Special Weather Statement, NWS Atlanta, GA

Area Forecast Discussion
National Weather Service Peachtree City GA
709 PM EDT Thu Apr 27 2017

.UPDATE...
Updated for the 00Z Aviation Discussion.

&&

.PREV DISCUSSION... /Issued 401 PM EDT Thu Apr 27 2017/

..Area Forecast Discussion...

SHORT TERM /Tonight through Friday Night/...

Current mosaic radar loop shows the main squall line now over
Central GA continuing to move east. Current surface analysis
continues to show this line moving into a very favorable area of
instability and with us in the prime time heating of the day can
expect to see a few more warnings before this is all over. There is
another much weaker line of showers moving east over NW GA and this
appears to be associated with the actual cold front. not expecting
much out of this second line but will defiantly keep an eye on it.
All of the Hi-Res models are in very good agreement showing this
squall line continuing to move east through the evening then
stalling somewhere across central/south GA after midnight. This
squall is expected to weaken as the precip diminishes through Fri
morning. The Hi-Res models are also showing some slight
redevelopment friday as the old boundary moves back northward as a
warm front through Fri evening. For now only seeing showers Fri as
there is very little moisture available across the region for the
boundary to work with. Keeping in a slight chance of precip across
mainly N GA Fri. Temps will continue on the warm side of things as
highs friday are expected to be in the 80s to near 90 across the
CWA.

01

LONG TERM /Saturday through Thursday/...
Saturday starts with a fairly stout 500mb ridge centered off the
South Carolina Coast with deep trough digging into NM and West TX.
Strong warm advection setting up ahead of the trough across all of
the southern states will make for a warm and muggy Saturday and
Sunday. For Saturday...given the high dewpoints and upper 80 deg
temps...models suggesting fairly unstable atmosphere across north
GA during the afternoon hours. GFS forecasting mid level lapse
rates near 7 deg c/km with SB CAPE surging past 4000 j/KG. Also of
note is a 250mb jet streak emanating out of the GOM ahead of the
advancing trof and around the upper ridge....which could serve as
a trigger for storms late in the day Saturday. Given these higher
values...if any storms can develop..particularly off the higher
terrain like we often see in summer convection...there would be a
higher probability of them becoming severe with hail and strong
damaging winds. Model soundings do show some mid level dry air
which would increase the risk for downburst type storms. Too early
to tell IF any storms can develop but the conditions would favor
some severe if they can.

For Sunday/Monday...the large scale trof begins to eject through
TX and LA with severe weather likely to develop out ahead of the
trough in the MS valley. Our area will see south to southwesterly
winds during the day increasing as the storm approaches. likely
to be partly to mostly cloudy with moist advection in place but
not expecting much precip as we will be lacking any real focus.
ECMWF is a tad slower than the GFS with bringing the front in. The
GFS would suggest Early Monday AM through the morning hours
whereas the ECMWF is a bit slower and lifts the main trof to the
NE owing to a fropa Monday Afternoon and evening. Will have
evaluate through the weekend as another caveat is the possibility
of Gulf Coast convection cutting off inflow to the north...which
is typical in a southwest flow regime that amenities out of south
LA. With the ECMWF lifting the trof out a little later and further
north...it would suggest a greater prob of severe for the region.
One item that appears to be lacking a bit is instability likely
due to significant cloud cover ahead of the system. too many
variables at this point to say for certain the severe threat.

Tuesday and Wednesday we are in between systems with another deep
trof digging into the lower MS valley by Thursday and thus another
chance of thunderstorms and/or severe storms.

30

&&

.AVIATION...
00Z Update...
Convection across central GA will dissipate over the next few
hours. Otherwise VFR for this evening with IFR cigs developing
late tonight over the entire forecast area. CIGS will rise to VFR
by early Friday afternoon. Patchy fog is also expected to develop
late tonight. Winds will become light southwest this evening, then
light south to southeast late tonight and remain southerly 5 to
10 kts Friday.

