Flash Flood Warning 39, NWS Quad Cities, IA

816 
WGUS73 KDVN 150909
FFSDVN

Flash Flood Statement
National Weather Service Quad Cities IA IL
Issued by National Weather Service Des Moines IA
409 AM CDT Sat Aug 15 2026

IAC057-087-101-111-177-ILC071-151430-
/O.CON.KDVN.FF.W.0039.000000T0000Z-260815T1430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Des Moines IA-Henry IA IA-Jefferson IA-Lee IA-Van Buren IA-
Henderson IL-
409 AM CDT Sat Aug 15 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 930 AM CDT THIS 
MORNING FOR DES MOINES, SOUTHERN HENRY IA, SOUTHEASTERN JEFFERSON, 
NORTHEASTERN LEE, NORTHEASTERN VAN BUREN AND SOUTHWESTERN HENDERSON 
COUNTIES...

At 409 AM CDT, Doppler radar indicated widespread moderate to at 
times heavy rain occurring across the warned area. Between 2 and 3 
inches of rain have already fallen. Additional rainfall amounts of 1 
to 2 inches are possible in the warned area. Flash flooding is 
ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Burlington, Mount Pleasant, Oquawka, West Burlington, New London, 
  Dallas City, Danville, Stronghurst, Birmingham, Salem, Middletown, 
  Carman, Stockport, Gladstone, Lockridge, Terre Haute, Hillsboro, 
  Rome, Westwood and Gulf Port.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Be aware of your surroundings and do not drive on flooded roads.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 4102 9172 4101 9138 4095 9096 4076 9090
      4064 9091 4064 9119 4072 9132 4081 9162
      4084 9201 4091 9204

FLASH FLOOD...RADAR INDICATED

$$

MM

829 
WGUS73 KDVN 151251
FFSDVN

Flash Flood Statement
National Weather Service Quad Cities IA IL
751 AM CDT Sat Aug 15 2026

IAC057-087-101-111-177-ILC071-151301-
/O.CAN.KDVN.FF.W.0039.000000T0000Z-260815T1430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Des Moines IA-Henry IA-Jefferson IA-Lee IA-Van Buren IA-Henderson
IL-
751 AM CDT Sat Aug 15 2026

...FLASH FLOOD WARNING IS CANCELLED FOR DES MOINES, SOUTHERN HENRY
IA, SOUTHEASTERN JEFFERSON, NORTHEASTERN LEE, NORTHEASTERN VAN BUREN
AND SOUTHWESTERN HENDERSON COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.

A Flood Watch remains in effect until 1000 AM CDT for portions of
Illinois, southeast Iowa, and northeast Missouri.

&&

LAT...LON 4102 9172 4101 9138 4095 9096 4076 9090
      4064 9091 4064 9119 4072 9132 4081 9162
      4084 9201 4091 9204

$$

Ervin

Area Forecast Discussion
National Weather Service Quad Cities IA IL
232 AM CDT Sat Aug 15 2026

.KEY MESSAGES...

- Widespread showers/storms south of Interstate 80 through early
  Saturday morning to pose a flash flood threat. There will be a
  low-end severe threat as well, with localized severe wind
  gusts possible.

- High pressure will bring a period of much needed quiet and dry
  weather Sunday through Monday, prior to the pattern becoming
  more active Tuesday through midweek.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 214 AM CDT Sat Aug 15 2026

Modest LLJ and stationary boundary near our south has allowed for
widespread storms to develop south of Interstate 80. These areas
have seen rounds of storms, which are producing heavy rainfall and
frequent lightning. There remains a Marginal Risk, level 1/5, for
severe weather tonight, with main concerns being precipitation
loaded downdrafts producing severe gusts. At this time, confidence
is low, with the threat being relatively isolated. Our main
concern will be heavy rainfall and flash flooding for the
remainder of the night. Locations south of Interstate 80 have
already seen rounds of heavy rainfall, with this continuing into
early Saturday morning. PWATs over 2.00" are being seen area-
wide, with our 00z DVN Balloon coming in with 2.09". Thus, areas
of repeating showers/storms can easily see upwards to 2.00"+ of
rain, with higher amounts likely. HREF guidance comes in quite
high on rainfall, bringing in a swath of very heavy rainfall
between the Interstate 80 and Highway 34 corridors.
Observational trends have indicated the heaviest swath of rain
is currently along/south of Highway 34 so far tonight, which is
where we might actually see these higher totals. Although, a
strengthening LLJ will push farther north through the night,
which may nudge this current axis north a bit. The HREF PMM
continues to show the potential for at least 3.00-5.00"+ in the
hardest hit areas. Locally higher amounts will be possible. As
such, the WPC continues to highlight our area in a Moderate
Risk, level 3/4, for Excessive Rainfall and Flash Flooding into
Saturday morning. The Flood Watch will remain in effect into
mid-morning Saturday.

