Alert archive / Pennsylvania / Flash Flood Watches in 2011

Flash Flood Watch 3, NWS Pittsburgh, PA

April 27, 201114 counties in Pennsylvania; 11 counties in Ohio; 6 counties in West Virginia

NWS Pittsburgh, PA issued this flash flood watch at Apr 27, 2011, 10:09 AM EDT for 14 counties in Pennsylvania; 11 counties in Ohio; 6 counties in West Virginia. It took effect at Apr 27, 2011, 5:00 PM EDT. It was in force for 11 hr.

The area

The counties it named.

The facts

Issued: Apr 27, 2011, 10:09 AM EDT (14:09 UTC)
In effect from: Apr 27, 2011, 5:00 PM EDT
Expired: Apr 28, 2011, 3:46 AM EDT
In force: 11 hr
Issued by: NWS Pittsburgh, PA
Flood severity: None

All 31 counties

Belmont County, OH, Carroll County, OH, Columbiana County, OH, Coshocton County, OH, Guernsey County, OH, Harrison County, OH, Jefferson County, OH, Monroe County, OH, Muskingum County, OH, Noble County, OH, Tuscarawas County, OH, Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Butler County, PA, Clarion County, PA, Fayette County, PA, Forest County, PA, Greene County, PA, Jefferson County, PA, Lawrence County, PA, Mercer County, PA, Venango County, PA, Washington County, PA, Westmoreland County, PA, Brooke County, WV, Hancock County, WV, Marion County, WV, Marshall County, WV, Ohio County, WV, Wetzel County, WV

The radar

The Pittsburgh radar (KPBZ), 25 km from the middle of the area, began a volume at 14:06 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 (KPIT), launched 12:00Z, 2.2 hours before the alert went out and 32 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: 393 J/kg
Mixed-layer CIN: -78 J/kg
Mixed-layer LCL: 1147 m above ground
0-6 km bulk shear: 57 kt
0-1 km storm-relative helicity: 110 m²/s²
0-3 km storm-relative helicity: 250 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.8

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 Pittsburgh, PA wrote its last area forecast discussion before this flash flood watch went out at Apr 27, 7:04 AM EDT, 3 hours 5 minutes earlier.

Area forecast discussion, Apr 27, 7:04 AM EDT, 3 hours 5 minutes before

<!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>

Hazardous weather outlook, Apr 27, 3:37 AM EDT, 6 hours 32 minutes before

<!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>

The office that day

Everything else NWS Pittsburgh, PA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 27, 3:18 PM EDT	Special Weather Statement	PBZ	Allegheny, Armstrong, Beaver, Butler, Clarion, Fayette and 7 more	57 min
Apr 27, 3:55 PM EDT	Severe Thunderstorm Warning	PBZ	Armstrong, Butler, Clarion, Forest, Jefferson, Mercer and 1 more	65 min
Apr 27, 4:06 PM EDT	Special Weather Statement	PBZ	Allegheny, Armstrong, Butler, Fayette, Greene, Indiana and 2 more	54 min
Apr 27, 4:30 PM EDT	Severe Thunderstorm Warning	PBZ	Armstrong, Indiana	30 min
Apr 27, 4:32 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Armstrong, Fayette, Indiana, Westmoreland	58 min
Apr 27, 4:50 PM EDT	Severe Thunderstorm Warning	PBZ	Jefferson	25 min
Apr 27, 5:01 PM EDT	Severe Thunderstorm Warning	PBZ	Indiana	44 min
Apr 27, 5:16 PM EDT	Severe Thunderstorm Warning	PBZ	Jefferson	44 min
Apr 26, 10:23 PM EDT	River Flood Watch	PBZ	Coshocton	37 hr
Apr 27, 12:20 PM EDT	Special Weather Statement	PBZ	Coshocton, Muskingum	55 min
Apr 27, 12:26 PM EDT	River Flood Watch	PBZ	Guernsey	9 hr
Apr 27, 1:16 PM EDT	Special Weather Statement	PBZ	Coshocton	44 min
Apr 27, 1:56 PM EDT	Special Weather Statement	PBZ	Guernsey, Muskingum, Noble, Tuscarawas	34 min
Apr 27, 2:12 PM EDT	High Wind Warning	PBZ	Guernsey, Noble, Tuscarawas	72 min
Apr 27, 2:47 PM EDT	Special Weather Statement	PBZ	Belmont, Carroll, Columbiana, Harrison, Jefferson, Monroe	43 min

Nearby

Flash Flood Watches in Pennsylvania, 2011 Flash Flood Watches in Ohio, 2011 Flash Flood Watches in West Virginia, 2011 Every flash flood watch in 2011

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.