Alert archive / Alabama / Frost Advisories in 2021

Frost Advisory 2, NWS Birmingham, AL

April 21, 202123 counties in Alabama

NWS Birmingham, AL issued this frost advisory at Apr 21, 2021, 3:09 AM CDT for 23 counties in Alabama. It took effect at Apr 21, 2021, 11:00 PM CDT. It was in force for 9 hr.

The area

The counties it named.

The facts

Issued
Apr 21, 2021, 3:09 AM CDT (08:09 UTC)
In effect from
Apr 21, 2021, 11:00 PM CDT
Expired
Apr 22, 2021, 8:00 AM CDT
In force
9 hr
Issued by
NWS Birmingham, AL
All 23 counties

Bibb County, AL, Blount County, AL, Calhoun County, AL, Chambers County, AL, Cherokee County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Etowah County, AL, Fayette County, AL, Jefferson County, AL, Lamar County, AL, Marion County, AL, Pickens County, AL, Randolph County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Tallapoosa County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL

The radar

The Birmingham radar (KBMX), 41 km from the middle of the area, began a volume at 08:09 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

Birmingham, AL (KBMX), launched 00:00Z, 8.2 hours before the alert went out and 40 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, Birmingham, AL 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, Birmingham, AL at 00:00Z on 2021-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 27 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
2626 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
27 m²/s²
0-3 km storm-relative helicity
69 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

586 
WWUS74 KBMX 210809
NPWBMX

URGENT - WEATHER MESSAGE
National Weather Service Birmingham AL
309 AM CDT Wed Apr 21 2021

ALZ011>015-017>029-212200-
/O.NEW.KBMX.FR.Y.0002.210422T0600Z-210422T1300Z/
Marion-Lamar-Fayette-Winston-Walker-Blount-Etowah-Calhoun-
Cherokee-Cleburne-Pickens-Tuscaloosa-Jefferson-Shelby-St. Clair-
Talladega-Clay-Randolph-
Including the cities of Hamilton, Sulligent, Vernon, Fayette, 
Double Springs, Jasper, Oneonta, Gadsden, Anniston, Centre, 
Heflin, Carrollton, Tuscaloosa, Birmingham, Hoover, Columbiana, 
Pelham, Alabaster, Pell City, Moody, Talladega, Sylacauga, 
Ashland, and Roanoke
309 AM CDT Wed Apr 21 2021

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

* WHAT...Temperatures between 33 and 36 degrees will result in 
  frost formation.

* WHERE...Northern portions of Central Alabama.

* 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.

&&

$$
2 follow-up statements
241 
WWUS74 KBMX 211845
NPWBMX

URGENT - WEATHER MESSAGE
National Weather Service Birmingham AL
145 PM CDT Wed Apr 21 2021

ALZ011>015-017>029-221300-
/O.CON.KBMX.FR.Y.0002.210422T0600Z-210422T1300Z/
Marion-Lamar-Fayette-Winston-Walker-Blount-Etowah-Calhoun-
Cherokee-Cleburne-Pickens-Tuscaloosa-Jefferson-Shelby-St. Clair-
Talladega-Clay-Randolph-
Including the cities of Hamilton, Sulligent, Vernon, Fayette, 
Double Springs, Jasper, Oneonta, Gadsden, Anniston, Centre, 
Heflin, Carrollton, Tuscaloosa, Birmingham, Hoover, Columbiana, 
Pelham, Alabaster, Pell City, Moody, Talladega, Sylacauga, 
Ashland, and Roanoke
145 PM CDT Wed Apr 21 2021

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

* WHAT...Temperatures between 33 and 36 degrees will result in 
  frost formation.

* WHERE...Northern portions of Central Alabama.

* 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.

&&

$$
218 
WWUS74 KBMX 220328
NPWBMX

URGENT - WEATHER MESSAGE
National Weather Service Birmingham AL
1028 PM CDT Wed Apr 21 2021

ALZ034>038-221300-
/O.EXB.KBMX.FR.Y.0002.210422T0400Z-210422T1300Z/
Bibb-Chilton-Coosa-Tallapoosa-Chambers-
Including the cities of Centreville, Clanton, Rockford, 
Alexander City, Dadeville, Valley, Lanett, and Lafayette
1028 PM CDT Wed Apr 21 2021

...FROST ADVISORY IN EFFECT UNTIL 8 AM CDT THURSDAY...

* WHAT...Temperatures between 33 and 38 degrees will result in 
  frost formation.

* WHERE...Bibb, Chilton, Coosa, Tallapoosa and Chambers Counties.

* WHEN...Until 8 AM CDT Thursday.

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

* ADDITIONAL DETAILS...Frost development may not be uniform or
  widespread, but some places it may be heavy and short lived
  while some areas have lighter effects.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

ALZ011>015-017>029-221300-
/O.EXT.KBMX.FR.Y.0002.210422T0400Z-210422T1300Z/
Marion-Lamar-Fayette-Winston-Walker-Blount-Etowah-Calhoun-
Cherokee-Cleburne-Pickens-Tuscaloosa-Jefferson-Shelby-St. Clair-
Talladega-Clay-Randolph-
Including the cities of Hamilton, Sulligent, Vernon, Fayette, 
Double Springs, Jasper, Oneonta, Gadsden, Anniston, Centre, 
Heflin, Carrollton, Tuscaloosa, Birmingham, Hoover, Columbiana, 
Pelham, Alabaster, Pell City, Moody, Talladega, Sylacauga, 
Ashland, and Roanoke
1028 PM CDT Wed Apr 21 2021

...FROST ADVISORY NOW IN EFFECT UNTIL 8 AM CDT THURSDAY...

* WHAT...Temperatures mainly between 32 and 37 degrees will 
  result in frost formation.

* WHERE...Northern portions of Central Alabama.

* WHEN...Until 8 AM CDT Thursday.

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

* ADDITIONAL DETAILS...Frost development may not be uniform or
  widespread, but some places it may be heavy and short lived
  while some areas have lighter effects. There may even be a few
  locations where a brief freeze occurs.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

Nearby

Frost Advisories in Alabama, 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.