Alert archive / California / Hard Freeze Warnings in 2021

Hard Freeze Warning 2, NWS Eureka, CA

March 15, 2021Lake County, Mendocino County, California

NWS Eureka, CA issued this hard freeze warning at Mar 15, 2021, 1:38 PM PDT for Lake County, Mendocino County, California. It took effect at Mar 16, 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 15, 2021, 1:38 PM PDT (20:38 UTC)
In effect from
Mar 16, 2021, 12:00 AM PDT
Expired
Mar 16, 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 20:38 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, 8.6 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 2021-03-15Temperature 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 2021-03-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -39 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
838 m above ground
0-6 km bulk shear
68 kt
0-1 km storm-relative helicity
-39 m²/s²
0-3 km storm-relative helicity
-20 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

873 
WWUS76 KEKA 152038
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
138 PM PDT Mon Mar 15 2021

CAZ110-111-114-161600-
/O.UPG.KEKA.HZ.A.0002.210316T0700Z-210316T1600Z/
/O.NEW.KEKA.HZ.W.0002.210316T0700Z-210316T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake County-
138 PM PDT Mon Mar 15 2021

...HARD FREEZE WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM
TUESDAY...

* WHAT...Sub-freezing temperatures as low as 22 expected.

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

* WHEN...From midnight tonight to 9 AM 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 who have 
in-ground sprinkler systems should drain them and cover above- 
ground pipes to protect them from freezing.

$$

CAZ101-103-104-112-113-115-161600-
/O.UPG.KEKA.FZ.A.0002.210316T0700Z-210316T1600Z/
/O.NEW.KEKA.FZ.W.0010.210316T0700Z-210316T1600Z/
Coastal Del Norte-Northern Humboldt Coast-Southwestern Humboldt-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake County-
138 PM PDT Mon Mar 15 2021

...FREEZE WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM TUESDAY...

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

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

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

$$
4 follow-up statements
843 
WWUS76 KEKA 152047
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
147 PM PDT Mon Mar 15 2021

CAZ104-152200-
/O.CAN.KEKA.FZ.W.0010.210316T0700Z-210316T1600Z/
Southwestern Humboldt-
147 PM PDT Mon Mar 15 2021

...FREEZE WARNING IS CANCELLED...

The growing season in Southwestern Humboldt County does not begin
until April 1st.

$$

CAZ110-111-114-161600-
/O.CON.KEKA.HZ.W.0002.210316T0700Z-210316T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake County-
147 PM PDT Mon Mar 15 2021

...HARD FREEZE WARNING REMAINS IN EFFECT FROM MIDNIGHT TONIGHT TO
9 AM TUESDAY...

* WHAT...Sub-freezing temperatures as low as 22 expected.

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

* WHEN...From midnight tonight to 9 AM 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 who have 
in-ground sprinkler systems should drain them and cover above- 
ground pipes to protect them from freezing.

$$

CAZ101-103-112-113-115-161600-
/O.CON.KEKA.FZ.W.0010.210316T0700Z-210316T1600Z/
Coastal Del Norte-Northern Humboldt Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake County-
147 PM PDT Mon Mar 15 2021

...FREEZE WARNING REMAINS IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM
TUESDAY...

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

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

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

$$
878 
WWUS76 KEKA 160200
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
700 PM PDT Mon Mar 15 2021

CAZ109-161000-
/O.EXA.KEKA.FZ.W.0010.210316T0700Z-210316T1600Z/
Mendocino Coast-
700 PM PDT Mon Mar 15 2021

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

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

* WHERE...Mendocino Coast County.

* WHEN...From midnight tonight 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.

&&

$$

CAZ110-111-114-161000-
/O.CON.KEKA.HZ.W.0002.210316T0700Z-210316T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake County-
700 PM PDT Mon Mar 15 2021

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

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

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

* WHEN...From midnight tonight 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.

&&

$$

CAZ101-103-112-113-115-161000-
/O.CON.KEKA.FZ.W.0010.210316T0700Z-210316T1600Z/
Coastal Del Norte-Northern Humboldt Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake County-
700 PM PDT Mon Mar 15 2021

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

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

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

* WHEN...From midnight tonight 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.

&&

$$
647 
WWUS76 KEKA 160926
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
226 AM PDT Tue Mar 16 2021

CAZ110-111-114-161600-
/O.CON.KEKA.HZ.W.0002.000000T0000Z-210316T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake County-
226 AM PDT Tue Mar 16 2021

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

* WHAT...Sub-freezing low temperatures from 23 to 28 expected.

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

* WHEN...From midnight tonight 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.

&&

$$

CAZ101-103-109-112-113-115-161600-
/O.CON.KEKA.FZ.W.0010.000000T0000Z-210316T1600Z/
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake County-
226 AM PDT Tue Mar 16 2021

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

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

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

* WHEN...From midnight tonight 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.

&&

$$
079 
WWUS76 KEKA 161608
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
908 AM PDT Tue Mar 16 2021

CAZ110-111-114-170015-
/O.EXP.KEKA.HZ.W.0002.000000T0000Z-210316T1600Z/
/O.NEW.KEKA.FZ.A.0003.210317T0700Z-210317T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake County-
908 AM PDT Tue Mar 16 2021

...FREEZE WATCH IN EFFECT FROM LATE TONIGHT THROUGH WEDNESDAY
MORNING...
...HARD FREEZE WARNING HAS EXPIRED...

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

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

* WHEN...From late tonight through Wednesday morning.

* IMPACTS...Frost and freeze conditions could kill crops, other
  sensitive vegetation and possibly damage unprotected outdoor
  plumbing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. 

$$

CAZ101-103-109-112-113-115-161715-
/O.EXP.KEKA.FZ.W.0010.000000T0000Z-210316T1600Z/
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake County-
908 AM PDT Tue Mar 16 2021

...FREEZE WARNING HAS EXPIRED...

Widespread frost is likely again tonight.

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 15, 3:21 AM PDTFreeze WatchEKADel Norte, Humboldt, Mendocino10 hr
Mar 15, 3:29 AM PDTHard Freeze WatchEKALake, Mendocino10 hr
Mar 15, 1:38 PM PDTFreeze WarningEKADel Norte, Humboldt, Mendocino19 hr

Nearby

Hard Freeze Warnings in California, 2021Every hard 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.