Severe Thunderstorm Warning 419, NWS Birmingham, AL

Area Forecast Discussion
National Weather Service Birmingham AL
722 PM CDT Fri Aug 11 2023

...New SHORT TERM, AVIATION...

.SHORT TERM...
(Tonight through Saturday)
Issued at 703 PM CDT FRI AUG 11 2023

An instability gradient was perched northwest to southeast over
central Alabama early this evening. Increased pops based on the
latest radar depiction. Low level convergence was somewhat weak
and there does not appear to be much in the way of upper support.
But there is an enhanced Bulk Shear value. Microburst potential
was very high as super high cape values were teamed with very high
moisture values. Therefore, we are experiencing a damaging wind
threat with some hail. The watch that was in place was allowed to
expire and we believe there will be a general weakening trend the
next few hours. So a strong to severe storm possible another few
hours and then diminishing. Do not anticipate redevelopment
overnight. It appears that some patchy fog will develop overnight,
mainly where it rained and to the east. Will monitor this evening
for specific area to cover.

The low level conditions remain very moist into Saturday. An
believe it or not, the low level thicknesses increase. Therefore,
highs will be 95 to 100 over a large part of the area with heat
indices 105 to 110 and greater by afternoon.

75

Previous short-term discussion:
(This afternoon through Saturday)
Issued at 1233 PM CDT FRI AUG 11 2023

Other than the isolated severe storm chances, very dangerous heat
will return as a major story through Saturday. We'll stay in a
warm-sector environment with the surface ridge off to our south.
Dewpoints will struggle to mix out due to the the depth of the
moist environment, remaining in the mid to upper 70s. Heat index
values today will easily rise to 105 or above across the western
and southern counties and may rise close to 105 as far north as
Birmingham this afternoon. The Heat Advisory may need to be
expanded northward if we don't see dewpoints mix down a degree or
two from what we're observing currently. Upper level heights are
expected to increase during the day on Saturday as the ridge
builds in from the west. We'll see very dangerous conditions,
perhaps the worst we've seen so far this summer. We'll need an
Excessive Heat Warning over a majority of Central Alabama, as heat
index will rise to 110 degrees or higher.

At least scattered showers and storms will remain possible during
the day on Saturday, with high-res guidance indicating yet another
upper level impulse diving southward around the upper ridge. We'll
have to watch for the potential of another MCS to develop and move
southward through the afternoon. Chance PoPs have been included
areawide for now, until higher confidence in placement of the
storms can be achieved.

56/GDG

&&

.LONG TERM...
(Saturday night through next Thursday)
Issued at 344 PM CDT FRI AUG 11 2023

No major changes were made to the extended forecast. Isolated to
scattered mainly diurnal convection chances are expected. Elevated
heat indices will likely require continued heat advisories and
some excessive heat warnings for Sunday and Monday. On Tuesday
some drier air should make its way into C AL with a frontal
boundary. Thus, the more humid air that could require a heat
advisory should be more confined to the SRN tier of counties
depending on the success and progression of the surface boundary.
By Wed, the boundary should make some further progress SWD
allowing more lower dew points to make their way into C AL. This
should alleviate the need for heat advisories for any part of C AL
for Wed or Thu.

08

Previous long-term discussion:
(Saturday through Thursday)
Issued at 341 AM CDT FRI AUG 11 2023

Saturday through Monday.

Broad Mid-level ridging will persist over the Four Corners States
while a local maximum will be found over East Texas and much of
Louisiana to start the long term forecast period. Heights look to
rise further over the local area Sunday through Monday followed by
some contraction over the northern portion of the area late
Monday into Tuesday. Expect partly cloudy skies with isolated
showers and thunderstorms mainly in the afternoon hours. The
combination of heat and humidity will result in heat index values
remaining below 105 degrees across portions of the far
northeastern counties with the central counties exceeding 105
degrees while the higher values will be found across our south and
southwest with readings near 110.

Tuesday through Thursday.

Global guidance solutions have come into better agreement of a
closed low over Wisconsin with a longwave trough swinging east
over the Mid Mississippi River Valley Region during this time
frame. The longwave troughing will move further east closer to the
area on Wednesday before a more zonal flow regime returns on
Thursday. A surface cold front is progged to push into the
northern portion of the forecast area on Tuesday, resulting in
scattered showers and storms south and southeast with lower
chances across the northern third of the area. With the zonal
flow regime aloft, the surface front looks to stall just south of
the Interstate 20 corridor on Wednesday and Thursday, resulting in
scattered showers and storms each afternoon near and south of the
boundary with more isolated activity to the north. Heat index
values are expected to exceed 105 degrees on Tuesday across the
southern third of the forecast area. Drier air will mix down on
Tuesday and persist through Wednesday, resulting in heat index
values projected to be below 105 degrees areawide for Wednesday
and Thursday.

