Alert archive / Missouri / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 3, NWS St. Louis, MO

April 2, 2018Jefferson County, Saint Louis County, Missouri; Monroe County, Saint Clair County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Apr 2, 2018, 11:13 PM CDT for Jefferson County, Saint Louis County, Missouri; Monroe County, Saint Clair County, Illinois. It was in force for 32 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: Apr 2, 2018, 11:13 PM CDT (04:13 UTC)
Expired: Apr 2, 2018, 11:45 PM 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, Jefferson County, MO, Saint Louis County, MO

The radar

The St Louis radar (KLSX), 62 km from the middle of the area, began a volume at 04:15 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
Apr 2, 11:14 PM CDT	HAIL 0.25	Barnhart, MO
Apr 2, 11:36 PM CDT	HAIL 0.5	3 Sse Centreville, IL
Apr 2, 11:40 PM CDT	HAIL 0.88	3 Sw Fairview Heights, IL

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 4.2 hours before the alert went out and 232 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: 549 m above ground
0-6 km bulk shear: 65 kt
0-1 km storm-relative helicity: 233 m²/s²
0-3 km storm-relative helicity: 495 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

121 
WUUS53 KLSX 030413
SVRLSX
ILC133-163-MOC099-189-030445-
/O.NEW.KLSX.SV.W.0003.180403T0413Z-180403T0445Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
1113 PM CDT MON APR 2 2018

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Northwestern Monroe County in southwestern Illinois...
  Central St. Clair County in southwestern Illinois...
  Northeastern Jefferson County in east central Missouri...
  South central St. Louis County in east central Missouri...

* Until 1145 PM CDT.

* At 1113 PM CDT, a severe thunderstorm was located over Imperial,
  moving northeast at 55 mph.

  HAZARD...Quarter size hail. 

  SOURCE...Radar indicated. 

  IMPACT...Damage to vehicles is expected. 

* Locations impacted include...
  Belleville, O'Fallon, East St. Louis, Arnold, Fairview Heights,
  Cahokia, Swansea, Shiloh, Waterloo, Columbia, Pevely, Centreville,
  Freeburg, Caseyville, Dupo, Millstadt, Herculaneum, Barnhart,
  Oakville and Cahokia Parks Airport.

This includes the following highways...
 Interstate 64 in Illinois between exits 9 and 14.
 Interstate 55 in Missouri between exits 178 and 191.

This also includes  Mastodon Historic Site and Gov. Dunklin's Grave
Historic Site.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3836 8974 3825 9041 3840 9048 3865 8999
TIME...MOT...LOC 0413Z 246DEG 46KT 3835 9036 

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

TES

1 follow-up statement

104 
WWUS53 KLSX 030442
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
1142 PM CDT MON APR 2 2018

ILC133-163-MOC099-189-030449-
/O.EXP.KLSX.SV.W.0003.000000T0000Z-180403T0445Z/
Monroe IL-St. Clair IL-Jefferson MO-St. Louis MO-
1142 PM CDT MON APR 2 2018

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN MONROE...CENTRAL
ST. CLAIR...NORTHEASTERN JEFFERSON AND SOUTH CENTRAL ST. LOUIS
COUNTIES WILL EXPIRE AT 1145 PM CDT...
                
The storms which prompted the warning have weakened below severe 
limits, and no longer poses an immediate threat to life or property.
Therefore the warning will be allowed to expire.  However hail up to 
nickle size is still possible with these thunderstorms.

LAT...LON 3836 8974 3825 9041 3840 9048 3865 8999
TIME...MOT...LOC 0439Z 246DEG 46KT 3847 9001 

$$

Byrd

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 2, 10:37 PM CDT	Special Weather Statement	LSX	Iron, Madison, Saint Francois	53 min
Apr 2, 11:16 PM CDT	Special Weather Statement	LSX	Crawford	29 min
Apr 2, 11:22 PM CDT	Special Weather Statement	LSX	Saint Charles	38 min
Apr 3, 12:02 AM CDT	Special Weather Statement	LSX	Saint Louis, City of Saint Louis	43 min
Apr 3, 12:38 AM CDT	Special Weather Statement	LSX	City of Saint Louis	52 min
Apr 3, 4:27 AM CDT	Freeze Warning	LSX	Iron, Madison, Reynolds	30 hr
Apr 3, 2:02 PM CDT	Special Weather Statement	LSX	Crawford, Washington	43 min
Apr 3, 2:20 PM CDT	Severe Thunderstorm Warning	LSX	Crawford, Washington	40 min
Apr 3, 2:37 PM CDT	Severe Thunderstorm Warning	LSX	Crawford, Iron, Washington	38 min
Apr 3, 2:51 PM CDT	Severe Thunderstorm Warning	LSX	Jefferson, Sainte Genevieve, Saint Francois, Washington	39 min
Apr 3, 3:13 PM CDT	Severe Thunderstorm Warning	LSX	Iron, Reynolds	47 min
Apr 3, 3:14 PM CDT	Severe Thunderstorm Warning	LSX	Iron, Madison, Reynolds, Saint Francois	46 min
Apr 3, 3:26 PM CDT	Severe Thunderstorm Warning	LSX	Sainte Genevieve, Saint Francois	49 min
Apr 3, 3:46 PM CDT	Severe Thunderstorm Warning	LSX	Iron, Madison, Reynolds	49 min
Apr 3, 3:58 PM CDT	Severe Thunderstorm Warning	LSX	Madison, Sainte Genevieve, Saint Francois	25 min
Apr 2, 7:46 PM CDT	Special Weather Statement	LSX	Clinton, Marion	44 min
Apr 2, 11:55 PM CDT	Special Weather Statement	LSX	Clinton	50 min
Apr 3, 8:23 AM CDT	River Flood Warning	LSX	Fayette	6 days
Apr 3, 10:08 AM CDT	Flash Flood Warning	LSX	Fayette	6 hr
Apr 3, 10:16 AM CDT	Special Weather Statement	LSX	Fayette	14 min
Apr 3, 3:21 PM CDT	Severe Thunderstorm Warning	LSX	Monroe, Randolph, Saint Clair	39 min

Nearby

Severe Thunderstorm Warnings in Missouri, 2018 Severe Thunderstorm Warnings in Illinois, 2018 Every severe thunderstorm warning in 2018

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.