Alert archive / California / Frost Advisories in 2021

Frost Advisory 3, NWS Eureka, CA

March 2, 20214 counties in California

NWS Eureka, CA issued this frost advisory at Mar 2, 2021, 2:37 PM PST for 4 counties in California. It took effect at Mar 3, 2021, 12:00 AM PST. It was in force for 9 hr.

The area

The counties it named.

The facts

Issued
Mar 2, 2021, 2:37 PM PST (22:37 UTC)
In effect from
Mar 3, 2021, 12:00 AM PST
Expired
Mar 3, 2021, 9:00 AM PST
In force
9 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 22:35 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 12:00Z, 10.6 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 2021-03-02Temperature 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 2021-03-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 14 square meters per square second.1939Sfc1 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
992 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
14 m²/s²
0-3 km storm-relative helicity
53 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

483 
WWUS76 KEKA 022237
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
237 PM PST Tue Mar 2 2021

CAZ101-103-109>115-031700-
/O.NEW.KEKA.FR.Y.0003.210303T0800Z-210303T1700Z/
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Northern Lake County-Southern Lake County-
237 PM PST Tue Mar 2 2021

...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM 
WEDNESDAY...

* WHAT...Temperatures as low as 34 will result in frost 
  formation.

* WHERE...Lake, Mendocino, and coastal Del Norte and Humboldt 
  counties.

* WHEN...From midnight tonight to 9 AM Wednesday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

$$
2 follow-up statements
875 
WWUS76 KEKA 030936
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
136 AM PST Wed Mar 3 2021

CAZ101-103-109>115-031700-
/O.CON.KEKA.FR.Y.0003.000000T0000Z-210303T1700Z/
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Northern Lake County-Southern Lake County-
136 AM PST Wed Mar 3 2021

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

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

* WHERE...Mendocino Coast, Coastal Del Norte, Southeastern 
  Mendocino Interior, Northern Humboldt Coast, Northeastern 
  Mendocino Interior, Northern Lake County, Southern Lake 
  County, Southwestern Mendocino Interior and Northwestern 
  Mendocino Interior Counties.

* WHEN...Until 9 AM PST 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.

&&

$$
302 
WWUS76 KEKA 031133
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
333 AM PST Wed Mar 3 2021

CAZ101-031945-
/O.NEW.KEKA.WI.Y.0009.210305T0000Z-210305T1500Z/
/O.CON.KEKA.FR.Y.0003.000000T0000Z-210303T1700Z/
Coastal Del Norte-
333 AM PST Wed Mar 3 2021

...FROST ADVISORY REMAINS IN EFFECT UNTIL 9 AM PST THIS MORNING...
...WIND ADVISORY IN EFFECT FROM 4 PM THURSDAY TO 7 AM PST
FRIDAY...

* WHAT...For the Frost Advisory, temperatures as low as 36 will 
  result in frost formation. For the Wind Advisory, south winds 15
  to 25 mph with gusts up to 45 mph expected.

* WHERE...Coastal Del Norte County.

* WHEN...For the Frost Advisory, until 9 AM PST this morning. 
  For the Wind Advisory, from 4 PM Thursday to 7 AM PST Friday.

* IMPACTS...Gusty winds could blow around unsecured objects. 
  Tree limbs could be blown down and a few power outages may 
  result. Frost could kill sensitive outdoor vegetation if left 
  uncovered.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Use extra caution when driving, especially if operating a high
profile vehicle. Secure outdoor objects.

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.

&&

$$

CAZ102-104>106-031945-
/O.NEW.KEKA.WI.Y.0009.210305T0000Z-210305T1500Z/
Del Norte Interior-Southwestern Humboldt-
Northern Humboldt Interior-Southern Humboldt Interior-
333 AM PST Wed Mar 3 2021

...WIND ADVISORY IN EFFECT FROM 4 PM THURSDAY TO 7 AM PST
FRIDAY...

* WHAT...South winds 15 to 25 mph with gusts up to 45 mph 
  expected.

* WHERE...Del Norte Interior, Southwestern Humboldt, Northern 
  Humboldt Interior and Southern Humboldt Interior Counties.

* WHEN...From 4 PM Thursday to 7 AM PST Friday.

* IMPACTS...Gusty winds could blow around unsecured objects. Tree
  limbs could be blown down and a few power outages may result.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Use extra caution when driving, especially if operating a high
profile vehicle. Secure outdoor objects.

&&

$$

CAZ103-109>115-031700-
/O.CON.KEKA.FR.Y.0003.000000T0000Z-210303T1700Z/
Northern Humboldt Coast-Mendocino Coast-
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
Northern Lake County-Southern Lake County-
333 AM PST Wed Mar 3 2021

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

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

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

* WHEN...Until 9 AM PST 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.

&&

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 1, 6:34 PM PSTFreeze WarningEKALake, Mendocino14 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.