05

&&

.AVIATION...
(00Z TAFS)
Issued at 703 PM CDT FRI AUG 11 2023

Showers and storms will remain possible the next few hours near
BHM/EET/MGM/TOI. The storms may produce very heavy rain and some
gusty winds. The storms should diminish with the loss of daytime
heating. Overnight, winds will be light and variable. Low level
moisture remains very high and some patchy fog will be possible.
Will monitor this evening for potential placement in the next
terminal issuance. On Saturday, winds will be westerly 5-10kts and
there will be chances of thunderstorms area wide by afternoon.

75

&&

.FIRE WEATHER...

Scattered showers and storms will continue this afternoon through
Saturday with afternoon relative humidity minimums in the 45 to 55
percent range for Saturday. A decrease in shower and thunderstorm
activity is forecast Sunday and Monday while heat index readings
will continue to exceed 105 degrees during the afternoon hours
across much of the area through this time frame.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     73  94  71  96 /  30  40  30  30
Anniston    74  94  73  96 /  30  40  30  20
Birmingham  74  95  75  96 /  40  40  30  20
Tuscaloosa  76  96  75  98 /  20  30  20  20
Calera      74  96  75  98 /  40  40  30  20
Auburn      73  94  74  95 /  30  30  30  20
Montgomery  76  98  76  99 /  50  30  30  20
Troy        76  98  76  99 /  50  30  30  30

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 9 PM CDT this evening for the following
counties: Autauga-Barbour-Bibb-Bullock-Chilton-Coosa-Dallas-
Elmore-Fayette-Greene-Hale-Jefferson-Lamar-Lee-Lowndes-Macon-
Marengo-Marion-Montgomery-Perry-Pickens-Pike-Russell-Shelby-
Sumter-Talladega-Tallapoosa-Tuscaloosa-Walker-Winston.

Excessive Heat Warning from 10 AM to 9 PM CDT Saturday for the
following counties: Autauga-Barbour-Bibb-Bullock-Chilton-Coosa-
Dallas-Elmore-Fayette-Greene-Hale-Jefferson-Lamar-Lee-Lowndes-
Macon-Marengo-Marion-Montgomery-Perry-Pickens-Pike-Russell-
Shelby-Sumter-Tallapoosa-Tuscaloosa-Walker-Winston.

Heat Advisory from 10 AM to 9 PM CDT Saturday for the following
counties: Blount-Calhoun-Chambers-Cherokee-Clay-Cleburne-Etowah-
Randolph-St. Clair-Talladega.

&&

SHORT TERM...75
LONG TERM....08
AVIATION...56

Hazardous Weather Outlook
National Weather Service Birmingham AL
315 PM CDT Fri Aug 11 2023

ALZ011>015-017>050-122315-
Marion-Lamar-Fayette-Winston-Walker-Blount-Etowah-Calhoun-Cherokee-
Cleburne-Pickens-Tuscaloosa-Jefferson-Shelby-St. Clair-Talladega-
Clay-Randolph-Sumter-Greene-Hale-Perry-Bibb-Chilton-Coosa-Tallapoosa-
Chambers-Marengo-Dallas-Autauga-Lowndes-Elmore-Montgomery-Macon-
Bullock-Lee-Russell-Pike-Barbour-
315 PM CDT Fri Aug 11 2023

This Hazardous Weather Outlook is for the counties served by the
National Weather Service office in Birmingham.

.DAY ONE...Outlook through Tonight.

Severe thunderstorms are possible through 7 pm this evening. The risk
area includes locations near and south of I-20. The main threats will
be damaging winds and large hail.

The combination of high temperatures and high surface dew points will
create a feels like temperature from 105 to 109 degrees today. The
threat area is generally west of I-22 and the US 280 corridor. This
roughly covers the western two thirds of central Alabama.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Severe thunderstorms are possible again on Saturday. The threat
window appears to be from noon to 7 pm for the northeast half of the
area. Please see graphic for specific locations. The main threats
will be damaging winds and large hail.

The hot area today will increase on Saturday. The western area will
have an Excessive Heat Warning where heat indices will be 110 or
greater. The remainder of central Alabama will also increase in the
feels like temperature and a Heat Advisory has been issued.

Heat and humidity will produce dangerous conditions through Tuesday.
Heat indices will be 105 or greater each afternoon in various
locations across central Alabama.

.SPOTTER INFORMATION STATEMENT...

Activation of storm spotters and emergency management may be needed
this afternoon and Saturday afternoon.

<!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>

<!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>

<!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>

<!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>

<!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>

<!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>