Alert archive / California / Freeze Warnings in 2021

Freeze Warning 15, NWS Eureka, CA

March 25, 2021Lake County, Mendocino County, California

NWS Eureka, CA issued this freeze warning at Mar 25, 2021, 2:12 PM PDT for Lake County, Mendocino County, California. It took effect at Mar 26, 2021, 12:00 AM PDT. 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 25, 2021, 2:12 PM PDT (21:12 UTC)
In effect from
Mar 26, 2021, 12:00 AM PDT
Expired
Mar 26, 2021, 9:00 AM PDT
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 21:16 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, 9.2 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 2021-03-25Temperature 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 2021-03-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 129 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
752 m above ground
0-6 km bulk shear
60 kt
0-1 km storm-relative helicity
129 m²/s²
0-3 km storm-relative helicity
114 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

106 
WWUS76 KEKA 252112
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
212 PM PDT Thu Mar 25 2021

CAZ110-111-114-260515-
/O.NEW.KEKA.FZ.W.0015.210326T0700Z-210326T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-
212 PM PDT Thu Mar 25 2021

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

* WHAT...Sub-freezing temperatures as low as 30 expected.

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

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

* 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.

&&

$$

CAZ101-103-109-112-113-115-260515-
/O.NEW.KEKA.FR.Y.0017.210326T0700Z-210326T1600Z/
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake-
212 PM PDT Thu Mar 25 2021

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

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

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

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

&&

$$
2 follow-up statements
184 
WWUS76 KEKA 260517
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
1017 PM PDT Thu Mar 25 2021

CAZ110-111-114-261600-
/O.CON.KEKA.FZ.W.0015.210326T0700Z-210326T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-
1017 PM PDT Thu Mar 25 2021

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

* WHAT...Sub-freezing temperatures as low as 30 expected.

* WHERE...Northeastern Mendocino Interior, Northern Lake, and
  Northwestern Mendocino Interior counties.

* WHEN...Until 9 AM Friday.

* 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.

$$

CAZ101-103-109-112-113-115-261600-
/O.CON.KEKA.FR.Y.0017.210326T0700Z-210326T1600Z/
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake-
1017 PM PDT Thu Mar 25 2021

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

* WHAT...Temperatures as low as 35 will result in frost 
  formation.

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

* WHEN...Until 9 AM Friday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

$$
048 
WWUS76 KEKA 261545
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
845 AM PDT Fri Mar 26 2021

CAZ110-111-114-261645-
/O.EXP.KEKA.FZ.W.0015.000000T0000Z-210326T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-
845 AM PDT Fri Mar 26 2021

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


$$

CAZ101-103-109-112-113-115-261645-
/O.EXP.KEKA.FR.Y.0017.000000T0000Z-210326T1600Z/
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake-
845 AM PDT Fri Mar 26 2021

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


$$

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 25, 2:05 AM PDTGale WarningEKA28 hr
Mar 25, 2:12 PM PDTFrost AdvisoryEKADel Norte, Humboldt, Mendocino19 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.