Saturday morning, we will start to see the thunderstorm activity
decrease from west-east, with much of the area trending dry by
midday. By late afternoon, a remnant boundary from overnight
convection will be draped over the area, roughly near the Interstate
80 corridor. The LLJ will start to increase as another wave moves
into western Iowa and tracks east through the day. We will start to
see isolated to scattered showers/storms develop along this axis,
with coverage increasing into the evening/overnight hours. This wave
will push through the area overnight Saturday, dragging a cold front
through as well. With this pattern in place, we will once again see
a round of overnight showers/storms. Overall, shear will be lower,
yet sufficient for a few organized thunderstorms, with sufficient
instability for some stronger storms with lightning. PWATs will be
well above seasonal norms, generally ranging between 2.00-2.25".
Thus, heavy rainfall can be expected in any thunderstorms Saturday
night into Sunday AM. Although, this system will feature weaker
overall forcing and be more progressive, which should help keep
areas of heavier rainfall more localized. Heaviest hit areas can see
upwards to 1.00-2.00" of rain from this round of storms, with <1.00"
elsewhere. A localized flash flood threat will be seen, with WPC
highlighting the whole area in a Marginal Risk, level 1/4, for
Excessive Rainfall and locations in west-central Illinois in a
Slight Risk, or level 2/4 threat.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 214 AM CDT Sat Aug 15 2026

Sunday Through Monday...

This timeframe will be relatively quiet, as we will be fully post
frontal and generally in cool/dry advection by midday Sunday. Upper
wave and cold front will be east of the area by early Sunday
morning, which will effectively help flatten the ridge that was set
up over the area the last week, which brought persistent rainfall.
Thus, this will shunt the active baroclinic zone south of the area,
with surface high pressure passing over through Monday. A period of
quiet and dry weather will be seen, with near seasonal temperatures.
Monday looks to be a beautiful day with mostly clear skies. Enjoy
this reprieve from the active stretch of weather that the region has
been experiencing, as the pattern becomes active once again Monday
night through midweek.

Tuesday and Beyond...

Monday night into Tuesday, weak ridging will pass east of the area,
pushing the surface high pressure out and resulting in increasing
llvl southwesterly flow. Temperatures and moisture will both
increase on Tuesday, with best moisture moving in later in the day.
LLJ will kick in Tuesday evening and through the night, as a quick-
moving upper wave approaches the area from the northwest. A
seasonally strong cold front will accompany this wave, providing
sufficient surface and upper level forcing for thunderstorms. A
brief look at model soundings during this timeframe would indicate
the potential for an overnight complex of thunderstorms passing
through the area, as we have seen over the last week. The main
difference with this system is that it will be progressive, pushing
out of the area by early-midday Wednesday and leaving us in a post-
frontal airmass through the remainder of the week. The best moisture
will move into the area ahead of the cold front Tuesday night, with
global guidance indicating 1.50-2.00" PWATs moving in. Thus, heavy
rainfall will be on the table with these storms. It's too early to
dive into the severe threat, but given the pattern and environment
in place, a few stronger storms will be possible.

After this wave pushes out of the area on Wednesday, we will see
weak zonal-northwesterly flow set up again over the region. Surface
high pressure will pass through late in the week, which should bring
a period of mostly dry weather. Although, there remains some
uncertainty, as some long term models indicate subtle waves passing
through bringing low-end PoPs. NBM favors the mostly-dry forecast,
leaving PoPs <20% through Friday. The post-frontal airmass will keep
temperatures cooler through the second half of the week, with most
in the mid 70s.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1240 AM CDT Sat Aug 15 2026

Shower and thunderstorm activity remains steady in the south
through the overnight hours with a slow northward progression in
shower/storm reach towards MLI and possibly CID. A few gusty
winds will be possible at southernmost sites, such as BRL. In
the north, fog and/or low ceilings should develop with IFR to
LIFR conditions, while the stormy south has more intermittent
IFR to LIFR potential. Shower activity diminishes early morning
with cigs slowly lifting. VFR conditions are possible in the
south during the afternoon. Another chance of showers/storms is
forecast towards the end of the TAF period.

