Alert archive / California / Frost Advisories in 2021

Frost Advisory 12, NWS Eureka, CA

March 19, 2021Lake County, Mendocino County, California

NWS Eureka, CA issued this frost advisory at Mar 19, 2021, 3:32 AM PDT for Lake County, Mendocino County, California. It took effect at Mar 20, 2021, 1:00 AM PDT. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued
Mar 19, 2021, 3:32 AM PDT (10:32 UTC)
In effect from
Mar 20, 2021, 1:00 AM PDT
Expired
Mar 20, 2021, 9:00 AM PDT
In force
8 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 10:35 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 346 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 2021-03-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 24 joules per kilogram.LCLLFCEL10008507005003002001001 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 2021-03-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 3 square meters per square second.1939587897Sfc1 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
24 J/kg
Mixed-layer CIN
-62 J/kg
Mixed-layer LCL
1446 m above ground
0-6 km bulk shear
93 kt
0-1 km storm-relative helicity
3 m²/s²
0-3 km storm-relative helicity
206 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

937 
WWUS76 KEKA 191032
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
332 AM PDT Fri Mar 19 2021

CAZ110-111-113>115-191845-
/O.NEW.KEKA.FR.Y.0012.210320T0800Z-210320T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southeastern Mendocino Interior-Northern Lake-Southern Lake-
332 AM PDT Fri Mar 19 2021

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

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

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

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

* 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
172 
WWUS76 KEKA 191830
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
1130 AM PDT Fri Mar 19 2021

CAZ110-111-113>115-200230-
/O.CON.KEKA.FR.Y.0012.210320T0800Z-210320T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southeastern Mendocino Interior-Northern Lake-Southern Lake-
1130 AM PDT Fri Mar 19 2021

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

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

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

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

* 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.

&&

$$
123 
WWUS76 KEKA 200356
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
856 PM PDT Fri Mar 19 2021

CAZ110-111-113>115-201600-
/O.CON.KEKA.FR.Y.0012.210320T0800Z-210320T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southeastern Mendocino Interior-Northern Lake-Southern Lake-
856 PM PDT Fri Mar 19 2021

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

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

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

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

* 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.

&&

$$
428 
WWUS76 KEKA 201603
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
903 AM PDT Sat Mar 20 2021

CAZ110-111-113>115-201715-
/O.EXP.KEKA.FR.Y.0012.000000T0000Z-210320T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southeastern Mendocino Interior-Northern Lake-Southern Lake-
903 AM PDT Sat Mar 20 2021

...FROST ADVISORY HAS EXPIRED...

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 18, 5:04 PM PDTWinter Weather AdvisoryEKA6 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.