Flash Flood Warning 27, NWS Quad Cities, IA

Area Forecast Discussion
National Weather Service Quad Cities IA IL
648 AM CDT Wed Jun 17 2026

.KEY MESSAGES...

- Slight/Enhanced Risk (level 2/3 of 5) for severe storms early
  this morning around sunrise, lasting through mid morning.The
  primary threat with these storms will be large to very large
  hail.

- Late this morning and through the afternoon, much of the area
  will have a threat for more severe storms, with the whole
  area under a severe threat ranging from a Slight Risk (level 2
  of 5) in our northwest to a Moderate Risk (level 4 of 5) in
  our extreme southeast/east.

- High moisture content over the area will allow for heavy
  rainfall with any storms through today. Flash flooding will be
  possible in areas that see repeating rounds of storms,
  especially in areas that recently saw heavy rainfall. Flood
  Watch remains in effect for areas in West-Central Illinois.

- Quiet weather will be seen through the second half of the
  work week, with the pattern becoming active again this weekend
  and beyond.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 215 AM CDT Wed Jun 17 2026

Severe weather is expected today as a seasonably strong system moves
through the region. This will bring two rounds of storms to eastern
Iowa, northwest Illinois, and northeast Missouri: a first round
in the morning hours (4-9 AM) and second round in the afternoon
hours (12-7 PM). Morning storms are anticipated to have a
primary threat of large hail and low damaging wind potential,
while afternoon storms will be capable of all hazards, including
tornadoes. In addition, heavy rain will lead to localized flash
flooding, especially in areas that see repeated rounds of
storms.

A strong shortwave will move from the Northern Plains into the Upper
Midwest this morning. Pressure heights are near or at the NAEFS
climatological minimum for mid-June, while winds aloft are near or
at their maximum. This can be seen in a strong (50-60 kts) zonal jet
at 500 mb sampled upstream with today's 00Z soundings. As this
system translates into the Upper Midwest early this morning,
southerly to southwesterly flow across the central Plains will
provide warm air advection and moisture, which will amplify with the
LLJ towards sunrise. As a result, dewpoints are forecast to rise
into the mid to upper 60s within a few hours after sunrise, creating
a sharp gradient between the northern and southern halves of
the CWA. Lift along this WAA wing will provide the focus for
morning convection, with showers and storms across the area.

For the morning, the greatest risk for severe storms is along and
south of Interstate 80, though there is some uncertainty given a
strong cap over the region. If storms are able to develop, shear
magnitude and direction suggests a mixed storm mode with multicell
and supercells storms. A favorable severe environment of high lapse
rates (7.5-8.5 degC/km) and up to 2000 J/kg of MUCAPE will support a
primary risk of large hail. In addition to the risk of large hail,
heavy rain will be possible with these these storms. This should be
a soaking rain this morning and flash flooding threat should be
limited, save for areas that have a long residence time with storms.
This would primarily occur with cells that move over the same areas,
as storms in this first round will be moving quickly towards the
east at 40-50 kts.

By mid- to late morning, these storms will move east into central
Illinois, giving the airmass time to recover. At this point, strong
southwesterly flow will continue to feed in moisture and
instability, providing the energy necessary for the second round of
storms. The greatest area of uncertainty is in how much recovery
time will be possible, as morning storms and showers could persist
longer than anticipated. If the atmosphere is able to recover
following morning storms, an environment favoring supercells will
develop, leading to the potential for all hazard severe
thunderstorms.

Around 12 PM, forcing along the cold front will plow into a region
of 2000 (north) to 4000 (south) J/kg of CAPE, providing the forcing
necessary for convective initiation. These storms will be fast
moving, with a storm motion of 50 kts to the east. Large hail and
damaging winds are possible with all storms. Tornado threat will be
more limited, with the best low level shear supporting the highest
tornado threat in west-central Illinois. These storms will exit into
central Illinois around 6-7 PM.

Once these storms move off to our east, CAA advection behind the
front will support westerly to northwesterly winds up to 20-25 mph,
leading to a breezy night.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 215 AM CDT Wed Jun 17 2026

Several pleasant, mainly dry days will follow our big system today.
This will lead to temperatures below normal for highs and lows
Thursday and Friday.  Dry air should keep any rain threat low,
though some energy skirting by aloft could bring some sprinkles
or even a tiny thunderstorm as early as Friday night.