&&

.HYDROLOGY...
Issued at 1122 AM CDT Fri Aug 14 2026

Rainfall ranging from 3 to 6 inches, with locally higher amounts
occurred last night across parts of the area. The area was
generally two counties wide, running from Keokuk County Iowa
into southern Henry County Illinois in the north, and Highway 34
in the south.

More heavy rainfall, potentially another 3 to 6 inches with
locally higher amounts, is expected tonight into Saturday
morning. Some models are indicating the same areas that were hit
last night would get hit again. Other models are slightly
further south.

Regardless of the location, soils across the area run from moist
to saturated. Heavy rainfall tonight has a high probability of
resulting in more flash flooding that may be considerable.

The persistent rounds of rain are causing a slow rise on area
rivers.

Based on rainfall through tonight, most rivers are projected to
only see within bank rises. However, slight changes in the
amount each basin receives over the next two days may cause some
rivers to go into flood, especially tributary rivers.

A better way to look at this is to look at the probabilities of
reaching minor and moderate flood stages using an ensemble spread
of precipitation over the next 10 days.

For the following rivers there is a 30-50 percent probability of
achieving minor flood stage through August 24th;

English and Iowa Rivers. Cedar River south of I-80

These rivers also have a 20-30 percent probability of achieving
moderate flood stage.

For the Skunk River, the probability of achieving minor flood
stage is 30 percent, and 20 percent for moderate flood stage.

For the Wapsipinicon River, the probabilities vary considerably.
Anamosa has a 37 percent change of reaching minor flood stage
while near DeWitt the probability is 83 percent.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Flood Watch until 10 AM CDT this morning for IAZ051>054-
     063>068-076>078-087>089-098-099.
IL...Flood Watch until 10 AM CDT this morning for ILZ007-009-
     015>018-024>026-034-035.
MO...Flood Watch until 10 AM CDT this morning for MOZ009-010.

&&

SHORT TERM...Gunkel
LONG TERM...Gunkel
AVIATION...Schultz
HYDROLOGY...08

Hazardous Weather Outlook
National Weather Service Quad Cities IA IL
316 AM CDT Sat Aug 15 2026

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-160830-
Buchanan-Delaware-Dubuque-Benton-Linn-Jones-Jackson-Iowa-Johnson-
Cedar-Clinton-Muscatine-Scott-Keokuk-Washington-Louisa-Jefferson-
Henry IA-Des Moines-Van Buren-Lee-Jo Daviess-Stephenson-Carroll-
Whiteside-Rock Island-Henry IL-Bureau-Putnam-Mercer-Henderson-
Warren-Hancock-McDonough-Scotland-Clark-
316 AM CDT Sat Aug 15 2026

This Hazardous Weather Outlook is for portions of north central
Illinois...northwest Illinois...west central Illinois...east
central Iowa...northeast Iowa...southeast Iowa and northeast
Missouri.

.DAY ONE...TODAY AND TONIGHT

Rounds of heavy rain producing storms will continue into early
Saturday morning. There will also be a low end severe threat in
storms south of Interstate 80, with isolated severe gusts being
the main concern. Very heavy rainfall and flash flooding will be
the primary concern, especially where storms move repeatedly
over the same area. Significant flash flooding is possible,
especially in urban areas and in counties that saw excessive
amounts of rain last night. Several area rivers will be on the
rise and have the potential to reach bankfull or even flood stage
over the weekend and into early next week.

Between the episodes of storms, high heat and humidity may
produce dangerous Heat Index readings near or over 100 degrees
Saturday afternoon south of Highway 34 in southeast Iowa.

More rounds of showers and storms are possible tonight into
Sunday morning. Heavy rainfall and lightning will be the primary
threats with any storm, with a low end severe threat for isolated
severe wind gusts as well.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

We may see some residual showers and storms Sunday morning,
largely posing a heavy rainfall and localized flash flood threat.

Tuesday night into Wednesday, a system will bring the chance for
strong to severe storms. The Storm Prediction Center has
highlighted much of our area in a Day 4 Slight Risk for severe
storms, or level 2 of 5 risk.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is likely through Saturday morning and then
again Saturday night. Reports of flooding would also be
appreciated.

ERVIN/GUNKEL

Preliminary Local Storm Report
National Weather Service Quad Cities IA IL
1231 AM CDT Sat Aug 15 2026

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

1139 PM     Tstm Wnd Dmg     1 NNW Montrose          40.54N 91.43W
08/14/2026                   Lee                IA   Public

            3 inch diameter tree limbs downed.

&&