Alert archive / Maryland / Flash Flood Warnings in 2010

Flash Flood Warning 39, NWS Baltimore/Washington

August 12, 2010Anne Arundel County, Baltimore County, City of Baltimore, Maryland

NWS Baltimore/Washington issued this flash flood warning at Aug 12, 2010, 11:02 PM EDT for Anne Arundel County, Baltimore County, City of Baltimore, Maryland. It was in force for 2 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: Aug 12, 2010, 11:02 PM EDT (03:02 UTC)
Expired: Aug 13, 2010, 1:11 AM EDT
In force: 2 hr
Issued by: NWS Baltimore/Washington
Area: Storm-based polygon
Flood severity: None

Counties Anne Arundel County, MD, Baltimore County, MD, City of Baltimore, MD

The radar

The Sterling radar (KLWX), 82 km from the middle of the area, began a volume at 03:04 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

Washington/Dulle, VA (KIAD), launched 00:00Z, 3.0 hours before the alert went out and 76 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: 446 J/kg
Mixed-layer CIN: -60 J/kg
Mixed-layer LCL: 767 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: -43 m²/s²
0-3 km storm-relative helicity: -15 m²/s²
Significant tornado parameter: -0.1
Supercell composite: -1.0

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 Baltimore/Washington wrote its last area forecast discussion before this flash flood warning went out at Aug 12, 2:49 PM EDT, 8 hours 13 minutes earlier.

Area forecast discussion, Aug 12, 2:49 PM EDT, 8 hours 13 minutes before

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Hazardous weather outlook, Aug 12, 6:13 PM EDT, 4 hours 49 minutes before

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In the hours before

Local storm report, Aug 12, 7:09 PM EDT, 3 hours 53 minutes before

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Local storm report, Aug 12, 7:11 PM EDT, 3 hours 51 minutes before

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Local storm report, Aug 12, 7:13 PM EDT, 3 hours 49 minutes before

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Local storm report, Aug 12, 7:23 PM EDT, 3 hours 39 minutes before

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Local storm report, Aug 12, 7:30 PM EDT, 3 hours 32 minutes before

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      <h1 id="headline">This service is currently unavailable.</h1>
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      <p id="message2">
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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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Local storm report, Aug 12, 7:49 PM EDT, 3 hours 13 minutes before

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<head>
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<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>
      <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 Baltimore/Washington issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 12, 8:06 PM EDT	Flash Flood Warning	LWX	Baltimore, Harford	114 min
Aug 12, 9:28 PM EDT	Special Weather Statement	LWX	Anne Arundel	47 min
Aug 12, 9:35 PM EDT	Flash Flood Warning	LWX	Carroll, Frederick	3 hr
Aug 12, 10:40 PM EDT	Flash Flood Warning	LWX	Carroll, Frederick, Howard, Montgomery	2 hr
Aug 13, 12:26 AM EDT	Flash Flood Warning	LWX	Anne Arundel, Calvert, Prince George's	109 min

Nearby

Flash Flood Warnings in Maryland, 2010 Every flash flood warning in 2010

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.