Alert archive / Missouri / Frost Advisories in 2021

Frost Advisory 2, NWS St. Louis, MO

April 14, 202120 counties in Missouri; 5 counties in Illinois

NWS St. Louis, MO issued this frost advisory at Apr 14, 2021, 2:32 PM CDT for 20 counties in Missouri; 5 counties in Illinois. It took effect at Apr 15, 2021, 1:00 AM CDT. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued
Apr 14, 2021, 2:32 PM CDT (19:32 UTC)
In effect from
Apr 15, 2021, 1:00 AM CDT
Expired
Apr 15, 2021, 8:00 AM CDT
In force
7 hr
Issued by
NWS St. Louis, MO
All 25 counties

Adams County, IL, Brown County, IL, Calhoun County, IL, Greene County, IL, Pike County, IL, Audrain County, MO, Boone County, MO, Callaway County, MO, Cole County, MO, Crawford County, MO, Franklin County, MO, Gasconade County, MO, Knox County, MO, Lewis County, MO, Lincoln County, MO, Marion County, MO, Moniteau County, MO, Monroe County, MO, Montgomery County, MO, Osage County, MO, Pike County, MO, Ralls County, MO, Shelby County, MO, Warren County, MO, Washington County, MO

The radar

The St Louis radar (KLSX), 85 km from the middle of the area, began a volume at 19:34 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 12:00Z, 7.5 hours before the alert went out and 272 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 12:00Z on 2021-04-14Temperature 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 12:00Z on 2021-04-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -81 square meters per square second.1939587897117136Sfc1 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
1376 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
-81 m²/s²
0-3 km storm-relative helicity
12 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

959 
WWUS73 KLSX 141932
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service Saint Louis MO
232 PM CDT Wed Apr 14 2021

ILZ058-095>098-MOZ018-019-026-027-034>036-041-042-047>052-150900-
/O.NEW.KLSX.FR.Y.0002.210415T0600Z-210415T1300Z/
Adams IL-Audrain MO-Boone MO-Brown IL-Calhoun IL-Callaway MO-
Cole MO-Greene IL-Knox MO-Lewis MO-Lincoln MO-Marion MO-
Moniteau MO-Monroe MO-Montgomery MO-Osage MO-Pike IL-Pike MO-
Ralls MO-Shelby MO-
Including the cities of Bowling Green, Columbia, Fulton, 
Hannibal, Jefferson City, Mexico, Mount Sterling, Pittsfield, 
and Quincy
232 PM CDT Wed Apr 14 2021

...FROST ADVISORY IN EFFECT FROM 1 AM TO 8 AM CDT THURSDAY...

* WHAT...Temperatures as low as 34 will result in frost 
  formation.

* WHERE...Portions of central and northeast Missouri as well as 
  west central Illinois.

* WHEN...From 1 AM to 8 AM CDT Thursday.

* IMPACTS...Frost could kill sensitive outdoor vegetation if 
  left uncovered.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

Byrd
3 follow-up statements
583 
WWUS73 KLSX 142301
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service Saint Louis MO
601 PM CDT Wed Apr 14 2021

MOZ059-060-062-072-073-151100-
/O.EXA.KLSX.FR.Y.0002.210415T0600Z-210415T1300Z/
Crawford MO-Franklin MO-Gasconade MO-Warren MO-Washington MO-
Including the cities of Sullivan, Union, and Washington
601 PM CDT Wed Apr 14 2021

...FROST ADVISORY IN EFFECT FROM 1 AM TO 8 AM CDT THURSDAY...

* WHAT...Temperatures as low as 35 will result in frost 
  formation.

* WHERE...Gasconade MO, Warren MO, Franklin MO, Crawford MO and 
  Washington MO Counties.

* WHEN...From 1 AM to 8 AM CDT Thursday.

