Flash Flood Warning 40, NWS Quad Cities, IA

408 
WGUS73 KDVN 160253
FFSDVN

Flash Flood Statement
National Weather Service Quad Cities IA IL
953 PM CDT Sat Aug 15 2026

IAC115-ILC131-160830-
/O.CON.KDVN.FF.W.0040.000000T0000Z-260816T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Louisa IA-Mercer IL-
953 PM CDT Sat Aug 15 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 330 AM CDT SUNDAY FOR
SOUTHEASTERN LOUISA AND WESTERN MERCER COUNTIES...

At 953 PM CDT, local law enforcement reported thunderstorms producing
heavy rain in Water reported over Highway 17 near New Boston, IL and
flooding on roadways in Grandview, IA. Between 1 and 2 inches of rain
have fallen. Additional rainfall amounts under a quarter inch are
anticipated in the warned area. Flash flooding is already occurring.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Law enforcement reported.

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...
  Aledo, Wapello, Millersburg, New Boston, Grandview, Eliza, Joy,
  Mannon, Toolesboro, Hamlet, Petersville, Snively Access Campground,
  Flaming Prairie Park, Marston, Mercer County Fairgrounds, Aledo
  Mercer County Airport and Gingle Corners.

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.

&&

LAT...LON 4133 9107 4133 9091 4132 9073 4120 9068
      4112 9088 4112 9096 4111 9111 4113 9118
      4128 9123

FLASH FLOOD...OBSERVED

$$

Uttech

067 
WGUS73 KDVN 160821
FFSDVN

Flash Flood Statement
National Weather Service Quad Cities IA IL
321 AM CDT Sun Aug 16 2026

IAC115-ILC131-160831-
/O.EXP.KDVN.FF.W.0040.000000T0000Z-260816T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Louisa IA-Mercer IL-
321 AM CDT Sun Aug 16 2026

...FLASH FLOOD WARNING WILL EXPIRE AT 330 AM CDT EARLY THIS MORNING
FOR SOUTHEASTERN LOUISA AND WESTERN MERCER COUNTIES...

The threat for heavy rain and flash flooding has ended. Flood waters
will continue to slowly recede.  Please continue to heed remaining
road closures.

&&

LAT...LON 4112 9096 4111 9111 4113 9118 4128 9123
      4133 9107 4133 9091 4132 9073 4120 9068
      4112 9088

$$

McClure

Area Forecast Discussion
National Weather Service Quad Cities IA IL
638 PM CDT Sat Aug 15 2026

.KEY MESSAGES...

- Chances for showers/storms return this evening and overnight
  as a weak cold front arrives in the area.

- 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.

- Strong to severe storms are possible Tuesday, as a much more
  potent cold front arrives into the region.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 113 PM CDT Sat Aug 15 2026

Low level moisture remains plentiful over the region in the wake of
the overnight storms and heavy rain. These rains fell in the
southern 1/2 of the area, and were heaviest in our far southern
counties. We now have saturated conditions found south of I-80, and
rather wet soil conditions found to the north. This antecedent
condition will keep the threat for isolated flash flooding possible
for any slow moving or strong thunderstorm tonight.

We do have the treat for additional storms tonight, but with a much
smaller footprint of heavy rainfall expected, and reasonable
confidence it will be a narrow swath of heavy rain, I am inclined to
hold off on any new flood watch for now.

Looking at the environment, much like yesterday, nearly every
model is too warm regarding low level temperatures, but humidity
remains very high, and is handled reasonably well. Thus, far,
this combination is keeping heat index readings under 95 degrees
in all areas. Tonight, the front will arrive rather late at
night, if not nearly morning, however, a pre-frontal wind shift
to the west is expected to combine with lift from a mid level
short wave to bring showers and storms to the area. There is
quite a bit of variation in placement of storms tonight, but
decent agreement on timing and character of storms. A small
cluster, possibly with an advancing cold pool is forecast to
move through between 7PM and Midnight. PWATs remain very high,
around 2 inches, but movement should be rather quick, especially
if storms are strong. Thus a narrow stripe of QPF around 1 inch
is possible, with amounts elsewhere very low, or dry. SPC
generally is following that progression as well, as we remain in
a marginal, level 1 risk. The late evening arrival supports a
cold pool and faster movement as well, in a mature stage of
convection. Wind gusts of 40-50 mph can be expected with this
line, with some threat 20-30% for winds over 60 mph.

