Alert archive / Alabama / Flash Flood Warnings in 2023

Flash Flood Warning 11, NWS Huntsville, AL

May 18, 2023Marshall County, Morgan County, Alabama

NWS Huntsville, AL issued this flash flood warning at May 18, 2023, 4:04 PM CDT for Marshall County, Morgan County, Alabama. It was in force for 3 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
May 18, 2023, 4:04 PM CDT (21:04 UTC)
Expired
May 18, 2023, 7:15 PM CDT
In force
3 hr
Issued by
NWS Huntsville, AL
Area
Storm-based polygon
Flood severity
None

Counties Marshall County, AL, Morgan County, AL

The radar

The Northeast Alabama radar (KHTX), 74 km from the middle of the area, began a volume at 21:04 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

Birmingham, AL (KBMX), launched 12:00Z, 9.1 hours before the alert went out and 138 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-pSkew-T log-p diagram, Birmingham, AL at 12:00Z on 2023-05-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 308 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Birmingham, AL at 12:00Z on 2023-05-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -6 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
308 J/kg
Mixed-layer CIN
-33 J/kg
Mixed-layer LCL
540 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
-6 m²/s²
0-3 km storm-relative helicity
19 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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 Huntsville, AL wrote its last area forecast discussion before this flash flood warning went out at May 18, 12:46 PM CDT, 3 hours 18 minutes earlier.

Area forecast discussion, May 18, 12:46 PM CDT, 3 hours 18 minutes before
Area Forecast Discussion
National Weather Service Huntsville AL
1246 PM CDT Thu May 18 2023

...New NEAR TERM, SHORT TERM, LONG TERM...

.NEAR TERM...
(Tonight)
Issued at 1246 PM CDT Thu May 18 2023

A shortwave entering middle TN into AL early this evening will
exit to the east overnight. Scattered to numerous thunderstorms
and showers should diminish and dissipate fairly quickly after
sunset. Lower stratus is forecast to develop with the moist
southeast low level flow overnight. This should keep overnight
lows on the mild side in the lower 60s for most spots, and
possibly upper 50s in a few.

&&

.SHORT TERM...
(Friday through Sunday)
Issued at 1246 PM CDT Thu May 18 2023

A minor upper ridge will shift east into the area on Friday, but
the low level wave in MS will remain somewhat intact, enhancing
low level convergence over MS into far western AL. This is where
chances of showers and thunderstorms will exist again on Friday.

A trough advancing southeast into the Great Lakes and lower MO
valley will bring a cold front with it into the OH Valley through
the Ozarks and Ouachita Mtns by Friday evening into the overnight.
Eventually,, multiple MCS clusters along this front will arrive in
TN into northern MS Saturday morning, and eventually through the
central TN valley including our forecast area during the day
Saturday. There will be 25-35kt of low to mid-level westerly flow,
so bulk shear may allow for storm organization and possibly a few
strong to severe cells.

The trough and front will exit the area allowing for a dry and
seasonable Saturday night through Sunday, with lows in the 50s and
highs in the upper 70s to around 80.

&&

.LONG TERM...
(Sunday night through Thursday)
Issued at 1246 PM CDT Thu May 18 2023

The region will be in a weak north to northwest flow pattern
between the split jet fields next week. This will keep stronger
troughing over the Great Lakes and northeast/east central U.S.
Rain chances will be much more limited, especially with a low
level and persistent ridge axis across the eastern U.S. This may
keep a drier and rather stable easterly flow component going for
several days. We will keep slight chances of afternoon showers or
perhaps a thunderstorm Monday and Tuesday, then dry. Wouldn't be
surprised if we are dry all of those days however, especially if
the ECMWF is correct.

&&

.AVIATION...
(18Z TAFS)
Issued at 1117 AM CDT Thu May 18 2023

VFR flight weather conditions are expected this afternoon outside
of TSRA activity for most areas west of K4A6-K4A9, including KHSV
and KMSL. However, MVFR ceilings below 030agl may persist at times
in northeast AL. Isolated to scattered SHRA and TSRA are expected
this afternoon into early evening, which may yield temporary IFR
or MVFR conditions due to lower visibility in RA or +RA. After the
SHRA and TSRA dissipate ~01-03Z, lower ceilings are expected to
develop in the 015-025agl range (MVFR), and eventually below
010agl (IFR) by 13-14Z.

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...None.
TN...None.
&&

NEAR TERM...17
SHORT TERM....17
LONG TERM....17
AVIATION...17

In the hours before

Special weather statement, May 18, 2:52 PM CDT, 1 hour 12 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>
Special weather statement, May 18, 3:05 PM CDT, 59 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>
Special weather statement, May 18, 3:15 PM CDT, 49 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>
Special weather statement, May 18, 3:32 PM CDT, 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>
Special weather statement, May 18, 3:43 PM CDT, 21 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>
Special weather statement, May 18, 3:55 PM CDT, 9 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 Huntsville, AL issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 18, 1:46 PM CDTSpecial Weather StatementHUNMarshall29 min
May 18, 2:16 PM CDTSpecial Weather StatementHUNJackson29 min
May 18, 2:41 PM CDTSpecial Weather StatementHUNMarshall34 min
May 18, 2:47 PM CDTSevere Thunderstorm WarningHUNMadison, Marshall, Morgan28 min
May 18, 2:52 PM CDTSpecial Weather StatementHUNLawrence38 min
May 18, 3:05 PM CDTSpecial Weather StatementHUNMadison40 min
May 18, 3:13 PM CDTSevere Thunderstorm WarningHUNLimestone, Madison47 min
May 18, 3:15 PM CDTSpecial Weather StatementHUNMorgan45 min
May 18, 3:27 PM CDTSevere Thunderstorm WarningHUNMadison33 min
May 18, 3:32 PM CDTSpecial Weather StatementHUNLawrence43 min
May 18, 3:55 PM CDTSpecial Weather StatementHUNMadison50 min
May 18, 4:12 PM CDTSpecial Weather StatementHUNMorgan48 min
May 18, 4:14 PM CDTSpecial Weather StatementHUNLawrence46 min
May 18, 4:16 PM CDTSpecial Weather StatementHUNLawrence44 min
May 18, 4:22 PM CDTFlash Flood WarningHUNMadison3 hr
May 18, 4:24 PM CDTSpecial Weather StatementHUNLimestone51 min
May 18, 4:30 PM CDTSevere Thunderstorm WarningHUNLimestone30 min
May 18, 4:36 PM CDTFlash Flood WarningHUNLawrence, Morgan3 hr
May 18, 4:46 PM CDTSpecial Weather StatementHUNLawrence44 min
May 18, 4:47 PM CDTSpecial Weather StatementHUNCullman43 min
May 18, 4:53 PM CDTSpecial Weather StatementHUNLimestone52 min
May 18, 4:58 PM CDTSpecial Weather StatementHUNLawrence47 min
May 18, 5:24 PM CDTSpecial Weather StatementHUNCullman51 min
May 18, 6:23 PM CDTSpecial Weather StatementHUNCullman37 min
May 18, 3:43 PM CDTSpecial Weather StatementHUNLincoln47 min
May 18, 4:07 PM CDTSpecial Weather StatementHUNMoore38 min
May 18, 4:26 PM CDTSevere Thunderstorm WarningHUNFranklin, Lincoln, Moore34 min
May 18, 4:49 PM CDTSpecial Weather StatementHUNMoore41 min
May 18, 4:56 PM CDTSpecial Weather StatementHUNMoore49 min

Nearby

Flash Flood Warnings in Alabama, 2023Every flash flood warning in 2023

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.