Severe Thunderstorm Warning 206, NWS Des Moines, IA

Area Forecast Discussion
National Weather Service Des Moines IA
305 PM CDT Wed Jun 10 2026

.KEY MESSAGES...

- Multiple rounds of severe storms and heavy rainfall expected
  tonight through Thursday. All severe hazards are expected,
  including damaging winds (potentially up to 80 mph early Thu),
  large hail, and tornadoes.

- Cooler, drier conditions develop on Friday

- Thunderstorm chances return Saturday, some of which may be
  severe.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 301 PM CDT Wed Jun 10 2026

The next 36 to 48 hours are going to see multiple rounds of severe
storms and heavy rainfall. To simplify the discussion and break up
the wall of text, we will be breaking it up into the 3 different
rounds of storms.

>> Round 0: Earlier This Morning (Wed AM)

Storms from this morning into mid-day today (we'll call them Round
0) produced rather healthy wind gusts of 50 to 60 mph as they moved
through north central into northeastern Iowa, with a few personal
weather stations reporting gusts just shy of 70 mph. Tree damage and
power outages were relayed from multiple towns impacted by the round
0 storms. These storms have since departed the area, allowing the
environment to start its path to recovery this afternoon.

>> Round 1: This Afternoon and Evening (Wed PM)

We now look ahead to our next round of storms expected to develop
over central into southern Iowa now through this evening. Cloud
cover from this morning's activity has begun to clear out from east
to west, allowing temperatures to warm over western into central
Iowa. Agitated cumulus over these areas, as well as model
soundings, suggest the elevated mixed layer is still keeping
things mostly capped off as of this writing. However, this warm
nose is forecast to cool quickly as surface temperatures warm
this afternoon, which will allow for convection to initiate
ahead of and along a boundary passing from west to east through
the area. Discrete supercells will be favored initially, thanks
to the large amounts of surface based CAPE (4000+ J/kg) and 0 to
6 km shear values of 40 to 50 kts. These storms will be capable
of all severe hazards, including damaging wind gusts, large
hail, and tornadoes. The tornado threat will be highest along
the southern Iowa border, where winds will be more south to
potentially south southeasterly with 80 to 100 m2/s2 of 0- 1km
SRH. The tornado threat will be lower farther north where low
level winds will be less favorable for tornadogenesis, but an
isolated tornado still can't be ruled out with any supercells,
especially with strong low level stretching along the boundary
(0- 3km CAPE of 150 to 200 J/kg). Large hail (2"+) will also be
in play given the potential for fairly large, rotating updrafts.
Of course, strong updrafts produce strong downdrafts,
especially in a 900 to 1000 J/kg downdraft CAPE environment,
leading to strong winds.

The east northeast storm motions along and ahead of the southwest to
northeast oriented boundary will eventually lead to competing
updrafts and likely a congealing of storms. This may favor a more
linear mode or a line of embedded supercells. It will also lead to
some training of storms and prolonged periods of heavy rainfall over
southern Iowa. Some model guidance is kicking out QPF amounts of
2 to 4 inches with isolated amounts nearing 6+ inches along the
Iowa/Missouri border. Should this occur, it would undoubtedly
lead to some hydro/flash flooding concerns, especially if it
lines up with any towns or urban areas. For this reason, have
decided to issue a Flood Watch for this area through the
afternoon and evening. For more information, see the hydro
discussion below.

Storms this afternoon and evening over central and southern Iowa
will eventually track south and east through the evening, departing
the area by around 11pm.

>> Round 2: Late Tonight into Early Thursday (Thu AM)

After the afternoon and evening storms move out, we will have a
brief lull through midnight. However, a second wave forming over
Kansas will lift northward through Thursday morning, nosing a 45 to
55 kt low level jet into eastern Nebraska and western Iowa. The
storms from the first round will have shunted the boundary and
instability gradient southward, giving them a more east to west
orientation. As the LLJ/shortwave intersect with this boundary,
storms will begin to develop along it. The exact track of these
overnight storms has been shaky among guidance, as it will depend on
how mesoscale features look after storms move through this evening.
That said, the expected region for the overnight storms is generally
along the I-80 corridor, although this will be subject to change
following round 1.