&&

.LONG TERM /SUNDAY THROUGH SATURDAY/...
Issued at 113 PM 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 is still
early, but SPC is outlining that period for a Slight, level 2,
severe threat, given the pattern and environment in place.

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 /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 632 PM CDT Sat Aug 15 2026

A weak cold front will move through eastern Iowa and northwest
Illinois this evening and tonight, bringing a chance for
scattered showers (20-50%) and storms mainly south of CID. With
low confidence on areal coverage, have mentioned the thunder
chances at MLI and BRL in PROB30s. Occasional MVFR ceilings are
possible at MLI overnight into Sunday AM, with periods of IFR
likely at DBQ. Additionally, fog may develop at DBQ tonight with
potential for visibilities to drop near or below 1 mile at
times.

&&

.HYDROLOGY...
Issued at 1225 PM CDT Sat Aug 15 2026

Rainfall ranging from 2 to 6 inches,fell across southern parts
of the area, mainly south of the tributary forecasts it was
expected to fall 24 hours ago. This is a helpful thing, though
flooding did impact portions of McDonough through Lee County
overnight, and this warranted minor flood warnings for the Skunk
River at August today, and a moderate flood warning for Colmar,
on the La Moine River.

Flood warnings and watches on portions of the Iowa,
Wapsipinicon, and upstream Skunk have been cancelled, as this
rainfall fell south or downstream of these forecast points.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.

&&

SHORT TERM...Ervin
LONG TERM...Ervin
AVIATION...Uttech
HYDROLOGY...08

Hazardous Weather Outlook
National Weather Service Quad Cities IA IL
148 PM 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-MOZ009-010-161900-
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-
148 PM 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...THIS AFTERNOON AND TONIGHT

Warm and humid conditions this afternoon could bring a few hours
of heat index reading around 100 degrees south of Interstate 80.
Be sure to take breaks, and drink water today.

Another round of showers and storms are possible tonight into
early 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.

A few area rivers are experiencing flooding. Please see the
latest Flood Statements and Flood Warnings for details.

.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 possible again tonight. Reports of flooding
would also be appreciated.

Special Weather Statement
National Weather Service Quad Cities IA IL
436 PM CDT Sat Aug 15 2026

IAZ063-064-067-076>078-087>089-098-099-ILZ015-016-024>026-034-035-
MOZ009-010-160030-
Iowa-Johnson-Muscatine-Keokuk-Washington-Louisa-Jefferson-
Henry IA-Des Moines-Van Buren-Lee-Rock Island-Henry IL-Mercer-
Henderson-Warren-Hancock-McDonough-Scotland-Clark-
Including the cities of Marengo, Iowa City, Muscatine, Sigourney,
Washington, Wapello, Fairfield, Mount Pleasant, Burlington,
Keosauqua, Fort Madison, Moline, Rock Island, Geneseo, Aledo,
Oquawka, Monmouth, Carthage, Macomb, Memphis, and Kahoka
436 PM CDT Sat Aug 15 2026

...Hot and Humid into This Evening...

Very humid conditions combined with temperatures in the 80s will
create peak heat indices in the upper 90s to lower 100s through
the early evening. If spending time outside, make sure to avoid
strenuous activities, drink plenty of water, and take breaks in
the shade or in air conditioning.

