Alert archive / California / Freeze Warnings in 2021

Freeze Warning 23, NWS Eureka, CA

November 23, 2021Del Norte County, Humboldt County, California

NWS Eureka, CA issued this freeze warning at Nov 23, 2021, 2:30 AM PST for Del Norte County, Humboldt County, California. It took effect at Nov 24, 2021, 2:00 AM PST. It was in force for 65 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Nov 23, 2021, 2:30 AM PST (10:30 UTC)
In effect from
Nov 24, 2021, 2:00 AM PST
Expired
Nov 24, 2021, 3:05 AM PST
In force
65 min
Issued by
NWS Eureka, CA

Counties Del Norte County, CA, Humboldt County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 86 km from the middle of the area, began a volume at 10:34 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

Medford/Jackson, OR (KMFR), launched 00:00Z, 10.5 hours before the alert went out and 158 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, Medford/Jackson, OR at 00:00Z 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, Medford/Jackson, OR at 00:00Z on 2021-11-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -6 square meters per square second.193958Sfc1 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
2103 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
-6 m²/s²
0-3 km storm-relative helicity
48 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

039 
WWUS76 KEKA 231030
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
230 AM PST Tue Nov 23 2021

CAZ102-105-106-232230-
/O.UPG.KEKA.FZ.A.0011.211124T0900Z-211124T1800Z/
/O.NEW.KEKA.FZ.W.0023.211124T1000Z-211124T1700Z/
Del Norte Interior-Northern Humboldt Interior-
Southern Humboldt Interior-
230 AM PST Tue Nov 23 2021

...FREEZE WARNING IN EFFECT FROM 2 AM TO 9 AM PST WEDNESDAY...

* WHAT...Sub-freezing temperatures as low as 29 expected.

* WHERE...Del Norte Interior, Northern Humboldt Interior and 
  Southern Humboldt Interior Counties.

* WHEN...From 2 AM to 9 AM PST Wednesday.

* IMPACTS...Frost and freeze conditions will kill crops and 
  other sensitive vegetation.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. Provide
adequate shelter for outdoor pets or consider bringing them
indoors.

Frost Advisories and Freeze Warnings are issued during the local
growing season as defined by climatology and local agriculture
experts. Once the growing season has ended these statements will
no longer be issued until the spring.

&&

$$

CAZ101-103-104-112-113-115-232230-
/O.NEW.KEKA.FR.Y.0053.211124T1000Z-211124T1700Z/
Coastal Del Norte-Northern Humboldt Coast-Southwestern Humboldt-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake-
230 AM PST Tue Nov 23 2021

...FROST ADVISORY IN EFFECT FROM 2 AM TO 9 AM PST WEDNESDAY...

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

* WHERE...Coastal Del Norte, Northern Humboldt Coast, 
  Southwestern Humboldt, Southwestern Mendocino Interior, 
  Southeastern Mendocino Interior and Southern Lake Counties.

* WHEN...From 2 AM to 9 AM PST Wednesday.

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


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

Frost Advisories and Freeze Warnings are issued during the local
growing season as defined by climatology and local agriculture
experts. Once the growing season has ended these statements will
no longer be issued until the spring.

&&

$$
3 follow-up statements
575 
WWUS76 KEKA 232221
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
221 PM PST Tue Nov 23 2021

CAZ103-240630-
/O.EXA.KEKA.FZ.W.0023.211124T1000Z-211124T1700Z/
/O.CON.KEKA.FR.Y.0053.211124T1000Z-211124T1700Z/
Northern Humboldt Coast-
221 PM PST Tue Nov 23 2021

...FREEZE WARNING IN EFFECT FROM 2 AM TO 9 AM PST WEDNESDAY...

* WHAT...For the Freeze Warning, sub-freezing temperatures as low
  as 32 expected.

* WHERE...Northern Humboldt Coast County.

* WHEN...From 2 AM to 9 AM PST Wednesday.

* IMPACTS...Frost and freeze conditions will kill crops and other
  sensitive vegetation.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. Provide
adequate shelter for outdoor pets or consider bringing them
indoors.

Frost Advisories and Freeze Warnings are issued during the local
growing season as defined by climatology and local agriculture
experts. Once the growing season has ended these statements will
no longer be issued until the spring.

&&

$$

CAZ102-105-106-240630-
/O.EXA.KEKA.FR.Y.0053.211124T1000Z-211124T1700Z/
/O.CON.KEKA.FZ.W.0023.211124T1000Z-211124T1700Z/
Del Norte Interior-Northern Humboldt Interior-
Southern Humboldt Interior-
221 PM PST Tue Nov 23 2021

...FREEZE WARNING REMAINS IN EFFECT FROM 2 AM TO 9 AM PST
WEDNESDAY...

* WHAT...For the Freeze Warning, sub-freezing temperatures as low
  as 29 expected.

* WHERE...Del Norte Interior, Northern Humboldt Interior and 
  Southern Humboldt Interior Counties.

* WHEN...From 2 AM to 9 AM PST Wednesday.

* IMPACTS...Frost and freeze conditions will kill crops and other
  sensitive vegetation.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. Provide
adequate shelter for outdoor pets or consider bringing them
indoors.

Frost Advisories and Freeze Warnings are issued during the local
growing season as defined by climatology and local agriculture
experts. Once the growing season has ended these statements will
no longer be issued until the spring.

