Alert archive / California / Freeze Warnings in 2021
Freeze Warning 2, NWS San Francisco Bay Area, CA
NWS San Francisco Bay Area, CA issued this freeze warning at Dec 10, 2021, 1:42 PM PST for 5 counties in California. It took effect at Dec 11, 2021, 12:00 AM PST. It was in force for 8 hr. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Dec 10, 2021, 1:42 PM PST (21:42 UTC)
- In effect from
- Dec 11, 2021, 12:00 AM PST
- Expired
- Dec 11, 2021, 8:00 AM PST
- In force
- 8 hr
- Issued by
- NWS San Francisco Bay Area, CA
Counties Marin County, CA, Monterey County, CA, Napa County, CA, San Benito County, CA, Sonoma County, CA
The radar
The San Francisco radar (KMUX), 50 km from the middle of the area, began a volume at 21:46 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, 9.7 hours before the alert went out and 19 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1499 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- -66 m²/s²
- 0-3 km storm-relative helicity
- 20 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
925 WWUS76 KMTR 102142 NPWMTR URGENT - WEATHER MESSAGE National Weather Service San Francisco Bay Area 142 PM PST Fri Dec 10 2021 CAZ516-110600- /O.UPG.KMTR.FZ.A.0001.211211T0800Z-211211T1600Z/ /O.NEW.KMTR.FZ.W.0002.211211T0800Z-211211T1600Z/ Southern Salinas Valley/Arroyo Seco and Lake San Antonio- Including the cities of Greenfield and King City 142 PM PST Fri Dec 10 2021 ...FREEZE WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 8 AM PST SATURDAY... * WHAT...A few to several hours of sub-freezing temperatures as low as 26 expected. * WHERE...Southern Salinas Valley/Arroyo Seco and Lake San Antonio. * WHEN...From midnight tonight to 8 AM PST Saturday. * IMPACTS...Frost and freeze conditions will kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing. * ADDITIONAL DETAILS...These temperatures will be even colder than last nights temperatures. Vulnerable populations should seek warming shelters. 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. && $$ CAZ506-518-110600- /O.NEW.KMTR.FZ.W.0002.211211T0800Z-211211T1600Z/ North Bay Interior Valleys- Mountains Of San Benito County And Interior Monterey County Including Pinnacles National Park- Including the cities of Santa Rosa, South Santa Rosa, Napa, San Rafael, Petaluma, Novato, and Rohnert Park 142 PM PST Fri Dec 10 2021 ...FREEZE WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 8 AM PST SATURDAY... * WHAT...A few to several hours of sub-freezing temperatures as low as 28 expected. * WHERE...North Bay Interior Valleys and Mountains Of San Benito County and Interior Monterey County Including Pinnacles National Park. * WHEN...From midnight tonight to 8 AM PST Saturday. * IMPACTS...Frost and freeze conditions will kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing. * ADDITIONAL DETAILS...These temperatures will be even colder than last nights temperatures. Vulnerable populations should seek warming shelters. PRECAUTIONARY/PREPAREDNESS ACTIONS... Take steps now to protect tender plants from the cold. To prevent freezing and possible bursting of outdoor water pipes they should be wrapped, drained, or allowed to drip slowly. Those that have in-ground sprinkler systems should drain them and cover above- ground pipes to protect them from freezing. && $$ For more information from the National Weather Service visit http://weather.gov/mtr
2 follow-up statements
611 WWUS76 KMTR 110549 NPWMTR URGENT - WEATHER MESSAGE National Weather Service San Francisco Bay Area 949 PM PST Fri Dec 10 2021 CAZ506-516-518-111300- /O.CON.KMTR.FZ.W.0002.211211T0800Z-211211T1600Z/ North 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 Santa Rosa, South Santa Rosa, Napa, San Rafael, Petaluma, Novato, Rohnert Park, Greenfield, and King City 949 PM PST Fri Dec 10 2021 ...FREEZE WARNING REMAINS IN EFFECT UNTIL 8 AM PST SATURDAY... * WHAT...Sub-freezing temperatures as low as 26 to 28 degrees expected. * WHERE...Southern Salinas Valley/Arroyo Seco and Lake San Antonio, North Bay Interior Valleys and Mountains Of San Benito County and Interior Monterey County Including Pinnacles National Park. * WHEN...Midnight until 8 AM PST Saturday. * IMPACTS...Frost and freeze conditions will kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing. * ADDITIONAL DETAILS...These temperatures will be even colder than last night's temperatures. Vulnerable populations should seek warming shelters. 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. && $$ For more information from the National Weather Service visit http://weather.gov/mtr
840 WWUS76 KMTR 111618 NPWMTR URGENT - WEATHER MESSAGE National Weather Service San Francisco Bay Area 818 AM PST Sat Dec 11 2021 CAZ506-516-518-111730- /O.EXP.KMTR.FZ.W.0002.000000T0000Z-211211T1600Z/ North Bay Interior Valleys- Southern Salinas Valley/Arroyo Seco and Lake San Antonio- Mountains Of San Benito County And Interior Monterey County Including Pinnacles National Park- Including the cities of Santa Rosa, South Santa Rosa, Napa, San Rafael, Petaluma, Novato, Rohnert Park, Greenfield, and King City 818 AM PST Sat Dec 11 2021 ...FREEZE WARNING HAS EXPIRED... $$ For more information from the National Weather Service visit http://weather.gov/mtr
The office that day
Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 10, 4:09 AM PST | Freeze Watch | MTR | Monterey | 10 hr |
| Dec 10, 8:42 AM PST | Small Craft Advisory | MTR | 60 hr | |
| Dec 10, 2:55 PM PST | Small Craft Advisory | MTR | 54 hr |
Nearby
Freeze Warnings in California, 2021Every freeze warning 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.