Alert archive / California / Frost Advisories in 2021

Frost Advisory 6, NWS Eureka, CA

March 7, 2021Humboldt County, Mendocino County, California

NWS Eureka, CA issued this frost advisory at Mar 7, 2021, 2:04 PM PST for Humboldt County, Mendocino County, California. It took effect at Mar 8, 2021, 12:00 AM PST. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued
Mar 7, 2021, 2:04 PM PST (22:04 UTC)
In effect from
Mar 8, 2021, 12:00 AM PST
Expired
Mar 8, 2021, 7:00 AM PST
In force
7 hr
Issued by
NWS Eureka, CA

Counties Humboldt County, CA, Mendocino County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 71 km from the middle of the area, began a volume at 22:08 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, 10.1 hours before the alert went out and 266 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 2021-03-07Temperature 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 2021-03-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 200 square meters per square second.1939587897117Sfc1 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
1554 m above ground
0-6 km bulk shear
91 kt
0-1 km storm-relative helicity
200 m²/s²
0-3 km storm-relative helicity
299 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

320 
WWUS76 KEKA 072204
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
204 PM PST Sun Mar 7 2021

CAZ110-111-114-115-080615-
/O.NEW.KEKA.FZ.W.0005.210308T0800Z-210308T1500Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake County-Southern Lake County-
204 PM PST Sun Mar 7 2021

...FREEZE WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 7 AM PST
MONDAY...

* WHAT...Sub-freezing temperatures as low as 29 expected.

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

* WHEN...From midnight tonight to 7 AM PST Monday.

* IMPACTS...Frost and freeze conditions will kill crops, other
  sensitive vegetation and possibly damage unprotected outdoor
  plumbing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. To prevent
freezing and possible bursting of outdoor water pipes they should
be wrapped, drained, or allowed to drip slowly. Those that have
in-ground sprinkler systems should drain them and cover above-
ground pipes to protect them from freezing..

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.

&&

$$

CAZ103-109-112-113-080615-
/O.NEW.KEKA.FR.Y.0006.210308T0800Z-210308T1500Z/
Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
204 PM PST Sun Mar 7 2021

...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 7 AM PST
MONDAY...

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

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

* WHEN...From midnight tonight to 7 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.

&&

$$
3 follow-up statements
779 
WWUS76 KEKA 080604
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
1004 PM PST Sun Mar 7 2021

CAZ110-111-114-115-081300-
/O.CON.KEKA.FZ.W.0005.210308T0800Z-210308T1500Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake County-Southern Lake County-
1004 PM PST Sun Mar 7 2021

...FREEZE WARNING REMAINS IN EFFECT UNTIL 7 AM PST MONDAY...

* WHAT...Sub-freezing temperatures as low as 28 expected.

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

* WHEN...Until 7 AM PST Monday.

* IMPACTS...Frost and freeze conditions will kill crops, other 
  sensitive vegetation and possibly damage unprotected outdoor 
  plumbing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. To prevent
freezing and possible bursting of outdoor water pipes they should
be wrapped, drained, or allowed to drip slowly. Those that have
in-ground sprinkler systems should drain them and cover above-
ground pipes to protect them from freezing..

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.

&&

$$

CAZ103-109-112-113-081300-
/O.CON.KEKA.FR.Y.0006.210308T0800Z-210308T1500Z/
Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
1004 PM PST Sun Mar 7 2021

...FROST ADVISORY REMAINS IN EFFECT UNTIL 7 AM PST MONDAY...

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

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

* WHEN...Until 7 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.

&&

$$
055 
WWUS76 KEKA 081302
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
502 AM PST Mon Mar 8 2021

CAZ110-111-114-115-081500-
/O.CON.KEKA.FZ.W.0005.000000T0000Z-210308T1500Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake County-Southern Lake County-
502 AM PST Mon Mar 8 2021

...FREEZE WARNING REMAINS IN EFFECT UNTIL 7 AM PST THIS MORNING...

* WHAT...Sub-freezing temperatures as low as 28 expected.

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

* WHEN...Until 7 AM PST Monday.

* IMPACTS...Frost and freeze conditions will kill crops, other 
  sensitive vegetation and possibly damage unprotected outdoor 
  plumbing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. To prevent
freezing and possible bursting of outdoor water pipes they should
be wrapped, drained, or allowed to drip slowly. Those that have
in-ground sprinkler systems should drain them and cover above-
ground pipes to protect them from freezing..

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.

&&

$$

CAZ103-109-112-113-081500-
/O.CON.KEKA.FR.Y.0006.000000T0000Z-210308T1500Z/
Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
502 AM PST Mon Mar 8 2021

...FROST ADVISORY REMAINS IN EFFECT UNTIL 7 AM PST THIS MORNING...

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

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

* WHEN...Until 7 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.

&&

$$
689 
WWUS76 KEKA 081510
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
710 AM PST Mon Mar 8 2021

CAZ110-111-114-115-081615-
/O.EXP.KEKA.FZ.W.0005.000000T0000Z-210308T1500Z/
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Northern Lake County-Southern Lake County-
710 AM PST Mon Mar 8 2021

...FREEZE WARNING HAS EXPIRED...



$$

CAZ103-109-112-113-081615-
/O.EXP.KEKA.FR.Y.0006.000000T0000Z-210308T1500Z/
Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
710 AM PST Mon Mar 8 2021

...FROST ADVISORY HAS EXPIRED...



$$

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 7, 2:04 PM PSTFreeze WarningEKALake, Mendocino17 hr
Mar 7, 2:09 PM PSTWinter Weather AdvisoryEKADel Norte, Humboldt, Lake, Mendocino, Trinity68 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.