Alert archive / California / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 20, NWS Sacramento, CA

May 27, 2009Tuolumne County, California

NWS Sacramento, CA issued this severe thunderstorm warning at May 27, 2009, 4:24 PM PDT for Tuolumne County, California. It was in force for 66 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: May 27, 2009, 4:24 PM PDT (23:24 UTC)
Expired: May 27, 2009, 5:30 PM PDT
In force: 66 min
Issued by: NWS Sacramento, CA
Area: Storm-based polygon

County Tuolumne County, CA

The radar

The Sacramento radar (KDAX), 159 km from the middle of the area, began a volume at 23:27 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, 11.4 hours before the alert went out and 370 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: 796 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: 22 m²/s²
0-3 km storm-relative helicity: -94 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 severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Sacramento, CA wrote its last area forecast discussion before this severe thunderstorm warning went out at May 27, 3:15 PM PDT, 1 hour 9 minutes earlier.

Area forecast discussion, May 27, 3:15 PM PDT, 1 hour 9 minutes before

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Hazardous weather outlook, May 27, 7:00 AM PDT, 9 hours 24 minutes before

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</head>
<body>
  <main class="wrap">
    <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.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
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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 Sacramento, CA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 27, 3:50 PM PDT	Severe Thunderstorm Warning	STO	Shasta	20 min
May 27, 3:56 PM PDT	Severe Thunderstorm Warning	STO	Nevada, Sierra	43 min
May 27, 4:05 PM PDT	Severe Thunderstorm Warning	STO	Shasta	31 min

Nearby

Severe Thunderstorm Warnings in California, 2009 Every severe thunderstorm warning 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.