Alert archive / California / Frost Advisories in 2020

Frost Advisory 2, NWS Eureka, CA

March 1, 2020Del Norte County, Humboldt County, Mendocino County, California

NWS Eureka, CA issued this frost advisory at Mar 1, 2020, 2:42 PM PST for Del Norte County, Humboldt County, Mendocino County, California. It took effect at Mar 2, 2020, 12:00 AM PST. It was in force for 9 hr.

The area

The counties it named.

The facts

Issued
Mar 1, 2020, 2:42 PM PST (22:42 UTC)
In effect from
Mar 2, 2020, 12:00 AM PST
Expired
Mar 2, 2020, 9:00 AM PST
In force
9 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 22:47 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 12:00Z, 10.7 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 12:00Z on 2020-03-01Temperature 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 12:00Z on 2020-03-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 73 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
841 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
73 m²/s²
0-3 km storm-relative helicity
103 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

434 
WWUS76 KEKA 012242
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
242 PM PST Sun Mar 1 2020

CAZ110-111-020645-
/O.NEW.KEKA.FZ.W.0002.200302T0800Z-200302T1700Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
242 PM PST Sun Mar 1 2020

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

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

* WHERE...Northwestern Mendocino Interior and Northeastern
  Mendocino Interior including Leggett, Laytonville, Willits,
  Potter Valley, and Covelo.

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

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

* ADDITIONAL DETAILS...Low temperatures will be several degrees
  warmer Monday night and Tuesday morning. However, frost will
  still be possible.

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. 

$$

CAZ101-103-020645-
/O.NEW.KEKA.FR.Y.0002.200302T0800Z-200302T1700Z/
Coastal Del Norte-Northern Humboldt Coast-
242 PM PST Sun Mar 1 2020

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

* WHAT...Temperatures as low as 34 will result in frost 
  formation.

* WHERE...Coastal Del Norte and Northern Humboldt Coast counties
  including Fieldbrook, Blue Lake, Freshwater, Hydesville, and
  Carlotta.

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

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

* ADDITIONAL DETAILS...Low temperatures are expected to be several
  degrees warmer Monday night and Tuesday morning. As a result,
  only patchy frost is expected in the coldest locations.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

$$
3 follow-up statements
072 
WWUS76 KEKA 020457
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
857 PM PST Sun Mar 1 2020

CAZ110-111-021300-
/O.CON.KEKA.FZ.W.0002.200302T0800Z-200302T1700Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
857 PM PST Sun Mar 1 2020

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

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

* WHERE...Northwestern Mendocino Interior and Northeastern 
  Mendocino Interior including Leggett, Laytonville, Willits, 
  Potter Valley, and Covelo.

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

* 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.

&&

$$

CAZ112-113-021300-
/O.EXA.KEKA.FR.Y.0002.200302T0800Z-200302T1700Z/
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
857 PM PST Sun Mar 1 2020

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

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

* WHERE...Southwestern Mendocino Interior and Southeastern
  Mendocino Interior Counties including Ukiah, Hopland, Navarro,
  and Boonville.

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

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

CAZ101-103-021300-
/O.CON.KEKA.FR.Y.0002.200302T0800Z-200302T1700Z/
Coastal Del Norte-Northern Humboldt Coast-
857 PM PST Sun Mar 1 2020

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

* WHAT...Temperatures as low as 34 will result in frost 
  formation.

* WHERE...Coastal Del Norte and Northern Humboldt Coast counties 
  including Fieldbrook, Blue Lake, Freshwater, Hydesville, and 
  Carlotta.

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

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$
738 
WWUS76 KEKA 021150
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
350 AM PST Mon Mar 2 2020

CAZ110-111-021700-
/O.CAN.KEKA.FZ.W.0002.000000T0000Z-200302T1700Z/
/O.EXA.KEKA.FR.Y.0002.000000T0000Z-200302T1700Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
350 AM PST Mon Mar 2 2020

...FROST ADVISORY IN EFFECT UNTIL 9 AM PST THIS MORNING...
...FREEZE WARNING IS CANCELLED...

* WHAT...Temperatures as low as 33 will result in frost formation.
  A few of the most wind protected valleys may drop slightly below
  freezing as well.

* WHERE...Northwestern Mendocino Interior and Northeastern 
  Mendocino Interior 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.

&&

$$

CAZ101-103-112-113-021700-
/O.CON.KEKA.FR.Y.0002.000000T0000Z-200302T1700Z/
Coastal Del Norte-Northern Humboldt Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
350 AM PST Mon Mar 2 2020

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

* WHAT...Temperatures as low as 34 will result in frost 
  formation.

* WHERE...Coastal Del Norte and Northern Humboldt Coast counties 
  including Fieldbrook, Blue Lake, Freshwater, Hydesville, and 
  Carlotta.

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

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$
024 
WWUS76 KEKA 021712
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
912 AM PST Mon Mar 2 2020

CAZ101-103-110>113-021815-
/O.EXP.KEKA.FR.Y.0002.000000T0000Z-200302T1700Z/
Coastal Del Norte-Northern Humboldt Coast-
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
912 AM PST Mon Mar 2 2020

...FROST ADVISORY HAS EXPIRED...

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 1, 2:42 PM PSTFreeze WarningEKAMendocino13 hr

Nearby

Frost Advisories in California, 2020Every frost advisory in 2020

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.