Alert archive / California / Frost Advisories in 2021

Frost Advisory 9, NWS Los Angeles, CA

December 14, 2021Los Angeles County, California

NWS Los Angeles, CA issued this frost advisory at Dec 14, 2021, 9:47 PM PST for Los Angeles County, California. It took effect at Dec 15, 2021, 3:00 AM PST. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued
Dec 14, 2021, 9:47 PM PST (05:47 UTC)
In effect from
Dec 15, 2021, 3:00 AM PST
Expired
Dec 15, 2021, 9:00 AM PST
In force
6 hr
Issued by
NWS Los Angeles, CA

County Los Angeles County, CA

The nearest sounding before it

San Diego, CA (KNKX), launched 00:00Z, 5.8 hours before the alert went out and 184 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, San Diego, CA at 00:00Z on 2021-12-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 5 joules per kilogram.LCLEL10008507005003002001001 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, San Diego, CA at 00:00Z on 2021-12-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -121 square meters per square second.1939587897117136Sfc1 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
5 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
470 m above ground
0-6 km bulk shear
79 kt
0-1 km storm-relative helicity
-121 m²/s²
0-3 km storm-relative helicity
224 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

941 
WWUS76 KLOX 150547
NPWLOX

URGENT - WEATHER MESSAGE
National Weather Service Los Angeles/Oxnard CA
947 PM PST Tue Dec 14 2021

CAZ036-044-045-088-547-151400-
/O.UPG.KLOX.FR.Y.0008.211215T1100Z-211215T1700Z/
/O.NEW.KLOX.FZ.W.0004.211215T1100Z-211215T1700Z/
Santa Ynez Valley-Ventura County Interior Valleys-
Ventura County Coastal Valleys-Santa Clarita Valley-
Los Angeles County San Fernando Valley-
Including the cities of Solvang, Santa Ynez, Santa Paula, 
Fillmore, Ojai, Piru, Thousand Oaks, Simi Valley, Moorpark, 
Newbury Park, Santa Clarita, Newhall, Valencia, Woodland Hills, 
Northridge, Burbank, and Universal City
947 PM PST Tue Dec 14 2021

...FREEZE WARNING IN EFFECT FROM 3 AM TO 9 AM PST WEDNESDAY...

* WHAT...Sub-freezing temperatures between 27 and 31 degrees are 
  expected.

* WHERE...Santa Ynez Valley, Ventura County Interior Valleys, 
  Ventura County Coastal Valleys, Santa Clarita Valley and San 
  Fernando Valley.

* WHEN...From 3 AM to 9 AM PST Wednesday.

* IMPACTS...Frost and freeze conditions will kill crops and other
  sensitive vegetation. Extended exposure to cold can cause
  hypothermia for animals and people. Vehicle windshields will be
  frosted.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. Plan for
extra time to defrost vehicle windshields.

&&

$$

CAZ039-151400-
/O.NEW.KLOX.FR.Y.0009.211215T1100Z-211215T1700Z/
/O.CON.KLOX.WI.Y.0122.000000T0000Z-211215T1100Z/
Santa Barbara County South Coast-
Including the cities of Santa Barbara, Montecito, and Carpinteria
947 PM PST Tue Dec 14 2021

...WIND ADVISORY REMAINS IN EFFECT UNTIL 3 AM PST WEDNESDAY...
...FROST ADVISORY IN EFFECT FROM 3 AM TO 9 AM PST WEDNESDAY...

* WHAT...For the Frost Advisory, Temperatures as low as 31 in wind
  sheltered areas will result in frost formation. For the Wind 
  Advisory, northwest winds 10 to 20 mph.

* WHERE...Santa Barbara County South Coast.

* WHEN...For the Frost Advisory, from 3 AM to 9 AM PST 
  Wednesday. For the Wind Advisory, until 3 AM PST Wednesday.

* IMPACTS...Gusty winds will blow around unsecured objects and
  make driving difficult, especially for high profile vehicles.
  Tree limbs could be blown down and a few power outages may
  result. Frost can damage sensitive plants and harm pets if left
  unprotected.

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.

