Alert archive / California / Frost Advisories in 2021

Frost Advisory 48, NWS Eureka, CA

November 6, 2021Humboldt County, Lake County, Mendocino County, California

NWS Eureka, CA issued this frost advisory at Nov 6, 2021, 3:28 AM PDT for Humboldt County, Lake County, Mendocino County, California. It took effect at Nov 7, 2021, 2:00 AM PST. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued
Nov 6, 2021, 3:28 AM PDT (10:28 UTC)
In effect from
Nov 7, 2021, 2:00 AM PST
Expired
Nov 7, 2021, 8:00 AM PST
In force
6 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 10:31 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 00:00Z, 10.5 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 00:00Z on 2021-11-06Temperature 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 00:00Z on 2021-11-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 77 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1056 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
77 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.

922 
WWUS76 KEKA 061028
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
328 AM PDT Sat Nov 6 2021

CAZ106-110-111-114-061830-
/O.UPG.KEKA.FZ.A.0009.211107T1000Z-211107T1600Z/
/O.NEW.KEKA.FR.Y.0048.211107T1000Z-211107T1600Z/
/O.NEW.KEKA.FZ.A.0010.211108T1000Z-211108T1600Z/
Southern Humboldt Interior-Northwestern Mendocino Interior-
Northeastern Mendocino Interior-Northern Lake-
328 AM PDT Sat Nov 6 2021

...FROST ADVISORY IN EFFECT FROM 2 AM TO 8 AM PST SUNDAY BELOW
3000 FEET...
...FREEZE WATCH IN EFFECT FROM LATE SUNDAY NIGHT THROUGH MONDAY
MORNING BELOW 3000 FEET...

* WHAT...For the Frost Advisory below 3000 feet, temperatures 
  None will result in frost formation. For the Freeze Watch 
  below 3000 feet, sub-freezing temperatures None possible.

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

* WHEN...For the Frost Advisory, from 2 AM to 8 AM PST Sunday. 
  For the Freeze Watch, from late Sunday night through Monday 
  morning.

* IMPACTS...Frost and freeze conditions could kill crops and 
  other sensitive vegetation.

* ADDITIONAL DETAILS...Valley fog could help protect some areas
  from freezing temperatures, particularly on Sunday. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. Provide
adequate shelter for outdoor pets or consider bringing them
indoors.

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
381 
WWUS76 KEKA 062041
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
141 PM PDT Sat Nov 6 2021

CAZ106-110-111-114-070445-
/O.CON.KEKA.FR.Y.0048.211107T1000Z-211107T1600Z/
/O.CON.KEKA.FZ.A.0010.211108T1000Z-211108T1600Z/
Southern Humboldt Interior-Northwestern Mendocino Interior-
Northeastern Mendocino Interior-Northern Lake-
141 PM PDT Sat Nov 6 2021

...FROST ADVISORY REMAINS IN EFFECT FROM 2 AM TO 8 AM PST SUNDAY
BELOW 3000 FEET...
...FREEZE WATCH REMAINS IN EFFECT FROM LATE SUNDAY NIGHT THROUGH
MONDAY MORNING BELOW 3000 FEET...

* WHAT...For the Frost Advisory below 3000 feet, temperatures 
  None will result in frost formation. For the Freeze Watch 
  below 3000 feet, sub-freezing temperatures None possible.

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

* WHEN...For the Frost Advisory, from 2 AM to 8 AM PST Sunday. 
  For the Freeze Watch, from late Sunday night through Monday 
  morning.

* IMPACTS...Frost and freeze conditions could kill crops and 
  other sensitive vegetation.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. Provide
adequate shelter for outdoor pets or consider bringing them
indoors.

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.

&&

$$
882 
WWUS76 KEKA 070544
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
1044 PM PDT Sat Nov 6 2021

CAZ106-110-111-114-071345-
/O.CON.KEKA.FR.Y.0048.211107T1000Z-211107T1600Z/
/O.CON.KEKA.FZ.A.0010.211108T1000Z-211108T1600Z/
Southern Humboldt Interior-Northwestern Mendocino Interior-
Northeastern Mendocino Interior-Northern Lake-
1044 PM PDT Sat Nov 6 2021

...FROST ADVISORY REMAINS IN EFFECT FROM 2 AM TO 8 AM PST SUNDAY
BELOW 3000 FEET...
...FREEZE WATCH REMAINS IN EFFECT FROM LATE SUNDAY NIGHT THROUGH
MONDAY MORNING BELOW 3000 FEET...

* WHAT...For the Frost Advisory below 3000 feet, temperatures 
  None will result in frost formation. For the Freeze Watch 
  below 3000 feet, sub-freezing temperatures None possible.

