Alert archive / Tennessee / Frost Advisories in 2021

Frost Advisory 3, NWS Nashville, TN

April 21, 202117 counties in Tennessee

NWS Nashville, TN issued this frost advisory at Apr 21, 2021, 2:13 AM CDT for 17 counties in Tennessee. 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, 2:13 AM CDT (07:13 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 Nashville, TN

Counties Cheatham County, TN, Davidson County, TN, Dickson County, TN, Giles County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Lawrence County, TN, Lewis County, TN, Marshall County, TN, Maury County, TN, Montgomery County, TN, Perry County, TN, Robertson County, TN, Stewart County, TN, Wayne County, TN, Williamson County, TN

The radar

The Nashville radar (KOHX), 80 km from the middle of the area, began a volume at 07:14 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

Nashville Metro, TN (KBNA), launched 00:00Z, 7.2 hours before the alert went out and 71 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, Nashville Metro, TN at 00:00Z on 2021-04-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 8 joules per kilogram.LCLEL10008507005003002001001 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, Nashville Metro, TN at 00:00Z on 2021-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 40 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
8 J/kg
Mixed-layer CIN
-2 J/kg
Mixed-layer LCL
2754 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
40 m²/s²
0-3 km storm-relative helicity
80 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

870 
WWUS74 KOHX 210713
NPWOHX

URGENT - WEATHER MESSAGE
National Weather Service Nashville TN
213 AM CDT Wed Apr 21 2021

TNZ008>011-028>034-062>066-075-077>080-221300-
/O.UPG.KOHX.FZ.A.0001.210422T0500Z-210422T1300Z/
/O.NEW.KOHX.FZ.W.0003.210422T0400Z-210422T1300Z/
Sumner-Macon-Clay-Pickett-Wilson-Trousdale-Smith-Jackson-Putnam-
Overton-Fentress-Rutherford-Cannon-De Kalb-White-Cumberland-
Bedford-Coffee-Warren-Grundy-Van Buren-
Including the cities of Hendersonville, Gallatin, Goodlettsville,
Lafayette, Celina, Byrdstown, Lebanon, Mount Juliet, Hartsville, 
Carthage, South Carthage, Gordonsville, Gainesboro, Cookeville, 
Livingston, Jamestown, Allardt, Murfreesboro, Smyrna, La Vergne, 
Woodbury, Smithville, Sparta, Crossville, Shelbyville, Tullahoma,
Manchester, McMinnville, Altamont, Coalmont, and Spencer
213 AM CDT Wed Apr 21 2021

...FREEZE WARNING IN EFFECT FROM 11 PM THIS EVENING TO 8 AM CDT
THURSDAY...

* WHAT...Sub-freezing temperatures in the low 30s expected, with
  upper 20s possible on the Cumberland Plateau.

* WHERE...Eastern half of Middle Tennessee.

* WHEN...From 11 PM this evening to 8 AM CDT Thursday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. To prevent
freezing and possible bursting of outdoor water pipes they should
be wrapped, drained, or allowed to drip slowly. Those that have
in-ground sprinkler systems should drain them and cover above-
ground pipes to protect them from freezing.

&&

$$

TNZ005>007-023>027-056>061-093>095-221300-
/O.NEW.KOHX.FR.Y.0003.210422T0400Z-210422T1300Z/
Stewart-Montgomery-Robertson-Houston-Humphreys-Dickson-Cheatham-
Davidson-Perry-Hickman-Lewis-Williamson-Maury-Marshall-Wayne-
Lawrence-Giles-
Including the cities of Dover, Clarksville, Springfield, Erin, 
Tennessee Ridge, Waverly, New Johnsonville, McEwen, Dickson, 
Ashland City, Kingston Springs, Nashville, Linden, Lobelville, 
Centerville, Hohenwald, Franklin, Brentwood, Columbia, Lewisburg,
Clifton, Waynesboro, Lawrenceburg, and Pulaski
213 AM CDT Wed Apr 21 2021

...FROST ADVISORY IN EFFECT FROM 11 PM THIS EVENING TO 8 AM CDT
THURSDAY...

* WHAT...Temperatures as low as 33 will result in frost 
  formation.

* WHERE...Western half of Middle Tennessee.

* WHEN...From 11 PM this evening 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
842 
WWUS74 KOHX 220720
NPWOHX

URGENT - WEATHER MESSAGE
National Weather Service Nashville TN
220 AM CDT Thu Apr 22 2021

TNZ009>011-029>034-063>066-077>080-221315-
/O.NEW.KOHX.FR.Y.0004.210423T0500Z-210423T1200Z/
/O.CON.KOHX.FZ.W.0003.000000T0000Z-210422T1300Z/
Macon-Clay-Pickett-Trousdale-Smith-Jackson-Putnam-Overton-
Fentress-Cannon-De Kalb-White-Cumberland-Coffee-Warren-Grundy-
Van Buren-
Including the cities of Lafayette, Celina, Byrdstown, Hartsville,
Carthage, South Carthage, Gordonsville, Gainesboro, Cookeville, 
Livingston, Jamestown, Allardt, Woodbury, Smithville, Sparta, 
Crossville, Tullahoma, Manchester, McMinnville, Altamont, 
Coalmont, and Spencer
220 AM CDT Thu Apr 22 2021

...FREEZE WARNING REMAINS IN EFFECT UNTIL 8 AM CDT THIS MORNING...
...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 7 AM CDT
FRIDAY...

* WHAT...For the Freeze Warning, sub-freezing temperatures as low
  as 28. For the Frost Advisory, temperatures as low as 34 will 
  result in frost formation.