&&

$$

CAZ034-035-040-151400-
/O.NEW.KLOX.FR.Y.0009.211215T1100Z-211215T1700Z/
San Luis Obispo County Central Coast-
Santa Barbara County Central Coast-Ventura County Coast-
Including the cities of San Luis Obispo, Pismo Beach, Morro Bay, 
Cambria, San Simeon, Santa Maria, Lompoc, Vandenberg, Ventura, 
Oxnard, and Camarillo
947 PM PST Tue Dec 14 2021

...FROST ADVISORY IN EFFECT FROM 3 AM TO 9 AM PST WEDNESDAY...

* WHAT...Temperatures as low as 31 will result in frost 
  formation.

* WHERE...San Luis Obispo County Central Coast, Santa Barbara 
  County Central Coast and Ventura County Coast.

* WHEN...From 3 AM to 9 AM PST Wednesday.

* IMPACTS...Frost can damage sensitive plants and harm pets if
  left unprotected.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

CAZ052-151100-
/O.CON.KLOX.WI.Y.0122.000000T0000Z-211215T1100Z/
Santa Barbara County Mountains-
Including the cities of San Marcos Pass, 
San Rafael Wilderness Area, and Dick Smith Wilderness Area
947 PM PST Tue Dec 14 2021

...WIND ADVISORY REMAINS IN EFFECT UNTIL 3 AM PST WEDNESDAY...

* WHAT...North to northwest winds 20 to 30 mph with gusts to 45
  mph with local gusts to 50 mph possible below favored passes 
  and canyons, especially around Montecito.

* WHERE...Santa Barbara County South Coast and Mountains.

* WHEN...Until 3 AM PST Wednesday.

* IMPACTS...Gusty winds will blow around unsecured objects and
  make driving difficult, especially for high profile vehicles.
  Roadways may be affected by gusty cross winds. This includes
  Highways 101, 154 and 192.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

$$

ASR
3 follow-up statements
738 
WWUS76 KLOX 150604
NPWLOX

URGENT - WEATHER MESSAGE
National Weather Service Los Angeles/Oxnard CA
1004 PM PST Tue Dec 14 2021

CAZ036-044-045-088-547-151415-
/O.CON.KLOX.FZ.W.0004.211215T1100Z-211215T1700Z/
Santa Ynez Valley-Ventura County Interior Valleys-
Ventura County Coastal Valleys-Santa Clarita Valley-
Los Angeles County San Fernando Valley-
Including the cities of Solvang, Santa Ynez, Santa Paula, 
Fillmore, Ojai, Piru, Thousand Oaks, Simi Valley, Moorpark, 
Newbury Park, Santa Clarita, Newhall, Valencia, Woodland Hills, 
Northridge, Burbank, and Universal City
1004 PM PST Tue Dec 14 2021

...FREEZE WARNING REMAINS IN EFFECT FROM 3 AM TO 9 AM PST
WEDNESDAY...

* WHAT...Sub-freezing temperatures between 27 and 31 degrees are 
  expected.

* WHERE...Santa Ynez Valley, Ventura County Interior Valleys, 
  Ventura County Coastal Valleys, Santa Clarita Valley and San 
  Fernando Valley.

* WHEN...From 3 AM to 9 AM PST Wednesday.

* IMPACTS...Frost and freeze conditions will kill crops and 
  other sensitive vegetation. Extended exposure to cold can 
  cause hypothermia for animals and people. Vehicle windshields 
  will be frosted.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. Plan for
extra time to defrost vehicle windshields.

&&

$$

CAZ548-151415-
/O.EXA.KLOX.FR.Y.0009.211215T1100Z-211215T1700Z/
Los Angeles County San Gabriel Valley-
Including the cities of Pasadena, San Gabriel, and Pomona
1004 PM PST Tue Dec 14 2021

...FROST ADVISORY IN EFFECT FROM 3 AM TO 9 AM PST WEDNESDAY...

* WHAT...Temperatures as low as 31 will result in frost 
  formation.

* WHERE...San Gabriel Valley.

* WHEN...From 3 AM to 9 AM PST Wednesday.

