Alert archive / Illinois / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 152, NWS St. Louis, MO

July 23, 2017Saint Clair County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Jul 23, 2017, 3:19 AM CDT for Saint Clair County, Illinois. It was in force for 41 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: Jul 23, 2017, 3:19 AM CDT (08:19 UTC)
Expired: Jul 23, 2017, 4:00 AM CDT
In force: 41 min
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Saint Clair County, IL

The radar

The St Louis radar (KLSX), 54 km from the middle of the area, began a volume at 08:22 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 23, 3:30 AM CDT	TSTM WND DMG	Belleville, IL	TWO LARGE TREE LIMBS BLOWN ONTO ROOF INTO HOUSE. EXTENSIVE ROOF DAMAGE.
Jul 23, 3:35 AM CDT	HAIL 1	Belleville, IL	NEAR INTERSECTION OF ROUTES 15 AND 158.
Jul 23, 3:41 AM CDT	TSTM WND GST 61	Scott Afb, IL

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 23, 12:38 AM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 8.3 hours before the alert went out and 221 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: 2392 J/kg
Mixed-layer CIN: -34 J/kg
Mixed-layer LCL: 1185 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 51 m²/s²
0-3 km storm-relative helicity: 233 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 6.0

Open this sounding in Storm Lab

The text

As transmitted.

106 
WUUS53 KLSX 230819
SVRLSX
ILC163-230900-
/O.NEW.KLSX.SV.W.0152.170723T0819Z-170723T0900Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
319 AM CDT SUN JUL 23 2017

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  St. Clair County in southwestern Illinois...

* Until 400 AM CDT.

* At 319 AM CDT, a severe thunderstorm was located over Millstadt,
  moving east at 35 mph.

  HAZARD...60 mph wind gusts and quarter size hail. 

  SOURCE...Radar indicated. 

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees. 

* Locations impacted include...
  Belleville, O'Fallon, East St. Louis, Collinsville, Fairview
  Heights, Cahokia, Swansea, Shiloh, Columbia, Mascoutah,
  Centreville, Lebanon, Freeburg, Caseyville, Washington Park, Dupo,
  Millstadt, Madison, New Baden and Scott AFB.

This includes Interstate 64 in Illinois between exits 9 and 27.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3844 9016 3847 9020 3853 9024 3858 9021
      3858 9019 3863 9018 3866 9018 3865 8971
      3835 8971
TIME...MOT...LOC 0819Z 273DEG 31KT 3848 9005 

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

Carney

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 22, 10:33 PM CDT	Special Weather Statement	LSX	Saint Clair	42 min
Jul 22, 11:11 PM CDT	Special Weather Statement	LSX	Madison	49 min
Jul 22, 11:34 PM CDT	Special Weather Statement	LSX	Saint Clair	41 min
Jul 23, 2:17 AM CDT	Severe Thunderstorm Warning	LSX	Pike	43 min
Jul 23, 2:48 AM CDT	Severe Thunderstorm Warning	LSX	Calhoun, Greene, Jersey, Madison, Pike	42 min
Jul 23, 3:14 AM CDT	Severe Thunderstorm Warning	LSX	Madison	46 min
Jul 23, 3:25 AM CDT	Severe Thunderstorm Warning	LSX	Greene, Jersey, Macoupin, Montgomery	50 min
Jul 23, 3:48 AM CDT	Severe Thunderstorm Warning	LSX	Bond, Clinton, Madison, Saint Clair, Washington	42 min
Jul 23, 4:08 AM CDT	Severe Thunderstorm Warning	LSX	Fayette, Macoupin, Montgomery	67 min
Jul 23, 4:24 AM CDT	Severe Thunderstorm Warning	LSX	Bond, Clinton, Fayette, Marion, Washington	52 min
Jul 23, 4:30 PM CDT	Severe Thunderstorm Warning	LSX	Greene, Macoupin	30 min
Jul 23, 5:01 PM CDT	Special Weather Statement	LSX	Macoupin	44 min
Jul 23, 5:14 PM CDT	Special Weather Statement	LSX	Pike	46 min
Jul 23, 6:52 PM CDT	Special Weather Statement	LSX	Jersey	53 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2017 Every severe thunderstorm warning in 2017

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.