Alert archive / Alabama / Frost Advisories in 2021

Frost Advisory 4, NWS Mobile, AL

November 23, 2021Okaloosa County, Santa Rosa County, Florida; 7 counties in Alabama

NWS Mobile, AL issued this frost advisory at Nov 23, 2021, 1:40 PM CST for Okaloosa County, Santa Rosa County, Florida; 7 counties in Alabama. It took effect at Nov 24, 2021, 12:00 AM CST. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued
Nov 23, 2021, 1:40 PM CST (19:40 UTC)
In effect from
Nov 24, 2021, 12:00 AM CST
Expired
Nov 24, 2021, 7:00 AM CST
In force
7 hr
Issued by
NWS Mobile, AL

Counties Butler County, AL, Conecuh County, AL, Covington County, AL, Crenshaw County, AL, Escambia County, AL, Monroe County, AL, Wilcox County, AL, Okaloosa County, FL, Santa Rosa County, FL

The radar

The Eglin Afb radar (KEVX), 127 km from the middle of the area, began a volume at 19:41 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 12:00Z, 7.7 hours before the alert went out and 203 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 12:00Z on 2021-11-23Temperature 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 12:00Z on 2021-11-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -144 square meters per square second.1939587897Sfc1 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
2901 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
-144 m²/s²
0-3 km storm-relative helicity
-72 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

994 
WWUS74 KMOB 231940
NPWMOB

URGENT - WEATHER MESSAGE
National Weather Service Mobile AL
140 PM CST Tue Nov 23 2021

ALZ054>060-240345-
/O.NEW.KMOB.FR.Y.0004.211124T0600Z-211124T1200Z/
Wilcox-Monroe-Conecuh-Butler-Crenshaw-Escambia-Covington-
Including the cities of Camden, Pine Hill, Homewood, Monroeville,
Evergreen, Greenville, Brantley, Luverne, Atmore, Brewton, 
Flomaton, Andalusia, and Opp
140 PM CST Tue Nov 23 2021

...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 6 AM CST
WEDNESDAY...

* WHAT...Low temperatures in the 33 to 37 degree range, wet bulb
  temperatures just below freezing, light winds and clear skies
  could result in frost formation.

* WHERE...Wilcox, Monroe, Conecuh, Butler, Crenshaw, Escambia 
  and Covington Counties.

* WHEN...From midnight tonight to 6 AM CST Wednesday.

* 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
732 
WWUS74 KMOB 232024 AAA
NPWMOB

URGENT - WEATHER MESSAGE...UPDATED
National Weather Service Mobile AL
224 PM CST Tue Nov 23 2021

FLZ203-205-240430-
/O.EXA.KMOB.FR.Y.0004.211124T0600Z-211124T1200Z/
Santa Rosa Inland-Okaloosa Inland-
Including the cities of Jay, Milton, and Crestview
224 PM CST Tue Nov 23 2021

...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 6 AM CST
WEDNESDAY...

* WHAT...Low temperatures in the 33 to 37 degree range, wet bulb
  temperatures just below freezing, light winds and clear skies
  could result in frost formation.

* WHERE...Santa Rosa Inland and Okaloosa Inland Counties.

* WHEN...From midnight tonight to 6 AM CST Wednesday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

ALZ054>060-240430-
/O.CON.KMOB.FR.Y.0004.211124T0600Z-211124T1200Z/
Wilcox-Monroe-Conecuh-Butler-Crenshaw-Escambia-Covington-
Including the cities of Camden, Pine Hill, Homewood, Monroeville,
Evergreen, Greenville, Brantley, Luverne, Atmore, Brewton, 
Flomaton, Andalusia, and Opp
224 PM CST Tue Nov 23 2021

...FROST ADVISORY REMAINS IN EFFECT FROM MIDNIGHT TONIGHT TO 6 AM
CST WEDNESDAY...

* WHAT...Low temperatures in the 33 to 37 degree range, wet bulb
  temperatures just below freezing, light winds and clear skies
  could result in frost formation.

* WHERE...Crenshaw, Escambia, Wilcox, Monroe, Conecuh, Butler 
  and Covington Counties.

* WHEN...From midnight tonight to 6 AM CST Wednesday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$
781 
WWUS74 KMOB 240238
NPWMOB

URGENT - WEATHER MESSAGE
National Weather Service Mobile AL
838 PM CST Tue Nov 23 2021

ALZ054>060-FLZ203-205-241100-
/O.EXT.KMOB.FR.Y.0004.211124T0600Z-211124T1300Z/
Wilcox-Monroe-Conecuh-Butler-Crenshaw-Escambia-Covington-
Santa Rosa Inland-Okaloosa Inland-
Including the cities of Camden, Pine Hill, Homewood, Monroeville,
Evergreen, Greenville, Brantley, Luverne, Atmore, Brewton, 
Flomaton, Andalusia, Opp, Jay, Milton, and Crestview
838 PM CST Tue Nov 23 2021

...FROST ADVISORY NOW IN EFFECT FROM MIDNIGHT TONIGHT TO 7 AM CST
WEDNESDAY...

* WHAT...Temperatures in the 33 to 37 degree range along with
  light winds and clear skies will favor frost formation.

* WHERE...In Alabama, Crenshaw, Escambia, Wilcox, Monroe, 
  Conecuh, Butler and Covington Counties. In Florida, Okaloosa 
  Inland and Santa Rosa Inland Counties.

* WHEN...From midnight tonight to 7 AM CST Wednesday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

The office that day

Everything else NWS Mobile, AL issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Nov 22, 7:06 PM CSTGale WarningMOB9 hr
Nov 22, 7:06 PM CSTSmall Craft AdvisoryMOB114 min

Nearby

Frost Advisories in Alabama, 2021Frost Advisories in Florida, 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.