* IMPACTS...Frost can damage sensitive plants and harm pets if 
  left unprotected.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

CAZ039-151415-
/O.CON.KLOX.WI.Y.0122.000000T0000Z-211215T1100Z/
/O.CON.KLOX.FR.Y.0009.211215T1100Z-211215T1700Z/
Santa Barbara County South Coast-
Including the cities of Santa Barbara, Montecito, and Carpinteria
1004 PM PST Tue Dec 14 2021

...WIND ADVISORY REMAINS IN EFFECT UNTIL 3 AM PST WEDNESDAY...
...FROST ADVISORY REMAINS IN EFFECT FROM 3 AM TO 9 AM PST
WEDNESDAY...

* WHAT...For the Frost Advisory, Temperatures as low as 31 in 
  wind sheltered areas will result in frost formation. For the 
  Wind Advisory, northwest winds 10 to 20 mph.

* WHERE...Santa Barbara County South Coast.

* WHEN...For the Wind Advisory, until 3 AM PST Wednesday. For 
  the Frost Advisory, from 3 AM to 9 AM PST Wednesday.

* IMPACTS...Gusty winds will blow around unsecured objects and 
  make driving difficult, especially for high profile vehicles. 
  Tree limbs could be blown down and a few power outages may 
  result. Frost can damage sensitive plants and harm pets if 
  left unprotected.


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.

&&

$$

CAZ034-035-040-151415-
/O.CON.KLOX.FR.Y.0009.211215T1100Z-211215T1700Z/
San Luis Obispo County Central Coast-
Santa Barbara County Central Coast-Ventura County Coast-
Including the cities of San Luis Obispo, Pismo Beach, Morro Bay, 
Cambria, San Simeon, Santa Maria, Lompoc, Vandenberg, Ventura, 
Oxnard, and Camarillo
1004 PM PST Tue Dec 14 2021

...FROST ADVISORY REMAINS IN EFFECT FROM 3 AM TO 9 AM PST
WEDNESDAY...

* WHAT...Temperatures as low as 31 will result in frost 
  formation.

* WHERE...San Luis Obispo County Central Coast, Santa Barbara 
  County Central Coast and Ventura County Coast.

* WHEN...From 3 AM to 9 AM PST Wednesday.

* IMPACTS...Frost can damage sensitive plants and harm pets if 
  left unprotected.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

CAZ052-151100-
/O.CON.KLOX.WI.Y.0122.000000T0000Z-211215T1100Z/
Santa Barbara County Mountains-
Including the cities of San Marcos Pass, 
San Rafael Wilderness Area, and Dick Smith Wilderness Area
1004 PM PST Tue Dec 14 2021

...WIND ADVISORY REMAINS IN EFFECT UNTIL 3 AM PST WEDNESDAY...

* WHAT...North to northwest winds 20 to 30 mph with gusts to 45 
  mph with local gusts to 50 mph possible below favored passes 
  and canyons, especially around Montecito.

* WHERE...Santa Barbara County South Coast and Mountains.

* WHEN...Until 3 AM PST Wednesday.

* IMPACTS...Gusty winds will blow around unsecured objects and 
  make driving difficult, especially for high profile vehicles. 
  Roadways may be affected by gusty cross winds. This includes 
  Highways 101, 154 and 192.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

$$

Phillips
437 
WWUS76 KLOX 151115
NPWLOX

URGENT - WEATHER MESSAGE
National Weather Service Los Angeles/Oxnard CA
315 AM PST Wed Dec 15 2021

CAZ039-151700-
/O.EXP.KLOX.WI.Y.0122.000000T0000Z-211215T1100Z/
/O.CON.KLOX.FR.Y.0009.000000T0000Z-211215T1700Z/
Santa Barbara County South Coast-
Including the cities of Santa Barbara, Montecito, and Carpinteria
315 AM PST Wed Dec 15 2021

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

* WHAT...Temperatures as low as 37 will result in frost 
  formation.

* WHERE...Santa Barbara County South Coast.

* WHEN...Until 9 AM PST this morning.

* IMPACTS...Frost can damage sensitive plants and harm pets if
  left unprotected.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

CAZ052-151215-
/O.EXP.KLOX.WI.Y.0122.000000T0000Z-211215T1100Z/
Santa Barbara County Mountains-
Including the cities of San Marcos Pass, 
San Rafael Wilderness Area, and Dick Smith Wilderness Area
315 AM PST Wed Dec 15 2021

...WIND ADVISORY HAS EXPIRED...

