Alert archive / California / Frost Advisories in 2020

Frost Advisory 9, NWS Eureka, CA

March 15, 2020Del Norte County, Humboldt County, Mendocino County, California

NWS Eureka, CA issued this frost advisory at Mar 15, 2020, 4:31 AM PDT for Del Norte County, Humboldt County, Mendocino County, California. It took effect at Mar 16, 2020, 1:00 AM PDT. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued
Mar 15, 2020, 4:31 AM PDT (11:31 UTC)
In effect from
Mar 16, 2020, 1:00 AM PDT
Expired
Mar 16, 2020, 9:00 AM PDT
In force
8 hr
Issued by
NWS Eureka, CA

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

The radar

The Eureka (Bunker Hill) radar (KBHX), 47 km from the middle of the area, began a volume at 11:32 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 00:00Z, 11.5 hours before the alert went out and 210 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 00:00Z on 2020-03-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 35 joules per kilogram.LCLLFCEL10008507005003002001001 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 00:00Z on 2020-03-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -8 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
35 J/kg
Mixed-layer CIN
-50 J/kg
Mixed-layer LCL
1212 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
-8 m²/s²
0-3 km storm-relative helicity
64 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.1

Open this sounding in Storm Lab

The text

As transmitted.

757 
WWUS76 KEKA 151131
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
431 AM PDT Sun Mar 15 2020

CAZ101-103-152000-
/O.NEW.KEKA.FR.Y.0009.200316T0800Z-200316T1600Z/
Coastal Del Norte-Northern Humboldt Coast-
431 AM PDT Sun Mar 15 2020

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

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

* WHERE...Coastal Del Norte County and Northern Coastal Humboldt
  County.

* WHEN...From 1 AM to 9 AM PDT Monday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$
3 follow-up statements
452 
WWUS76 KEKA 151945
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
1245 PM PDT Sun Mar 15 2020

CAZ101-103-160415-
/O.CON.KEKA.FR.Y.0009.200316T0800Z-200316T1600Z/
Coastal Del Norte-Northern Humboldt Coast-
1245 PM PDT Sun Mar 15 2020

...FROST ADVISORY REMAINS IN EFFECT FROM 1 AM TO 9 AM PDT
MONDAY...

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

* WHERE...Coastal Del Norte County and Northern Coastal Humboldt 
  County.

* WHEN...From 1 AM to 9 AM PDT Monday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$
183 
WWUS76 KEKA 160433
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
933 PM PDT Sun Mar 15 2020

CAZ115-161600-
/O.NEW.KEKA.FZ.W.0004.200316T0800Z-200316T1600Z/
/O.NEW.KEKA.HZ.W.0002.200316T0800Z-200316T1600Z/
/O.EXA.KEKA.FR.Y.0009.200316T0800Z-200316T1600Z/
Southern Lake County-
933 PM PDT Sun Mar 15 2020

...HARD FREEZE WARNING IN EFFECT FROM 1 AM TO 9 AM MONDAY...
...FROST ADVISORY IN EFFECT FROM 1 AM TO 9 AM MONDAY...

* WHAT...For the Hard Freeze Warning, sub-freezing temperatures as
  low as 25 expected. For the Frost Advisory, temperatures as low
  as 33 will result in frost formation.

* WHERE...Southern Lake County County.

* WHEN...From 1 AM to 9 AM 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. 

$$

CAZ110-114-161600-
/O.NEW.KEKA.FZ.W.0004.200316T0800Z-200316T1600Z/
/O.NEW.KEKA.HZ.W.0002.200316T0800Z-200316T1600Z/
Northwestern Mendocino Interior-Northern Lake County-
933 PM PDT Sun Mar 15 2020

...FREEZE WARNING IN EFFECT FROM 1 AM TO 9 AM MONDAY...
...HARD FREEZE WARNING IN EFFECT FROM 1 AM TO 9 AM MONDAY...

* WHAT...For the Hard Freeze Warning, sub-freezing temperatures as
  low as 26 expected. For the Freeze Warning, sub-freezing
  temperatures as low as 30 expected.

* WHERE...Northwestern Mendocino Interior and Northern Lake 
  County Counties.

* WHEN...From 1 AM to 9 AM 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. 

$$

CAZ113-161600-
/O.NEW.KEKA.FZ.W.0004.200316T0800Z-200316T1600Z/
/O.EXA.KEKA.FR.Y.0009.200316T0800Z-200316T1600Z/
Southeastern Mendocino Interior-
933 PM PDT Sun Mar 15 2020

...FREEZE WARNING IN EFFECT FROM 1 AM TO 9 AM MONDAY...
...FROST ADVISORY IN EFFECT FROM 1 AM TO 9 AM MONDAY...

