Alert archive / California / Frost Advisories in 2021

Frost Advisory 24, NWS Eureka, CA

April 8, 20214 counties in California

NWS Eureka, CA issued this frost advisory at Apr 8, 2021, 1:51 PM PDT for 4 counties in California. It took effect at Apr 9, 2021, 3:00 AM PDT. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued
Apr 8, 2021, 1:51 PM PDT (20:51 UTC)
In effect from
Apr 9, 2021, 3:00 AM PDT
Expired
Apr 9, 2021, 9:00 AM PDT
In force
6 hr
Issued by
NWS Eureka, CA

Counties Del Norte County, CA, Humboldt County, CA, Lake County, CA, Mendocino County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 72 km from the middle of the area, began a volume at 20:50 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 12:00Z, 8.9 hours before the alert went out and 244 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 12:00Z on 2021-04-08Temperature 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, Medford/Jackson, OR at 12:00Z on 2021-04-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 29 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
944 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
29 m²/s²
0-3 km storm-relative helicity
134 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

246 
WWUS76 KEKA 082051
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
151 PM PDT Thu Apr 8 2021

CAZ102-105-106-110-111-090530-
/O.NEW.KEKA.FR.Y.0024.210409T1000Z-210409T1600Z/
Del Norte Interior-Northern Humboldt Interior-
Southern Humboldt Interior-Northwestern Mendocino Interior-
Northeastern Mendocino Interior-
151 PM PDT Thu Apr 8 2021

...FROST ADVISORY IN EFFECT FROM 3 AM TO 9 AM PDT FRIDAY...

* WHAT...Temperatures as low as 36 will result in frost 
  formation.

* WHERE...Del Norte Interior, Northern Humboldt Interior, 
  Southern Humboldt Interior, Northwestern Mendocino Interior 
  and Northeastern Mendocino Interior Counties.

* WHEN...From 3 AM to 9 AM PDT 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.

&&

$$
3 follow-up statements
433 
WWUS76 KEKA 090500
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
1000 PM PDT Thu Apr 8 2021

CAZ102-105-106-110-111-091600-
/O.CON.KEKA.FR.Y.0024.210409T1000Z-210409T1600Z/
Del Norte Interior-Northern Humboldt Interior-
Southern Humboldt Interior-Northwestern Mendocino Interior-
Northeastern Mendocino Interior-
1000 PM PDT Thu Apr 8 2021

...FROST ADVISORY REMAINS IN EFFECT FROM 3 AM TO 9 AM PDT
FRIDAY...

* WHAT...Temperatures as low as 36 will result in frost 
  formation.

* WHERE...Del Norte Interior, Northern Humboldt Interior, Southern
  Humboldt Interior, Northwestern Mendocino Interior and
  Northeastern Mendocino Interior.

* WHEN...From 3 AM to 9 AM PDT 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.

&&

$$
195 
WWUS76 KEKA 090957
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
257 AM PDT Fri Apr 9 2021

CAZ102-105-106-110-111-091600-
/O.CON.KEKA.FR.Y.0024.210409T1000Z-210409T1600Z/
Del Norte Interior-Northern Humboldt Interior-
Southern Humboldt Interior-Northwestern Mendocino Interior-
Northeastern Mendocino Interior-
257 AM PDT Fri Apr 9 2021

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

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

* WHERE...Northwestern Mendocino Interior, Del Norte Interior, 
  Northern Humboldt Interior, Northeastern Mendocino Interior 
  and Southern Humboldt Interior Counties.

* WHEN...Until 9 AM PDT 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.

&&

$$
543 
WWUS76 KEKA 091014
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
314 AM PDT Fri Apr 9 2021

CAZ104-114-091600-
/O.EXA.KEKA.FR.Y.0024.000000T0000Z-210409T1600Z/
Southwestern Humboldt-Northern Lake-
314 AM PDT Fri Apr 9 2021

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

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

* WHERE...Southwestern Humboldt and Northern Lake Counties.

* WHEN...Until 9 AM PDT 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.

&&

$$

CAZ102-105-106-110-111-091600-
/O.CON.KEKA.FR.Y.0024.000000T0000Z-210409T1600Z/
Del Norte Interior-Northern Humboldt Interior-
Southern Humboldt Interior-Northwestern Mendocino Interior-
Northeastern Mendocino Interior-
314 AM PDT Fri Apr 9 2021

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

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

* WHERE...Northeastern Mendocino Interior, Northwestern 
  Mendocino Interior, Del Norte Interior, Northern Humboldt 
  Interior and Southern Humboldt Interior Counties.

* WHEN...Until 9 AM PDT 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.

&&

$$

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.