Alert archive / Oklahoma / Freeze Warnings in 2021

Freeze Warning 4, NWS Tulsa, OK

April 21, 20214 counties in Arkansas; 5 counties in Oklahoma

NWS Tulsa, OK issued this freeze warning at Apr 21, 2021, 1:18 PM CDT for 4 counties in Arkansas; 5 counties in Oklahoma. It took effect at Apr 22, 2021, 1:00 AM CDT. It was in force for 7 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Apr 21, 2021, 1:18 PM CDT (18:18 UTC)
In effect from
Apr 22, 2021, 1:00 AM CDT
Expired
Apr 22, 2021, 8:00 AM CDT
In force
7 hr
Issued by
NWS Tulsa, OK

Counties Benton County, AR, Carroll County, AR, Madison County, AR, Washington County, AR, Adair County, OK, Craig County, OK, Delaware County, OK, Nowata County, OK, Ottawa County, OK

The radar

The Tulsa radar (KINX), 95 km from the middle of the area, began a volume at 18:19 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, 6.3 hours before the alert went out and 88 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 2021-04-21Temperature 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, Springfield, MO at 12:00Z on 2021-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -21 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
1618 m above ground
0-6 km bulk shear
80 kt
0-1 km storm-relative helicity
-21 m²/s²
0-3 km storm-relative helicity
39 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

166 
WWUS74 KTSA 211818
NPWTSA

URGENT - WEATHER MESSAGE
National Weather Service Tulsa OK
118 PM CDT Wed Apr 21 2021

ARZ001-002-010-011-OKZ056>058-063-069-221300-
/O.UPG.KTSA.FR.Y.0001.210422T0600Z-210422T1300Z/
/O.NEW.KTSA.FZ.W.0004.210422T0600Z-210422T1300Z/
Benton-Carroll-Washington AR-Madison-Nowata-Craig-Ottawa-Delaware-
Adair-
Including the cities of Rogers, Bentonville, Berryville, 
Eureka Springs, Fayetteville, Springdale, Huntsville, Nowata, 
Vinita, Miami, Grove, Jay, and Stilwell
118 PM CDT Wed Apr 21 2021

...FREEZE WARNING IN EFFECT FROM 1 AM TO 8 AM CDT THURSDAY...

* WHAT...Sub-freezing temperatures as low as 31 expected.

* WHERE...In Oklahoma, Nowata, Craig, Ottawa, Delaware and Adair 
  Counties. In Arkansas, Benton, Carroll, Washington AR and 
  Madison Counties.

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

* IMPACTS...These conditions will kill plants and other tender 
  vegetation that are left outdoors or unprotected.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Precautions should be taken to protect small plants and tender 
vegetation.

&&

$$

Stay tuned to NOAA weather radio,commercial radio or television
for the latest information,forecasts,and warnings.
For more information from the National Weather Service visit
https://weather.gov/tsa
2 follow-up statements
867 
WWUS74 KTSA 220838
NPWTSA

URGENT - WEATHER MESSAGE
National Weather Service Tulsa OK
338 AM CDT Thu Apr 22 2021

ARZ001-002-010-011-OKZ056>058-063-069-221300-
/O.CON.KTSA.FZ.W.0004.000000T0000Z-210422T1300Z/
Benton-Carroll-Washington AR-Madison-Nowata-Craig-Ottawa-Delaware-
Adair-
Including the cities of Rogers, Bentonville, Berryville, 
Eureka Springs, Fayetteville, Springdale, Huntsville, Nowata, 
Vinita, Miami, Grove, Jay, and Stilwell
338 AM CDT Thu Apr 22 2021

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

* WHAT...Sub-freezing temperatures as low as 31 expected.

* WHERE...In Oklahoma, Nowata, Craig, Ottawa, Delaware and Adair 
  Counties. In Arkansas, Benton, Carroll, Washington AR and 
  Madison Counties.

* WHEN...Until 8 AM CDT Thursday.

* IMPACTS...These conditions will kill plants and other tender 
  vegetation that are left outdoors or unprotected.

PRECAUTIONARY/PREPAREDNESS ACTIONS...
Precautions should be taken to protect small plants and tender 
vegetation.

&&

$$

Stay tuned to NOAA weather radio,commercial radio or television
for the latest information,forecasts,and warnings.
For more information from the National Weather Service visit
https://weather.gov/tsa
914 
WWUS74 KTSA 221255
NPWTSA

URGENT - WEATHER MESSAGE
National Weather Service Tulsa OK
755 AM CDT Thu Apr 22 2021

ARZ001-002-010-011-OKZ056>058-063-069-221400-
/O.EXP.KTSA.FZ.W.0004.000000T0000Z-210422T1300Z/
Benton-Carroll-Washington AR-Madison-Nowata-Craig-Ottawa-Delaware-
Adair-
Including the cities of Rogers, Bentonville, Berryville, 
Eureka Springs, Fayetteville, Springdale, Huntsville, Nowata, 
Vinita, Miami, Grove, Jay, and Stilwell
755 AM CDT Thu Apr 22 2021

...FREEZE WARNING WILL EXPIRE AT 8 AM CDT THIS MORNING...

Temperatures have begun to warm above freezing over most locations
this morning...with any remaining locations warming over the next
hour. Thus...the freeze warning will be allowed to expire. 

$$

Stay tuned to NOAA weather radio,commercial radio or television
for the latest information,forecasts,and warnings.
For more information from the National Weather Service visit
https://weather.gov/tsa

The office that day

Everything else NWS Tulsa, OK issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 21, 3:41 AM CDTFrost AdvisoryTSABenton, Carroll, Madison, Washington10 hr

Nearby

Freeze Warnings in Oklahoma, 2021Freeze Warnings in Arkansas, 2021Every freeze warning 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.