* IMPACTS...Frost could kill sensitive outdoor vegetation if 
  left uncovered.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

ILZ058-095>098-MOZ018-019-026-027-034>036-041-042-047>052-151100-
/O.CON.KLSX.FR.Y.0002.210415T0600Z-210415T1300Z/
Adams IL-Audrain MO-Boone MO-Brown IL-Calhoun IL-Callaway MO-
Cole MO-Greene IL-Knox MO-Lewis MO-Lincoln MO-Marion MO-
Moniteau MO-Monroe MO-Montgomery MO-Osage MO-Pike IL-Pike MO-
Ralls MO-Shelby MO-
Including the cities of Bowling Green, Columbia, Fulton, 
Hannibal, Jefferson City, Mexico, Mount Sterling, Pittsfield, 
and Quincy
601 PM CDT Wed Apr 14 2021

...FROST ADVISORY REMAINS IN EFFECT FROM 1 AM TO 8 AM CDT
THURSDAY...

* WHAT...Temperatures as low as 34 will result in frost 
  formation.

* WHERE...Portions of central and northeast Missouri as well as 
  west central Illinois.

* WHEN...From 1 AM to 8 AM CDT Thursday.

* IMPACTS...Frost could kill sensitive outdoor vegetation if 
  left uncovered.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

Glass
771 
WWUS73 KLSX 150844
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service Saint Louis MO
344 AM CDT Thu Apr 15 2021

ILZ058-095>098-MOZ018-019-026-027-034>036-041-042-047>052-059-060-
062-072-073-151300-
/O.CON.KLSX.FR.Y.0002.000000T0000Z-210415T1300Z/
Adams IL-Audrain MO-Boone MO-Brown IL-Calhoun IL-Callaway MO-
Cole MO-Crawford MO-Franklin MO-Gasconade MO-Greene IL-Knox MO-
Lewis MO-Lincoln MO-Marion MO-Moniteau MO-Monroe MO-Montgomery MO-
Osage MO-Pike IL-Pike MO-Ralls MO-Shelby MO-Warren MO-
Washington MO-
Including the cities of Bowling Green, Columbia, Fulton, 
Hannibal, Jefferson City, Mexico, Mount Sterling, Pittsfield, 
Quincy, Sullivan, Union, and Washington
344 AM CDT Thu Apr 15 2021

...FROST ADVISORY REMAINS IN EFFECT UNTIL 8 AM CDT THIS MORNING...

* WHAT...Temperatures as low as 34 will result in frost 
  formation.

* WHERE...Portions of central and eastern Missouri as well as 
  west central Illinois.

* WHEN...Until 8 AM CDT this morning.

* IMPACTS...Frost could kill sensitive outdoor vegetation if 
  left uncovered.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

GKS
227 
WWUS73 KLSX 151255
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service Saint Louis MO
755 AM CDT Thu Apr 15 2021

ILZ058-095>098-MOZ018-019-026-027-034>036-041-042-047>052-059-060-
062-072-073-151400-
/O.EXP.KLSX.FR.Y.0002.000000T0000Z-210415T1300Z/
Adams IL-Audrain MO-Boone MO-Brown IL-Calhoun IL-Callaway MO-
Cole MO-Crawford MO-Franklin MO-Gasconade MO-Greene IL-Knox MO-
Lewis MO-Lincoln MO-Marion MO-Moniteau MO-Monroe MO-Montgomery MO-
Osage MO-Pike IL-Pike MO-Ralls MO-Shelby MO-Warren MO-
Washington MO-
Including the cities of Bowling Green, Columbia, Fulton, 
Hannibal, Jefferson City, Mexico, Mount Sterling, Pittsfield, 
Quincy, Sullivan, Union, and Washington
755 AM CDT Thu Apr 15 2021

...FROST ADVISORY WILL EXPIRE AT 8 AM CDT THIS MORNING...

Temperatures have warmed up to near 40 degrees across the 
advisory area.


$$

Byrd

Nearby

Frost Advisories in Missouri, 2021Frost Advisories in Illinois, 2021Every frost advisory 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.