Flash Flood Warning 25, NWS Des Moines, IA

534 
WGUS73 KDMX 121852
FFSDMX

Flash Flood Statement
National Weather Service Des Moines IA
152 PM CDT Wed Aug 12 2026

IAC083-121902-
/O.CAN.KDMX.FF.W.0025.000000T0000Z-260812T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hardin IA-
152 PM CDT Wed Aug 12 2026

...FLASH FLOOD WARNING IS CANCELLED FOR HARDIN COUNTY...

The heavy rain has ended and any flash flooding impacts have ended. 
Thus, flooding is no longer expected to pose a threat.

&&

LAT...LON 4247 9346 4247 9350 4252 9350 4252 9303
      4247 9303 4247 9300 4224 9300 4224 9346

$$

Ansorge

Area Forecast Discussion
National Weather Service Des Moines IA
647 AM CDT Wed Aug 12 2026

 ...Updated for the 12z Aviation Discussion...

.KEY MESSAGES...

- Another chance of severe thunderstorms this morning with
  damaging wind being the primary threat. Isolated instances of
  large hail and locally heavy rainfall are also possible.

- Hot and humid conditions continue through today with heat
  indices nearing or just exceeding 100 degrees across southern
  and portions of central Iowa.

- More shower and storm chances tonight and tomorrow, with
  additional shower and storm chances through the weekend.
  Locally heavy rain and severe weather is possible, but details
  will be better assessed with time.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 315 AM CDT Wed Aug 12 2026

Showers and thunderstorms are again expected this morning and severe
weather is possible. A cluster of storms in southern South
Dakota/northern Nebraska is currently ongoing and moving towards
Iowa, with an expected arrival in western Iowa in the early morning
hours. As has been the case the past several nights, there is no
clear-cut solution with how things will evolve. The devil lies in
the details. Mesoanalysis shows a deeply unstable environment across
Iowa with a strong CAPE gradient farther to the west. This cluster
is expected to ride the CAPE gradient to the southeast, though it
has to fight mid-level convective inhibition. RAP analysis shows the
Low Level Jet (LLJ) is just now beginning to nose into Iowa.
Deterministic models show the jet strengthening around 7am/12z this
morning. As it does this, the cluster would be energized and begin
to build towards the northeast into central Iowa. Another part of
the uncertainty comes from a lack of moisture return. Moisture
transport shows some signal in the mid-levels, and mesoanalysis
hints at better moisture transport with the still-strengthening LLJ.
Another solution that would bring storms even farther north is if
storms are enhanced by shortwave energy ahead of the main cluster.
If everything materializes, there is a decent signal for a damaging
wind threat with this cluster as it moves through Iowa. Compared to
previous nights, confidence is much higher in the evolution of
storms.

Once storms clear the area, which should be around mid to late
morning, with the potential to be as late as 1pm/18z, hot and humid
conditions are expected with heat indices again approaching the 100
degree mark. There is more uncertainty in terms of heat than in
previous days, as storms are progged to track farther south than in
previous nights over the area forecast to be warmest, which could
lessen heat indices. Once again, atmospheric recovery is expected
through the day today, though capping is still going to be in place
to inhibit storms during the daytime hours. Otherwise, storm chances
once again return tonight driven by a shortwave that will move over
the area. Confidence with storms tonight looks much higher than
previous nights have been given a more pronounced shortwave. Severe
wind gusts are not out of the question with this setup, however the
signal for heavy and excessive rainfall looks the greatest with
decent moisture return and PWATs over 2 across the area. There is
still some disagreement with the specific location of where the
heaviest rain will fall. At the very least, flash flooding would be
a concern over any cities/towns.

Thursday looks to bring cooler temperatures to much of the state,
save for far southern Iowa. with temperatures in the upper 80s
across the south, and upper 70s to low 80s across north and central
Iowa. It may not be as dry, however, with the potential for showers
and thunderstorms through the day for at least some part of the
state along a boundary that looks to set up across central Iowa.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 249 PM CDT Tue Aug 11 2026

Active weather persists into Thursday night as another shortwave
traverse into the Plains, The SPC currently highlights the southern
CWA in a Marginal Risk (Level 1 of 5) for Thursday. The active
pattern remains in place through Saturday, maintaining low-end
severe storm probabilities. A more robust cold front will finally
sweep through the region on Sunday, bringing a cooler and drier
airmass. Highs look to top out in the upper 70s in northern Iowa to
lower 80s in southern Iowa.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 641 AM CDT Wed Aug 12 2026

Main aviation focus is on the showers and storms ongoing and
expected to move through most of the area this morning.
Convective evolution has not followed previous expectations
particularly well and CAMs are still a bit varied on their
evolution from here, though many are not capturing current
trends well either. This being said, timing in current TAFs may
still need further adjustments as KOTM is seeing the new storm
development out ahead of the main line, and other sites will
eventually see the main line come through, though the extent and
severity of which remains to be seen. Generally expecting some
amount of thunderstorms to affect KFOD and KDSM and probably
KALO with time if storms can hold together with additional new
development also possible in that area. KMCW remains further
north and will likely only see a shower or two if anything
unless things trend more north. Storms could have gusty and
erratic winds associated with them, and should they become more
organized again, these winds could become severe. Storms clear
the area by mid morning to midday with dry conditions behind
through the rest of the daytime. There are more widespread storm
chances again overnight into Thursday morning but will be
addressed in future issuances. Behind the storms, winds will
largely be out of the east and light under 10-12 knots.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
None.

&&

SHORT TERM...67
LONG TERM...TDR
AVIATION...05

Hazardous Weather Outlook
National Weather Service Des Moines IA
513 AM CDT Wed Aug 12 2026

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-
081>086-092>097-131015-
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-
513 AM CDT Wed Aug 12 2026

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...Today and tonight

Strong to severe storms are possible this morning with damaging
wind gusts, large hail, and isolated heavy rainfall possible.

Warm and humid conditions are expected this afternoon in southern
Iowa where heat indices may near 100 degrees.

Another round of storms is expected overnight with gusty winds,
hail, and locally heavy rainfall possible.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Additional chances for thunderstorms continue through the end of
this week. Severe weather and excessive rainfall are possible at
times through at least Friday.

Warm and humid conditions are expected to continue into late this
week over southern Iowa where heat indices may near 100 degrees.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed at times over the next few days.
Severe weather and rainfall reports are also appreciated.

Ansorge