Alert archive / Missouri / Freeze Warnings in 2021

Freeze Warning 5, NWS St. Louis, MO

April 21, 202129 counties in Missouri; 17 counties in Illinois

NWS St. Louis, MO issued this freeze warning at Apr 21, 2021, 3:08 AM CDT for 29 counties in Missouri; 17 counties in Illinois. It took effect at Apr 22, 2021, 12:00 AM CDT. It was in force for 9 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Apr 21, 2021, 3:08 AM CDT (08:08 UTC)
In effect from
Apr 22, 2021, 12:00 AM CDT
Expired
Apr 22, 2021, 9:00 AM CDT
In force
9 hr
Issued by
NWS St. Louis, MO
All 46 counties

Adams County, IL, Bond County, IL, Brown County, IL, Calhoun County, IL, Clinton County, IL, Fayette County, IL, Greene County, IL, Jersey County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Monroe County, IL, Montgomery County, IL, Pike County, IL, Randolph County, IL, Saint Clair County, IL, Washington County, IL, Audrain County, MO, Boone County, MO, Callaway County, MO, City of Saint Louis, MO, Cole County, MO, Crawford County, MO, Franklin County, MO, Gasconade County, MO, Iron County, MO, Jefferson County, MO, Knox County, MO, Lewis County, MO, Lincoln County, MO, Madison County, MO, Marion County, MO, Moniteau County, MO, Monroe County, MO, Montgomery County, MO, Osage County, MO, Pike County, MO, Ralls County, MO, Reynolds County, MO, Saint Charles County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Shelby County, MO, Warren County, MO, Washington County, MO

The radar

The St Louis radar (KLSX), 18 km from the middle of the area, began a volume at 08:10 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.

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 8.1 hours before the alert went out and 241 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-pSkew-T log-p diagram, Lincoln, IL at 00:00Z on 2021-04-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 00:00Z on 2021-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -62 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
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
731 m above ground
0-6 km bulk shear
85 kt
0-1 km storm-relative helicity
-62 m²/s²
0-3 km storm-relative helicity
-8 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

524 
WWUS73 KLSX 210808
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service St Louis MO
308 AM CDT Wed Apr 21 2021

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-212315-
/O.NEW.KLSX.FZ.W.0005.210422T0500Z-210422T1400Z/
/O.CON.KLSX.FZ.W.0004.000000T0000Z-210421T1400Z/
Greene IL-Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL-
Marion IL-Washington IL-Randolph IL-Adams IL-Brown IL-Pike IL-
Calhoun IL-Jersey IL-Madison IL-Saint Clair-Monroe IL-Knox MO-
Lewis MO-Shelby MO-Marion MO-Monroe MO-Ralls MO-Pike MO-Boone MO-
Audrain MO-Moniteau MO-Cole MO-Osage MO-Callaway MO-Montgomery MO-
Lincoln MO-Gasconade MO-Warren MO-Saint Charles MO-Franklin MO-
Saint Louis MO-Saint Louis City MO-Jefferson MO-Crawford MO-
Washington MO-Saint Francois MO-Sainte Genevieve MO-Iron MO-
Madison MO-Reynolds MO-
Including the cities of Mount Sterling, Quincy, Cahokia, Union,
Bowling Green, Columbia, Pittsfield, Alton, Sparta, Centralia,
Farmington, Vandalia, Litchfield, Saint Louis, Jefferson City,
Belleville, Edwardsville, Chester, Hannibal, Fulton, Saint
Charles, Mexico, Sullivan, Washington, and Salem
308 AM CDT Wed Apr 21 2021

...FREEZE WARNING REMAINS IN EFFECT UNTIL 9 AM CDT THIS MORNING...
...ADDITIONAL FREEZE WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM 
CDT THURSDAY...

* WHAT...For the ongoing Freeze Warning, sub-freezing temperatures 
  as low as 26 expected.

For the second Freeze Warning, sub-freezing temperatures as low as 
28.

* WHERE...For the ongoing Freeze Warning, all of Missouri and 
  southwest Illinois.