&&

$$

CAZ109-240630-
/O.EXA.KEKA.FR.Y.0053.211124T1000Z-211124T1700Z/
Mendocino Coast-
221 PM PST Tue Nov 23 2021

...FROST ADVISORY IN EFFECT FROM 2 AM TO 9 AM PST WEDNESDAY...

* WHAT...Temperatures as low as 34 will result in frost 
  formation.

* WHERE...Mendocino Coast County.

* WHEN...From 2 AM to 9 AM PST Wednesday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

Frost Advisories and Freeze Warnings are issued during the local
growing season as defined by climatology and local agriculture
experts. Once the growing season has ended these statements will
no longer be issued until the spring.

&&

$$

CAZ101-104-112-113-115-240630-
/O.CON.KEKA.FR.Y.0053.211124T1000Z-211124T1700Z/
Coastal Del Norte-Southwestern Humboldt-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake-
221 PM PST Tue Nov 23 2021

...FROST ADVISORY REMAINS IN EFFECT FROM 2 AM TO 9 AM PST
WEDNESDAY...

* WHAT...Temperatures as low as 34 will result in frost 
  formation.

* WHERE...Coastal Del Norte, Southeastern Mendocino Interior, 
  Southwestern Humboldt, Southwestern Mendocino Interior and 
  Southern Lake Counties.

* WHEN...From 2 AM to 9 AM PST Wednesday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

Frost Advisories and Freeze Warnings are issued during the local
growing season as defined by climatology and local agriculture
experts. Once the growing season has ended these statements will
no longer be issued until the spring.

&&

$$
815 
WWUS76 KEKA 240620
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
1020 PM PST Tue Nov 23 2021

CAZ102-103-105-106-241700-
/O.CON.KEKA.FZ.W.0023.211124T1000Z-211124T1700Z/
/O.CON.KEKA.FR.Y.0053.211124T1000Z-211124T1700Z/
Del Norte Interior-Northern Humboldt Coast-
Northern Humboldt Interior-Southern Humboldt Interior-
1020 PM PST Tue Nov 23 2021

...FREEZE WARNING REMAINS IN EFFECT FROM 2 AM TO 9 AM PST
WEDNESDAY...

* WHAT...For the Freeze Warning, sub-freezing temperatures as 
  low as 32 expected.

* WHERE...Northern Humboldt Coast County.

* WHEN...From 2 AM to 9 AM PST Wednesday.

* IMPACTS...Frost and freeze conditions will kill crops and other
  sensitive vegetation.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. Provide
adequate shelter for outdoor pets or consider bringing them
indoors.

Frost Advisories and Freeze Warnings are issued during the local
growing season as defined by climatology and local agriculture
experts. Once the growing season has ended these statements will
no longer be issued until the spring.

$$

CAZ101-104-109-112-113-115-241700-
/O.CON.KEKA.FR.Y.0053.211124T1000Z-211124T1700Z/
Coastal Del Norte-Southwestern Humboldt-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake-
1020 PM PST Tue Nov 23 2021

...FROST ADVISORY REMAINS IN EFFECT FROM 2 AM TO 9 AM 
WEDNESDAY...

* WHAT...Temperatures as low as 34 will result in frost 
  formation.

* WHERE...Mendocino Coast County.

* WHEN...From 2 AM to 9 AM Wednesday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

Frost Advisories and Freeze Warnings are issued during the local
growing season as defined by climatology and local agriculture
experts. Once the growing season has ended these statements will
no longer be issued until the spring.

$$
821 
WWUS76 KEKA 241105
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
305 AM PST Wed Nov 24 2021

CAZ102-103-105-106-241700-
/O.CAN.KEKA.FZ.W.0023.000000T0000Z-211124T1700Z/
/O.CON.KEKA.FR.Y.0053.000000T0000Z-211124T1700Z/
Del Norte Interior-Northern Humboldt Coast-
Northern Humboldt Interior-Southern Humboldt Interior-
305 AM PST Wed Nov 24 2021

...FROST ADVISORY REMAINS IN EFFECT UNTIL 9 AM PST THIS MORNING...
...FREEZE WARNING IS CANCELLED...

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

* WHERE...Northern Humboldt Coast, Del Norte Interior, Northern 
  Humboldt Interior and Southern Humboldt Interior Counties.

* WHEN...Until 9 AM PST 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.

Frost Advisories and Freeze Warnings are issued during the local
growing season as defined by climatology and local agriculture
experts. Once the growing season has ended these statements will
no longer be issued until the spring.

&&

$$

CAZ101-104-109-112-113-115-241700-
/O.CON.KEKA.FR.Y.0053.000000T0000Z-211124T1700Z/
Coastal Del Norte-Southwestern Humboldt-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake-
305 AM PST Wed Nov 24 2021

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

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

* WHERE...Mendocino Coast, Coastal Del Norte, Southeastern 
  Mendocino Interior, Southwestern Humboldt, Southwestern 
  Mendocino Interior and Southern Lake Counties.

* WHEN...Until 9 AM PST 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.

Frost Advisories and Freeze Warnings are issued during the local
growing season as defined by climatology and local agriculture
experts. Once the growing season has ended these statements will
no longer be issued until the spring.

&&

$$

The office that day

Everything else NWS Eureka, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Nov 23, 2:30 AM PSTFrost AdvisoryEKADel Norte, Humboldt, Mendocino31 hr

Nearby

Freeze Warnings in California, 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.