Alert archive / California / Frost Advisories in 2021

Frost Advisory 2, NWS Eureka, CA

March 1, 2021Humboldt County, Lake County, Mendocino County, California

NWS Eureka, CA issued this frost advisory at Mar 1, 2021, 2:42 PM PST for Humboldt County, Lake County, Mendocino County, California. It took effect at Mar 1, 2021, 11:00 PM PST. It was in force for 10 hr.

The area

The counties it named.

The facts

Issued
Mar 1, 2021, 2:42 PM PST (22:42 UTC)
In effect from
Mar 1, 2021, 11:00 PM PST
Expired
Mar 2, 2021, 9:00 AM PST
In force
10 hr
Issued by
NWS Eureka, CA

Counties Humboldt County, CA, Lake County, CA, Mendocino County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 115 km from the middle of the area, began a volume at 22:46 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, 10.7 hours before the alert went out and 246 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 2021-03-01Temperature 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, Oakland, CA at 12:00Z on 2021-03-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 57 square meters per square second.1939Sfc1 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
2486 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
57 m²/s²
0-3 km storm-relative helicity
69 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

588 
WWUS76 KEKA 012242
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
242 PM PST Mon Mar 1 2021

CAZ110>115-021700-
/O.NEW.KEKA.FR.Y.0002.210302T0700Z-210302T1700Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Northern Lake County-Southern Lake County-
242 PM PST Mon Mar 1 2021

...FROST ADVISORY IN EFFECT FROM 11 PM THIS EVENING TO 9 AM 
TUESDAY...

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

* WHERE...Portions of Lake and interior Mendocino counties. 

* WHEN...From 11 PM this evening 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.

$$
2 follow-up statements
484 
WWUS76 KEKA 020234
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
634 PM PST Mon Mar 1 2021

CAZ111-114-021700-
/O.UPG.KEKA.FR.Y.0002.210302T0700Z-210302T1700Z/
/O.NEW.KEKA.FZ.W.0002.210302T0700Z-210302T1700Z/
Northeastern Mendocino Interior-Northern Lake County-
634 PM PST Mon Mar 1 2021

...FREEZE WARNING IN EFFECT FROM 11 PM THIS EVENING TO 9 AM PST
TUESDAY...

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

* WHERE...Northeastern Mendocino Interior and Northern Lake
  County, including Covelo and Lake Pillsbury.

* WHEN...From 11 PM this evening to 9 AM PST 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.

&&

$$

CAZ110-112-113-115-021700-
/O.CON.KEKA.FR.Y.0002.210302T0700Z-210302T1700Z/
Northwestern Mendocino Interior-Southwestern Mendocino Interior-
Southeastern Mendocino Interior-Southern Lake County-
634 PM PST Mon Mar 1 2021

...FROST ADVISORY REMAINS IN EFFECT FROM 11 PM THIS EVENING TO
9 AM PST TUESDAY...

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

* WHERE...Southwestern Mendocino Interior, Southeastern Mendocino
  Interior, Northwestern Mendocino Interior and Southern Lake
  County...including Ukiah, Willits, Laytonville, Boonville, 
  Lakeport, Clearlake, and Middletown.

* WHEN...From 11 PM this evening to 9 AM PST 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.

&&

$$
976 
WWUS76 KEKA 021159
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
359 AM PST Tue Mar 2 2021

CAZ110-115-021700-
/O.UPG.KEKA.FR.Y.0002.000000T0000Z-210302T1700Z/
/O.EXA.KEKA.FZ.W.0002.000000T0000Z-210302T1700Z/
Northwestern Mendocino Interior-Southern Lake County-
359 AM PST Tue Mar 2 2021

...FREEZE WARNING IN EFFECT UNTIL 9 AM PST THIS MORNING...

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

* WHERE...Northwestern Mendocino Interior and Southern Lake 
  County Counties.

* WHEN...Until 9 AM PST this morning.

* 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.

&&

$$

CAZ111-114-021700-
/O.CON.KEKA.FZ.W.0002.000000T0000Z-210302T1700Z/
Northeastern Mendocino Interior-Northern Lake County-
359 AM PST Tue Mar 2 2021

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

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

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

* WHEN...Until 9 AM PST this morning.

* 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.

&&

$$

CAZ103-021700-
/O.EXA.KEKA.FR.Y.0002.000000T0000Z-210302T1700Z/
Northern Humboldt Coast-
359 AM PST Tue Mar 2 2021

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

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

* WHERE...Northern Humboldt Coast County.

* 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.

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.

&&

$$

CAZ112-113-021700-
/O.CON.KEKA.FR.Y.0002.000000T0000Z-210302T1700Z/
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
359 AM PST Tue Mar 2 2021

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

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

* WHERE...Southwestern Mendocino Interior and Southeastern 
  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.

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.

&&

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 1, 2:56 PM PSTSmall Craft AdvisoryEKA48 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.