Alert archive / California / Flash Flood Warnings in 2023

Flash Flood Warning 10, NWS Los Angeles, CA

January 10, 2023San Luis Obispo County, California

NWS Los Angeles, CA issued this flash flood warning at Jan 10, 2023, 4:47 AM PST for San Luis Obispo County, California. It was in force for 58 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: Jan 10, 2023, 4:47 AM PST (12:47 UTC)
Expired: Jan 10, 2023, 5:45 AM PST
In force: 58 min
Issued by: NWS Los Angeles, CA
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County San Luis Obispo County, CA

The radar

The Vandenberg AFB radar (KVBX), 61 km from the middle of the area, began a volume at 12:50 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, 0.8 hours before the alert went out and 304 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: 24 J/kg
Mixed-layer CIN: -17 J/kg
Mixed-layer LCL: 1000 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: 6 m²/s²
0-3 km storm-relative helicity: -8 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

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

NWS Los Angeles, CA wrote its last area forecast discussion before this flash flood warning went out at Jan 10, 4:03 AM PST, 44 minutes earlier.

Area forecast discussion, Jan 10, 4:03 AM PST, 44 minutes before

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In the hours before

Local storm report, Jan 9, 11:34 PM PST, 5 hours 13 minutes before

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Special weather statement, Jan 10, 3:00 AM PST, 1 hour 47 minutes before

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Special weather statement, Jan 10, 4:06 AM PST, 41 minutes before

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The office that day

Everything else NWS Los Angeles, CA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 9, 4:44 PM PST	Flash Flood Warning Considerable damage threat	LOX	San Luis Obispo, Santa Barbara	4 hr
Jan 9, 4:57 PM PST	Areal Flood Advisory	LOX	Los Angeles	4 hr
Jan 9, 5:08 PM PST	Flash Flood Warning Considerable damage threat	LOX	Ventura	4 hr
Jan 9, 5:55 PM PST	Special Marine Warning	LOX		95 min
Jan 9, 6:20 PM PST	Special Weather Statement	LOX	Ventura	40 min
Jan 9, 6:43 PM PST	Flash Flood Warning	LOX	Los Angeles	6 hr
Jan 9, 7:15 PM PST	Flash Flood Warning Considerable damage threat	LOX	Los Angeles	6 hr
Jan 9, 8:06 PM PST	Special Weather Statement	LOX	Los Angeles	24 min
Jan 9, 8:46 PM PST	Areal Flood Warning	LOX	Los Angeles, San Luis Obispo, Santa Barbara, Ventura	10 hr
Jan 9, 8:46 PM PST	Areal Flood Advisory	LOX	Los Angeles	4 hr
Jan 9, 11:10 PM PST	Areal Flood Warning	LOX	San Luis Obispo, Santa Barbara	6 hr
Jan 9, 11:17 PM PST	Areal Flood Warning	LOX	Santa Barbara	14 hr
Jan 10, 12:59 AM PST	Areal Flood Warning	LOX	Los Angeles	6 hr
Jan 10, 2:49 AM PST	Special Marine Warning	LOX		116 min
Jan 10, 3:00 AM PST	Special Weather Statement	LOX	San Luis Obispo	75 min
Jan 10, 4:06 AM PST	Special Weather Statement	LOX	San Luis Obispo	69 min
Jan 10, 7:35 AM PST	Special Marine Warning	LOX		40 min
Jan 10, 8:05 AM PST	Special Weather Statement	LOX	Ventura	25 min
Jan 10, 8:12 AM PST	Areal Flood Advisory	LOX	Los Angeles, Ventura	2 hr
Jan 10, 8:55 AM PST	Special Marine Warning	LOX		80 min
Jan 10, 9:00 AM PST	Special Weather Statement	LOX	Los Angeles	45 min
Jan 10, 10:35 AM PST	Special Marine Warning	LOX		40 min
Jan 10, 10:45 AM PST	Areal Flood Advisory	LOX	Los Angeles	90 min
Jan 10, 11:20 AM PST	Special Marine Warning	LOX		40 min

Nearby

Flash Flood Warnings in California, 2023 Every flash flood warning in 2023

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.