Alert archive / Illinois / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 285, NWS St. Louis, MO

September 7, 2012Macoupin County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Sep 7, 2012, 4:32 PM CDT for Macoupin County, Illinois. It was in force for 43 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 7, 2012, 4:32 PM CDT (21:32 UTC)
Expired
Sep 7, 2012, 5:15 PM CDT
In force
43 min
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Macoupin County, IL

The radar

The St Louis radar (KLSX), 84 km from the middle of the area, began a volume at 21:33 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

TimeReportWhereRemark
Sep 7, 4:47 PM CDTHAIL 0.253 Ene Medora, ILJUST PEA SIZE HAIL AND STRONG WINDS...NO DAMAGE.

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.

IssuedProductOfficeLasted
Sep 7, 2:35 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 9.5 hours before the alert went out and 159 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-pSkew-T log-p diagram, Lincoln, IL at 12:00Z on 2012-09-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 367 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 12:00Z on 2012-09-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 93 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
367 J/kg
Mixed-layer CIN
-412 J/kg
Mixed-layer LCL
1436 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
93 m²/s²
0-3 km storm-relative helicity
102 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

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

097 
WUUS53 KLSX 072132
SVRLSX
ILC117-072215-
/O.NEW.KLSX.SV.W.0285.120907T2132Z-120907T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
432 PM CDT FRI SEP 7 2012

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN MACOUPIN COUNTY IN SOUTHWEST ILLINOIS...

* UNTIL 515 PM CDT

* AT 428 PM CDT...A SEVERE THUNDERSTORM WAS LOCATED NEAR KEMPER...AND
  MOVING EAST AT 40 MPH.

  HAZARD...QUARTER 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...
  GILLESPIE...STAUNTON...SHIPMAN...WILSONVILLE...BENLD...MOUNT
  OLIVE...MEDORA...PIASA...CHESTERFIELD...PLAINVIEW...ROYAL LAKES...
  PRUETT...DORCHESTER...HORNSBY AND WHITE CITY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3900 8974 3909 9015 3928 9015 3922 8970
      3900 8970
TIME...MOT...LOC 2132Z 282DEG 34KT 3919 9016

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

$$

TRUETT
1 follow-up statement
899 
WWUS53 KLSX 072217
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
517 PM CDT FRI SEP 7 2012

ILC117-072226-
/O.EXP.KLSX.SV.W.0285.000000T0000Z-120907T2215Z/
MACOUPIN IL-
517 PM CDT FRI SEP 7 2012

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN MACOUPIN COUNTY HAS
EXPIRED...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED BELOW SEVERE
LIMITS...AND NO LONGER POSES AN IMMEDIATE THREAT TO LIFE OR PROPERTY.
HOWEVER HEAVY RAIN WILL CONTINUE BETWEEN CARLINVILLE AND STAUNTON 
THROUGH 530 PM.  

IN ADDITION...STRONG THUNDERSTORMS MAY REDEVELOP...AND A SEVERE 
THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 10 PM CDT.  

LAT...LON 3900 8974 3909 9015 3928 9015 3922 8970
      3900 8970
TIME...MOT...LOC 2132Z 306DEG 13KT 3919 8996

$$

TRUETT

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 7, 3:36 PM CDTSevere Thunderstorm WarningLSXCalhoun54 min
Sep 7, 4:00 PM CDTSevere Thunderstorm WarningLSXGreene, Jersey45 min
Sep 7, 4:11 PM CDTSevere Thunderstorm WarningLSXMonroe24 min
Sep 7, 4:58 PM CDTSevere Thunderstorm WarningLSXSaint Clair, Washington47 min
Sep 7, 5:36 PM CDTSevere Thunderstorm WarningLSXBond, Madison, Montgomery54 min
Sep 7, 6:50 PM CDTSevere Thunderstorm WarningLSXClinton, Saint Clair, Washington40 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2012Every 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.