Alert archive / California / Frost Advisories in 2021

Frost Advisory 56, NWS Eureka, CA

December 2, 2021Mendocino County, California

NWS Eureka, CA issued this frost advisory at Dec 2, 2021, 2:47 PM PST for Mendocino County, California. It took effect at Dec 3, 2021, 12:00 AM PST. It was in force for 9 hr.

The area

The counties it named.

The facts

Issued
Dec 2, 2021, 2:47 PM PST (22:47 UTC)
In effect from
Dec 3, 2021, 12:00 AM PST
Expired
Dec 3, 2021, 9:00 AM PST
In force
9 hr
Issued by
NWS Eureka, CA

County Mendocino County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 139 km from the middle of the area, began a volume at 22:53 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, 10.8 hours before the alert went out and 218 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 2021-12-02Temperature 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 2021-12-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -6 square meters per square second.193958Sfc1 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
2387 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
-6 m²/s²
0-3 km storm-relative helicity
-3 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

958 
WWUS76 KEKA 022247
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
247 PM PST Thu Dec 2 2021

CAZ112-113-115-030700-
/O.NEW.KEKA.FR.Y.0056.211203T0800Z-211203T1700Z/
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake-
247 PM PST Thu Dec 2 2021

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

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

* WHERE...Southwestern Mendocino Interior, Southeastern 
  Mendocino Interior and Southern Lake Counties.

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

* 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.

&&

$$
2 follow-up statements
412 
WWUS76 KEKA 030646
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
1046 PM PST Thu Dec 2 2021

CAZ112-113-115-031700-
/O.CON.KEKA.FR.Y.0056.211203T0800Z-211203T1700Z/
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake-
1046 PM PST Thu Dec 2 2021

...FROST ADVISORY REMAINS IN EFFECT UNTIL 9 AM PST FRIDAY...

* WHAT...Temperatures as low as 35 will result in patchy frost 
  formation.

* WHERE...Colder sheltered spots in the Southwestern Mendocino 
  Interior, Southeastern Mendocino Interior and Southern Lake 
  Counties.

* WHEN...Until 9 AM PST Friday.

* 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.

&&

$$
584 
WWUS76 KEKA 031659
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
859 AM PST Fri Dec 3 2021

CAZ112-113-115-031800-
/O.EXP.KEKA.FR.Y.0056.000000T0000Z-211203T1700Z/
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Southern Lake-
859 AM PST Fri Dec 3 2021

...FROST ADVISORY WILL EXPIRE AT 9 AM PST THIS MORNING...

$$

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.