Alert archive / Missouri / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 18, NWS St. Louis, MO

February 29, 2012Jefferson County, Saint Francois County, Washington County, Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Feb 29, 2012, 1:52 AM CST for Jefferson County, Saint Francois County, Washington County, Missouri. It was in force for 53 min. 3 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: Feb 29, 2012, 1:52 AM CST (07:52 UTC)
Expired: Feb 29, 2012, 2:45 AM CST
In force: 53 min
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Jefferson County, MO, Saint Francois County, MO, Washington County, MO

The radar

The St Louis radar (KLSX), 87 km from the middle of the area, began a volume at 07:55 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
Feb 29, 2:15 AM CST	TSTM WND GST 40	Potosi, MO
Feb 29, 2:15 AM CST	HAIL 0.25	Potosi, MO
Feb 29, 2:22 AM CST	TSTM WND GST 50	De Soto, MO	SMALL 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
Feb 29, 1:14 AM CST	Tornado Watch	SPC	11 hr

The nearest sounding before it

Springfield, MO (KSGF), launched 00:00Z, 7.9 hours before the alert went out and 302 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: 75 J/kg
Mixed-layer CIN: -196 J/kg
Mixed-layer LCL: 595 m above ground
0-6 km bulk shear: 76 kt
0-1 km storm-relative helicity: 482 m²/s²
0-3 km storm-relative helicity: 563 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.4

Open this sounding in Storm Lab

The text

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

308 
WUUS53 KLSX 290752
SVRLSX
MOC099-187-221-290845-
/O.NEW.KLSX.SV.W.0018.120229T0752Z-120229T0845Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
152 AM CST WED FEB 29 2012

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN JEFFERSON COUNTY IN EAST CENTRAL MISSOURI...
  ST. FRANCOIS COUNTY IN SOUTHEAST MISSOURI...
  WASHINGTON COUNTY IN EAST CENTRAL MISSOURI...

* UNTIL 245 AM CST

* AT 150 AM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN
  EXCESS OF 60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE EXTENDING
  FROM 6 MILES SOUTH OF ANTHONIES MILL TO VIBURNUM...AND MOVING EAST
  AT 50 MPH. PENNY SIZE HAIL MAY ALSO ACCOMPANY THESE DAMAGING WINDS.

* LOCATIONS IMPACTED INCLUDE...
  POTOSI...DE SOTO...BISMARCK...LEADWOOD...BONNE TERRE...DESLOGE...
  COURTOIS...OLD MINES...MINERAL POINT...IRONDALE...OLYMPIAN
  VILLAGE...PARK HILLS...LATTY...SHIRLEY...BELGRADE...CADET...
  CALEDONIA...BLACKWELL...FRANKCLAY AND VALLES MILL.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WATCH REMAINS IN EFFECT FOR THE WARNED AREA. TORNADOES CAN
DEVELOP QUICKLY FROM SEVERE THUNDERSTORMS. ALTHOUGH NOT IMMEDIATELY
LIKELY...IF A TORNADO IS SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF
SAFETY INSIDE A STURDY STRUCTURE...SUCH AS A BASEMENT OR SMALL
INTERIOR ROOM.

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 3774 9110 3808 9109 3819 9044 3803 9042
      3798 9033 3789 9044 3788 9046 3787 9045
      3776 9050
TIME...MOT...LOC 0752Z 261DEG 44KT 3800 9104 3774 9118
WIND...HAIL 60MPH 0.75IN

$$

TILLY

1 follow-up statement

990 
WWUS53 KLSX 290839
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
239 AM CST WED FEB 29 2012

MOC099-187-221-290849-
/O.EXP.KLSX.SV.W.0018.000000T0000Z-120229T0845Z/
JEFFERSON MO-ST. FRANCOIS MO-WASHINGTON MO-
239 AM CST WED FEB 29 2012

...THE SEVERE THUNDERSTORM WARNING FOR WASHINGTON...ST. FRANCOIS AND
SOUTHERN JEFFERSON COUNTIES WILL EXPIRE AT 245 AM CST...

THE LINE OF STORMS WHICH PROMPTED THE WARNING HAVE MOVED OUT OF THE
WARNED AREA.

ADDITIONAL STRONG THUNDERSTORMS ARE STILL POSSIBLE...AND A TORNADO 
WATCH REMAINS IN EFFECT UNTIL 900 AM CST. 

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 3774 9110 3808 9109 3819 9044 3803 9042
      3798 9033 3789 9044 3788 9046 3787 9045
      3776 9050
TIME...MOT...LOC 0839Z 254DEG 52KT 3814 9017 3788 9031

$$

TILLY

The office that day

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

Issued	Product	Office	Counties	Lasted
Feb 29, 1:21 AM CST	Tornado Warning	LSX	Crawford	39 min
Feb 29, 2:13 AM CST	Tornado Warning	LSX	Jefferson, Saint Francois, Washington	20 min
Feb 29, 2:22 AM CST	Severe Thunderstorm Warning	LSX	Iron, Reynolds	38 min
Feb 29, 2:31 AM CST	Severe Thunderstorm Warning	LSX	Jefferson, Sainte Genevieve	31 min
Feb 29, 2:50 AM CST	Severe Thunderstorm Warning	LSX	Madison	40 min
Feb 29, 3:05 AM CST	Tornado Warning	LSX	Madison	25 min

Nearby

Severe Thunderstorm Warnings in Missouri, 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.