Alert archive / California / Frost Advisories in 2021

Frost Advisory 18, NWS Eureka, CA

March 26, 2021Humboldt County, Lake County, Mendocino County, California

NWS Eureka, CA issued this frost advisory at Mar 26, 2021, 2:32 PM PDT for Humboldt County, Lake County, Mendocino County, California. It took effect at Mar 27, 2021, 1:00 AM PDT. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued
Mar 26, 2021, 2:32 PM PDT (21:32 UTC)
In effect from
Mar 27, 2021, 1:00 AM PDT
Expired
Mar 27, 2021, 9:00 AM PDT
In force
8 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 21:37 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, 9.5 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 2021-03-26Temperature 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 2021-03-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 81 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
1438 m above ground
0-6 km bulk shear
68 kt
0-1 km storm-relative helicity
81 m²/s²
0-3 km storm-relative helicity
81 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

075 
WWUS76 KEKA 262132
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
232 PM PDT Fri Mar 26 2021

CAZ110>112-114-115-270545-
/O.NEW.KEKA.FR.Y.0018.210327T0800Z-210327T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southwestern Mendocino Interior-Northern Lake-Southern Lake-
232 PM PDT Fri Mar 26 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, Southwestern 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.

&&

$$
4 follow-up statements
374 
WWUS76 KEKA 262327
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
427 PM PDT Fri Mar 26 2021

CAZ103-109-113-270730-
/O.EXA.KEKA.FR.Y.0018.210327T0800Z-210327T1600Z/
Northern Humboldt Coast-Mendocino Coast-
Southeastern Mendocino Interior-
427 PM PDT Fri Mar 26 2021

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

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

* WHERE...Northern Humboldt Coast, Mendocino Coast and 
  Southeastern Mendocino Interior 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.

&&

$$

CAZ110>112-114-115-270730-
/O.CON.KEKA.FR.Y.0018.210327T0800Z-210327T1600Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southwestern Mendocino Interior-Northern Lake-Southern Lake-
427 PM PDT Fri Mar 26 2021

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

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

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

&&

$$
683 
WWUS76 KEKA 270439
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
939 PM PDT Fri Mar 26 2021

CAZ103-109>115-271245-
/O.CON.KEKA.FR.Y.0018.210327T0800Z-210327T1600Z/
Northern Humboldt Coast-Mendocino Coast-
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Northern Lake-Southern Lake-
939 PM PDT Fri Mar 26 2021

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

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

* WHERE...Mendocino Coast, Southwestern Mendocino Interior, 
  Southeastern Mendocino Interior, Northern Humboldt Coast, 
  Northeastern Mendocino Interior, Northern Lake, Southern Lake 
  and Northwestern Mendocino Interior 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.

&&

$$
998 
WWUS76 KEKA 271246
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
546 AM PDT Sat Mar 27 2021

CAZ103-109>115-271600-
/O.CON.KEKA.FR.Y.0018.000000T0000Z-210327T1600Z/
Northern Humboldt Coast-Mendocino Coast-
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Northern Lake-Southern Lake-
546 AM PDT Sat Mar 27 2021

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

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

* WHERE...Mendocino Coast, Southwestern Mendocino Interior, 
  Southeastern Mendocino Interior, Northern Humboldt Coast, 
  Northeastern Mendocino Interior, Northern Lake, Southern Lake 
  and Northwestern Mendocino Interior 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.

&&

$$
889 
WWUS76 KEKA 271546
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
846 AM PDT Sat Mar 27 2021

CAZ103-109>115-271700-
/O.EXP.KEKA.FR.Y.0018.000000T0000Z-210327T1600Z/
Northern Humboldt Coast-Mendocino Coast-
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Northern Lake-Southern Lake-
846 AM PDT Sat Mar 27 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 26, 2:41 AM PDTSmall Craft AdvisoryEKA37 hr
Mar 26, 2:41 AM PDTHazardous Seas WarningEKA24 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.