Regardless of where storms end up being, the expected progression is
for storms to initially form along the nose of the LLJ in a
west to east orientation. These storms will initially train
behind each other, given the easterly storm motions expected,
leading to a potential hydro threat through central Iowa. Soils
are fairly dry in these regions, so flash flooding will be
mainly confined to urban areas. See the hydro discussion below
for more details. With the highly unstable environment along the
boundary (3000+ J/kg of MUCAPE and 40 to 50 kts of 0 to 6 km
shear), supercells could develop initially making damaging
winds, hail and tornadoes all a possibility over western Iowa.
However, models suggest storms will quickly evolve and grow
upscale into an MCS as they progress eastward through Iowa along
the instability gradient. This will pose a risk for damaging
winds up to 80 mph and potentially a few mesovortexes/embedded
tornadoes along the line, especially as we get closer to sunrise
on Thursday. This line of storms is expected along the I-80
corridor from roughly 4 am to 11 am, including the Des Moines
metro area. Additional storms and stratiform precipitation may
linger longer over northern Iowa into mid-day, but the most
impactful conditions are expected with this leading line of
storms.

>> Round 3: Thursday afternoon into the Evening (Thu PM)

The wave responsible for the storms late tonight into early Thursday
morning will track eastward over the state during the day Thursday,
likely keeping rain over the area in some capacity throughout the
day, especially north. The trailing cold front from this wave is
then expected to develop more storms in the afternoon and evening
over central into eastern Iowa, although the severity of these
storms is a bit uncertain for our area. The round 2 storms are
trending a bit later into the morning on Thursday, which may limit
the amount of time the atmosphere has to recover on Thursday
afternoon. This is especially true if showers and storms linger
behind the morning MCS. That said, models still suggest that some
clearing will develop over southern Iowa, allowing for mixed-layer
instability values to climb back to around 3000+ J/kg Thursday
afternoon. The shear won't be as strong (30 to 40 kts ahead of the
front), but still conducive for organized storms and severe weather.
With surface based storms expected, all severe hazards will be
possible over central into eastern Iowa tomorrow afternoon,
including damaging winds, hail and tornadoes. That said, the tornado
threat will likely be best nearer to the triple point in northern to
northeastern Iowa where the more southeasterly winds meet the better
low level instability/stretching. Again, this will all be contingent
on how rounds 1 and 2 play out, and very well could end up being
mostly east of our forecast area.

Of note, behind the wave and cold front, models are producing quite
gusty winds as dry and cooler air fills in behind the low Thursday
afternoon and evening. Wind gusts of 30 to 40 mph look possible
behind this front.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 301 PM CDT Wed Jun 10 2026

Behind the cold front on Thursday, conditions become cooler and
drier through Friday. Thunderstorm chances then return again on
Saturday, with severe storms possible once again Saturday afternoon.
With so much ongoing in the short-term, will discuss this risk more
thoroughly once we are through the current active period.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1234 PM CDT Wed Jun 10 2026

Breezy to gusty SSW winds will continue through much of the day,
with wind gusts dropping out after midnight. Several rounds of
thunderstorms are expected through the TAF period, with the
first beginning as early as 18z impacting most northern sites
and has been reflected in a TEMPO. The second round of
thunderstorms is expected to begin around 00z. Confidence in
coverage of this round is lower and thunder mentions have been
left as PROB30. KOTM is the most likely site to be impacted by
this round, but ongoing thunderstorm development makes it
difficult to time out when thunderstorms will be over the
terminal. Have left showers as prevailing and PROB30 for thunder
as a result. The final round is expected to begin around 12z
Thursday, with more widespread coverage. Thunder mentions were
PROB30'ed again here and timing will be refined in later
issuances.

&&

.HYDROLOGY...
Issued at 1134 AM CDT Wed Jun 10 2026

Flash flood concerns exist through Thursday morning due to rainfall
earlier today as well as additional rain later today into tonight.
See the latest WPC Day1/Day2 Excessive Rainfall Outlooks (EROs) and
Mesoscale Precipitation Discussions (MPDs), as well as NWC Flood
Hazard Outlooks (FHOs) and Area Hydrologic Discussions (AHDs) for
more details. We issued a flash flood watch up to I-80 to
highlight the threat through Thursday morning.

