Alert archive / California / Frost Advisories in 2021

Frost Advisory 2, NWS San Diego, CA

March 15, 2021Riverside County, San Bernardino County, San Diego County, California

NWS San Diego, CA issued this frost advisory at Mar 15, 2021, 1:01 PM PDT for Riverside County, San Bernardino County, San Diego County, California. It took effect at Mar 16, 2021, 12:00 AM PDT. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued
Mar 15, 2021, 1:01 PM PDT (20:01 UTC)
In effect from
Mar 16, 2021, 12:00 AM PDT
Expired
Mar 16, 2021, 8:17 AM PDT
In force
8 hr
Issued by
NWS San Diego, CA

Counties Riverside County, CA, San Bernardino County, CA, San Diego County, CA

The radar

The Santa Ana Mts radar (KSOX), 122 km from the middle of the area, began a volume at 20:03 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

San Diego, CA (KNKX), launched 12:00Z, 8.0 hours before the alert went out and 145 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 12:00Z on 2021-03-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 14 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 12:00Z on 2021-03-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 3 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
14 J/kg
Mixed-layer CIN
-2 J/kg
Mixed-layer LCL
607 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
3 m²/s²
0-3 km storm-relative helicity
90 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

686 
WWUS76 KSGX 152001
NPWSGX

URGENT - WEATHER MESSAGE
National Weather Service SAN DIEGO CA
101 PM PDT Mon Mar 15 2021

CAZ055-056-058-060>062-065-160500-
/O.CON.KSGX.HW.W.0007.000000T0000Z-210316T1000Z/
San Bernardino County Mountains-Riverside County Mountains-
San Diego County Mountains-Apple and Lucerne Valleys-
Coachella Valley-San Diego County Deserts-
San Gorgonio Pass Near Banning-
Including the cities of Crestline, Lake Arrowhead, Big Bear City,
Big Bear Lake, Running Springs, Wrightwood, Idyllwild-Pine Cove, 
Julian, Pine Valley, Victorville, Hesperia, Apple Valley, Indio, 
Palm Springs, Cathedral City, Palm Desert, Palm Desert Country, 
La Quinta, Coachella, Borrego Springs, Banning, 
and Desert Hot Springs
101 PM PDT Mon Mar 15 2021

...HIGH WIND WARNING REMAINS IN EFFECT UNTIL 3 AM PDT TUESDAY...

* WHAT...West winds 30 to 40 mph with gusts to 60 mph expected. 
  Local gusts to 85 mph in favored locations.

* WHERE...San Bernardino County Mountains, San Diego County 
  Deserts, Apple and Lucerne Valleys and Coachella Valley.

* WHEN...Until 3 AM PDT Tuesday.

* IMPACTS...Damaging winds will blow down trees and power lines. 
  Power outages are possible. Travel will be difficult, 
  especially for high profile vehicles.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Use caution if you must drive.

&&

$$

CAZ050-160500-
/O.NEW.KSGX.FR.Y.0002.210316T0700Z-210316T1600Z/
/O.EXT.KSGX.WI.Y.0016.000000T0000Z-210316T0800Z/
San Diego County Valleys-
Including the cities of Escondido, El Cajon, San Marcos, La Mesa,
Santee, and Poway
101 PM PDT Mon Mar 15 2021

...WIND ADVISORY NOW IN EFFECT UNTIL 1 AM PDT TUESDAY...
...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM PDT
TUESDAY...

* WHAT...For the Frost Advisory, temperatures as low as 33 degrees 
  will result in frost formation. For the Wind Advisory, west 
  winds 15 to 25 mph with gusts to 40 mph.

* WHERE...San Diego County Valleys.

* WHEN...For the Frost Advisory, from midnight tonight to 9 AM 
  PDT Tuesday. For the Wind Advisory, until 1 AM PDT Tuesday.

* 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.

&&

$$

CAZ048-160500-
/O.NEW.KSGX.FR.Y.0002.210316T0700Z-210316T1600Z/
San Bernardino and Riverside County Valleys-The Inland Empire-
Including the cities of Moreno Valley and Rancho Cucamonga
101 PM PDT Mon Mar 15 2021

...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM PDT
TUESDAY...