For the second Freeze Warning, most of central, east-central, and 
northeast Missouri, as well as west-central Illinois.

* WHEN...For the first Freeze Warning, ongoing until 9 AM CDT this 
  morning.

For the second Freeze Warning, midnight tonight until 9 AM CDT 
Thursday morning.

* IMPACTS...Frost and freeze conditions could kill crops, other 
  sensitive vegetation and possibly damage unprotected outdoor 
  plumbing.

$$

BRC
4 follow-up statements
004 
WWUS73 KLSX 211340
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service St Louis MO
840 AM CDT Wed Apr 21 2021

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-220445-
/O.EXP.KLSX.FZ.W.0004.000000T0000Z-210421T1400Z/
/O.CON.KLSX.FZ.W.0005.210422T0500Z-210422T1400Z/
Greene IL-Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL-
Marion IL-Washington IL-Randolph IL-Adams IL-Brown IL-Pike IL-
Calhoun IL-Jersey IL-Madison IL-Saint Clair-Monroe IL-Knox MO-
Lewis MO-Shelby MO-Marion MO-Monroe MO-Ralls MO-Pike MO-Boone MO-
Audrain MO-Moniteau MO-Cole MO-Osage MO-Callaway MO-Montgomery MO-
Lincoln MO-Gasconade MO-Warren MO-Saint Charles MO-Franklin MO-
Saint Louis MO-Saint Louis City MO-Jefferson MO-Crawford MO-
Washington MO-Saint Francois MO-Sainte Genevieve MO-Iron MO-
Madison MO-Reynolds MO-
Including the cities of Mount Sterling, Quincy, Cahokia, Union,
Bowling Green, Columbia, Pittsfield, Alton, Sparta, Centralia,
Farmington, Vandalia, Litchfield, Saint Louis, Jefferson City,
Belleville, Edwardsville, Chester, Hannibal, Fulton, Saint
Charles, Mexico, Sullivan, Washington, and Salem
840 AM CDT Wed Apr 21 2021

...FREEZE WARNING REMAINS IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM 
CDT THURSDAY...
...FREEZE WARNING WILL EXPIRE AT 9 AM CDT THIS MORNING...

* WHAT...Sub-freezing temperatures as low as 29 expected.

* WHERE...Portions of southwest and west central Illinois. Portions 
  of central and eastern Missouri.

* WHEN...From Midnight tonight to 9 AM CDT Thursday.

* IMPACTS...Frost and freeze conditions could kill crops, other 
  sensitive vegetation and possibly damage unprotected outdoor 
  plumbing.

$$

GKS
161 
WWUS73 KLSX 211955
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service St Louis MO
255 PM CDT Wed Apr 21 2021

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-221400-
/O.CON.KLSX.FZ.W.0005.210422T0500Z-210422T1400Z/
Greene IL-Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL-
Marion IL-Washington IL-Randolph IL-Adams IL-Brown IL-Pike IL-
Calhoun IL-Jersey IL-Madison IL-Saint Clair-Monroe IL-Knox MO-
Lewis MO-Shelby MO-Marion MO-Monroe MO-Ralls MO-Pike MO-Boone MO-
Audrain MO-Moniteau MO-Cole MO-Osage MO-Callaway MO-Montgomery MO-
Lincoln MO-Gasconade MO-Warren MO-Saint Charles MO-Franklin MO-
Saint Louis MO-Saint Louis City MO-Jefferson MO-Crawford MO-
Washington MO-Saint Francois MO-Sainte Genevieve MO-Iron MO-
Madison MO-Reynolds MO-
Including the cities of Mount Sterling, Quincy, Cahokia, Union,
Bowling Green, Columbia, Pittsfield, Alton, Sparta, Centralia,
Farmington, Vandalia, Litchfield, Saint Louis, Jefferson City,
Belleville, Edwardsville, Chester, Hannibal, Fulton, Saint
Charles, Mexico, Sullivan, Washington, and Salem
255 PM CDT Wed Apr 21 2021

...FREEZE WARNING REMAINS IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM 
CDT THURSDAY...

