Alert archive / California / Freeze Warnings in 2021

Freeze Warning 20, NWS Eureka, CA

October 11, 20214 counties in California

NWS Eureka, CA issued this freeze warning at Oct 11, 2021, 2:11 PM PDT for 4 counties in California. It took effect at Oct 12, 2021, 2:00 AM PDT. 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
Oct 11, 2021, 2:11 PM PDT (21:11 UTC)
In effect from
Oct 12, 2021, 2:00 AM PDT
Expired
Oct 12, 2021, 9:00 AM PDT
In force
7 hr
Issued by
NWS Eureka, CA

Counties Del Norte County, CA, Humboldt County, CA, Lake County, CA, Mendocino County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 72 km from the middle of the area, began a volume at 21:12 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 12:00Z, 9.2 hours before the alert went out and 244 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 12:00Z on 2021-10-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 24 joules per kilogram.LCLLFCEL10008507005003002001001 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 12:00Z on 2021-10-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 97 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
24 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
823 m above ground
0-6 km bulk shear
58 kt
0-1 km storm-relative helicity
97 m²/s²
0-3 km storm-relative helicity
142 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

041 
WWUS76 KEKA 112111
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
211 PM PDT Mon Oct 11 2021

CAZ106>108-120515-
/O.UPG.KEKA.HZ.A.0003.211012T0900Z-211012T1600Z/
/O.NEW.KEKA.HZ.W.0004.211012T0900Z-211012T1600Z/
Southern Humboldt Interior-Northern Trinity-Southern Trinity-
211 PM PDT Mon Oct 11 2021

...HARD FREEZE WARNING IN EFFECT FROM 2 AM TO 9 AM PDT TUESDAY...

* WHAT...Sub-freezing temperatures as low as 23 expected.

* WHERE...Southern Humboldt Interior, Northern Trinity and 
  Southern Trinity Counties.

* WHEN...From 2 AM to 9 AM PDT Tuesday.

* 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.

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.

&&

$$

CAZ111-120515-
/O.UPG.KEKA.FZ.A.0007.211012T0900Z-211012T1600Z/
/O.NEW.KEKA.FZ.W.0020.211012T0900Z-211012T1600Z/
Northeastern Mendocino Interior-
211 PM PDT Mon Oct 11 2021

...FREEZE WARNING IN EFFECT FROM 2 AM TO 9 AM PDT TUESDAY...

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

* WHERE...Northeastern Mendocino Interior County.

* WHEN...From 2 AM to 9 AM PDT Tuesday.

* 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.

&&

$$

CAZ102-105-110-114-120515-
/O.NEW.KEKA.FZ.W.0020.211012T0900Z-211012T1600Z/
Del Norte Interior-Northern Humboldt Interior-
Northwestern Mendocino Interior-Northern Lake-
211 PM PDT Mon Oct 11 2021

...FREEZE WARNING IN EFFECT FROM 2 AM TO 9 AM PDT TUESDAY...

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

* WHERE...Del Norte Interior, Northern Humboldt Interior, 
  Northwestern Mendocino Interior and Northern Lake Counties.

* WHEN...From 2 AM to 9 AM PDT Tuesday.

* 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.

&&

$$
3 follow-up statements
817 
WWUS76 KEKA 120502
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
1002 PM PDT Mon Oct 11 2021

CAZ106>108-121315-
/O.CON.KEKA.HZ.W.0004.211012T0900Z-211012T1600Z/
Southern Humboldt Interior-Northern Trinity-Southern Trinity-
1002 PM PDT Mon Oct 11 2021

...HARD FREEZE WARNING REMAINS IN EFFECT FROM 2 AM TO 9 AM PDT
TUESDAY...

* WHAT...Sub-freezing temperatures as low as 23 expected.

* WHERE...Southern Trinity, Northern Trinity and Southern 
  Humboldt Interior Counties.

* WHEN...From 2 AM to 9 AM PDT Tuesday.

* 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.

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.

&&

$$

CAZ102-105-110-111-114-121315-
/O.CON.KEKA.FZ.W.0020.211012T0900Z-211012T1600Z/
Del Norte Interior-Northern Humboldt Interior-
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-
1002 PM PDT Mon Oct 11 2021

...FREEZE WARNING REMAINS IN EFFECT FROM 2 AM TO 9 AM PDT
TUESDAY...

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

* WHERE...Northeastern Mendocino Interior, Northwestern 
  Mendocino Interior, Del Norte Interior, Northern Humboldt 
  Interior and Northern Lake Counties.

* WHEN...From 2 AM to 9 AM PDT Tuesday.

* 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.

&&

$$
673 
WWUS76 KEKA 121056
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
356 AM PDT Tue Oct 12 2021

CAZ106>108-121600-
/O.CON.KEKA.HZ.W.0004.000000T0000Z-211012T1600Z/
Southern Humboldt Interior-Northern Trinity-Southern Trinity-
356 AM PDT Tue Oct 12 2021

...HARD FREEZE WARNING REMAINS IN EFFECT UNTIL 9 AM PDT THIS
MORNING...

* WHAT...Sub-freezing temperatures as low as 23.

* WHERE...Southern Trinity, Northern Trinity and Southern 
  Humboldt Interior Counties.

* WHEN...Until 9 AM PDT this morning.

* 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.

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.

&&

$$

CAZ102-105-110-111-114-121600-
/O.CON.KEKA.FZ.W.0020.000000T0000Z-211012T1600Z/
Del Norte Interior-Northern Humboldt Interior-
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-
356 AM PDT Tue Oct 12 2021

...FREEZE WARNING REMAINS IN EFFECT UNTIL 9 AM PDT THIS MORNING...

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

* WHERE...Northeastern Mendocino Interior, Northwestern 
  Mendocino Interior, Del Norte Interior, Northern Humboldt 
  Interior and Northern Lake Counties.

* WHEN...Until 9 AM PDT this morning.

* 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.

&&

$$
335 
WWUS76 KEKA 121545
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
845 AM PDT Tue Oct 12 2021

CAZ106>108-121645-
/O.EXP.KEKA.HZ.W.0004.000000T0000Z-211012T1600Z/
Southern Humboldt Interior-Northern Trinity-Southern Trinity-
845 AM PDT Tue Oct 12 2021

...HARD FREEZE WARNING WILL EXPIRE AT 9 AM PDT THIS MORNING...



$$

CAZ102-105-110-111-114-121645-
/O.EXP.KEKA.FZ.W.0020.000000T0000Z-211012T1600Z/
Del Norte Interior-Northern Humboldt Interior-
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-
845 AM PDT Tue Oct 12 2021

...FREEZE WARNING WILL EXPIRE AT 9 AM PDT THIS MORNING...



$$

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 11, 7:58 AM PDTHard Freeze WatchEKAHumboldt, Trinity6 hr
Oct 11, 2:06 PM PDTHazardous Seas WarningEKA13 hr
Oct 11, 2:11 PM PDTHard Freeze WarningEKAHumboldt, Trinity19 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.