//ATL Confidence...00Z Update...
Medium on CIGS late tonight and on winds Friday afternoon.
High on remaining elements.

17

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          64  85  65  88 /  30  20  10  20
Atlanta         64  84  68  87 /  20  20   5  20
Blairsville     57  80  62  83 /  10  20  20  30
Cartersville    61  84  66  87 /  10  20  10  20
Columbus        69  87  69  89 /  40  20   5  20
Gainesville     62  82  65  86 /  20  20  10  30
Macon           69  88  66  90 /  60  20   5  20
Rome            60  84  66  88 /  10  20  10  20
Peachtree City  65  84  65  87 /  20  20   5  20
Vidalia         69  92  70  91 /  60  10  10  10

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
Tornado Watch until 8 PM EDT this evening for the following
zones: Baldwin...Bibb...Bleckley...Butts...Chattahoochee...
Crawford...Crisp...Dodge...Dooly...Emanuel...Glascock...Greene...
Hancock...Houston...Jasper...Jefferson...Johnson...Jones...
Lamar...Laurens...Macon...Marion...Monroe...Montgomery...
Morgan...Muscogee...Peach...Pulaski...Putnam...Schley...
Stewart...Sumter...Talbot...Taliaferro...Taylor...Telfair...
Toombs...Treutlen...Twiggs...Upson...Warren...Washington...
Webster...Wheeler...Wilcox...Wilkinson.

&&

SHORT TERM...17
LONG TERM....SNELSON
AVIATION...17

Hazardous Weather Outlook
National Weather Service Peachtree City GA
1142 AM EDT Thu Apr 27 2017

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-281545-
Baldwin-Banks-Barrow-Bartow-Bibb-Bleckley-Butts-Carroll-Catoosa-
Chattahoochee-Chattooga-Cherokee-Clarke-Clayton-Cobb-Coweta-
Crawford-Crisp-Dade-Dawson-DeKalb-Dodge-Dooly-Douglas-Emanuel-
Fannin-Fayette-Floyd-Forsyth-Gilmer-Glascock-Gordon-Greene-
Gwinnett-Hall-Hancock-Haralson-Harris-Heard-Henry-Houston-Jackson-
Jasper-Jefferson-Johnson-Jones-Lamar-Laurens-Lumpkin-Macon-
Madison-Marion-Meriwether-Monroe-Montgomery-Morgan-Murray-
Muscogee-Newton-North Fulton-Oconee-Oglethorpe-Paulding-Peach-
Pickens-Pike-Polk-Pulaski-Putnam-Rockdale-Schley-South Fulton-
Spalding-Stewart-Sumter-Talbot-Taliaferro-Taylor-Telfair-Toombs-
Towns-Treutlen-Troup-Twiggs-Union-Upson-Walker-Walton-Warren-
Washington-Webster-Wheeler-White-Whitfield-Wilcox-Wilkes-
Wilkinson-
1142 AM EDT Thu Apr 27 2017

This Hazardous Weather Outlook is for portions of North and Central Georgia.

.DAY ONE...This Afternoon and Tonight...

A cold front and associated line of thunderstorms will move
across the area today. This line will primarily affect locations
south and east of Interstate 85 today...however a few isolated
showers and thunderstorms are possible north and west of
Interstate 85. Isolated severe storms will be possible...mainly
along south of a Columbus to Athens line this afternoon. The
primary severe threats will be damaging wind gusts...small
hail...and perhaps a brief spin up tornado or two.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday...

Isolated thunderstorms will be possible Friday...becoming more
scattered Saturday and Sunday as a moist airmass moves in.
Isolated severe weather will be possible with these
storms...mainly in the form of damaging winds and large hail.

A cold front will approach the area Sunday night into Monday.
Severe weather will be a concern as a line of organized
thunderstorms accompanies the front.

After a quiet Tuesday...thunderstorms return again on Wednesday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed through tonight...however we
encourage sending us any reports of hail...wind damage or
possible tornados.

<!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>