Alert archive / California / Flash Flood Watches in 2009

Flash Flood Watch 7, NWS San Diego, CA

December 12, 20094 counties in California

NWS San Diego, CA issued this flash flood watch at Dec 12, 2009, 5:59 PM PST for 4 counties in California. It was in force for 15 hr.

The area

The counties it named.

The facts

Issued: Dec 12, 2009, 5:59 PM PST (01:59 UTC)
Expired: Dec 13, 2009, 9:00 AM PST
In force: 15 hr
Issued by: NWS San Diego, CA
Flood severity: None

Counties Orange County, CA, Riverside County, CA, San Bernardino County, CA, San Diego County, CA

The radar

The Santa Ana Mts radar (KSOX), 88 km from the middle of the area, began a volume at 02:00 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

San Diego, CA (KNKX), launched 00:00Z, 2.0 hours before the alert went out and 124 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: 163 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 593 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 64 m²/s²
0-3 km storm-relative helicity: 101 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

What forecasters said that day

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

NWS San Diego, CA wrote its last area forecast discussion before this flash flood watch went out at Dec 12, 2:10 PM PST, 3 hours 49 minutes earlier.

Area forecast discussion, Dec 12, 2:10 PM PST, 3 hours 49 minutes before

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Hazardous weather outlook, Dec 12, 5:01 AM PST, 12 hours 58 minutes before

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<body>
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    <section class="card" role="status" aria-live="polite">
      <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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        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 San Diego, CA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 12, 4:57 PM PST	Areal Flood Advisory	SGX	Riverside, San Bernardino	9 hr
Dec 13, 1:19 AM PST	Flash Flood Warning	SGX	San Diego	109 min
Dec 13, 5:49 AM PST	Areal Flood Advisory	SGX	Riverside	3 hr

Nearby

Flash Flood Watches in California, 2009 Every flash flood watch in 2009

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.