* WHAT...For the Freeze Warning, sub-freezing temperatures as 
  low as 31 expected. For the Frost Advisory, temperatures as 
  low as 33 will result in frost formation.

* WHERE...Southeastern Mendocino Interior County.

* WHEN...From 1 AM to 9 AM 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. 

$$

CAZ111-161600-
/O.NEW.KEKA.HZ.W.0002.200316T0800Z-200316T1600Z/
Northeastern Mendocino Interior-
933 PM PDT Sun Mar 15 2020

...HARD FREEZE WARNING IN EFFECT FROM 1 AM TO 9 AM MONDAY...

* WHAT...Sub-freezing temperatures as low as 24 expected.

* WHERE...Northeastern Mendocino Interior County.

* WHEN...From 1 AM to 9 AM 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. 

$$

CAZ109-112-161600-
/O.EXA.KEKA.FR.Y.0009.200316T0800Z-200316T1600Z/
Mendocino Coast-Southwestern Mendocino Interior-
933 PM PDT Sun Mar 15 2020

...FROST ADVISORY IN EFFECT FROM 1 AM TO 9 AM MONDAY...

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

* WHERE...Mendocino Coast and Southwestern Mendocino Interior 
  Counties.

* WHEN...From 1 AM to 9 AM Monday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

$$

CAZ101-103-161600-
/O.CON.KEKA.FR.Y.0009.200316T0800Z-200316T1600Z/
Coastal Del Norte-Northern Humboldt Coast-
933 PM PDT Sun Mar 15 2020

...FROST ADVISORY REMAINS IN EFFECT FROM 1 AM TO 9 AM MONDAY...

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

* WHERE...Coastal Del Norte and Northern Humboldt Coast Counties.

* WHEN...From 1 AM to 9 AM Monday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

$$
002 
WWUS76 KEKA 161554
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
854 AM PDT Mon Mar 16 2020

CAZ115-161700-
/O.EXP.KEKA.FZ.W.0004.000000T0000Z-200316T1600Z/
/O.EXP.KEKA.HZ.W.0002.000000T0000Z-200316T1600Z/
/O.EXP.KEKA.FR.Y.0009.000000T0000Z-200316T1600Z/
Southern Lake County-
854 AM PDT Mon Mar 16 2020

...FREEZE WARNING WILL EXPIRE AT 9 AM PDT THIS MORNING...
...HARD FREEZE WARNING WILL EXPIRE AT 9 AM PDT THIS MORNING...
...FROST ADVISORY WILL EXPIRE AT 9 AM PDT THIS MORNING...


$$

CAZ110-114-161700-
/O.EXP.KEKA.FZ.W.0004.000000T0000Z-200316T1600Z/
/O.EXP.KEKA.HZ.W.0002.000000T0000Z-200316T1600Z/
Northwestern Mendocino Interior-Northern Lake County-
854 AM PDT Mon Mar 16 2020

...FREEZE WARNING WILL EXPIRE AT 9 AM PDT THIS MORNING...
...HARD FREEZE WARNING WILL EXPIRE AT 9 AM PDT THIS MORNING...


$$

CAZ113-161700-
/O.EXP.KEKA.FZ.W.0004.000000T0000Z-200316T1600Z/
/O.EXP.KEKA.FR.Y.0009.000000T0000Z-200316T1600Z/
Southeastern Mendocino Interior-
854 AM PDT Mon Mar 16 2020

...FREEZE WARNING WILL EXPIRE AT 9 AM PDT THIS MORNING...
...FROST ADVISORY WILL EXPIRE AT 9 AM PDT THIS MORNING...


$$

CAZ111-161700-
/O.EXP.KEKA.HZ.W.0002.000000T0000Z-200316T1600Z/
Northeastern Mendocino Interior-
854 AM PDT Mon Mar 16 2020

...HARD FREEZE WARNING WILL EXPIRE AT 9 AM PDT THIS MORNING...


$$

CAZ101-103-109-112-161700-
/O.EXP.KEKA.FR.Y.0009.000000T0000Z-200316T1600Z/
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-
854 AM PDT Mon Mar 16 2020

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


$$

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 15, 11:06 AM PDTWinter Weather AdvisoryEKALake, Mendocino4 hr

Nearby

Frost Advisories in California, 2020Every frost advisory in 2020

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.