Flash Flood Warning 26, NWS Des Moines, IA

758 
WGUS73 KDMX 141258
FFSDMX

Flash Flood Statement
National Weather Service Des Moines IA
758 AM CDT Fri Aug 14 2026

IAC001-009-029-077-141308-
/O.CAN.KDMX.FF.W.0026.000000T0000Z-260814T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Adair IA-Audubon IA-Cass IA-Guthrie IA-
758 AM CDT Fri Aug 14 2026

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHERN ADAIR, NORTHEASTERN 
CASS, SOUTHERN AUDUBON AND SOUTHERN GUTHRIE COUNTIES...

Runoff from earlier heavy rain is receding. Please heed any road 
closures.

Additional heavy rain later today may lead to a renewed flash flood 
threat. A Flood Watch remains in effect until 1000 AM CDT Saturday 
for portions of central, north central, northeast, northwest, south 
central, southeast, southwest, and west central Iowa.

&&

LAT...LON 4150 9505 4150 9504 4156 9504 4158 9504
      4163 9504 4161 9474 4157 9424 4155 9424
      4150 9424 4149 9424 4146 9424 4142 9424
      4141 9424 4139 9424 4137 9424 4138 9469
      4146 9506

$$

Zogg

Area Forecast Discussion
National Weather Service Des Moines IA
326 AM CDT Fri Aug 14 2026

.KEY MESSAGES...

- The heavy rainfall threat for Iowa continues due to ongoing
  convection with efficient rainfall production, and further
  still by convection expected tomorrow.

- Severe weather is possible tomorrow, with damaging wind gusts
  and heavy rain as the primary threats. Large hail and a
  tornado or two are also possible.

- The pattern remains active with storm chances through the
  weekend and mid next week.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 325 AM CDT Fri Aug 14 2026

Convection is ongoing across central Iowa which the HRRR has been
struggling to assimilate over the past several hours (up to 06z/1am
Friday). The Friday 00z suite of CAMs has the basic footprint down
for the ongoing convection, however, they have been struggling with
timing for convection. One potential reason for this is that CAMs
are not properly modeling the Elevated Mixed Layer (EML). Model
soundings suggest decent capping up to around 700mb. Looking at
mesoanalysis, these storms are forming in an area with decent deep
moisture convergence. The expectation through the night is that
these storms will continue to develop and push to the
north/northeast into the mid to late morning hours. Models show the
low level jet weakening around 12z/7am, which would lead to any
remaining convection decaying as it loses its forcing. Until that
happens, the ongoing convection will have fairly high rain rates, as
they are not moving particularly quickly. SO far, these storms have
already produced over 1in of rainfall in an hour, with one swath of
just over 2in in an hour. Unseasonably high dewpoints and PWAT
values exceeding 2in aid to the heavy rainfall potential, however,
with convection being elevated updrafts would not be as deep to take
advantage of the whole warm cloud layer (around 13500ft).

Due to the poor representation of ongoing convection, more
uncertainties crop up as we move through the day today, where the
bulk of our heavy rain potential lies. In central Nebraska, an MCS
driven by a shortwave is in the process of decaying. As it decays,
an associated MCV will move towards Iowa which will serve as the
focus point for the next round of storms. There is some severe
potential with convection in the afternoon, given decent shear (25-
35kts) and a strong push of instability into Iowa. Damaging winds
looks to be the primary threat, with large hail and a tornado or two
possible. See SWODY1 for details. The uncertainties are with the
location of the MCV and how convection behaves as it forms. The most
likely scenario is cells that quickly grow upscale before moving
east along the instability gradient that sets up, which looks to
mainly be south of the Highway 20 corridor. The northward or
southward extent of this line will have implications on which areas
receive the most rainfall. As mentioned before, PWAT values are
quite high and there is another push of moisture through the day.
This, combined with warm cloud depths will lead to efficient
rainfall production.