Special Weather Statement
National Weather Service Quad Cities IA IL
511 PM CDT Sat Aug 15 2026

IAZ051-052-063-160000-
Benton-Linn-Iowa-
Including the cities of Vinton, Cedar Rapids, and Marengo
511 PM CDT Sat Aug 15 2026

...Brief Funnel Clouds Possible Early This Evening...

Conditions are favorable for the development of brief funnel
clouds. These types of funnel clouds rarely touch down, and if
they do, they typically produce brief weak tornadoes. The
National Weather Service will continue to closely monitor the
situation. If you see a funnel cloud or tornado, seek shelter
indoors and then contact your local law enforcement agency for
relay to the National Weather Service.

Special Weather Statement
National Weather Service Quad Cities IA/IL
531 PM CDT Sat Aug 15 2026

IAZ098-099-MOZ010-152300-
Van Buren IA-Lee IA-Clark MO-
531 PM CDT Sat Aug 15 2026

...A strong thunderstorm will impact portions of southeastern Van
Buren, west central Lee and northwestern Clark Counties through 600
PM CDT...

At 531 PM CDT, trained weather spotters reported a strong
thunderstorm near Croton, or 11 miles north of Kahoka, moving east at
25 mph.

HAZARD...Wind gusts of 50 to 55 mph.

SOURCE...Trained weather spotters.

IMPACT...Strong winds could break tree limbs, knock down weak trees
         and blow around unsecured objects.

Locations impacted include...
Donnellson, Franklin, Croton, Farmington, Revere, Charleston, Anson,
Lee County Fairgrounds, Chambersburg, Heath Memorial Conservation
Area, Shimek State Forest, Battle of Athens Campground, Indian Lake
Park, Primrose, Peaksville, Wilson Lake, and Argyle.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4056 9193 4071 9172 4065 9145 4042 9166
TIME...MOT...LOC 2231Z 287DEG 22KT 4058 9180

MAX HAIL SIZE...<0.75 IN
MAX WIND GUST...55 MPH

Uttech

Special Weather Statement
National Weather Service Quad Cities IA/IL
758 PM CDT Sat Aug 15 2026

IAZ064-067-076>078-087>089-098-160200-
Henry IA-Keokuk IA-Des Moines IA-Washington IA-Muscatine IA-
Van Buren IA-Louisa IA-Jefferson IA-Johnson IA-
758 PM CDT Sat Aug 15 2026

...Strong thunderstorms will impact portions of Henry, southeastern
Keokuk, northwestern Des Moines, Washington, southwestern Muscatine,
northern Van Buren, Louisa, Jefferson and southeastern Johnson
Counties through 900 PM CDT...

At 756 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Washington to near Douds. Movement was
east at 30 mph.

HAZARD...Winds in excess of 40 mph and flooding.

SOURCE...Radar indicated.

IMPACT...Gusty winds could cause minor tree limb damage and blow
         around unsecured objects. Slowing or redirecting of traffic
         due to ponding or flowing water. Closure of waterfront
         access due to flooding.

Locations impacted include...
Fairfield, Mount Pleasant, Washington, Wapello, Columbus Junction,
New London, Winfield, Wayland, Morning Sun, Brighton, Richland,
Ainsworth, Batavia, Birmingham, Columbus City, Libertyville,
Stockport, Lockridge, Crawfordsville, and Maharishi Vedic City.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

If the heavy rain continues, a flash flood warning may be needed.

&&

LAT...LON 4125 9218 4144 9149 4142 9148 4142 9137
      4134 9137 4134 9125 4106 9115 4089 9137
      4081 9218
TIME...MOT...LOC 0056Z 253DEG 28KT 4127 9166 4089 9204

MAX HAIL SIZE...<0.75 IN
MAX WIND GUST...40 MPH

Gunkel

Special Weather Statement
National Weather Service Quad Cities IA/IL
843 PM CDT Sat Aug 15 2026

IAZ064-067-068-078-089-ILZ015-024>026-160230-
Warren IL-Mercer IL-Henderson IL-Rock Island IL-Scott IA-
Des Moines IA-Muscatine IA-Louisa IA-Johnson IA-
843 PM CDT Sat Aug 15 2026

...Strong thunderstorms will impact portions of northwestern Warren,
Mercer, northeastern Henderson, southwestern Rock Island,
southwestern Scott, Des Moines, Muscatine, Louisa and southeastern
Johnson Counties through 930 PM CDT...

