Severe Thunderstorm Warning 331, NWS Des Moines, IA

847 
WWUS53 KDMX 062118
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
418 PM CDT Sun Sep 6 2026

IAC047-062128-
/O.CAN.KDMX.SV.W.0331.000000T0000Z-260906T2130Z/
Crawford IA-
418 PM CDT Sun Sep 6 2026

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL CRAWFORD COUNTY
IS CANCELLED...

The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4235 9496 4221 9463 4205 9463 4186 9481
      4186 9484 4207 9507
TIME...MOT...LOC 2118Z 304DEG 23KT 4208 9475 

$$

IAC025-027-161-062130-
/O.CON.KDMX.SV.W.0331.000000T0000Z-260906T2130Z/
Sac IA-Calhoun IA-Carroll IA-
418 PM CDT Sun Sep 6 2026

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM CDT
FOR SOUTHEASTERN SAC...SOUTHWESTERN CALHOUN AND CARROLL COUNTIES...

At 418 PM CDT, a severe thunderstorm was located over Glidden, or 5
miles east of Carroll, moving southeast at 25 mph.

HAZARD...60 mph wind gusts and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Carroll, Lake City, Glidden, Arcadia, Breda, Auburn, Dedham, Halbur,
Lidderdale, Lanesboro, Willey, Ralston, Hobbs County Park, Arthur N
Neu Airport, and Swan Lake State Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4235 9496 4221 9463 4205 9463 4186 9481
      4186 9484 4207 9507
TIME...MOT...LOC 2118Z 304DEG 23KT 4208 9475 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.88 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Donavon

799 
WWUS53 KDMX 062132
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
432 PM CDT Sun Sep 6 2026

IAC025-027-161-062141-
/O.EXP.KDMX.SV.W.0331.000000T0000Z-260906T2130Z/
Sac IA-Calhoun IA-Carroll IA-
432 PM CDT Sun Sep 6 2026

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN SAC...
SOUTHWESTERN CALHOUN AND CARROLL COUNTIES HAS EXPIRED...

The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been allowed to expire.  However, gusty
winds and heavy rain are still possible with this thunderstorm.

A severe thunderstorm warning remains in effect for northeast 
Carroll County.

LAT...LON 4235 9496 4221 9463 4205 9463 4186 9481
      4186 9484 4207 9507
TIME...MOT...LOC 2131Z 304DEG 23KT 4204 9468 

$$

Donavon

Area Forecast Discussion
National Weather Service Des Moines IA
331 PM CDT Sun Sep 6 2026

.KEY MESSAGES...

- Flash Flood Watch issued for portions of northwest Iowa
  through Monday morning.

- Storms continue into Monday morning. Another round of severe
  storms possible Tuesday afternoon.

- Cooler temperatures and lower humidity arrive late week.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 322 PM CDT Sun Sep 6 2026

We kick off the first Sunday of September on an active note. Showers
and storms have lingered throughout the morning and into the early
afternoon, fueled by areas of deep moisture convergence. CAMS
suggested the potential for more organized cells to form due later
on increasing shear, but this has not yet materialized. Convection
continuing to develop ahead of the main line is disrupting
inflow to the primary updrafts and preventing the development of
a single dominant cold pool. Currently, storms are feeding off
a robust instability axis with MLCAPE around 3000 J/kg although
effective shear around 30 kts is keeping activity disorganized.
Regardless, a few severe storms still remain possible with
damaging winds being the primary concerns. Slow storm motions
and efficient rain have led to some areas recording 3-5 inches
of rainfall as storms train over the same areas. With storms
expected to persist through the afternoon, CAM QPF highlight
localized maximums potentially exceeding 5 inches over west
central Iowa. Consequently, the weather prediction center (WPC)
has outlined much of northwest Iowa in a Moderate Risk for flash
flooding, and a Flash Flood Watch is in effect. Somewhat
mitigating the flash flood threat are the dry antecedent
conditions; much of NW Iowa remains in a moderate drought, with
Ida County experiencing a small sliver of severe drought.

Tonight

Convection will continue to slowly shift south and east this
evening, gradually weakening with the loss of diurnal heating.
However, a Strengthening low level jet across central and
western Iowa could reignite scattered showers and storms late
tonight into early tomorrow morning. Severe weather is not
expected overnight as MUCAPE values drop to around ~500 J/KG.

