Alert archive / California / Flash Flood Warnings in 2023

Flash Flood Warning 14, NWS Los Angeles, CA

March 10, 2023San Luis Obispo County, California

NWS Los Angeles, CA issued this flash flood warning at Mar 10, 2023, 5:10 AM PST for San Luis Obispo County, California. It was in force for 13 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: Mar 10, 2023, 5:10 AM PST (13:10 UTC)
Expired: Mar 10, 2023, 6:32 PM PST
In force: 13 hr
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 13:11 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

Vandenberg AFB, CA (KVBG), launched 12:00Z, 1.2 hours before the alert went out and 73 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 758 m above ground
0-6 km bulk shear: 55 kt
0-1 km storm-relative helicity: 491 m²/s²
0-3 km storm-relative helicity: 469 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 Mar 10, 4:30 AM PST, 40 minutes earlier.

Area forecast discussion, Mar 10, 4:30 AM PST, 40 minutes before

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In the hours before

Local storm report, Mar 10, 4:22 AM PST, 48 minutes before

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Local storm report, Mar 10, 4:33 AM PST, 37 minutes before

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Local storm report, Mar 10, 4:35 AM PST, 35 minutes before

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Local storm report, Mar 10, 4:36 AM PST, 34 minutes before

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      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
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        The site you requested is temporarily down for maintenance or an unexpected outage.
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Local storm report, Mar 10, 4:39 AM PST, 31 minutes before

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      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
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      <p id="message2">
        Please try again in a few minutes.
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      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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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
Mar 10, 1:23 AM PST	Areal Flood Advisory	LOX	San Luis Obispo	10 hr
Mar 10, 2:02 AM PST	High Wind Warning	LOX	Los Angeles, San Luis Obispo, Santa Barbara	20 hr
Mar 10, 5:32 AM PST	Areal Flood Advisory	LOX	Santa Barbara	6 hr
Mar 10, 7:20 AM PST	Flash Flood Warning Considerable damage threat	LOX	San Luis Obispo	11 hr
Mar 10, 10:56 AM PST	River Flood Warning	LOX	San Luis Obispo	8 hr
Mar 10, 11:21 AM PST	Areal Flood Advisory	LOX	Santa Barbara	7 hr
Mar 10, 12:47 PM PST	Areal Flood Advisory	LOX	Ventura	6 hr
Mar 10, 2:21 PM PST	Areal Flood Advisory	LOX	Los Angeles	5 hr
Mar 10, 3:28 PM PST	Areal Flood Advisory	LOX	Los Angeles	4 hr

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.