Severe Thunderstorm Warning 72, NWS Des Moines, IA

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

.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 18Z TAFS through 18Z Monday afternoon/
Issued at 1245 PM CDT Sun May 7 2023

Mostly VFR early but showers and thunderstorms become numerous
this evening into tonight. MVFR to IFR conditions are expected to
expand over central Iowa during this time and persist into Monday
morning. Surface winds to be southeast early becoming northwest by
Monday morning.

&&

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

&&

DISCUSSION...Cogil
AVIATION...Cogil

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
430 PM CDT SUN MAY 7 2023

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

0417 PM     HAIL             LAMBS GROVE             41.70N 93.08W
05/07/2023  M2.00 INCH       JASPER             IA   TRAINED SPOTTER

            IMAGE SUBMITTED VIA SOCIAL MEDIA.

&&

DODSON

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

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

0414 PM     HAIL             2 W LAUREL              41.88N 92.96W
05/07/2023  M1.00 INCH       MARSHALL           IA   PUBLIC

            IMAGE SUBMITTED VIA SOCIAL MEDIA. TIMING
            BASED ON RADAR.

&&

DODSON

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

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

0421 PM     HAIL             2 ESE NEWTON            41.68N 93.01W
05/07/2023  E1.75 INCH       JASPER             IA   PUBLIC

            VIA MPING.

&&

CC

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
440 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

            IMAGE SUBMITTED VIA SOCIAL MEDIA, TIMING
            BASED ON RADAR.

&&

DODSON

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

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

0442 PM     HAIL             1 NW GRINNELL           41.75N 92.73W
05/07/2023  E1.75 INCH       POWESHIEK          IA   PUBLIC

            VIA SOCIAL MEDIA.

&&

CC

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