Alert archive / Illinois / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 65, NWS St. Louis, MO

April 26, 2017Randolph County, Saint Clair County, Washington County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Apr 26, 2017, 1:54 PM CDT for Randolph County, Saint Clair County, Washington County, Illinois. It was in force for 51 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: Apr 26, 2017, 1:54 PM CDT (18:54 UTC)
Expired: Apr 26, 2017, 2:45 PM CDT
In force: 51 min
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Hail: 0.75 in
Wind: 70.0 mph

Counties Randolph County, IL, Saint Clair County, IL, Washington County, IL

The radar

The St Louis radar (KLSX), 100 km from the middle of the area, began a volume at 18:55 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
Apr 26, 2:05 PM CDT	TSTM WND DMG	Percy, IL	SEVERAL LARGE TREE LIMBS SNAPPED OFF OF A TREE IN TOWN.

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
Apr 26, 12:46 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 6.9 hours before the alert went out and 236 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1086 m above ground
0-6 km bulk shear: 73 kt
0-1 km storm-relative helicity: 52 m²/s²
0-3 km storm-relative helicity: 221 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.5

Open this sounding in Storm Lab

The text

As transmitted.

035 
WUUS53 KLSX 261854
SVRLSX
ILC157-163-189-261945-
/O.NEW.KLSX.SV.W.0065.170426T1854Z-170426T1945Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
154 PM CDT WED APR 26 2017

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  Southwestern Washington County in south central Illinois...
  Randolph County in southwestern Illinois...
  Southeastern St. Clair County in southwestern Illinois...

* Until 245 PM CDT.

* At 153 PM CDT, a severe thunderstorm was located near Steeleville,
  moving northeast at 45 mph.

  HAZARD...70 mph wind gusts. 

  SOURCE...Trained weather spotters. 

  IMPACT...Expect considerable tree damage. Damage is likely to 
           mobile homes, roofs, and outbuildings. 

* Locations impacted include...
  Chester, Sparta, Bremen, Steeleville, Marissa, Percy, Coulterville,
  Tilden, Evansville, Lively Grove, Baldwin, Posen, Eden, Preston,
  Blair, St. Libory, Prairie Du Rocher, Prairie, Lenzburg and
  Johannisburg.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3822 8959 3795 8960 3782 8968 3780 8968
      3807 9011 3822 8995 3822 8990 3825 8992
      3844 8971 3842 8971 3842 8970 3844 8967
      3845 8963 3821 8925
TIME...MOT...LOC 1853Z 235DEG 37KT 3805 8973 

HAIL...<.75IN
WIND...70MPH
 
$$

Carney

1 follow-up statement

716 
WWUS53 KLSX 261911
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
211 PM CDT WED APR 26 2017

ILC157-163-189-261945-
/O.CON.KLSX.SV.W.0065.000000T0000Z-170426T1945Z/
Washington IL-Randolph IL-St. Clair IL-
211 PM CDT WED APR 26 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 245 PM CDT
FOR SOUTHWESTERN WASHINGTON...RANDOLPH AND SOUTHEASTERN ST. CLAIR
COUNTIES...

At 210 PM CDT, a severe thunderstorm was located near Coulterville,
moving northeast at 35 mph.

HAZARD...70 mph wind gusts. 

SOURCE...Public. At 140 pm tree damage was reported in Chester. 

IMPACT...Expect considerable tree damage. Damage is likely to mobile 
         homes, roofs, and outbuildings. 

Locations impacted include...
Chester, Sparta, Bremen, Steeleville, Marissa, Percy, Coulterville,
Tilden, Lively Grove, Baldwin, Posen, Eden, Preston, Blair, St.
Libory, Lenzburg, Johannisburg, Oakdale, Houston and Venedy.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3822 8959 3795 8960 3782 8968 3780 8968
      3805 8993 3827 8985 3844 8971 3842 8971
      3842 8970 3844 8967 3845 8963 3821 8925
TIME...MOT...LOC 1910Z 232DEG 32KT 3813 8962 

HAIL...<.75IN
WIND...70MPH
 
$$

Carney

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 25, 9:49 PM CDT	River Flood Warning	LSX	Pike	46 days
Apr 26, 1:14 PM CDT	Severe Thunderstorm Warning	LSX	Randolph	46 min
Apr 26, 2:32 PM CDT	Severe Thunderstorm Warning	LSX	Clinton, Marion, Washington	43 min
Apr 26, 3:15 PM CDT	Special Weather Statement	LSX	Marion	45 min
Apr 26, 3:24 PM CDT	Severe Thunderstorm Warning	LSX	Marion	25 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.