Monday into Tuesday

Overnight showers and storms should diminish as we head into
tomorrow morning and drier air filters in for Monday. Winds across
northern Iowa will be breezy ahead of an approaching cold front, at
with gusts reaching up to 25 mph at times. Additional storms are
possible ahead of this boundary late Monday night into Tuesday
morning. A severe weather threat may materialize by Tuesday
afternoon; the Storm Prediction Center (SPC) day 3 highlights
central Iowa in a Marginal Risk. Details regarding this severe
threat will be fine tuned in future AFD issuances.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Issued at 322 PM CDT Sun Sep 6 2026

Storms will exit the region behind the cold front on Wednesday,
ushering in cooler temperatures and lower humidity. Highs in
the lower 80s are expected through Thursday, with precipitation
chances potentially returning by Friday.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1240 PM CDT Sun Sep 6 2026

Most of central Iowa is under at least MVFR conditions due to
diurnal cumulus bubbling up. IFR conditions are present at KMCW
due to lower ceilings. Storms are expected to increase in
coverage across western Iowa and portions of central Iowa.
PROB30 groups have been introduced at KDSM and KFOD to highlight
this. VFR conditions are expected to return overnight and winds
will increase towards the end of this TAF insurance across
northern Iowa.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Flood Watch through late tonight for IAZ004-015-023-033-034-
044.

&&

SHORT TERM...TDR
LONG TERM...TDR
AVIATION...TDR

Hazardous Weather Outlook
National Weather Service Des Moines IA
107 PM CDT Sun Sep 6 2026

IAZ005>007-016-017-024>028-035>039-045>050-057>062-070>075-
081>086-092>097-071815-
Kossuth-Winnebago-Worth-Hancock-Cerro Gordo-Humboldt-Wright-
Franklin-Butler-Bremer-Webster-Hamilton-Hardin-Grundy-Black Hawk-
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-
107 PM CDT Sun Sep 6 2026

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...This afternoon and tonight

Thunderstorms are possible through tonight, particularly in
western Iowa. A strong storm with damaging wind, heavy rain, or
large hail cannot be ruled out.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Thunderstorms are possible again Monday night to Tuesday night
across a large part of the state. An isolated severe storm is
possible.

Heat returns Tuesday afternoon with heat indices near 100 degrees
currently being forecast.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected.

&&

NWS Des Moines will discontinue the Hazardous Weather Outlook
product (HWO) on September 30th, 2026. Weather hazards and
outlooks will continue to be provided through the standard
forecast channels, including weather briefing packets, forecast
discussions, weather story graphics, the experimental graphical
hazardous weather outlook, and updated hazard messaging. All
local products and visual tools are accessible directly at
weather.gov/desmoines.

IAZ004-015-023-033-034-044-071815-
Emmet-Palo Alto-Pocahontas-Sac-Calhoun-Crawford-
107 PM CDT Sun Sep 6 2026

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...This afternoon and tonight

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

In addition to the heavy rain potential, a few strong storms with
damaging winds are also possible.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Thunderstorms are possible again Monday night to Tuesday night
across a large part of the state. An isolated severe storm is
possible.

Heat returns Tuesday afternoon with heat indices near 100 degrees
currently being forecast.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is possible and rainfall and severe weather
reports are appreciated.

&&

NWS Des Moines will discontinue the Hazardous Weather Outlook
product (HWO) on September 30th, 2026. Weather hazards and
outlooks will continue to be provided through the standard
forecast channels, including weather briefing packets, forecast
discussions, weather story graphics, the experimental graphical
hazardous weather outlook, and updated hazard messaging. All
local products and visual tools are accessible directly at
weather.gov/desmoines.

Preliminary Local Storm Report
National Weather Service Des Moines IA
202 PM CDT Sun Sep 6 2026

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

0155 PM     Flash Flood      1 NNE Graettinger       43.24N 94.75W
09/06/2026                   Palo Alto          IA   Emergency Mngr

            Significant ponding several feet deep with
            bundles of wood floating at EPS Buildings
            location on the north side of town. Water is
            also over the road on North Van Gordon Ave.

&&

RD