Severe Thunderstorm Warning 241, NWS Omaha, NE

Area Forecast Discussion
National Weather Service Omaha/Valley NE
611 AM CDT Thu Aug 24 2017

.UPDATE...
Issued at 609 AM CDT Thu Aug 24 2017

Have updated the forecast to include much higher pops for ongoing
activity in northeast NE and northwest IA this morning.

&&

.SHORT TERM...(Today through Saturday)
Issued at 322 AM CDT Thu Aug 24 2017

Scattered showers and storms are moving across parts of NE, IA, and
SD this morning, just starting to work into northeast NE. Subjective
00Z upper-air analysis indicates an upper-level low now centered in
QB, with upper-level ridge axis from WY/MT into SK, and with
northwesterly/cyclonic flow across the north central US, while weak
and broad ridging dominated the southern US. An 850mb high was
centered around the IA/MO border, with broad ridging across the
southern Plains to upper Midwest. Moisture was returning on the
western edge of the high, with a narrow band of 8C+ dewpoints from
western NE to northern SD associated with southerly wind component.
Surface ridge at 07Z extended from western ON through the MS River
valley, with a surface low centered in southeastern MT.

Main forecast concern is shower/storm potential through Saturday.
Through the last week or so, the CAMs have had something of a
dry/slow-onset bias for convection; this morning, the CAMs are
capturing ongoing convection well, while it's the parameterized
models that are not seeing ongoing activity. HRRR/RAP bring ongoing
activity into northeast NE to northwest IA through this morning,
with at least isolated to scattered showers/storms festering through
the day and gradually dropping southward toward east central NE.
Have leaned toward these wetter solutions and increased POPs through
the day today. Synoptic support for precipitation actually improves
later today and this evening, with a shortwave dropping through the
northwesterly flow. This, with continued 850mb southerly winds
providing warm/moist air advection, should allow for expanding
shower/storm coverage this evening, though perhaps more in central
NE. Do think activity will trend downward/quieter tonight as the
evening activity slides southward, and have trimmed POPs somewhat
tonight. A little shower/storm activity could linger on the nose of
the low-level jet in northeast NE into the late night/Friday morning.

Pattern doesn't change much on Friday, with continued southerly
850mb flow providing continued moisture advection into central to
northeast NE/northwest IA, northwesterly upper-level flow, and
surface low well west of the area. Have low confidence on whether
showers/storms will fester on Friday and have pretty much left the
blend alone, but suspect there is about an equal chance that the
area could be totally dry during the day or that festering isolated
to scattered showers/storms like the ongoing activity could be
present on Friday, too. By Friday evening, another shortwave trough
is progged to slide across SD, drawing the surface low further east
and closer to northeastern NE. Showers/storms look likely to develop
in southeast SD through the evening and continue overnight, filling
southward into northeast NE and eventually into northwest IA. Again,
showers/storms should clear out of the area in the morning as the
shortwave pulls away, with the surface low weakening into a
trough.

.LONG TERM...(Saturday night through Wednesday)
Issued at 322 AM CDT Thu Aug 24 2017

As a deeper upper-level low digs into the upper Midwest on Saturday
night into Sunday, the lingering surface front across the Dakotas
will drop southward through eastern NE/western IA. Model solutions
continue to range from a nearly dry frontal passage with just
isolated showers/storms to a washout across the area, and chance
POPs in the blend will ride for now. Either way, the front and its
associated precipitation (if any) does seem likely to move through
by later Sunday, with a surface high and mid-level ridge moving in
behind it for Sunday night and Monday. After that, model blends are
dry through Wednesday as an upper-level ridge locks into the
Rockies and an upper-level trough/potential tropical cyclone
remnant interact to the east. Temperatures should remain near to
below normal through the period.

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 609 AM CDT Thu Aug 24 2017

VFR conditions through the period. Thunderstorms will be in the
vicinity of KOFK just to the north til about 14z this morning.
Not confident they will make it all the way to KOMA, so left that
location dry. Also some LLWS at KOFK this morning too. Additional
thunderstorms could impact KOFK later in the period.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&

UPDATE...DeWald
SHORT TERM...Mayes
LONG TERM...Mayes
AVIATION...DeWald

Hazardous Weather Outlook
National Weather Service Omaha/Valley NE
700 AM CDT Thu Aug 24 2017

IAZ043-055-056-069-NEZ011-012-015>018-030>034-042>045-050>053-065-
066-250200-
Monona-Harrison-Shelby-Pottawattamie-Knox-Cedar-Thurston-Antelope-
Pierce-Wayne-Boone-Madison-Stanton-Cuming-Burt-Platte-Colfax-
Dodge-Washington-Butler-Saunders-Douglas-Sarpy-Seward-Lancaster-
700 AM CDT Thu Aug 24 2017

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST
IOWA...WEST CENTRAL IOWA...EAST CENTRAL NEBRASKA...NORTHEAST
NEBRASKA AND SOUTHEAST NEBRASKA.

.DAY ONE...TODAY AND TONIGHT

Isolated to scattered thunderstorms are possible today and tonight
for central to northeastern Nebraska into northwestern Iowa.
Widespread severe weather is not likely, but small hail and gusty
winds are possible in the strongest storms.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

Chances for on-and-off thunderstorms continue from Friday through
Sunday.

..SPOTTER INFORMATION STATEMENT...

Spotter activation should not be needed today or tonight.

IAZ079-080-090-091-NEZ067-068-078-088>093-250200-
Mills-Montgomery-Fremont-Page-Cass-Otoe-Saline-Jefferson-Gage-
Johnson-Nemaha-Pawnee-Richardson-
700 AM CDT Thu Aug 24 2017

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST IOWA
AND SOUTHEAST NEBRASKA.

.DAY ONE...TODAY AND TONIGHT

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

Chances for thunderstorms return on Friday evening, with on and
off chances of storms through Monday.

..SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today or tonight.

<!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>