Alert archive / Illinois / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 141, NWS St. Louis, MO

April 29, 2012Montgomery County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Apr 29, 2012, 7:58 AM CDT for Montgomery County, Illinois. It was in force for 20 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Apr 29, 2012, 7:58 AM CDT (12:58 UTC)
Expired: Apr 29, 2012, 8:18 AM CDT
In force: 20 min
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

County Montgomery County, IL

The radar

The Lincoln radar (KILX), 98 km from the middle of the area, began a volume at 13:01 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.

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 1.0 hours before the alert went out and 111 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: 1 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 414 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 139 m²/s²
0-3 km storm-relative helicity: 135 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

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

210 
WUUS53 KLSX 291258
SVRLSX
ILC135-291330-
/O.NEW.KLSX.SV.W.0141.120429T1258Z-120429T1330Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
758 AM CDT SUN APR 29 2012

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EAST CENTRAL MONTGOMERY COUNTY IN SOUTH CENTRAL ILLINOIS...

* UNTIL 830 AM CDT

* AT 754 AM CDT...A SEVERE THUNDERSTORM WAS LOCATED NEAR NOKOMIS...
  AND MOVING EAST AT 35 MPH.

  HAZARD...QUARTER SIZE HAIL.

  SOURCE...RADAR INDICATED.

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

* LOCATIONS IMPACTED INCLUDE...
  OHLMAN.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3922 8914 3922 8933 3934 8933 3935 8914
TIME...MOT...LOC 1258Z 249DEG 28KT 3926 8920

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

$$

TILLY

1 follow-up statement

162 
WWUS53 KLSX 291318
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
818 AM CDT SUN APR 29 2012

ILC135-291327-
/O.CAN.KLSX.SV.W.0141.000000T0000Z-120429T1330Z/
MONTGOMERY IL-
818 AM CDT SUN APR 29 2012

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL MONTGOMERY COUNTY
IS CANCELLED...

THE STORM WHICH PROMPTED THE WARNING HAS MOVED OUT OF THE WARNED 
AREA.  HOWEVER ADDITIONAL THUNDERSTORMS CAPABLE OF PRODUCING HEAVY 
RAIN WILL STILL BE POSSIBLE THIS MORNING. A FLASH FLOOD WARNING 
REMAINS IN EFFECT FOR THE AREA UNTIL 200 PM CDT. 

LAT...LON 3922 8914 3922 8933 3934 8933 3935 8914
TIME...MOT...LOC 1317Z 256DEG 26KT 3929 8903

$$

TILLY

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 28, 7:41 PM CDT	Areal Flood Advisory	LSX	Clinton, Saint Clair, Washington	6 hr
Apr 28, 8:12 PM CDT	Severe Thunderstorm Warning	LSX	Monroe	48 min
Apr 28, 8:39 PM CDT	Severe Thunderstorm Warning	LSX	Monroe	36 min
Apr 28, 9:05 PM CDT	Severe Thunderstorm Warning	LSX	Monroe, Randolph, Saint Clair	33 min
Apr 28, 9:31 PM CDT	Severe Thunderstorm Warning	LSX	Randolph, Saint Clair, Washington	33 min
Apr 28, 10:01 PM CDT	Severe Thunderstorm Warning	LSX	Bond, Macoupin, Madison, Montgomery	34 min
Apr 28, 10:25 PM CDT	Severe Thunderstorm Warning	LSX	Macoupin, Montgomery	28 min
Apr 29, 1:44 AM CDT	Severe Thunderstorm Warning	LSX	Madison	46 min
Apr 29, 4:59 AM CDT	Severe Thunderstorm Warning	LSX	Calhoun	46 min
Apr 29, 5:32 AM CDT	Severe Thunderstorm Warning	LSX	Greene, Jersey	36 min
Apr 29, 7:54 AM CDT	Flash Flood Warning	LSX	Macoupin, Montgomery	6 hr
Apr 29, 4:00 PM CDT	Flash Flood Watch	LSX	Bond, Calhoun, Clinton, Fayette, Greene, Jersey and 8 more	15 hr

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.