Alert archive / California / Frost Advisories in 2021

Frost Advisory 47, NWS Eureka, CA

October 14, 20214 counties in California

NWS Eureka, CA issued this frost advisory at Oct 14, 2021, 2:05 PM PDT for 4 counties in California. It took effect at Oct 15, 2021, 1:00 AM PDT. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued
Oct 14, 2021, 2:05 PM PDT (21:05 UTC)
In effect from
Oct 15, 2021, 1:00 AM PDT
Expired
Oct 15, 2021, 9:00 AM PDT
In force
8 hr
Issued by
NWS Eureka, CA

Counties Humboldt County, CA, Lake County, CA, Mendocino County, CA, Trinity County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 102 km from the middle of the area, began a volume at 21:04 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 267 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 2021-10-14Temperature 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 2021-10-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -32 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
1599 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
-32 m²/s²
0-3 km storm-relative helicity
151 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

659 
WWUS76 KEKA 142105
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
205 PM PDT Thu Oct 14 2021

CAZ106-108-110-111-114-150515-
/O.NEW.KEKA.FR.Y.0047.211015T0800Z-211015T1600Z/
Southern Humboldt Interior-Southern Trinity-
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-
205 PM PDT Thu Oct 14 2021

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

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

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

* WHEN...From 1 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.

&&

$$
2 follow-up statements
915 
WWUS76 KEKA 150546
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
1046 PM PDT Thu Oct 14 2021

CAZ106-108-110-111-114-151600-
/O.CON.KEKA.FR.Y.0047.211015T0800Z-211015T1600Z/
Southern Humboldt Interior-Southern Trinity-
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-
1046 PM PDT Thu Oct 14 2021

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

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

* WHERE...Sheltered valleys across Southern Trinity County, 
  Northwestern Mendocino Interior, Northeastern Mendocino 
  Interior, Northern Lake and Southern Humboldt Interior.

* WHEN...Until 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.

&&

$$
349 
WWUS76 KEKA 151534
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
834 AM PDT Fri Oct 15 2021

CAZ106-108-110-111-114-151645-
/O.EXP.KEKA.FR.Y.0047.000000T0000Z-211015T1600Z/
Southern Humboldt Interior-Southern Trinity-
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake-
834 AM PDT Fri Oct 15 2021

...FROST ADVISORY WILL EXPIRE AT 9 AM PDT 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.