Areal Flood Warning 13, NWS St. Louis, MO

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
657 AM CDT Thu Aug 4 2022

.SHORT TERM...  (Through Late Tonight)
Issued at 332 AM CDT Thu Aug 4 2022

The primary focus for heavy rain and flooding has moved south across
the eastern Ozarks this morning.  Short range guidance shows strong
low level moisture convergence continuing this morning along the
southern edge of an 850mb trough due to a 20-30kt southwest low
level jet.  The mid/upper level short wave the the 850mb trough is
attached to will drift east into the Ohio Valley this morning,
which should allow the low level jet to weaken which will reduce the
coverage of storms.  That being said, we remain in a very
moist airmass with 2.5+ inch p-wat values.  Some drier air will
attempt to move in from the northwest this morning behind the 850mb
trough and surface front, but 2 inch p-wats will likely remain over
southeast Missouri and southern Illinois through the day.  This high
moisture content along with a warm cloud depth approaching 14,000ft
at times will continue to support very efficient rain producing
convection today. Will therefore leave the flash flood watch
unchanged this morning.  Even with the diminishing forcing this
morning, there will still be the low level outflow boundary left
from these storms, as well as the surface front hanging over the
area today.  These boundaries will provide a focusing mechanism for
additional thunderstorm development through the day, mainly along
and southeast of I-44 in Missouri up to I-55 in Illinois where the
deep moisture will remain in place. Clouds and precip will keep a
damper on diurnal heating today, but temperatures will still rise
into the mid and upper 80s in most locations. The threat for rain
should finally end this evening with the loss of daytime heating.

Carney

.LONG TERM...  (Friday through Wednesday)
Issued at 332 AM CDT Thu Aug 4 2022

Models continue to show the upper level ridge which is currently
over the Rockies and western Plains will build east Friday through
Sunday.  Deterministic guidance is persistently cutting off a small
closed low over the Mid Mississippi Valley as a weak trough is
squeezed between the Plains ridge and the North Atlantic ridge.  It
increasingly looks like this weak low will keep temperatures in
check this weekend as it pushes the upper ridge axis farther north
across Iowa and northern Illinois.  This should be where the low
level thermal ridge sets up.  850mb temperatures do not exceed 21-
22C which should limit highs to the low and mid 90s.  Therefore
while Friday through Sunday look hot and humid, it looks more like
"typical" hot and humid with highs in the upper 80s to mid 90s and
heat index values topping out around 100 rather than excessively
hot.  Additionally, the weak closed low meandering across the Mid
Mississippi Valley could lead to widely scattered afternoon
thunderstorms which would dampen the heat potential further.

The next upstream short wave dips into the northern Plains Sunday
night and down across the Midwest and into the Great Lakes
Monday/Tuesday.  The trough looks deeper on the latest deterministic
model runs, but there continue to be timing and amplitude
differences.  Ensemble cluster analysis illustrates this well, with
primarily monopole variances in EOF1 and 2 associated with the trough
indicating amplitude uncertainty for Monday through Wednesday.  A
dipole variance shows up on Monday in EOF2 indicating position
uncertainty, and indeed this period is when there are the greatest
position differences between the deterministic GFS and ECMWF.
Regardless of these differences, the weather should get cooler with
more precipitation as the trough digs into the Mississippi Valley
and pushes a cold front into the region.

Carney

&&

.AVIATION...  (For the 12z TAFs through 12z Friday Morning)
Issued at 649 AM CDT Thu Aug 4 2022

A broad area of rain with embedded thunderstorms across southeast
Missouri into south central will continue to produce MVFR and IFR
visibility in occasional heavy rain this morning. Farther north in
east central Missouri and southwest Illinois, scattered to
numerous showers will likewise produce MVFR/IFR conditions in
occasional heavy rain. All of this activity is expected to weaken,
though probably not totally dissipate through 18Z. Additional
thunderstorm activity is possible across southeast Missouri into
south central Illinois this afternoon and evening.

Northwest of the area of rain, areas of MVFR/IFR ceilings and
visibilities have developed...mainly across northeast Missouri
into west central Illinois. Ceilings as low as 200 ft are being
reported. These low ceilings will likely persist for another 2-3
hours before lifting and scattering...VFR flight conditions are
expected across central and northeast Missouri into west central
Illinois thereafter.

Carney

&&

.PRELIMINARY POINT TEMPS/POPS...
Saint Louis     87  74  89  75 /  40  10  20   5
Quincy          87  70  86  72 /  10   5   5   0
Columbia        90  70  91  72 /  10  10  10   0
Jefferson City  91  71  92  73 /  20  10  10   5
Salem           83  71  86  72 /  70  20  40  10
Farmington      86  71  88  71 /  80  30  40  10

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Flood Watch until 10 AM CDT this morning for Crawford MO-Iron MO-
     Jefferson MO-Madison MO-Reynolds MO-Saint Francois MO-
     Sainte Genevieve MO-Washington MO.

     Flood Watch until 7 AM CDT this morning for Cole MO-Franklin MO-
     Gasconade MO-Moniteau MO-Osage MO.

IL...Flood Watch until 10 AM CDT this morning for Bond IL-Clinton IL-
     Fayette IL-Marion IL-Monroe IL-Randolph IL-Saint Clair-
     Washington IL.

&&

WFO LSX

Hazardous Weather Outlook
National Weather Service St Louis MO
413 AM CDT Thu Aug 4 2022

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-051200-
Greene IL-Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL-
Marion IL-Washington IL-Randolph IL-Adams IL-Brown IL-Pike IL-
Calhoun IL-Jersey IL-Madison IL-Saint Clair-Monroe IL-Knox MO-
Lewis MO-Shelby MO-Marion MO-Monroe MO-Ralls MO-Pike MO-Boone MO-
Audrain MO-Moniteau MO-Cole MO-Osage MO-Callaway MO-Montgomery MO-
Lincoln MO-Gasconade MO-Warren MO-Saint Charles MO-Franklin MO-
Saint Louis MO-Saint Louis City MO-Jefferson MO-Crawford MO-
Washington MO-Saint Francois MO-Sainte Genevieve MO-Iron MO-
Madison MO-Reynolds MO-
413 AM CDT Thu Aug 4 2022

This Hazardous Weather Outlook is for portions of eastern and
central Missouri as well as west central and southwest Illinois.

.DAY ONE...Today and tonight.

Thunderstorms capable of producing locally heavy rain will continue
to be possible today. These storms will be most likely across parts
of southeast Missouri and south central Illinois.

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

There is a chance for thunderstorms Friday through Wednesday

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report rainfall totals as well as any
observations of flooding.

Carney

<!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>