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

* WHEN...For the Frost Advisory, from 2 AM to 8 AM PST Sunday. 
  For the Freeze Watch, from late Sunday night through Monday 
  morning.

* IMPACTS...Frost and freeze conditions could kill crops and 
  other sensitive vegetation.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. Provide
adequate shelter for outdoor pets or consider bringing them
indoors.

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.

&&

$$
228 
WWUS76 KEKA 071141
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
341 AM PST Sun Nov 7 2021

CAZ106-110-071945-
/O.UPG.KEKA.FZ.A.0010.211108T1000Z-211108T1600Z/
/O.NEW.KEKA.FR.Y.0049.211108T1000Z-211108T1600Z/
/O.NEW.KEKA.WI.Y.0016.211108T2200Z-211109T0600Z/
/O.CON.KEKA.FR.Y.0048.000000T0000Z-211107T1600Z/
Southern Humboldt Interior-Northwestern Mendocino Interior-
341 AM PST Sun Nov 7 2021

...FROST ADVISORY REMAINS IN EFFECT UNTIL 8 AM PST THIS MORNING...
...FROST ADVISORY IN EFFECT FROM 2 AM TO 8 AM PST MONDAY... 
...WIND ADVISORY IN EFFECT FROM 2 PM TO 10 PM PST MONDAY ABOVE 
1500 FEET...

* WHAT...For the frost advisory, temperatures below 36 will lead
  to frost formation in clear valleys. For the Wind Advisory 
  above 1500 feet, southeast winds 25 to 35 mph with gusts up to 
  55 mph expected.

* WHERE...Southern Humboldt Interior and Northwestern Mendocino 
  Interior Counties.

* WHEN...For the first Frost Advisory, until 8 AM PST this 
  morning. For the second Frost Advisory, from 2 AM to 8 AM PST 
  Monday. For the Wind Advisory, from 2 PM to 10 PM PST Monday.

* 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.

&&

$$

CAZ111-114-071945-
/O.UPG.KEKA.FZ.A.0010.211108T1000Z-211108T1600Z/
/O.NEW.KEKA.FR.Y.0049.211108T1000Z-211108T1600Z/
/O.CON.KEKA.FR.Y.0048.000000T0000Z-211107T1600Z/
Northeastern Mendocino Interior-Northern Lake-
341 AM PST Sun Nov 7 2021

...FROST ADVISORY REMAINS IN EFFECT UNTIL 8 AM PST THIS MORNING...
...FROST ADVISORY IN EFFECT FROM 2 AM TO 8 AM PST MONDAY...

* WHAT...For the frost advisory, temperatures below 36 will lead
  to frost formation in clear valleys. 

* WHERE...Northeastern Mendocino Interior and Northern Lake 
  Counties.

* WHEN...For the first Frost Advisory, until 8 AM PST this 
  morning. For the second Frost Advisory, from 2 AM to 8 AM PST 
  Monday.

* 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.

&&

$$

CAZ101-103-104-109-071945-
/O.NEW.KEKA.WI.Y.0016.211108T2200Z-211109T0600Z/
Coastal Del Norte-Northern Humboldt Coast-Southwestern Humboldt-
Mendocino Coast-
341 AM PST Sun Nov 7 2021

...WIND ADVISORY IN EFFECT FROM 2 PM TO 10 PM PST MONDAY...

* WHAT...Southeast winds 25 to 35 mph with gusts up to 55 mph 
  expected.

* WHERE...Coastal Del Norte, Northern Humboldt Coast, 
  Southwestern Humboldt and Mendocino Coast Counties.

* WHEN...From 2 PM to 10 PM PST Monday.

* 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.

&&

$$

CAZ102-105-071945-
/O.NEW.KEKA.WI.Y.0016.211108T2200Z-211109T0600Z/
Del Norte Interior-Northern Humboldt Interior-
341 AM PST Sun Nov 7 2021

...WIND ADVISORY IN EFFECT FROM 2 PM TO 10 PM PST MONDAY ABOVE
1500 FEET...

* WHAT...Southeast winds 25 to 35 mph with gusts up to 60 mph 
  expected above 1500 feet.

* WHERE...Del Norte Interior and Northern Humboldt Interior 
  Counties.

* WHEN...From 2 PM to 10 PM PST Monday.

* 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.

&&

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Nov 6, 2:31 AM PDTSpecial Weather StatementEKAHumboldt44 min
Nov 6, 3:01 AM PDTGale WatchEKA25 hr
Nov 6, 3:01 AM PDTSmall Craft AdvisoryEKA23 hr
Nov 6, 3:28 AM PDTFreeze WatchEKAHumboldt, Lake, Mendocino25 hr
Nov 6, 3:45 AM PDTWinter Storm WatchEKA25 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.