* WHERE...Eastern half of Middle Tennessee.

* WHEN...For the Freeze Warning, until 8 AM CDT this morning. 
  For the Frost Advisory, from midnight tonight to 7 AM CDT 
  Friday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. To prevent
freezing and possible bursting of outdoor water pipes they should
be wrapped, drained, or allowed to drip slowly. Those that have
in-ground sprinkler systems should drain them and cover above-
ground pipes to protect them from freezing.

&&

$$

TNZ008-028-062-075-221300-
/O.CON.KOHX.FZ.W.0003.000000T0000Z-210422T1300Z/
Sumner-Wilson-Rutherford-Bedford-
Including the cities of Hendersonville, Gallatin, Goodlettsville,
Lebanon, Mount Juliet, Murfreesboro, Smyrna, La Vergne, 
and Shelbyville
220 AM CDT Thu Apr 22 2021

...FREEZE WARNING REMAINS IN EFFECT UNTIL 8 AM CDT THIS MORNING...

* WHAT...Sub-freezing temperatures in the low 30s expected, with 
  upper 20s possible on the Cumberland Plateau.

* WHERE...Eastern half of Middle Tennessee.

* WHEN...Until 8 AM CDT today.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. To prevent
freezing and possible bursting of outdoor water pipes they should
be wrapped, drained, or allowed to drip slowly. Those that have
in-ground sprinkler systems should drain them and cover above-
ground pipes to protect them from freezing.

&&

$$

TNZ005>007-023>027-056>061-093>095-221300-
/O.CON.KOHX.FR.Y.0003.000000T0000Z-210422T1300Z/
Stewart-Montgomery-Robertson-Houston-Humphreys-Dickson-Cheatham-
Davidson-Perry-Hickman-Lewis-Williamson-Maury-Marshall-Wayne-
Lawrence-Giles-
Including the cities of Dover, Clarksville, Springfield, Erin, 
Tennessee Ridge, Waverly, New Johnsonville, McEwen, Dickson, 
Ashland City, Kingston Springs, Nashville, Linden, Lobelville, 
Centerville, Hohenwald, Franklin, Brentwood, Columbia, Lewisburg,
Clifton, Waynesboro, Lawrenceburg, and Pulaski
220 AM CDT Thu Apr 22 2021

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

* WHAT...Temperatures as low as 33 will result in frost 
  formation.

* WHERE...Western half of Middle Tennessee.

* WHEN...Until 8 AM CDT today.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$
687 
WWUS74 KOHX 221310
NPWOHX

URGENT - WEATHER MESSAGE
National Weather Service Nashville TN
810 AM CDT Thu Apr 22 2021

TNZ009>011-029>034-063>066-077>080-222000-
/O.EXP.KOHX.FZ.W.0003.000000T0000Z-210422T1300Z/
/O.CON.KOHX.FR.Y.0004.210423T0500Z-210423T1200Z/
Macon-Clay-Pickett-Trousdale-Smith-Jackson-Putnam-Overton-
Fentress-Cannon-De Kalb-White-Cumberland-Coffee-Warren-Grundy-
Van Buren-
Including the cities of Lafayette, Celina, Byrdstown, Hartsville,
Carthage, South Carthage, Gordonsville, Gainesboro, Cookeville, 
Livingston, Jamestown, Allardt, Woodbury, Smithville, Sparta, 
Crossville, Tullahoma, Manchester, McMinnville, Altamont, 
Coalmont, and Spencer
810 AM CDT Thu Apr 22 2021

...FROST ADVISORY REMAINS IN EFFECT FROM MIDNIGHT TONIGHT TO 7 AM
CDT FRIDAY...
...FREEZE WARNING HAS EXPIRED...

* WHAT...Temperatures as low as 36 will result in frost 
  formation.

* WHERE...Eastern Portion of Middle Tennessee just west of and
  across Cumberland Plateau Region. 

* WHEN...For Frost Advisory, midnight tonight to 7 AM CDT Friday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

TNZ008-028-062-075-221415-
/O.EXP.KOHX.FZ.W.0003.000000T0000Z-210422T1300Z/
Sumner-Wilson-Rutherford-Bedford-
Including the cities of Hendersonville, Gallatin, Goodlettsville,
Lebanon, Mount Juliet, Murfreesboro, Smyrna, La Vergne, 
and Shelbyville
810 AM CDT Thu Apr 22 2021

...FREEZE WARNING HAS EXPIRED...

The freeze warning for these locations has expired.

$$

TNZ005>007-023>027-056>061-093>095-221415-
/O.EXP.KOHX.FR.Y.0003.000000T0000Z-210422T1300Z/
Stewart-Montgomery-Robertson-Houston-Humphreys-Dickson-Cheatham-
Davidson-Perry-Hickman-Lewis-Williamson-Maury-Marshall-Wayne-
Lawrence-Giles-
Including the cities of Dover, Clarksville, Springfield, Erin, 
Tennessee Ridge, Waverly, New Johnsonville, McEwen, Dickson, 
Ashland City, Kingston Springs, Nashville, Linden, Lobelville, 
Centerville, Hohenwald, Franklin, Brentwood, Columbia, Lewisburg,
Clifton, Waynesboro, Lawrenceburg, and Pulaski
810 AM CDT Thu Apr 22 2021

...FROST ADVISORY HAS EXPIRED...

The frost advisory for these locations has expired.

$$
JB Wright

The office that day

Everything else NWS Nashville, TN issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 21, 2:13 AM CDTFreeze WarningOHXBedford, Cannon, Clay, Coffee, Cumberland, DeKalb and 15 more30 hr

Nearby

Frost Advisories in Tennessee, 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.