Alert archive / Missouri / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 10, NWS St. Louis, MO

March 27, 2021Saint Charles County, Saint Louis County, Missouri; Jersey County, Madison County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Mar 27, 2021, 4:52 PM CDT for Saint Charles County, Saint Louis County, Missouri; Jersey County, Madison County, Illinois. It was in force for 38 min. 29 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: Mar 27, 2021, 4:52 PM CDT (21:52 UTC)
Expired: Mar 27, 2021, 5:30 PM CDT
In force: 38 min
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Jersey County, IL, Madison County, IL, Saint Charles County, MO, Saint Louis County, MO

The radar

The St Louis radar (KLSX), 16 km from the middle of the area, began a volume at 21:55 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
Mar 27, 5:04 PM CDT	HAIL 0.75	3 W Weldon Spring, MO
Mar 27, 5:05 PM CDT	HAIL 1.75	2 Wsw Weldon Spring, MO	1.75 INCH HAIL AT THE NWS OFFICE IN WELDON SPRING.
Mar 27, 5:07 PM CDT	HAIL 0.7	1 S Harvester, MO
Mar 27, 5:07 PM CDT	HAIL 0.75	2 Ese Weldon Spring, MO
Mar 27, 5:07 PM CDT	HAIL 1	Weldon Spring, MO	VIA FACEBOOK WITH MEASUREMENTS. HAIL OF VARIABLE SIZE BUT 1IN MAX.
Mar 27, 5:08 PM CDT	HAIL 0.75	2 W Weldon Spring, MO	REPORT FROM MPING: DIME (0.75 IN.).
Mar 27, 5:09 PM CDT	HAIL 1	3 Ssw Weldon Spring, MO
Mar 27, 5:11 PM CDT	HAIL 0.25	Saint Peters, MO	VIA TWITTER.
Mar 27, 5:11 PM CDT	HAIL 1	3 S Weldon Spring, MO	REPORT FROM MPING: QUARTER (1.00 IN.).
Mar 27, 5:13 PM CDT	HAIL 1	2 E Harvester, MO	REPORT FROM MPING: QUARTER (1.00 IN.).
Mar 27, 5:15 PM CDT	HAIL 0.75	2 Nw Maryland Heights, MO	REPORT FROM MPING: DIME (0.75 IN.).
Mar 27, 5:16 PM CDT	HAIL 0.75	1 Ene Harvester, MO	REPORT FROM MPING: DIME (0.75 IN.).
Mar 27, 5:17 PM CDT	HAIL 0.7	2 Sse Saint Charles, MO
Mar 27, 5:17 PM CDT	HAIL 1	2 Nw Maryland Heights, MO	REPORT FROM MPING: QUARTER (1.00 IN.).
Mar 27, 5:18 PM CDT	HAIL 0.75	2 Sse Saint Charles, MO	REPORT FROM MPING: DIME (0.75 IN.).
Mar 27, 5:20 PM CDT	HAIL 0.88	2 Ene Maryland Heights, MO
Mar 27, 5:21 PM CDT	HAIL 0.75	3 Nw Maryland Heights, MO
Mar 27, 5:21 PM CDT	HAIL 1	1 Ene Maryland Heights, MO	REPORT FROM MPING: QUARTER (1.00 IN.).
Mar 27, 5:22 PM CDT	HAIL 0.5	1 Wnw Maryland Heights, MO
Mar 27, 5:22 PM CDT	HAIL 0.75	1 S Harvester, MO	VIA TWITTER WITH PICTURE.
Mar 27, 5:25 PM CDT	HAIL 0.5	1 Ssw Hazelwood, MO
Mar 27, 5:27 PM CDT	HAIL 1	Hazelwood, MO
Mar 27, 5:27 PM CDT	HAIL 1	Hazelwood, MO	CORRECTS PREVIOUS HAIL REPORT FROM HAZELWOOD.
Mar 27, 5:29 PM CDT	HAIL 0.75	1 Nnw Hazelwood, MO	REPORT FROM MPING: DIME (0.75 IN.).
Mar 27, 5:29 PM CDT	HAIL 1	Florissant, MO	VIA FACEBOOK REPORT WITH PICTURE.
Mar 27, 5:31 PM CDT	HAIL 0.75	1 Sse Florissant, MO	REPORT FROM MPING: DIME (0.75 IN.).
Mar 27, 5:33 PM CDT	HAIL 0.75	1 Sse Florissant, MO	REPORT FROM MPING: DIME (0.75 IN.).
Mar 27, 5:35 PM CDT	HAIL 1	1 Wnw Spanish Lake, MO
Mar 27, 5:38 PM CDT	HAIL 0.5	Florissant, MO

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
Mar 27, 4:44 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 9.9 hours before the alert went out and 227 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: 1078 m above ground
0-6 km bulk shear: 78 kt
0-1 km storm-relative helicity: 369 m²/s²
0-3 km storm-relative helicity: 384 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

762 
WUUS53 KLSX 272152
SVRLSX
ILC083-119-MOC183-189-272230-
/O.NEW.KLSX.SV.W.0010.210327T2152Z-210327T2230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service St Louis MO
452 PM CDT Sat Mar 27 2021

The National Weather Service in St Louis has issued a

* Severe Thunderstorm Warning for...
  West central Madison County in southwestern Illinois...
  Southeastern Jersey County in southwestern Illinois...
  St. Charles County in east central Missouri...
  Northern St. Louis County in east central Missouri...

