Alert archive / California / Severe Thunderstorm Warnings in 2024

Severe Thunderstorm Warning 1, NWS San Francisco Bay Area, CA

February 19, 2024San Mateo County, California

NWS San Francisco Bay Area, CA issued this severe thunderstorm warning at Feb 19, 2024, 3:54 PM PST for San Mateo County, California. It was in force for 22 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Feb 19, 2024, 3:54 PM PST (23:54 UTC)
Expired: Feb 19, 2024, 4:16 PM PST
In force: 22 min
Issued by: NWS San Francisco Bay Area, CA
Area: Storm-based polygon
Tornado: Possible
Hail: 0.75 in
Wind: 60.0 mph

County San Mateo County, CA

The radar

The San Francisco radar (KMUX), 51 km from the middle of the area, began a volume at 23:56 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, 11.9 hours before the alert went out and 35 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 66 J/kg
Mixed-layer CIN: -9 J/kg
Mixed-layer LCL: 723 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: 235 m²/s²
0-3 km storm-relative helicity: 269 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS San Francisco Bay Area, CA wrote its last area forecast discussion before this severe thunderstorm warning went out at Feb 19, 1:18 PM PST, 2 hours 36 minutes earlier.

Area forecast discussion, Feb 19, 1:18 PM PST, 2 hours 36 minutes before

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In the hours before

Special weather statement, Feb 19, 12:44 PM PST, 3 hours 10 minutes before

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Special weather statement, Feb 19, 1:35 PM PST, 2 hours 19 minutes before

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Special weather statement, Feb 19, 2:03 PM PST, 1 hour 51 minutes before

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Special weather statement, Feb 19, 2:59 PM PST, 55 minutes before

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Special weather statement, Feb 19, 3:29 PM PST, 25 minutes before

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Special weather statement, Feb 19, 3:42 PM PST, 12 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Feb 18, 4:53 PM PST	Areal Flood Advisory	MTR	Marin, Napa, Sonoma	31 hr
Feb 18, 6:51 PM PST	Areal Flood Advisory	MTR	Marin, Napa, Sonoma	27 hr
Feb 18, 6:58 PM PST	Areal Flood Advisory	MTR	Alameda, Contra Costa, Santa Clara	6 hr
Feb 18, 9:23 PM PST	Areal Flood Advisory	MTR	San Mateo, Santa Clara, Santa Cruz	5 hr
Feb 18, 9:39 PM PST	Areal Flood Advisory	MTR	Alameda, Santa Clara, Santa Cruz	3 hr
Feb 19, 12:04 AM PST	Areal Flood Advisory	MTR	Monterey	7 hr
Feb 19, 12:11 AM PST	Areal Flood Advisory	MTR	San Benito	7 hr
Feb 19, 10:10 AM PST	Special Marine Warning	MTR		20 min
Feb 19, 10:29 AM PST	Special Weather Statement	MTR	Marin	31 min
Feb 19, 11:47 AM PST	Special Marine Warning	MTR		28 min
Feb 19, 12:28 PM PST	Special Marine Warning	MTR		32 min
Feb 19, 12:33 PM PST	Special Marine Warning	MTR		27 min
Feb 19, 12:44 PM PST	Special Weather Statement	MTR	Marin	31 min
Feb 19, 1:01 PM PST	Special Marine Warning	MTR		29 min
Feb 19, 1:30 PM PST	Special Marine Warning	MTR		30 min
Feb 19, 1:35 PM PST	Special Weather Statement	MTR	Marin	25 min
Feb 19, 1:57 PM PST	Special Marine Warning	MTR		33 min
Feb 19, 2:03 PM PST	Special Weather Statement	MTR	San Mateo	27 min
Feb 19, 2:59 PM PST	Special Weather Statement	MTR	Contra Costa	31 min
Feb 19, 3:29 PM PST	Special Weather Statement	MTR	Contra Costa	31 min
Feb 19, 3:31 PM PST	Special Marine Warning	MTR		29 min
Feb 19, 3:38 PM PST	Special Marine Warning	MTR		37 min
Feb 19, 3:42 PM PST	Special Weather Statement	MTR	San Mateo	33 min
Feb 19, 3:59 PM PST	Special Marine Warning	MTR		31 min

Nearby

Severe Thunderstorm Warnings in California, 2024 Every severe thunderstorm warning in 2024

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.