 3:07 AM CDT	Heat Advisory	LSX	Madison, Monroe, Randolph, Saint Clair	12 hr
Sep 5, 6:36 AM CDT	Severe Thunderstorm Warning	LSX	Adams, Brown, Pike	30 min
Sep 5, 7:56 AM CDT	Severe Thunderstorm Warning	LSX	Greene, Macoupin, Montgomery	64 min
Sep 5, 8:38 AM CDT	Severe Thunderstorm Warning	LSX	Fayette, Montgomery	37 min
Sep 5, 9:08 AM CDT	Tornado Warning	LSX	Fayette, Montgomery	37 min
Sep 5, 9:40 AM CDT	Severe Thunderstorm Warning	LSX	Fayette	50 min
Sep 5, 10:00 AM CDT	Severe Thunderstorm Warning	LSX	Clinton, Fayette, Marion	48 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.