Alert archive / California / Freeze Warnings in 2021

Freeze Warning 11, NWS Eureka, CA

March 16, 2021Lake County, Mendocino County, California

NWS Eureka, CA issued this freeze warning at Mar 16, 2021, 1:27 PM PDT for Lake County, Mendocino County, California. It took effect at Mar 17, 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 16, 2021, 1:27 PM PDT (20:27 UTC)
In effect from
Mar 17, 2021, 12:00 AM PDT
Expired
Mar 17, 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 20:32 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, 8.5 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 2021-03-16Temperature 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 2021-03-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 45 square meters per square second.19395878Sfc1 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
1193 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
45 m²/s²
0-3 km storm-relative helicity
115 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

528 
WWUS76 KEKA 162027
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
127 PM PDT Tue Mar 16 2021

CAZ110-111-114-171600-
/O.UPG.KEKA.FZ.A.0003.210317T0700Z-210317T1600Z/
/O.NEW.KEKA.FZ.W.0011.210317T0700Z-210317T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake County-
127 PM PDT Tue Mar 16 2021

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

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

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

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

$$

CAZ101-103-109-112-113-115-171600-
/O.NEW.KEKA.FR.Y.0011.210317T0700Z-210317T1600Z/
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake County-
127 PM PDT Tue Mar 16 2021

...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM 
WEDNESDAY...

* 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 Wednesday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

$$
3 follow-up statements
838 
WWUS76 KEKA 170206
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
706 PM PDT Tue Mar 16 2021

CAZ115-171015-
/O.UPG.KEKA.FR.Y.0011.210317T0700Z-210317T1600Z/
/O.EXA.KEKA.FZ.W.0011.210317T0700Z-210317T1600Z/
Southern Lake-
706 PM PDT Tue Mar 16 2021

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

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

* WHERE...Southern Lake County.

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

* 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.

&&

$$

CAZ110-111-114-171015-
/O.CON.KEKA.FZ.W.0011.210317T0700Z-210317T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-
706 PM PDT Tue Mar 16 2021

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

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

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

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

* 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.

&&

$$

CAZ101-103-109-112-113-171015-
/O.CON.KEKA.FR.Y.0011.210317T0700Z-210317T1600Z/
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
706 PM PDT Tue Mar 16 2021

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

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

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

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

&&

$$
559 
WWUS76 KEKA 170935
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
235 AM PDT Wed Mar 17 2021

CAZ110-111-114-115-171600-
/O.CON.KEKA.FZ.W.0011.000000T0000Z-210317T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-Southern Lake-
235 AM PDT Wed Mar 17 2021

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

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

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

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

* 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.

&&

$$

CAZ101-103-109-112-113-171600-
/O.CON.KEKA.FR.Y.0011.000000T0000Z-210317T1600Z/
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
235 AM PDT Wed Mar 17 2021

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

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

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

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

&&

$$
538 
WWUS76 KEKA 171601
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
901 AM PDT Wed Mar 17 2021

CAZ110-111-114-115-171715-
/O.EXP.KEKA.FZ.W.0011.000000T0000Z-210317T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-Southern Lake-
901 AM PDT Wed Mar 17 2021

...FREEZE WARNING HAS EXPIRED...

Warmer temperatures and rain are expected tonight.

$$

CAZ101-103-109-112-113-171715-
/O.EXP.KEKA.FR.Y.0011.000000T0000Z-210317T1600Z/
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
901 AM PDT Wed Mar 17 2021

...FROST ADVISORY HAS EXPIRED...

Warmer temperatures and rain are expected tonight.

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 15, 10:44 PM PDTSmall Craft AdvisoryEKA20 hr
Mar 16, 3:09 AM PDTGale WatchEKA11 hr
Mar 16, 9:08 AM PDTFreeze WatchEKALake, Mendocino4 hr
Mar 16, 1:27 PM PDTFrost AdvisoryEKADel Norte, Humboldt, Mendocino20 hr
Mar 16, 1:39 PM PDTWinter Storm WatchEKA14 hr
Mar 16, 2:25 PM PDTGale WarningEKA46 hr
Mar 16, 2:25 PM PDTSmall Craft AdvisoryEKA36 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.