Greatest concern is potential flash flooding tonight in central and
southern Iowa. Training storms may produce up to 3-4+ inches of rain
in those areas. Flash flood threat in central Iowa would mainly
involve urban areas including the Des Moines metro area. Higher end
rainfall may lead to flooding of creeks and small streams. In
southern Iowa, flash flood concerns involve more than urban areas,
such as roads going through lower areas or near streams. Higher end
rainfall there may lead to more significant flash flooding.

With much of the potential flash flooding occurring during the
night, floodwaters can be more difficult to see especially in areas
that lack urban lighting. We would like to remind people to avoid
driving into flooded areas, instead find an alternate route. Also
people living in areas prone to flash flood impacts should plan in
advance what to do if floodwaters threaten their areas tonight.

Longer term, the risk of river flooding over the next several days
is minimal (generally less than 15-25%), however minor to moderate
within-bank rises are again possible in basins that receive heavier
rainfall.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Flood Watch from late tonight through Thursday morning for
IAZ057>060-070>072-081-082-092.
Flood Watch through Thursday morning for IAZ061-062-073>075-
083>086-093>097.

&&

SHORT TERM...Dodson
LONG TERM...Dodson
AVIATION...Rotter
HYDROLOGY...Zogg

Hazardous Weather Outlook
National Weather Service Des Moines IA
308 PM CDT Wed Jun 10 2026

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-
081>086-092>097-112015-
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-
308 PM CDT Wed Jun 10 2026

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...This afternoon and tonight

Several rounds of thunderstorms are forecast today through
Thursday. Severe storms with large hail, damaging wind gusts, and
tornadoes are all possible, as is heavy rain. There is an
Enhanced Risk (Level 3 of 5) for severe weather both days in
eastern to southern Iowa.

A Flood Watch is in effect for the area. Please refer to the
National Weather Service website at weather.gov/desmoines for
further details.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Storms continue from overnight Wednesday night into Thursday
morning with additional development possible in the afternoon to
evening. Severe storms with all hazards are possible.

Additional storms are expected to develop on Saturday with severe
storms possible in southern Iowa.

A Flood Watch is in effect for the area. Please refer to the
National Weather Service website at weather.gov/desmoines for
further details.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed at times today through Thursday.
Rainfall reports are also appreciated.

Preliminary Local Storm Report
National Weather Service Des Moines IA
510 PM CDT Wed Jun 10 2026

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

0430 PM     Hail             Weldon                  40.90N 93.74W
06/10/2026  M2.00 Inch       Clarke             IA   Broadcast Media

            Delayed report - time estimated from radar.
            Received email from media relaying 2 hail in
            Weldon.

&&

Preliminary Local Storm Report
National Weather Service Des Moines IA
513 PM CDT Wed Jun 10 2026

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

0511 PM     Tornado          6 SSE Moulton           40.61N 92.63W
06/10/2026                   Davis              IA   Broadcast Media

            Confirmed tornado via broadcast media.

&&

TR

Preliminary Local Storm Report
National Weather Service Des Moines IA
522 PM CDT Wed Jun 10 2026

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

0412 PM     Tstm Wnd Dmg     Garden Grove            40.83N 93.61W
06/10/2026                   Decatur            IA   Emergency Mngr

            Building damage per EMA.

&&

TR

Preliminary Local Storm Report
National Weather Service Des Moines IA
534 PM CDT Wed Jun 10 2026

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

0524 PM     Tstm Wnd Gst     8 S Bloomfield          40.63N 92.43W
06/10/2026  E70 MPH          Davis              IA   Trained Spotter

            Report from trained spotter.

&&

Preliminary Local Storm Report
National Weather Service Des Moines IA
535 PM CDT Wed Jun 10 2026

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

0525 PM     Tornado          6 SE Moulton            40.62N 92.60W
06/10/2026                   Davis              IA   Trained Spotter

            Brief touchdown.

&&

TR

Preliminary Local Storm Report
National Weather Service Des Moines IA
536 PM CDT Wed Jun 10 2026

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

0507 PM     Tstm Wnd Gst     4 SE Kirkville          41.11N 92.45W
06/10/2026  M60 MPH          Wapello            IA   ASOS

&&