Alert archive / Pennsylvania / Mesoscale Discussions in 2007

Mesoscale Discussion 1869

August 23, 200716 counties in Ohio; 21 counties in Pennsylvania; 4 counties in West Virginia

The Storm Prediction Center issued this mesoscale discussion at Aug 23, 2007, 5:30 PM EDT for 16 counties in Ohio; 21 counties in Pennsylvania; 4 counties in West Virginia. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued: Aug 23, 2007, 5:30 PM EDT (21:30 UTC)
Expired: Aug 23, 2007, 6:30 PM EDT
In force: 60 min
Issued by: the Storm Prediction Center

All 41 counties

Belmont County, OH, Carroll County, OH, Columbiana County, OH, Coshocton County, OH, Guernsey County, OH, Harrison County, OH, Holmes County, OH, Jefferson County, OH, Mahoning County, OH, Medina County, OH, Portage County, OH, Stark County, OH, Summit County, OH, Trumbull County, OH, Tuscarawas County, OH, Wayne County, OH, Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Bedford County, PA, Blair County, PA, Butler County, PA, Cambria County, PA, Clarion County, PA, Clearfield County, PA, Fayette County, PA, Forest County, PA, Fulton County, PA, Greene County, PA, Indiana County, PA, Jefferson County, PA, Lawrence County, PA, Mercer County, PA, Somerset County, PA, Venango County, PA, Washington County, PA, Westmoreland County, PA, Brooke County, WV, Hancock County, WV, Marshall County, WV, Ohio County, WV

The radar

The Pittsburgh radar (KPBZ), 3 km from the middle of the area, began a volume at 21:33 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

Pittsburgh, PA (KAGC), launched 12:00Z, 9.5 hours before the alert went out and 19 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: 1968 J/kg
Mixed-layer CIN: -39 J/kg
Mixed-layer LCL: 835 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 50 m²/s²
0-3 km storm-relative helicity: 49 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</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>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 23, 2:48 AM EDT	Mesoscale Discussion	SPC	Defiance, Fulton, Henry, Lucas, Williams	27 min
Aug 23, 11:17 AM EDT	Mesoscale Discussion	SPC	Carroll, Columbiana, Coshocton, Guernsey, Harrison, Holmes and 6 more	88 min
Aug 23, 2:43 PM EDT	Severe Thunderstorm Watch	SPC	Ashland, Belmont, Carroll, Columbiana, Coshocton, Guernsey and 14 more	6 hr
Aug 23, 3:07 PM EDT	Mesoscale Discussion	SPC	Defiance, Fulton, Hancock, Henry, Lucas, Paulding and 4 more	83 min
Aug 23, 4:09 PM EDT	Severe Thunderstorm Watch	SPC	Defiance, Fulton, Henry, Lucas, Ottawa, Paulding and 3 more	8 hr
Aug 23, 6:38 PM EDT	Mesoscale Discussion	SPC	Defiance, Fulton, Henry, Lucas, Williams, Wood	97 min

Nearby

Mesoscale Discussions in Pennsylvania, 2007 Mesoscale Discussions in Ohio, 2007 Mesoscale Discussions in West Virginia, 2007 Every mesoscale discussion in 2007

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.