Alert archive / Missouri / Frost Advisories in 2021

Frost Advisory 1, NWS St. Louis, MO

April 2, 20217 counties in Missouri; Randolph County, Illinois

NWS St. Louis, MO issued this frost advisory at Apr 2, 2021, 2:44 PM CDT for 7 counties in Missouri; Randolph County, Illinois. It took effect at Apr 3, 2021, 2:00 AM CDT. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued
Apr 2, 2021, 2:44 PM CDT (19:44 UTC)
In effect from
Apr 3, 2021, 2:00 AM CDT
Expired
Apr 3, 2021, 8:20 AM CDT
In force
6 hr
Issued by
NWS St. Louis, MO

Counties Randolph County, IL, Crawford County, MO, Iron County, MO, Madison County, MO, Reynolds County, MO, Saint Francois County, MO, Sainte Genevieve County, MO, Washington County, MO

The radar

The St Louis radar (KLSX), 105 km from the middle of the area, began a volume at 19:46 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

Springfield, MO (KSGF), launched 12:00Z, 7.7 hours before the alert went out and 300 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, Springfield, MO at 12:00Z on 2021-04-02Temperature 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, Springfield, MO at 12:00Z on 2021-04-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 128 square meters per square second.19395878Sfc1 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
2603 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
128 m²/s²
0-3 km storm-relative helicity
181 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

441 
WWUS73 KLSX 021944
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service Saint Louis MO
244 PM CDT Fri Apr 2 2021

ILZ079-MOZ072>075-084-085-099-030745-
/O.NEW.KLSX.FR.Y.0001.210403T0700Z-210403T1400Z/
Crawford MO-Iron MO-Madison MO-Randolph IL-Reynolds MO-
Saint Francois MO-Sainte Genevieve MO-Washington MO-
Including the cities of Chester, Farmington, and Sparta
244 PM CDT Fri Apr 2 2021

...FROST ADVISORY IN EFFECT FROM 2 AM TO 9 AM CDT SATURDAY...

* WHAT...Temperatures as low as 34 will result in frost formation,
  particularly in wind protected areas.

* WHERE...In Missouri, Crawford MO, Washington MO, Saint 
  Francois MO, Sainte Genevieve MO, Iron MO, Madison MO and 
  Reynolds MO Counties. In Illinois, Randolph IL County.

* WHEN...From 2 AM to 9 AM CDT Saturday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

19
2 follow-up statements
047 
WWUS73 KLSX 030830
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service Saint Louis MO
330 AM CDT Sat Apr 3 2021

ILZ079-MOZ072>075-084-085-099-031400-
/O.CON.KLSX.FR.Y.0001.000000T0000Z-210403T1400Z/
Crawford MO-Iron MO-Madison MO-Randolph IL-Reynolds MO-
Saint Francois MO-Sainte Genevieve MO-Washington MO-
Including the cities of Chester, Farmington, and Sparta
330 AM CDT Sat Apr 3 2021

...FROST ADVISORY REMAINS IN EFFECT UNTIL 9 AM CDT THIS MORNING...

* WHAT...Temperatures as low as 33 will result in frost 
  formation, particularly in wind protected areas.

* WHERE...In Missouri, Crawford MO, Washington MO, Saint 
  Francois MO, Sainte Genevieve MO, Iron MO, Madison MO and 
  Reynolds MO Counties. In Illinois, Randolph IL County.

* WHEN...Until 9 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
788 
WWUS73 KLSX 031320
NPWLSX

URGENT - WEATHER MESSAGE
National Weather Service Saint Louis MO
820 AM CDT Sat Apr 3 2021

ILZ079-MOZ072>075-084-085-099-031430-
/O.CAN.KLSX.FR.Y.0001.000000T0000Z-210403T1400Z/
Crawford MO-Iron MO-Madison MO-Randolph IL-Reynolds MO-
Saint Francois MO-Sainte Genevieve MO-Washington MO-
Including the cities of Chester, Farmington, and Sparta
820 AM CDT Sat Apr 3 2021

...FROST ADVISORY IS CANCELLED...

Temperatures have warmed up into the low 40s across the advisory
area.

$$

Gosselin

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.