Warm begins to spread northward again towards Saturday, as the flow
aloft shifts towards a more active zonal flow regime. Models remain
consistent in showing a warm front developing over the Midwest
Saturday night, and having at least one significant wave of
rain and thunderstorms/ potentially an MCS Sunday and Sunday
night. There is latitude differences in the latest
deterministic guidance, with the GFS shifting that axis a bit
south, and the EC and GEM maintaining a more northerly frontal
zone. Regardless, that will be the next period for us to focus
on for both heavy rainfall and a thunderstorm risk.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 648 AM CDT Wed Jun 17 2026

A severe, bowing line of storms is bearing down on KCID around
12Z and will quickly track southeast through KMLI and KBRL in
the 13Z to 14Z timeframe. There have been several reports of
50-60+ kt gusts with this line and expect that threat, along
with heavy rain, hail, lightning, and IFR conditions to
accompany the line of storms. Additional storms are following in
the wake of this line, so expect scattered to widespread storms
through early afternoon, with some strong to severe thunderstorm
development again possible at KMLI and KBRL in the early
afternoon with potential for damaging winds, hail, and possibly
tornadoes. Farther north, KDBQ will remain north of the severe
line of storms in more stratiform rain with embedded
thunderstorm activity and occasional lightning through around
18-19Z. Additional isolated storms are possible with the cold
frontal passage late this afternoon into early evening for KCID,
KDBQ, and KMLI, and a lower potential (less than 30%) at KBRL.
Winds remain breezy throughout the day outside of storms, with
breezy winds and VFR conditions behind storms this afternoon
and evening. Low-level wind shear develops at most terminals
again for a few hours this evening.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...Flood Watch through this evening for ILZ009-016>018.
MO...None.

&&

SHORT TERM...Ellingworth
LONG TERM...Ervin
AVIATION...NWS

Hazardous Weather Outlook
National Weather Service Quad Cities IA IL
321 AM CDT Wed Jun 17 2026

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-180830-
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-
321 AM CDT Wed Jun 17 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

The Wapsipinicon River is experiencing flooding. Please see the
latest Flood Statements and Flood Warnings for details.

A strong system will bring the potential for severe thunderstorms
today. A Moderate, level 4 of 5, risk is forecast for central
Illinois, with an Enhanced, level 3 of 5, risk of severe
thunderstorms south of Highway 30 and the remainder of the area
under a Slight, level 2 of 5, risk. The first round of thunderstorms
will continue through late morning today, with a primary risk of
large hail. After 12 PM, a second round of thunderstorms is expected
along and ahead of the cold front, with all severe weather hazards
possible, including tornadoes. Localized flash flooding will be
possible during both rounds, especially in areas that see multiple
rounds of storms.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

The next chance for thunderstorms will be Sunday and Sunday night.

.SPOTTER INFORMATION STATEMENT...
Spotter activation is expected this morning and this afternoon.

Ellingworth/Ervin

Preliminary Local Storm Report
National Weather Service Quad Cities IA IL
830 AM CDT Wed Jun 17 2026

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

0828 AM     Tstm Wnd Gst     1 NNE New Windsor       41.22N 90.44W
06/17/2026  E60 MPH          Mercer             IL   Mesonet

&&

arg

Preliminary Local Storm Report
National Weather Service Quad Cities IA IL
833 AM CDT Wed Jun 17 2026

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

0822 AM     Tstm Wnd Dmg     2 E Kirkwood            40.86N 90.71W
06/17/2026                   Warren             IL   Trained Spotter

            Tree tops snapped at the location.

&&

arg

Preliminary Local Storm Report
National Weather Service Quad Cities IA IL
839 AM CDT Wed Jun 17 2026

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

0839 AM     Tstm Wnd Gst     1 ESE Cambridge         41.30N 90.17W
06/17/2026  M73 MPH          Henry              IL   Emergency Mngr

&&

arg

Preliminary Local Storm Report
National Weather Service Quad Cities IA IL
846 AM CDT Wed Jun 17 2026

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

0843 AM     Tstm Wnd Dmg     2 WSW Gerlaw            40.97N 90.64W
06/17/2026                   Warren             IL   Trained Spotter

            Spotter reports widespread tree damage
            across northern Warren County with many
            whole trees down and large branches down.

&&

arg

Preliminary Local Storm Report
National Weather Service Quad Cities IA IL
857 AM CDT Wed Jun 17 2026

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

0805 AM     Tstm Wnd Dmg     Mediapolis              41.01N 91.16W
06/17/2026                   Des Moines         IA   Public

            tree down on house along with many
            powerlines down.

&&

arg

Preliminary Local Storm Report
National Weather Service Quad Cities IA IL
906 AM CDT Wed Jun 17 2026

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

0802 AM     Tstm Wnd Gst     3 NW Kingston           41.02N 91.07W
06/17/2026  M62 MPH          Des Moines         IA   Mesonet

            Corrects previous tstm wnd gst report from 3
            NW Kingston.

&&

arg