Alert archive / California / Frost Advisories in 2021

Frost Advisory 16, NWS Eureka, CA

March 24, 2021Lake County, Mendocino County, California

NWS Eureka, CA issued this frost advisory at Mar 24, 2021, 2:08 PM PDT for Lake County, Mendocino County, California. It took effect at Mar 25, 2021, 5:00 AM PDT. It was in force for 4 hr.

The area

The counties it named.

The facts

Issued
Mar 24, 2021, 2:08 PM PDT (21:08 UTC)
In effect from
Mar 25, 2021, 5:00 AM PDT
Expired
Mar 25, 2021, 9:00 AM PDT
In force
4 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 21:06 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, 9.1 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 2021-03-24Temperature 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 2021-03-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 88 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
3089 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
88 m²/s²
0-3 km storm-relative helicity
82 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

348 
WWUS76 KEKA 242108
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
208 PM PDT Wed Mar 24 2021

CAZ110-111-114-115-250515-
/O.NEW.KEKA.FR.Y.0016.210325T1200Z-210325T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-Southern Lake-
208 PM PDT Wed Mar 24 2021

...FROST ADVISORY IN EFFECT FROM 5 AM TO 9 AM PDT THURSDAY...

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

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

* WHEN...From 5 AM to 9 AM PDT Thursday.

* 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
729 
WWUS76 KEKA 250503
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
1003 PM PDT Wed Mar 24 2021

CAZ110-111-114-115-251600-
/O.CON.KEKA.FR.Y.0016.210325T1200Z-210325T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-Southern Lake-
1003 PM PDT Wed Mar 24 2021

...FROST ADVISORY REMAINS IN EFFECT FROM 5 AM TO 9 AM THURSDAY...

* WHAT...Temperatures as low as 32 will result in frost formation.

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

* WHEN...From 5 AM to 9 AM Thursday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

$$
582 
WWUS76 KEKA 251545
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
845 AM PDT Thu Mar 25 2021

CAZ110-111-114-115-251645-
/O.EXP.KEKA.FR.Y.0016.000000T0000Z-210325T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-Southern Lake-
845 AM PDT Thu Mar 25 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 24, 8:09 AM PDTGale WatchEKA18 hr
Mar 24, 2:13 PM PDTSmall Craft AdvisoryEKA28 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.