At 841 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Letts to near New Boston to 6 miles north
of Danville. Movement was east at 40 mph.

HAZARD...Winds in excess of 40 mph and very heavy rainfall
         leading to flooding.

SOURCE...Radar indicated.

IMPACT...Gusty winds could cause minor tree limb damage and blow
         around unsecured objects. Slowing or redirecting of traffic
         due to ponding or flowing water. Closure of waterfront
         access due to flooding.

Locations impacted include...
Davenport, Rock Island, Muscatine, Aledo, Wapello, Columbus Junction,
Oquawka, Milan, Burgess, Mediapolis, Blue Grass, Buffalo, Andalusia,
Fruitland, Viola, Danville, Morning Sun, Millersburg, Matherville,
and New Boston.

This includes Interstate 280 between mile markers 5 and 14.

Peak hourly rain rates between 1 to 2 inches possible in the hardest
hit areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is occurring and may lead to localized flooding.
Do not drive your vehicle through flooded roadways.

If the heavy rain continues, a flash flood warning may be needed.

&&

LAT...LON 4084 9136 4146 9137 4150 9137 4155 9054
      4095 9062
TIME...MOT...LOC 0141Z 263DEG 35KT 4140 9121 4121 9103 4095 9128

MAX HAIL SIZE...<0.75 IN
MAX WIND GUST...40 MPH

Uttech

Special Weather Statement
National Weather Service Quad Cities IA/IL
904 PM CDT Sat Aug 15 2026

IAZ065-067-068-ILZ015-016-024-160245-
Mercer IL-Rock Island IL-Henry IL-Scott IA-Muscatine IA-Cedar IA-
904 PM CDT Sat Aug 15 2026

...Strong thunderstorms will impact portions of eastern Mercer, Rock
Island, western Henry, Scott, northern Muscatine and southeastern
Cedar Counties through 945 PM CDT...

At 904 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Atalissa to Andalusia to near Shale City.
Movement was northeast at 40 mph.

HAZARD...Wind gusts of 50 to 55 mph and heavy rainfall leading
         to minor flooding.

SOURCE...Radar indicated.

IMPACT...Strong winds could break tree limbs, knock down weak trees
         and blow around unsecured objects. Slowing or redirecting
         of traffic due to ponding or flowing water. Closure of
         waterfront access due to flooding.

Locations impacted include...
Davenport, Moline, Rock Island, Bettendorf, Muscatine, East Moline,
Durant, Silvis, Eldridge, Milan, Colona, Le Claire, Coal Valley,
Wilton, Burgess, Hampton, Orion, Port Byron, Walcott, and Blue Grass.

This includes the following highways...
 Interstate 74 in Iowa between mile markers 1 and 5.
 Interstate 80 in Iowa between mile markers 271 and 306.
 Interstate 80 in Illinois between mile markers 1 and 12.
 Interstate 74 in Illinois between mile markers 1 and 33.
 Interstate 88 between mile markers 1 and 2.
 Interstate 280 between mile markers 1 and 18.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is occurring and may lead to localized flooding.
Do not drive your vehicle through flooded roadways.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 4115 9044 4112 9044 4111 9066 4140 9080
      4149 9126 4173 9092 4167 9032 4115 9023
TIME...MOT...LOC 0204Z 232DEG 34KT 4149 9116 4143 9074 4120 9066

MAX HAIL SIZE...<0.75 IN
MAX WIND GUST...55 MPH

Uttech