Alert archive / Missouri / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 449, NWS St. Louis, MO

July 7, 2011Jefferson County, Sainte Genevieve County, Saint Francois County, Missouri

NWS St. Louis, MO issued this severe thunderstorm warning at Jul 7, 2011, 6:42 PM CDT for Jefferson County, Sainte Genevieve County, Saint Francois County, Missouri. It was in force for 48 min. 2 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: Jul 7, 2011, 6:42 PM CDT (23:42 UTC)
Expired: Jul 7, 2011, 7:30 PM CDT
In force: 48 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, Sainte Genevieve County, MO

The radar

The St Louis radar (KLSX), 78 km from the middle of the area, began a volume at 23:42 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
Jul 7, 6:48 PM CDT	TSTM WND DMG	2 Nw French Village, MO	SEVEN TO EIGHT INCH BLOCKING HIGHWAY D ABOUT ONE TO TWO MILES NORTH OF THE INTERSECTION OF D AND Y. IN ADDITION... SEVERAL TOPS OF TREE LIMBS SNAPPED OFF.
Jul 7, 6:52 PM CDT	TSTM WND DMG	1 W French Village, MO	SIX 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
Jul 7, 5:03 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 11.7 hours before the alert went out and 283 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: 894 J/kg
Mixed-layer CIN: -40 J/kg
Mixed-layer LCL: 836 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: -1 m²/s²
0-3 km storm-relative helicity: 32 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

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

387 
WUUS53 KLSX 072342
SVRLSX
MOC099-186-187-080030-
/O.NEW.KLSX.SV.W.0449.110707T2342Z-110708T0030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
642 PM CDT THU JUL 7 2011

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN JEFFERSON COUNTY IN EAST CENTRAL MISSOURI...
  NORTHWESTERN STE. GENEVIEVE COUNTY IN SOUTHEAST MISSOURI...
  NORTHERN ST. FRANCOIS COUNTY IN SOUTHEAST MISSOURI...

* UNTIL 730 PM CDT

* AT 638 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS
  OF 60 MPH.  THIS STORM WAS LOCATED 8 MILES NORTHEAST OF BONNE
  TERRE...AND MOVING EAST AT 10 MPH.

* LOCATIONS IMPACTED INCLUDE...
  ROCKY RIDGE AND FRENCH VILLAGE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 60 MILES PER
HOUR...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN. FOR
YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR
HOME OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE
INTO AREAS WHERE WATER COVERS THE ROAD.

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.

&&

LAT...LON 3792 9058 3810 9060 3816 9027 3815 9027
      3793 9020
TIME...MOT...LOC 2342Z 264DEG 10KT 3802 9047
WIND...HAIL 60MPH <.75IN

$$

TRUETT

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 6, 8:31 PM CDT	Areal Flood Advisory	LSX	Saint Louis, City of Saint Louis	3 hr
Jul 7, 5:24 PM CDT	Severe Thunderstorm Warning	LSX	Jefferson, Saint Francois, Washington	24 min
Jul 7, 5:46 PM CDT	Areal Flood Advisory	LSX	Franklin, Jefferson, Saint Charles, Saint Louis, City of Saint Louis	3 hr
Jul 7, 5:55 PM CDT	Severe Thunderstorm Warning	LSX	Franklin, Jefferson, Saint Louis, City of Saint Louis	50 min
Jul 7, 6:29 PM CDT	Flash Flood Warning	LSX	Jefferson, Sainte Genevieve, Saint Francois, Saint Louis, Washington	6 hr
Jul 7, 6:47 PM CDT	Tornado Warning	LSX	Jefferson, Sainte Genevieve, Saint Francois	28 min

Nearby

Severe Thunderstorm Warnings in Missouri, 2011 Every severe thunderstorm warning in 2011

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.