* WHAT...Sub-freezing temperatures as low as 28 expected.

* WHERE...Portions of south central, southwest, and west central 
  Illinois. Portions of central, east central, northeast, and 
  southeast Missouri.

* WHEN...From Midnight tonight to 9 AM CDT Thursday.

* IMPACTS...Frost and freeze conditions could kill crops, other 
  sensitive vegetation and possibly damage unprotected outdoor 
  plumbing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

Carney
708 
WWUS73 KLSX 220751
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service St Louis MO
251 AM CDT Thu Apr 22 2021

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-221400-
/O.CON.KLSX.FZ.W.0005.000000T0000Z-210422T1400Z/
Greene IL-Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL-
Marion IL-Washington IL-Randolph IL-Adams IL-Brown IL-Pike IL-
Calhoun IL-Jersey IL-Madison IL-Saint Clair-Monroe IL-Knox MO-
Lewis MO-Shelby MO-Marion MO-Monroe MO-Ralls MO-Pike MO-Boone MO-
Audrain MO-Moniteau MO-Cole MO-Osage MO-Callaway MO-Montgomery MO-
Lincoln MO-Gasconade MO-Warren MO-Saint Charles MO-Franklin MO-
Saint Louis MO-Saint Louis City MO-Jefferson MO-Crawford MO-
Washington MO-Saint Francois MO-Sainte Genevieve MO-Iron MO-
Madison MO-Reynolds MO-
Including the cities of Mount Sterling, Quincy, Cahokia, Union,
Bowling Green, Columbia, Pittsfield, Alton, Sparta, Centralia,
Farmington, Vandalia, Litchfield, Saint Louis, Jefferson City,
Belleville, Edwardsville, Chester, Hannibal, Fulton, Saint
Charles, Mexico, Sullivan, Washington, and Salem
251 AM CDT Thu Apr 22 2021

...FREEZE WARNING REMAINS IN EFFECT UNTIL 9 AM CDT THIS MORNING...

* WHAT...Sub-freezing temperatures as low as 28.

* WHERE...Portions of south central, southwest, and west central 
  Illinois. Portions of central, east central, northeast, and 
  southeast Missouri.

* WHEN...Until 9 AM CDT this morning.

* IMPACTS...Frost and freeze conditions could kill crops, other 
  sensitive vegetation and possibly damage unprotected outdoor 
  plumbing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

Elmore
094 
WWUS73 KLSX 221335
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service St Louis MO
835 AM CDT Thu Apr 22 2021

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-221445-
/O.EXP.KLSX.FZ.W.0005.000000T0000Z-210422T1400Z/
Greene IL-Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL-
Marion IL-Washington IL-Randolph IL-Adams IL-Brown IL-Pike IL-
Calhoun IL-Jersey IL-Madison IL-Saint Clair-Monroe IL-Knox MO-
Lewis MO-Shelby MO-Marion MO-Monroe MO-Ralls MO-Pike MO-Boone MO-
Audrain MO-Moniteau MO-Cole MO-Osage MO-Callaway MO-Montgomery MO-
Lincoln MO-Gasconade MO-Warren MO-Saint Charles MO-Franklin MO-
Saint Louis MO-Saint Louis City MO-Jefferson MO-Crawford MO-
Washington MO-Saint Francois MO-Sainte Genevieve MO-Iron MO-
Madison MO-Reynolds MO-
Including the cities of Mount Sterling, Quincy, Cahokia, Union,
Bowling Green, Columbia, Pittsfield, Alton, Sparta, Centralia,
Farmington, Vandalia, Litchfield, Saint Louis, Jefferson City,
Belleville, Edwardsville, Chester, Hannibal, Fulton, Saint
Charles, Mexico, Sullivan, Washington, and Salem
835 AM CDT Thu Apr 22 2021

...FREEZE WARNING WILL EXPIRE AT 9 AM CDT THIS MORNING...

The threat has ended as temperatures have warmed above the freezing 
mark across the area.

$$

GKS

Nearby

Freeze Warnings in Missouri, 2021Freeze Warnings in Illinois, 2021Every freeze 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.