Alert archive / California / Freeze Warnings in 2021

Freeze Warning 7, NWS Eureka, CA

March 11, 2021Lake County, Mendocino County, California

NWS Eureka, CA issued this freeze warning at Mar 11, 2021, 1:04 PM PST for Lake County, Mendocino County, California. It took effect at Mar 12, 2021, 12:00 AM PST. It was in force for 9 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
Mar 11, 2021, 1:04 PM PST (21:04 UTC)
In effect from
Mar 12, 2021, 12:00 AM PST
Expired
Mar 12, 2021, 9:00 AM PST
In force
9 hr
Issued by
NWS Eureka, CA

Counties Lake County, CA, Mendocino County, CA

The radar

The Beale AFB radar (KBBX), 128 km from the middle of the area, began a volume at 21:05 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

Oakland, CA (KOAK), launched 12:00Z, 9.1 hours before the alert went out and 188 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, Oakland, CA at 12:00Z on 2021-03-11Temperature 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, Oakland, CA at 12:00Z on 2021-03-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -10 square meters per square second.1939Sfc1 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
743 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
-10 m²/s²
0-3 km storm-relative helicity
1 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

072 
WWUS76 KEKA 112104
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
104 PM PST Thu Mar 11 2021

CAZ110-111-113>115-120515-
/O.NEW.KEKA.FZ.W.0007.210312T0800Z-210312T1700Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southeastern Mendocino Interior-Northern Lake County-
Southern Lake County-
104 PM PST Thu Mar 11 2021

...FREEZE WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM PST
FRIDAY...

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

* WHERE...Portions of the Northwestern Mendocino Interior,
  Northeastern Mendocino Interior, Southeastern Mendocino
  Interior, Northern Lake County and Southern Lake County.
  Locations include Covelo, Laytonville, Willits, Potter Valley,
  Ukiah, Hopland, Lakeport, and Upper Lake. 

* WHEN...From midnight tonight to 9 AM PST 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..

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.

&&

$$

CAZ103-109-112-120515-
/O.NEW.KEKA.FR.Y.0008.210312T0800Z-210312T1700Z/
Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-
104 PM PST Thu Mar 11 2021

...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM PST
FRIDAY...

* WHAT...Temperatures as low as 32 will result in frost 
  formation.

* WHERE...Portions of the Northern Humboldt Coast, Mendocino Coast
  and Southwestern Mendocino Interior Counties. Locations include
  Boonville, Navarro, inland areas near Fort Bragg, Carlotta,
  Eureka, Arcata, Blue Lake, and McKinleyville. 

* WHEN...From midnight tonight to 9 AM PST Friday.

* 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
447 
WWUS76 KEKA 120511
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
911 PM PST Thu Mar 11 2021

CAZ110-111-113>115-121315-
/O.CON.KEKA.FZ.W.0007.210312T0800Z-210312T1700Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southeastern Mendocino Interior-Northern Lake County-
Southern Lake County-
911 PM PST Thu Mar 11 2021

...FREEZE WARNING REMAINS IN EFFECT UNTIL 9 AM PST FRIDAY...

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

* WHERE...Portions of the Northwestern Mendocino Interior, 
  Northeastern Mendocino Interior, Southeastern Mendocino 
  Interior, Northern Lake County and Southern Lake County. 
  Locations include Covelo, Laytonville, Willits, Potter Valley, 
  Ukiah, Hopland, Lakeport, and Upper Lake.

* WHEN...From midnight tonight to 9 AM PST 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..

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.

&&

$$

CAZ103-109-112-121315-
/O.CON.KEKA.FR.Y.0008.210312T0800Z-210312T1700Z/
Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-
911 PM PST Thu Mar 11 2021

...FROST ADVISORY REMAINS IN EFFECT UNTIL 9 AM PST FRIDAY...

* WHAT...Temperatures as low as 32 will result in frost 
  formation.

* WHERE...Portions of the Northern Humboldt Coast, Mendocino 
  Coast and Southwestern Mendocino Interior Counties. Locations 
  include Boonville, Navarro, inland areas near Fort Bragg, 
  Carlotta, Eureka, Arcata, Blue Lake, and McKinleyville.

* WHEN...From midnight tonight to 9 AM PST Friday.

* 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.

&&

$$
593 
WWUS76 KEKA 121219
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
419 AM PST Fri Mar 12 2021

CAZ110-111-113>115-121700-
/O.CON.KEKA.FZ.W.0007.000000T0000Z-210312T1700Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southeastern Mendocino Interior-Northern Lake County-
Southern Lake County-
419 AM PST Fri Mar 12 2021

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

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

* WHERE...Southeastern Mendocino Interior, Northeastern 
  Mendocino Interior, Northern Lake County, Southern Lake County 
  and Northwestern Mendocino Interior Counties.

* WHEN...Until 9 AM PST 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.

&&

$$

CAZ103-109-112-121700-
/O.CON.KEKA.FR.Y.0008.000000T0000Z-210312T1700Z/
Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-
419 AM PST Fri Mar 12 2021

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

* WHAT...Temperatures as low as 32 will result in frost 
  formation.

* WHERE...Mendocino Coast, Southwestern Mendocino Interior and 
  Northern Humboldt Coast 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.

&&

$$
143 
WWUS76 KEKA 121655
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
855 AM PST Fri Mar 12 2021

CAZ110-111-113>115-121800-
/O.EXP.KEKA.FZ.W.0007.000000T0000Z-210312T1700Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southeastern Mendocino Interior-Northern Lake County-
Southern Lake County-
855 AM PST Fri Mar 12 2021

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


$$

CAZ103-109-112-121800-
/O.EXP.KEKA.FR.Y.0008.000000T0000Z-210312T1700Z/
Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-
855 AM PST Fri Mar 12 2021

...FROST ADVISORY WILL EXPIRE AT 9 AM PST THIS MORNING...


$$

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 11, 1:04 PM PSTFrost AdvisoryEKAHumboldt, Mendocino20 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.