Severe Thunderstorm Warning 79, NWS Des Moines, IA

Area Forecast Discussion
National Weather Service Des Moines IA
655 PM CDT Sun May 7 2023

...Updated for the 00z Aviation Discussion...

.DISCUSSION.../Tonight through Sunday/
Issued at 313 PM CDT Sun May 7 2023

Key Messages:

-Severe storms expected this evening into the overnight mainly
 southern half of the state.
-Quiet weather mid week with seasonable temperatures.
-Increase threat for precipitation late in the week.

Convection has continued to bubble for much of the morning into the
early afternoon along the instability gradient in central Iowa. Most
recently, an elevated cell has produced 2.5" hail near Carroll as it
rides along the instability gradient.  The forecast has many areas
of uncertainty with regards to placement and timing although there
is certainty in the fact the ample severe weather is expected this
evening into the overnight.  This storm should act to reinforce the
low level boundary near the I80 to Highway 30 corridor late this
afternoon with the boundary acting as a focus for convection.
Instability in southern Iowa where sun has been ample today has
risen to in excess of 3000 J/KG along with impressive mid level
lapse rates, especially towards western Iowa.  Certainly these lapse
rates helped in the large size of hail seen near Carroll and these
are expected to continue across the southern half of the state into
the evening.  Most CAMs output have storms developing around 5 to 6
pm near the boundary and intensifying quickly.  The initial storms
are expected to remain near the boundary and move nearly parallel
with large hail holding as a main threat. A narrow corridor of low
level instability and increasing effective SRH should provide a
for some threat of a few tornadoes in this corridor near the
boundary. In addition, some threat of heavy rainfall is expected
as storms move east along the boundary often over the same areas.

As the evening progresses, guidance continues to indicate a forward
moving organizing in Nebraska and racing east into southwest Iowa.
This convection is expected to move propagate in the strong
instability that will exist across southern Iowa into northern
Missouri by late evening into the early morning hours. Damaging
winds and a few tornadoes may also occur with this system as it
races east.  The heavy rain threat will continue as well as the
comma head likley moves over the same areas as the initial
convection.

The storms are expected to exit by Monday morning with increasing
subsidence in the wake of the storm providing relatively quiet
weather for much of the day. The overall quiet weather is expected
to continue for much of the work week with mild temperatures.  There
is some indication for an increasing threat of precipitation towards
Friday.

&&

.AVIATION.../For the 00Z TAFS through 00Z Monday evening/
Issued at 644 PM CDT Sun May 7 2023

Main focus continues to be on convective trends rest of this
evening into the early overnight hours. Although VFR conditions
are currently ongoing across most sites, MVFR to maybe IFR
conditions are still expected to expand over portions of central
Iowa. Convective storm trends continue to look a bit further
south, mainly impacting KDSM and KOTM bringing TSRA at times with
some severe potential as well. Amendments likely as storms re-
initiate tonight to update timing/CIGs/VISBYs/Winds in the
vicinity of storms. Further north, rain is expected to expand
across the area as storms grow upscale late tonight but some
uncertainty remains in terms of thunder potential at sites further
north. Ceilings do look to lower to at least MVFR, if not lower,
into tomorrow morning before gradually improving through the day.
Winds near storms will likely be gusty but otherwise surface winds
switch to be out of the north by 12Z tomorrow.

&&

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

DISCUSSION...Cogil
AVIATION...KCM

Hazardous Weather Outlook
National Weather Service Des Moines IA
337 PM CDT Sun May 7 2023

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-
081>086-092>097-082045-
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-Audubon-Guthrie-Dallas-Polk-Jasper-
Poweshiek-Cass-Adair-Madison-Warren-Marion-Mahaska-Adams-Union-
Clarke-Lucas-Monroe-Wapello-Taylor-Ringgold-Decatur-Wayne-
Appanoose-Davis-
337 PM CDT Sun May 7 2023

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...This afternoon and tonight

There is an enhanced threat of severe weather tonight. Large
hail, damaging winds, and a few tornadoes may all be possible at
times, with the greatest risk over southern and central Iowa.
Locally heavy rainfall is also expected.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Additional thunderstorm chances are forecast on Monday and at
intervals from Wednesday into next weekend, however, the overall
threat of severe weather appears low at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed tonight.

Dodson

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
613 PM CDT SUN MAY 7 2023

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0541 PM     HAIL             1 W ROSE HILL           41.32N 92.48W
05/07/2023  M2.00 INCH       MAHASKA            IA   PUBLIC

            DELAYED REPORT. TIME ESTIMATED FROM RADAR.

&&

DODSON

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
617 PM CDT SUN MAY 7 2023

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0543 PM     HAIL             ROSE HILL               41.32N 92.46W
05/07/2023  E2.00 INCH       MAHASKA            IA   BROADCAST MEDIA

            DELAYED REPORT. IMAGE PROVIDED VIA SOCIAL
            MEDIA. TIME ESTIMATED FROM RADAR.

&&

DODSON

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
621 PM CDT SUN MAY 7 2023

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0417 PM     HAIL             NEWTON                  41.70N 93.05W
05/07/2023  E2.00 INCH       JASPER             IA   PUBLIC

            DELAYED REPORT. IMAGE SUBMITTED VIA SOCIAL
            MEDIA. PRECISE MEASUREMENT OF 2.13 INCHES.
            TIME ESTIMATED FROM RADAR.

&&

DODSON

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
805 PM CDT SUN MAY 7 2023

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0756 PM     HAIL             BRIDGEWATER             41.25N 94.67W
05/07/2023  E1.00 INCH       ADAIR              IA   PUBLIC

&&

JAZ

<!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>