Alert archive / California / Frost Advisories in 2021

Frost Advisory 5, NWS San Francisco Bay Area, CA

November 23, 20217 counties in California

NWS San Francisco Bay Area, CA issued this frost advisory at Nov 23, 2021, 1:46 PM PST for 7 counties in California. It took effect at Nov 24, 2021, 3:00 AM PST. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued
Nov 23, 2021, 1:46 PM PST (21:46 UTC)
In effect from
Nov 24, 2021, 3:00 AM PST
Expired
Nov 24, 2021, 9:00 AM PST
In force
6 hr
Issued by
NWS San Francisco Bay Area, CA

Counties Alameda County, CA, Contra Costa County, CA, Marin County, CA, Monterey County, CA, Napa County, CA, San Benito County, CA, Sonoma County, CA

The radar

The San Francisco radar (KMUX), 56 km from the middle of the area, began a volume at 21:47 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 12:00Z, 9.8 hours before the alert went out and 17 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 12:00Z on 2021-11-23Temperature 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 12:00Z on 2021-11-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 74 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1744 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
74 m²/s²
0-3 km storm-relative helicity
124 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

025 
WWUS76 KMTR 232146
NPWMTR

URGENT - WEATHER MESSAGE
National Weather Service San Francisco Bay Area
146 PM PST Tue Nov 23 2021

CAZ510-516-518-240600-
/O.NEW.KMTR.FR.Y.0005.211124T1100Z-211124T1700Z/
East Bay Interior Valleys-
Southern Salinas Valley/Arroyo Seco and Lake San Antonio-
Mountains Of San Benito County And Interior Monterey County
Including Pinnacles National Park-
Including the cities of Concord, Antioch, Livermore, 
Walnut Creek, Pleasanton, Pittsburg, San Ramon, Greenfield, 
and King City
146 PM PST Tue Nov 23 2021

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

* WHAT...Overnight low temperatures for the interior valleys will
  be in low to mid 30s tonight and will result in frost 
  formation.

* WHERE...East Bay Interior Valleys, Southern Salinas 
  Valley/Arroyo Seco and Lake San Antonio and Mountains Of San 
  Benito County and Interior Monterey County Including Pinnacles 
  National Park.

* WHEN...Several hours of temperatures at freezing are expected 
  early Wednesday morning.

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


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

ED

$$

For more information from the National Weather Service visit
http://weather.gov/mtr
3 follow-up statements
812 
WWUS76 KMTR 240306
NPWMTR

URGENT - WEATHER MESSAGE
National Weather Service San Francisco Bay Area
706 PM PST Tue Nov 23 2021

CAZ506-241200-
/O.EXA.KMTR.FR.Y.0005.211124T1100Z-211124T1700Z/
North Bay Interior Valleys-
Including the cities of Santa Rosa, South Santa Rosa, Napa, 
San Rafael, Petaluma, Novato, and Rohnert Park
706 PM PST Tue Nov 23 2021

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

* WHAT...Overnight low temperatures for the interior valleys will
  be in low to mid 30s tonight and will result in frost 
  formation.

* WHERE...North Bay Interior Valleys.

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

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


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants and sensitive animals from
the cold.

&&

$$

CAZ510-516-518-241200-
/O.CON.KMTR.FR.Y.0005.211124T1100Z-211124T1700Z/
East Bay Interior Valleys-
Southern Salinas Valley/Arroyo Seco and Lake San Antonio-
Mountains Of San Benito County And Interior Monterey County
Including Pinnacles National Park-
Including the cities of Concord, Antioch, Livermore, 
Walnut Creek, Pleasanton, Pittsburg, San Ramon, Greenfield, 
and King City
706 PM PST Tue Nov 23 2021

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

* WHAT...Overnight low temperatures for the interior valleys will
  be in low to mid 30s tonight and will result in frost 
  formation.

* WHERE...Southern Salinas Valley/Arroyo Seco and Lake San 
  Antonio, East Bay Interior Valleys and Mountains Of San Benito 
  County and Interior Monterey County Including Pinnacles 
  National Park.

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

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants and sensitive animals 
from the cold.

&&

$$

For more information from the National Weather Service visit
http://weather.gov/mtr
048 
WWUS76 KMTR 240925
NPWMTR

URGENT - WEATHER MESSAGE
National Weather Service San Francisco Bay Area
125 AM PST Wed Nov 24 2021

CAZ510-516-518-241700-
/O.CON.KMTR.FR.Y.0005.211124T1100Z-211124T1700Z/
East Bay Interior Valleys-
Southern Salinas Valley/Arroyo Seco and Lake San Antonio-
Mountains Of San Benito County And Interior Monterey County
Including Pinnacles National Park-
Including the cities of Concord, Antioch, Livermore, 
Walnut Creek, Pleasanton, Pittsburg, San Ramon, Greenfield, 
and King City
125 AM PST Wed Nov 24 2021

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

* WHAT...Low temperatures for the interior valleys will be in low
  to mid 30s and will result in frost formation.

* WHERE...Southern Salinas Valley/Arroyo Seco and Lake San 
  Antonio, East Bay Interior Valleys and Mountains Of San Benito 
  County and Interior Monterey County Including Pinnacles 
  National Park.

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

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

CAZ506-241700-
/O.CON.KMTR.FR.Y.0005.211124T1100Z-211124T1700Z/
North Bay Interior Valleys-
Including the cities of Santa Rosa, South Santa Rosa, Napa, 
San Rafael, Petaluma, Novato, and Rohnert Park
125 AM PST Wed Nov 24 2021

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

* WHAT...Low temperatures for the interior valleys will be in low
  to mid 30s and will result in frost formation.

* WHERE...North Bay Interior Valleys.

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

* 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/mtr
824 
WWUS76 KMTR 241656
NPWMTR

URGENT - WEATHER MESSAGE
National Weather Service San Francisco Bay Area
856 AM PST Wed Nov 24 2021

CAZ510-516-518-241800-
/O.EXP.KMTR.FR.Y.0005.000000T0000Z-211124T1700Z/
East Bay Interior Valleys-
Southern Salinas Valley/Arroyo Seco and Lake San Antonio-
Mountains Of San Benito County And Interior Monterey County
Including Pinnacles National Park-
Including the cities of Concord, Antioch, Livermore, 
Walnut Creek, Pleasanton, Pittsburg, San Ramon, Greenfield, 
and King City
856 AM PST Wed Nov 24 2021

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

Daytime heating will quickly allow temps to bounce back into the
50s and 60s this morning.

$$

CAZ506-241800-
/O.EXP.KMTR.FR.Y.0005.000000T0000Z-211124T1700Z/
North Bay Interior Valleys-
Including the cities of Santa Rosa, South Santa Rosa, Napa, 
San Rafael, Petaluma, Novato, and Rohnert Park
856 AM PST Wed Nov 24 2021

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

Daytime heating will quickly allow temps to bounce back into the
50s and 60s this morning.

$$

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

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.