Alert archive / Alabama / Flash Flood Watches in 2017

Flash Flood Watch 6, NWS Birmingham, AL

August 8, 201730 counties in Alabama

NWS Birmingham, AL issued this flash flood watch at Aug 8, 2017, 9:54 AM CDT for 30 counties in Alabama. It took effect at Aug 8, 2017, 10:00 AM CDT. It was in force for 33 hr.

The area

The counties it named.

The facts

Issued: Aug 8, 2017, 9:54 AM CDT (14:54 UTC)
In effect from: Aug 8, 2017, 10:00 AM CDT
Expired: Aug 9, 2017, 7:00 PM CDT
In force: 33 hr
Issued by: NWS Birmingham, AL
Flood severity: None

All 30 counties

Autauga County, AL, Bibb County, AL, Calhoun County, AL, Chambers County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Dallas County, AL, Elmore County, AL, Fayette County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Lamar County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Marengo County, AL, Montgomery County, AL, Perry County, AL, Pickens County, AL, Randolph County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Talladega County, AL, Tallapoosa County, AL, Tuscaloosa County, AL, Walker County, AL

The radar

The Birmingham radar (KBMX), 19 km from the middle of the area, began a volume at 14:54 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

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 2.9 hours before the alert went out and 210 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: 93 J/kg
Mixed-layer CIN: -63 J/kg
Mixed-layer LCL: 786 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 16 m²/s²
0-3 km storm-relative helicity: 124 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.1

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 Birmingham, AL wrote its last area forecast discussion before this flash flood watch went out at Aug 8, 8:27 AM CDT, 1 hour 27 minutes earlier.

Area forecast discussion, Aug 8, 8:27 AM CDT, 1 hour 27 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, Aug 8, 9:44 AM CDT, 10 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 Birmingham, AL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 8, 7:51 AM CDT	Areal Flood Advisory	BMX	Jefferson	114 min
Aug 8, 9:12 AM CDT	Areal Flood Advisory	BMX	Shelby, Talladega	2 hr
Aug 8, 9:37 AM CDT	River Flood Warning	BMX	Jefferson	17 hr
Aug 8, 12:29 PM CDT	Areal Flood Advisory	BMX	Tuscaloosa	2 hr
Aug 8, 2:54 PM CDT	Special Weather Statement	BMX	Perry	36 min
Aug 8, 3:29 PM CDT	Special Weather Statement	BMX	Perry	31 min

Nearby

Flash Flood Watches in Alabama, 2017 Every flash flood watch in 2017

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.