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

* WHERE...San Bernardino and Riverside County Valleys-The Inland 
  Empire.

* WHEN...From midnight tonight to 9 AM PDT Tuesday.

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


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

CAZ043-552-554-160500-
/O.EXT.KSGX.WI.Y.0016.000000T0000Z-210316T0800Z/
San Diego County Coastal Areas-Orange County Coastal Areas-
Orange County Inland Areas-
Including the cities of Vista, Carlsbad, Encinitas, Chula Vista, 
National City, San Diego, Huntington Beach, Costa Mesa, 
Santa Ana, Anaheim, Garden Grove, Irvine, Orange, Fullerton, 
and Mission Viejo
101 PM PDT Mon Mar 15 2021

...WIND ADVISORY NOW IN EFFECT UNTIL 1 AM PDT TUESDAY...

* WHAT...West winds 10 to 20 mph with gusts to 35 mph expected.

* WHERE...Orange County Coastal Areas, Orange County Inland 
  Areas and San Diego County Coastal Areas.

* WHEN...Until 1 AM PDT Tuesday.

* 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.

&&

$$

For more information from the National Weather Service visit
http://weather.gov/sandiego
3 follow-up statements
998 
WWUS76 KSGX 160349
NPWSGX

URGENT - WEATHER MESSAGE
National Weather Service SAN DIEGO CA
849 PM PDT Mon Mar 15 2021

CAZ055-056-058-060>062-065-161000-
/O.CON.KSGX.HW.W.0007.000000T0000Z-210316T1000Z/
San Bernardino County Mountains-Riverside County Mountains-
San Diego County Mountains-Apple and Lucerne Valleys-
Coachella Valley-San Diego County Deserts-
San Gorgonio Pass Near Banning-
Including the cities of Crestline, Lake Arrowhead, Big Bear City,
Big Bear Lake, Running Springs, Wrightwood, Idyllwild-Pine Cove, 
Julian, Pine Valley, Victorville, Hesperia, Apple Valley, Indio, 
Palm Springs, Cathedral City, Palm Desert, Palm Desert Country, 
La Quinta, Coachella, Borrego Springs, Banning, 
and Desert Hot Springs
849 PM PDT Mon Mar 15 2021

...HIGH WIND WARNING REMAINS IN EFFECT UNTIL 3 AM PDT TUESDAY...

* WHAT...West winds 30 to 40 mph with gusts to 65 mph expected. 

* WHERE...San Bernardino County Mountains, San Diego County 
  Deserts, Apple and Lucerne Valleys and Coachella Valley.

* WHEN...Until 3 AM PDT Tuesday.

* IMPACTS...Damaging winds will blow down trees and power lines.
  Power outages are possible. Travel will be difficult, especially
  for high profile vehicles.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Use caution if you must drive.

&&

$$

CAZ050-161030-
/O.CON.KSGX.WI.Y.0016.000000T0000Z-210316T0800Z/
/O.CON.KSGX.FR.Y.0002.210316T0700Z-210316T1600Z/
San Diego County Valleys-
Including the cities of Escondido, El Cajon, San Marcos, La Mesa,
Santee, and Poway
849 PM PDT Mon Mar 15 2021

...WIND ADVISORY REMAINS IN EFFECT UNTIL 1 AM PDT TUESDAY...
...FROST ADVISORY REMAINS IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM
PDT TUESDAY...

* WHAT...For the Frost Advisory, temperatures as low as 33 degrees
  will result in frost formation. For the Wind Advisory, west
  winds 10 to 20 mph with gusts to 35 mph.

* WHERE...San Diego County Valleys.

* WHEN...For the Frost Advisory, from midnight tonight to 9 AM 
  PDT Tuesday. For the Wind Advisory, until 1 AM PDT Tuesday.

* 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.

&&

$$

CAZ048-161030-
/O.CON.KSGX.FR.Y.0002.210316T0700Z-210316T1600Z/
San Bernardino and Riverside County Valleys-The Inland Empire-
Including the cities of Moreno Valley and Rancho Cucamonga
849 PM PDT Mon Mar 15 2021

...FROST ADVISORY REMAINS IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM
PDT TUESDAY...

