Alert archive / California / Frost Advisories in 2025

Frost Advisory 30, NWS San Francisco Bay Area, CA

March 17, 20255 counties in California

NWS San Francisco Bay Area, CA issued this frost advisory at Mar 17, 2025, 2:21 AM PDT for 5 counties in California. It took effect at Mar 18, 2025, 2:00 AM PDT. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued
Mar 17, 2025, 2:21 AM PDT (09:21 UTC)
In effect from
Mar 18, 2025, 2:00 AM PDT
Expired
Mar 18, 2025, 9:00 AM PDT
In force
7 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 09:25 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 00:00Z, 9.4 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.

Skew-T log-pSkew-T log-p diagram, Oakland, CA at 00:00Z on 2025-03-17Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Oakland, CA at 00:00Z on 2025-03-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 64 square meters per square second.1939587897117Sfc1 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
764 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
64 m²/s²
0-3 km storm-relative helicity
96 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The office that day

Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 17, 2:33 AM PDTSmall Craft AdvisoryMTR30 hr
Mar 17, 9:10 AM PDTSpecial Weather StatementMTRMarin35 min
Mar 17, 9:39 AM PDTSpecial Weather StatementMTRNapa36 min
Mar 17, 9:49 AM PDTSpecial Marine WarningMTR26 min
Mar 17, 10:01 AM PDTSpecial Weather StatementMTRMarin29 min
Mar 17, 10:12 AM PDTSpecial Marine WarningMTR33 min
Mar 17, 10:39 AM PDTSpecial Weather StatementMTRSan Mateo36 min
Mar 17, 10:58 AM PDTSpecial Weather StatementMTRSan Mateo17 min
Mar 17, 11:01 AM PDTSpecial Weather StatementMTRContra Costa29 min
Mar 17, 11:07 AM PDTSpecial Weather StatementMTRSan Mateo23 min
Mar 17, 11:36 AM PDTSpecial Marine WarningMTR24 min
Mar 17, 11:38 AM PDTSpecial Weather StatementMTRSanta Cruz37 min
Mar 17, 11:58 AM PDTSpecial Marine WarningMTR17 min
Mar 17, 12:02 PM PDTSpecial Weather StatementMTRSanta Cruz28 min
Mar 17, 12:22 PM PDTSpecial Weather StatementMTRAlameda23 min
Mar 17, 12:45 PM PDTSpecial Weather StatementMTRSanta Clara30 min
Mar 17, 12:56 PM PDTSpecial Weather StatementMTRSanta Cruz34 min

Nearby

Frost Advisories in California, 2025Every frost advisory in 2025

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.