Alert archive / California / Frost Advisories in 2021

Frost Advisory 14, NWS Eureka, CA

March 22, 2021Del Norte County, Humboldt County, Mendocino County, California

NWS Eureka, CA issued this frost advisory at Mar 22, 2021, 3:28 AM PDT for Del Norte County, Humboldt County, Mendocino County, California. It took effect at Mar 23, 2021, 1:00 AM PDT. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued
Mar 22, 2021, 3:28 AM PDT (10:28 UTC)
In effect from
Mar 23, 2021, 1:00 AM PDT
Expired
Mar 23, 2021, 9:00 AM PDT
In force
8 hr
Issued by
NWS Eureka, CA

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

The radar

The Eureka (Bunker Hill) radar (KBHX), 47 km from the middle of the area, began a volume at 10:28 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 00:00Z, 10.5 hours before the alert went out and 210 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 00:00Z on 2021-03-22Temperature 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, Medford/Jackson, OR at 00:00Z on 2021-03-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 29 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
1734 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
29 m²/s²
0-3 km storm-relative helicity
90 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

590 
WWUS76 KEKA 221028
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
328 AM PDT Mon Mar 22 2021

CAZ110-111-114-221830-
/O.NEW.KEKA.FZ.W.0013.210323T0800Z-210323T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-
328 AM PDT Mon Mar 22 2021

...FREEZE WARNING IN EFFECT FROM 1 AM TO 9 AM PDT TUESDAY...

* WHAT...Sub-freezing temperatures in the low 30s and upper 20s 
  expected.

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

* WHEN...From 1 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.

&&

$$

CAZ101-103-109-112-113-115-221830-
/O.NEW.KEKA.FR.Y.0014.210323T0800Z-210323T1600Z/
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake-
328 AM PDT Mon Mar 22 2021

...FROST ADVISORY IN EFFECT FROM 1 AM TO 9 AM PDT TUESDAY...

* WHAT...Temperatures in the low to mid 30s will result in frost 
  formation.

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

* WHEN...From 1 AM to 9 AM PDT Tuesday.

* 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
796 
WWUS76 KEKA 221918
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
1218 PM PDT Mon Mar 22 2021

CAZ110-111-114-230330-
/O.CON.KEKA.FZ.W.0013.210323T0800Z-210323T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-
1218 PM PDT Mon Mar 22 2021

...FREEZE WARNING REMAINS IN EFFECT FROM 1 AM TO 9 AM PDT
TUESDAY...

* WHAT...Sub-freezing temperatures in the low 30s and upper 20s 
  expected.

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

* WHEN...From 1 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.

&&

$$

CAZ101-103-109-112-113-115-230330-
/O.CON.KEKA.FR.Y.0014.210323T0800Z-210323T1600Z/
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake-
1218 PM PDT Mon Mar 22 2021

...FROST ADVISORY REMAINS IN EFFECT FROM 1 AM TO 9 AM PDT
TUESDAY...

* WHAT...Temperatures in the low to mid 30s will result in frost 
  formation.

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

* WHEN...From 1 AM to 9 AM PDT Tuesday.

* 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.

&&

$$
535 
WWUS76 KEKA 230329
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
829 PM PDT Mon Mar 22 2021

CAZ110-111-114-231600-
/O.CON.KEKA.FZ.W.0013.210323T0800Z-210323T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-
829 PM PDT Mon Mar 22 2021

...FREEZE WARNING REMAINS IN EFFECT FROM 1 AM TO 9 AM TUESDAY...

* WHAT...Sub-freezing temperatures in the upper 20s to lower 30s 
  expected.

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

* WHEN...From 1 AM to 9 AM 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.

$$

CAZ101-103-109-112-113-115-231600-
/O.CON.KEKA.FR.Y.0014.210323T0800Z-210323T1600Z/
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake-
829 PM PDT Mon Mar 22 2021

...FROST ADVISORY REMAINS IN EFFECT FROM 1 AM TO 9 AM TUESDAY...

* WHAT...Temperatures in the lower to mid 30s will result in 
  frost formation.

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

* WHEN...From 1 AM to 9 AM Tuesday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

$$
995 
WWUS76 KEKA 231543
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
843 AM PDT Tue Mar 23 2021

CAZ110-111-114-231645-
/O.EXP.KEKA.FZ.W.0013.000000T0000Z-210323T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-
843 AM PDT Tue Mar 23 2021

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



$$

CAZ101-103-109-112-113-115-231645-
/O.EXP.KEKA.FR.Y.0014.000000T0000Z-210323T1600Z/
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake-
843 AM PDT Tue Mar 23 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 22, 3:10 AM PDTGale WatchEKA11 hr
Mar 22, 3:10 AM PDTSmall Craft AdvisoryEKA4 days
Mar 22, 3:28 AM PDTFreeze WarningEKALake, Mendocino30 hr
Mar 22, 2:17 PM PDTGale WarningEKA37 hr

Nearby

Frost Advisories in California, 2021Every frost advisory 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.