* WHAT...Temperatures as low as 30 degrees will result in frost 
  formation.

* WHERE...San Bernardino and Riverside County Valleys-The Inland 
  Empire.

* WHEN...From midnight tonight to 9 AM PDT Tuesday.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

CAZ043-552-554-160800-
/O.CON.KSGX.WI.Y.0016.000000T0000Z-210316T0800Z/
San Diego County Coastal Areas-Orange County Coastal Areas-
Orange County Inland Areas-
Including the cities of Vista, Carlsbad, Encinitas, Chula Vista, 
National City, San Diego, Huntington Beach, Costa Mesa, 
Santa Ana, Anaheim, Garden Grove, Irvine, Orange, Fullerton, 
and Mission Viejo
849 PM PDT Mon Mar 15 2021

...WIND ADVISORY REMAINS IN EFFECT UNTIL 1 AM PDT TUESDAY...

* WHAT...West winds 10 to 20 mph with gusts to 40 mph expected.

* WHERE...Orange County Coastal Areas, Orange County Inland 
  Areas and San Diego County Coastal Areas.

* WHEN...Until 1 AM PDT Tuesday.

* 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.

&&

$$

For more information from the National Weather Service visit
http://weather.gov/sandiego
983 
WWUS76 KSGX 161057
NPWSGX

URGENT - WEATHER MESSAGE
National Weather Service SAN DIEGO CA
357 AM PDT Tue Mar 16 2021

CAZ055-056-058-060-062-065-161600-
/O.NEW.KSGX.WI.Y.0017.210316T1057Z-210316T1600Z/
San Bernardino County Mountains-Riverside County Mountains-
San Diego County Mountains-Apple and Lucerne Valleys-
San Diego County Deserts-San Gorgonio Pass Near Banning-
Including the cities of Julian, Borrego Springs, 
and Desert Hot Springs
357 AM PDT Tue Mar 16 2021

...WIND ADVISORY IN EFFECT UNTIL 9 AM PDT THIS MORNING...

* WHAT...West winds 20 to 30 mph with gusts to 55 mph.

* WHERE...Mostly along the east slopes of the mountains into the
  adjacent desert areas.

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

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

* ADDITIONAL DETAILS...Winds will gradually diminish through the
  morning.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

$$

CAZ048-050-161600-
/O.CON.KSGX.FR.Y.0002.000000T0000Z-210316T1600Z/
San Bernardino and Riverside County Valleys-The Inland Empire-
San Diego County Valleys-
Including the cities of Moreno Valley and Rancho Cucamonga
357 AM PDT Tue Mar 16 2021

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

* WHAT...Temperatures will fall into the lower to mid 30s for a
  few hours around sunrise, resulting in frost formation.

* WHERE...Inland San Diego County valleys near the foothills and
  portions of the Inland Empire.

* WHEN...Until 9 AM PDT 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.

&&

$$

For more information from the National Weather Service visit
http://weather.gov/sandiego

17
818 
WWUS76 KSGX 161517
NPWSGX

URGENT - WEATHER MESSAGE
National Weather Service SAN DIEGO CA
817 AM PDT Tue Mar 16 2021

CAZ048-050-161630-
/O.CAN.KSGX.FR.Y.0002.000000T0000Z-210316T1600Z/
San Bernardino and Riverside County Valleys-The Inland Empire-
San Diego County Valleys-
817 AM PDT Tue Mar 16 2021

...FROST ADVISORY IS CANCELLED...


$$

CAZ055-056-058-060-062-065-161630-
/O.CAN.KSGX.WI.Y.0017.000000T0000Z-210316T1600Z/
San Bernardino County Mountains-Riverside County Mountains-
San Diego County Mountains-Apple and Lucerne Valleys-
San Diego County Deserts-San Gorgonio Pass Near Banning-
817 AM PDT Tue Mar 16 2021

...WIND ADVISORY IS CANCELLED...

Winds have fallen below Advisory criteria most areas and will
continue to decrease this morning.

$$

For more information from the National Weather Service visit
http://weather.gov/sandiego

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 15, 1:43 AM PDTHigh Surf AdvisorySGXOrange, San Diego20 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.