Alert archive / Tennessee / Flash Flood Watches in 2020

Flash Flood Watch 7, NWS Memphis, TN

August 27, 202018 counties in Mississippi; 21 counties in Tennessee; 10 counties in Arkansas

NWS Memphis, TN issued this flash flood watch at Aug 27, 2020, 1:04 AM CDT for 18 counties in Mississippi; 21 counties in Tennessee; 10 counties in Arkansas. It took effect at Aug 27, 2020, 1:00 PM CDT. It was in force for 39 hr.

The area

The counties it named.

The facts

Issued: Aug 27, 2020, 1:04 AM CDT (06:04 UTC)
In effect from: Aug 27, 2020, 1:00 PM CDT
Expired: Aug 29, 2020, 3:46 AM CDT
In force: 39 hr
Issued by: NWS Memphis, TN
Flood severity: None

All 49 counties

Clay County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Greene County, AR, Lee County, AR, Mississippi County, AR, Phillips County, AR, Poinsett County, AR, St. Francis County, AR, Alcorn County, MS, Benton County, MS, Coahoma County, MS, DeSoto County, MS, Itawamba County, MS, Lafayette County, MS, Lee County, MS, Marshall County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Tallahatchie County, MS, Tate County, MS, Tippah County, MS, Tishomingo County, MS, Tunica County, MS, Union County, MS, Benton County, TN, Carroll County, TN, Chester County, TN, Crockett County, TN, Decatur County, TN, Dyer County, TN, Fayette County, TN, Gibson County, TN, Hardeman County, TN, Hardin County, TN, Haywood County, TN, Henderson County, TN, Henry County, TN, Lake County, TN, Lauderdale County, TN, Madison County, TN, McNairy County, TN, Obion County, TN, Shelby County, TN, Tipton County, TN, Weakley County, TN

The radar

The Memphis radar (KNQA), 43 km from the middle of the area, began a volume at 06:06 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

Little Rock, AR (KLZK), launched 00:00Z, 6.1 hours before the alert went out and 65 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: 966 J/kg
Mixed-layer CIN: -61 J/kg
Mixed-layer LCL: 1166 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 124 m²/s²
0-3 km storm-relative helicity: 163 m²/s²
Significant tornado parameter: 0.5
Supercell composite: 5.5

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 Memphis, TN wrote its last area forecast discussion before this flash flood watch went out at Aug 26, 11:09 PM CDT, 1 hour 55 minutes earlier.

Area forecast discussion, Aug 26, 11:09 PM CDT, 1 hour 55 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 26, 3:36 AM CDT, 21 hours 28 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>

In the hours before

Special weather statement, Aug 26, 10:06 PM CDT, 2 hours 58 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 Memphis, TN issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 26, 10:06 PM CDT	Special Weather Statement	MEG	DeSoto, Tate	24 min
Aug 26, 10:13 PM CDT	Areal Flood Advisory	MEG	DeSoto, Lafayette, Panola, Tate, Tunica	2 hr
Aug 26, 10:53 PM CDT	Areal Flood Advisory	MEG	DeSoto, Marshall, Tate	2 hr
Aug 27, 2:33 AM CDT	Wind Advisory	MEG	Benton, Coahoma, DeSoto, Marshall, Panola, Quitman and 3 more	37 hr
Aug 27, 5:20 PM CDT	Tornado Warning	MEG	Coahoma	25 min
Aug 27, 5:38 PM CDT	Tornado Warning	MEG	Coahoma	37 min
Aug 27, 6:23 PM CDT	Areal Flood Advisory	MEG	Coahoma	3 hr
Aug 27, 4:17 PM CDT	Tornado Warning	MEG	Phillips	25 min
Aug 27, 5:34 PM CDT	Tornado Warning	MEG	Lee, Phillips	11 min
Aug 27, 5:46 PM CDT	Tornado Warning	MEG	Lee, Phillips, St. Francis	29 min
Aug 27, 6:17 PM CDT	Tornado Warning	MEG	Lee, Phillips	8 min
Aug 27, 6:25 PM CDT	Tornado Warning	MEG	Lee, St. Francis	19 min
Aug 27, 6:46 PM CDT	Tornado Warning	MEG	Cross, St. Francis	17 min

Nearby

Flash Flood Watches in Tennessee, 2020 Flash Flood Watches in Mississippi, 2020 Flash Flood Watches in Arkansas, 2020 Every flash flood watch in 2020

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.