Severe Thunderstorm Warning 121, NWS Des Moines, IA

Area Forecast Discussion
National Weather Service Des Moines IA
258 AM CDT Fri Jun 30 2023

.DISCUSSION.../Today through Thursday/
Issued at 254 AM CDT Fri Jun 30 2023

Key Messages:

- Storms this morning with a few severe storms possible over
  southern Iowa.
- Storm chances persist this afternoon through Saturday though
  severe weather chances look low.
- For the next 7 days, the coolest day will be Saturday and the
  warmest looks to be July 4th.

Thunderstorms are once again ongoing across Nebraska this morning
with a weakening complex over northeast Nebraska and more vigorous
activity over southeast Nebraska in the area of greater instability
and near the nose of the low level jet. There is a third area of
storms over north central Kansas that is lifting northeast as well.
It is a much less volatile setup than yesterday morning but a low
end severe weather threat with damaging winds and large hail
possible. The northern area of storms may move into northern Iowa
but the severe weather threat will be quite low. The convection over
Kansas and southeast Nebraska will continue to lift northeast with
the theta-e advection region and there will be a chance for a few
severe storms over southern Iowa and closer to the MUCAPE
instability axis that will be across that area. These storms will
move through the area this morning. As mentioned, instability and
forcing is not as strong as Thursday but 0-3 km theta-e difference
of 25-30K are favorable for cold pool development. The DCAPE
gradient is right at the IA/MO border and focused to the south and
the lack of DCAPE and the 0-3 km theta-e further north will be a
limiting factor for damaging winds north of Highway 34 or the lower
2 tiers of counties across IA.

The western long wave trough is crossing the Rocky Mountain range
this morning and will move into the Western Plains this afternoon.
Scattered thunderstorm development this afternoon is possible in
response to a lead short wave ahead of the trough. Additional storms
are possible tonight and into Saturday. The severe weather threat
this afternoon through Saturday is low though a few strong storms
are possible. Still monitoring the potential for landspout funnels
Saturday afternoon as the upper trough passes overhead. This open
wave is not as favorable as having a closed low but the vorticity
stretching potential is good with 0-3 km CAPE values greater than
100 J/kg and a weak nearly stationary boundary over northern Iowa.

The trough passes to the east by Sunday leaving Iowa in weak
northwest flow into Monday and that flow will transition to more
westerly/zonal flow Tuesday and for much of next week. Still have
precipitation chance mention in the forecast for July 4th, mainly
over northern Iowa. These chances will be dependent on a boundary
placement dropping south through the Dakotas and Minnesota. At this
time, any chance would be late and confined to northwest Iowa.
Greater precipitation chances are still targeting July 5th.

Otherwise, some lingering fog early this morning with much of the
smoke having dispersed or has moved to the east. Saturday still
looks to be the coolest day with mostly cloudy skies and
precipitation around with highs in the 70s to low 80s. Warmer air
does arrive with the transition to westerly flow next week and this
may bring widespread highs in the 90s next Tuesday, the 4th, before
the boundary arrives.

&&

.AVIATION.../For the 06Z TAFS through 06Z Friday night/
Issued at 1143 PM CDT Thu Jun 29 2023

VFR conditions remain across all terminals this evening. A bit
better signal for isolated patchy fog has been seen in recent
guidance this evening, largely occurring over KDSM and KOTM until
sunrise before dissipating. Otherwise still watching trends with
the expected showers and storms Friday morning. Recent trends keep
best chances for storm activity across the south, impacting KOTM
and KDSM around 12z and lasting until roughly 17-18z. Beyond that,
there are general chances for scattered showers and thunderstorms
across the state for the remainder of the period, though
uncertainty is on the higher end at this time. Will have to see
how the morning activity plays out, which will influence the
coverage, timing and intensity of any possible storms later in the
day. Will continue to watch over changes and update as needed.
Winds will remain on the light side, with overall cloud cover
looking to mainly range between mid to upper level clouds.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

DISCUSSION...Donavon
AVIATION...Bury

Hazardous Weather Outlook
National Weather Service Des Moines IA
310 AM CDT Fri Jun 30 2023

IAZ004>007-015>017-023>028-033>039-044>050-010815-
Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-
Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Sac-Calhoun-
Webster-Hamilton-Hardin-Grundy-Black Hawk-Crawford-Carroll-Greene-
Boone-Story-Marshall-Tama-
310 AM CDT Fri Jun 30 2023

This Hazardous Weather Outlook is for portions of northern Iowa.

.DAY ONE...Today and tonight

A few scattered thunderstorms are possible this morning with more
widespread thunderstorm activity toward southern Iowa. Scattered
thunderstorms are expected again later this afternoon and through
the evening. A few stronger storms are possible, but overall the
severe threat is low.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Additional scattered thunderstorms are possible on Saturday and
into Sunday morning. At this time the severe potential remains
low. Thunderstorm chances will then return around Tuesday to
Wednesday next week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

IAZ057>062-070>075-081>086-092>097-010815-
Audubon-Guthrie-Dallas-Polk-Jasper-Poweshiek-Cass-Adair-Madison-
Warren-Marion-Mahaska-Adams-Union-Clarke-Lucas-Monroe-Wapello-
Taylor-Ringgold-Decatur-Wayne-Appanoose-Davis-
310 AM CDT Fri Jun 30 2023

This Hazardous Weather Outlook is for portions of southern Iowa.

.DAY ONE...Today and tonight

Storms will move across southern Iowa this morning which may be
severe, with wind and hail the main hazards. Scattered thunderstorms
are expected again later this afternoon and through the evening. A
few stronger storms are possible, but overall the severe threat is
low.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Additional scattered thunderstorms are possible on Saturday and
into Sunday morning. At this time the severe potential remains
low. Thunderstorm chances will then return around Tuesday to
Wednesday next week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this morning.

Hagenhoff

<!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>