As the MCS exits the area, the rest of tonight looks to be fairly
dry. Most of the day tomorrow will be fairly dry before more shower
and thunderstorm chances return Saturday night into Sunday
morning.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 252 PM CDT Thu Aug 13 2026

The ring of fire pattern continues through Saturday night. PWATs
over 2" linger until a cold front sweeps through Sunday morning.
GEFS/EPS guidance highlights Saturday into Sunday morning as another
period of storm chances, with similar potential for marginal severe
chances and flash flooding as we have seen most of this week. High
pressure and drier canadian air may bring a brief break from any
rain chances before the ridge breaks down a bit and shortwaves and
enhanced flow return to our part of Midwest by midweek. This will
need to be monitored for renewed severe weather and heavy rain
concerns.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1038 PM CDT Thu Aug 13 2026

Storms lifting northward out of Kansas, along with additional
t-storm development associated with the low level jet, will
begin to impact the KDSM/KOTM terminals after 08Z tonight.
Storms will then continue to lift n/newd and impact KFOD/KALO
and possibly KMCW between Expect decreasing CIGs to MVFR to IFR,
with occasional lower VSBYs with heavier thunderstorms. After
the initial round of storms, persistent MVFR to IFR may linger
through the day, especially in the north through the afternoon.
There is a chance for additional thunderstorm development
tomorrow afternoon and into tomorrow tonight.

&&

.HYDROLOGY...
Issued at 326 AM CDT Thu Aug 13 2026

Periods of heavy rainfall remain possible through tonight.
Cumulative impacts from several rounds of moderate to heavy rainfall
beginning Thursday morning and another round currently ongoing
across central Iowa followed by more storms later today and tonight.
These may lead to river and/or flash flooding and certainly will
lead to significant ponding.

WPC has carried the previous Day 2 excessive rainfall outlook (ERO)
to moderate risk for Today into the Day 1 outlook and includes much
of central and southern Iowa. The primary concern with the current
convection is it is moving across areas that received 2-4 inches of
rainfall less than 24 hrs ago. In addition, this heavy rain may move
into the Des Moines metro and lead to urban impacts. Will also be
monitoring Walnut Creek, which responded to the previous rainfall
and reach action stage. Additional heavy rainfall will increase the
potential for flooding along these faster responding streams
including Walnut Creek.

Little change regarding the potential for river flooding, as
significant within-bank rises are still expected on many streams. At
least isolated to scattered minor river flooding is possible, with
more significant flooding possible as well. Since QPF will be around
rainfall-runoff inflection point, just a little more QPF than
forecast may produce more significant flooding. For example, if QPF
averages around 0.5 to 1 inch more than forecast, then widespread
minor river flooding with multiple locations seeing moderate or
possibly major flooding may occur.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Saturday morning for IAZ023>028-033>039-
044>050-057>062-070>075-081>086-092>097.

&&

SHORT TERM...67
LONG TERM...De Bruin
AVIATION...Fowle
HYDROLOGY...Donavon/Zogg

Hazardous Weather Outlook
National Weather Service Des Moines IA
354 AM CDT Fri Aug 14 2026

IAZ004>007-015>017-150900-
Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-
354 AM CDT Fri Aug 14 2026

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...Today and tonight

Storms are expected this morning and again this afternoon and
evening. Severe weather and excessive rainfall are possible.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

There are additional chances for thunderstorms Saturday night
into Sunday morning.

.SPOTTER INFORMATION STATEMENT...

Severe weather and rainfall reports are appreciated.

IAZ023>028-033>039-044>050-057>062-070>075-081>086-092>097-150900-
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-
354 AM CDT Fri Aug 14 2026

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...Today and tonight

Storms are expected this morning and again this afternoon and
evening. Severe weather and excessive rainfall are possible.

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

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

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

There are additional chances for thunderstorms Saturday night
into Sunday morning.

.SPOTTER INFORMATION STATEMENT...

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