The winds have diminished to below advisory levels.

$$

CAZ036-044-045-088-547-151700-
/O.CON.KLOX.FZ.W.0004.000000T0000Z-211215T1700Z/
Santa Ynez Valley-Ventura County Interior Valleys-
Ventura County Coastal Valleys-Santa Clarita Valley-
Los Angeles County San Fernando Valley-
Including the cities of Solvang, Santa Ynez, Santa Paula, 
Fillmore, Ojai, Piru, Thousand Oaks, Simi Valley, Moorpark, 
Newbury Park, Santa Clarita, Newhall, Valencia, Woodland Hills, 
Northridge, Burbank, and Universal City
315 AM PST Wed Dec 15 2021

...FREEZE WARNING REMAINS IN EFFECT UNTIL 9 AM PST THIS MORNING...

* WHAT...Sub-freezing temperatures between 27 and 31 degrees are 
  expected.

* WHERE...Santa Ynez Valley, Ventura County Interior Valleys, 
  Ventura County Coastal Valleys, Santa Clarita Valley and San 
  Fernando Valley.

* WHEN...Until 9 AM PST this morning.

* IMPACTS...Frost and freeze conditions will kill crops and other
  sensitive vegetation. Extended exposure to cold can cause
  hypothermia for animals and people. Vehicle windshields will be
  frosted.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. Plan for
extra time to defrost vehicle windshields.

&&

$$

CAZ034-035-040-548-151700-
/O.CON.KLOX.FR.Y.0009.000000T0000Z-211215T1700Z/
San Luis Obispo County Central Coast-
Santa Barbara County Central Coast-Ventura County Coast-
Los Angeles County San Gabriel Valley-
Including the cities of San Luis Obispo, Pismo Beach, Morro Bay, 
Cambria, San Simeon, Santa Maria, Lompoc, Vandenberg, Ventura, 
Oxnard, Camarillo, Pasadena, San Gabriel, and Pomona
315 AM PST Wed Dec 15 2021

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

* WHAT...Temperatures as low as 31 will result in frost 
  formation.

* WHERE...San Luis Obispo County Central Coast, Santa Barbara 
  County Central Coast and Ventura County Coast.

* WHEN...Until 9 AM PST this morning.

* IMPACTS...Frost can damage sensitive plants and harm pets if
  left unprotected.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

ASR
854 
WWUS76 KLOX 151701
NPWLOX

URGENT - WEATHER MESSAGE
National Weather Service Los Angeles/Oxnard CA
901 AM PST Wed Dec 15 2021

CAZ036-044-045-088-547-151815-
/O.EXP.KLOX.FZ.W.0004.000000T0000Z-211215T1700Z/
Santa Ynez Valley-Ventura County Interior Valleys-
Ventura County Coastal Valleys-Santa Clarita Valley-
Los Angeles County San Fernando Valley-
Including the cities of Solvang, Santa Ynez, Santa Paula, 
Fillmore, Ojai, Piru, Thousand Oaks, Simi Valley, Moorpark, 
Newbury Park, Santa Clarita, Newhall, Valencia, Woodland Hills, 
Northridge, Burbank, and Universal City
901 AM PST Wed Dec 15 2021

...FREEZE WARNING HAS EXPIRED...

Freeze conditions are no longer occurring.

$$

CAZ034-035-039-040-548-151815-
/O.EXP.KLOX.FR.Y.0009.000000T0000Z-211215T1700Z/
San Luis Obispo County Central Coast-
Santa Barbara County Central Coast-
Santa Barbara County South Coast-Ventura County Coast-
Los Angeles County San Gabriel Valley-
Including the cities of San Luis Obispo, Pismo Beach, Morro Bay, 
Cambria, San Simeon, Santa Maria, Lompoc, Vandenberg, 
Santa Barbara, Montecito, Carpinteria, Ventura, Oxnard, 
Camarillo, Pasadena, San Gabriel, and Pomona
901 AM PST Wed Dec 15 2021

...FROST ADVISORY HAS EXPIRED...

Frost conditions are no longer occurring. 

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 14, 8:26 PM PSTFrost AdvisoryLOXLos Angeles81 min
Dec 14, 9:47 PM PSTFreeze WarningLOXLos Angeles11 hr
Dec 14, 10:17 PM PSTHigh Surf AdvisoryLOX16 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.