* Until 530 PM CDT.

* At 451 PM CDT, a severe thunderstorm was located over New Melle,
  moving east at 50 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...
  O'Fallon, St. Charles, St. Peters, Florissant, Chesterfield,
  Wildwood, Granite City, Wentzville, Alton, Maryland Heights,
  Hazelwood, Ferguson, Godfrey, Creve Coeur, Overland, Jennings, Lake
  St. Louis, St. Ann, Bridgeton and Dardenne Prairie.

This includes Interstate 70 in Missouri between exits 214 and 231.
 
This also includes Babler Memorial State Park and First Missouri
State Capitol Historic Site.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3874 9019 3877 9017 3877 9018 3873 9022
      3861 9073 3864 9073 3859 9078 3855 9095
      3858 9097 3874 9096 3887 9058 3887 9055
      3889 9053 3899 9025 3876 9011
TIME...MOT...LOC 2151Z 249DEG 43KT 3867 9086 

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

BRC

1 follow-up statement

417 
WWUS53 KLSX 272206
SVSLSX

Severe Weather Statement
National Weather Service St Louis MO
506 PM CDT Sat Mar 27 2021

ILC083-119-MOC183-189-272230-
/O.CON.KLSX.SV.W.0010.000000T0000Z-210327T2230Z/
Madison IL-Jersey IL-St. Charles MO-St. Louis MO-
506 PM CDT Sat Mar 27 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 PM CDT
FOR WEST CENTRAL MADISON AND SOUTHEASTERN JERSEY COUNTIES IN
SOUTHWESTERN ILLINOIS...CENTRAL ST. CHARLES AND NORTHERN ST. LOUIS
COUNTIES IN EAST CENTRAL MISSOURI...

At 505 PM CDT, a severe thunderstorm was located over Weldon Spring,
moving east at 50 mph.

HAZARD...Golf ball size hail and 60 mph wind gusts.

SOURCE...Trained weather spotters.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Expect wind 
         damage to roofs, siding, and trees.

Locations impacted include...
O'Fallon, St. Charles, St. Peters, Florissant, Chesterfield,
Wildwood, Granite City, Alton, Maryland Heights, Hazelwood, Ferguson,
Godfrey, Creve Coeur, Overland, Jennings, Lake St. Louis, St. Ann,
Bridgeton, Dardenne Prairie and Bellefontaine Neighbors.

This also includes First Missouri State Capitol Historic Site.
 
This includes Interstate 70 in Missouri between exits 214 and 231.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3874 9019 3877 9017 3877 9018 3873 9022
      3862 9071 3863 9073 3864 9073 3865 9076
      3880 9079 3887 9058 3887 9055 3889 9053
      3899 9025 3876 9011
TIME...MOT...LOC 2205Z 249DEG 43KT 3873 9065 

HAIL...1.75IN
WIND...60MPH
 
$$

BRC

The office that day

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

Issued	Product	Office	Counties	Lasted
Mar 27, 4:16 PM CDT	Severe Thunderstorm Warning	LSX	Franklin, Gasconade, Saint Charles, Warren	44 min
Mar 27, 4:23 PM CDT	Severe Thunderstorm Warning	LSX	Lincoln, Pike	52 min
Mar 27, 5:24 PM CDT	Severe Thunderstorm Warning	LSX	Franklin, Gasconade	15 min
Mar 27, 5:26 PM CDT	Severe Thunderstorm Warning	LSX	Saint Charles, Saint Louis, City of Saint Louis	38 min
Mar 27, 5:36 PM CDT	Severe Thunderstorm Warning	LSX	Crawford, Washington	28 min
Mar 27, 4:47 PM CDT	Severe Thunderstorm Warning	LSX	Greene, Macoupin	43 min
Mar 27, 5:18 PM CDT	Severe Thunderstorm Warning	LSX	Macoupin, Montgomery	42 min
Mar 27, 6:56 PM CDT	Severe Thunderstorm Warning	LSX	Bond, Clinton, Madison, Saint Clair	49 min

Nearby

Severe Thunderstorm Warnings in Missouri, 2021 Severe Thunderstorm Warnings in Illinois, 2021 Every severe thunderstorm warning in 2021

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.