Hail in Illinois, June 17, 2026

Area Forecast Discussion
National Weather Service Quad Cities IA IL
228 PM CDT Wed Jun 17 2026

.KEY MESSAGES...

-Another round of thunderstorms remains possible through this evening
 especially across the southern DVN CWA, with all severe
 weather hazards possible.

- Because of the heavy rain this morning in many places and the chance
  for more storms, A flash flooding threat will continue south
  of Hwy 30 into the evening.

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

&&

.UPDATE...
Issued at 1135 AM CDT Wed Jun 17 2026

Our focus is now on the assessment of morning storms and their
effect on the afternoon activity. While there is a notable
imprint on the temperature field, one challenge with this event
is that it is far more spring-like than summertime. In other
words, the strength of the low pressure (992 mb) will help drive
parameter fields by stronger advection than we would typically
see in June. As a testament to this is an impressive June
temperature gradient across the area with mid to upper 50s north
and central to low 80s just south of the CWA.

The surface warm front modulated by outflow from the morning
storms is draped just south of the CWA border. Strong WAA aloft
and moisture transport are resulting in regularly developing
thunderstorms near the 850 mb frontal zone over the I-80
corridor, with mainly a flash flood threat. Also impressive
cloud-to-ground lightning even when rain rates diminish some.
Near the surface warm front, satellite indicates fairly solid
cloud cover near the Iowa/Missouri border. However, some of this
is transitioning to towering cumuliform clouds from near
Ottumwa southwestward along a confluence axis. We are thinking
this may be the start of the afternoon round of storms as it
progresses eastward across locations near/south of U.S. Highway
34, and likely some gradual northeast expansion, possibly even
near to the I-80 corridor in Illinois.

As upper forcing from a 120 kt upper jet impinges over this
area, mature convection should gradually develop. These storms
will be at least close to being rooted in the boundary layer,
but even if slightly elevated will have severe potential. The
parameter space remains favorable for significant severe
weather, including hail even though we did not have much with
the morning activity. Of greater concern is if rooted in the
boundary layer there would be the threat of tornadoes, some
potentially significant given a stout parameter gradient (as
shown by a forecast STP gradient of 1-6 by 3 PM). Whether that
truly manifests into surface-based supercells in our CWA is
still an uncertainty.

Now this is not to say there is not a severe, and even a lower
end  tornado threat, further north toward Iowa City and the
Quad Cities, simply because of the dynamics with this system.
Dew points in the mid 60s have returned to central Iowa on
southeast winds, and continued pressure falls will help keep
that low-level theat-a advection increasing ahead of the low
pressure. In tandem with effective shear in the 1-6 km layer of
50+ kts, at least some organization for scattered severe is
plausible, and we'll have to keep a close eye on the low-levels.
As long as storms keep regenerating along this I-80 corridor,
it may prevent true low-level warming and CAPE from building up
to the I-80 corridor in our CWA.

Confidence is high in any severe weather threat clearing our
area near 7 PM. Isolated showers and storms in northwest
Illinois may continue to 9 PM before the forcing has pushed
east.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 225 PM CDT Wed Jun 17 2026

Building upon the Update discussion above, increasing shear profiles
with the arrival of stronger wind flow at several levels is
occurring, with effective shear profiles of 50-60 KTs. A secondary
warm front lifting up to the I-80 corridor while a cool front is
squeezing eastward acrs western into central IA. But the prime
interaction with building/re-building instability/CAPEs with a sharp
tight gradient is aligning along an agitated CU field seen on the
VIS satellite loop from acrs west central ILwest-southwestwrad acrs
far northern MO and west of the Kansas City area. This is where new
supercellular storm development is expected soon, thus the DVN
southern third to quarter of the CWA will be at risk for this
development, with the activity then slipping south of the CWA
through late afternoon. The other action zone of mainly elevated
storms closer to the upper low/trough will rotate acrs southern MN,
far northeast IA and into WI through mid evening, possibly making
the bulk of the DVN CWA in between these two main convection zones.
Thus there may be just a few stray elevated showers or storms moving
acrs the local area after the potential storms in our south migrate
southward to CAPE feed, but may still have to watch the strength of
these "in-between" storms.

Post frontal west-northwesterly boundary layer feed to bring about
low temps down in the 50s for much of the area by Thursday morning.
Later on Thursday looks like a blustery post-frontal day with plenty
of cumulus development and/or wrap around for partly to mostly
cloudy conditions for much of Thursday. With the diurnal heating and
continuing cyclonic flow aloft, there may be a few isolated to sctrd
showers embedded in the CU fields. clear out and sfc wind decrease
making for a cool night into Friday morning with widespread lows
well down in the 50s.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Issued at 225 PM CDT Wed Jun 17 2026

Quick look at the longer range suggests some return flow warming for
Friday ahead of a clipper-like system that will look to drop down in
northwesterly steering flow acrs the western GRT LKS. This will
bring a chance for a shower and possible storm in or near the CWA
late Friday and Friday evening. Continued warming for Saturday
trying to pull some 80s up acrs the local area. Then eyes turn to
MCS generation acrs the central plains Sat night, and the potential
for this feature to propagate eastward and impact the local area on
Sunday sometime with strong storms and heavy rainfall. Beyond that,
upper jet ensembles suggests a return to northwesterly steering flow
acrs the upper MS RVR Valley early to mid next week making the area
susceptible to clipper-type wave generated precip events every other
day or so, depending on moisture return for these waves to
utilize.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1258 PM CDT Wed Jun 17 2026

Scattered storms with MVFR to VFR visibilities continue at KMLI
for the next hour or so. Also expect some shower activity at or
near KDBQ, KCID, and KBRL at times this afternoon. Additional
scattered strong to severe thunderstorms are forecast to develop
in a west to east orientation near or just south of KBRL between
19Z to 21Z this afternoon, but only included these as a TEMPO
group for now as it is possible that they develop just far
enough south to not impact the terminal at all. Another round of
isolated storms are possible with the cold front passage between
22Z-01Z this evening for KCID, KDBQ, and KMLI, and a lower
potential (around 30%) at KBRL. Ceilings return to VFR behind
the storms this evening. Breezy southeast to south winds
persist ahead of the cold front then turn westerly behind the
front this evening. Gusts should drop off with a small inversion
setting up overnight. Wind gusts should pick back up out of the
northwest daytime Thursday, with scattered to broken MVFR
ceilings moving into KDBQ late tonight and for a few hours
Thursday morning at KCID, KMLI, and KBRL. Low-level wind shear
develops at most terminals for a few hours this evening.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Flood Watch until 7 PM CDT this evening for IAZ063>068-076>078-
     087>089-098-099.
IL...Flood Watch until 7 PM CDT this evening for ILZ009-015>018-
     024>026-034-035.
MO...Flood Watch until 7 PM CDT this evening for MOZ009-010.

&&

UPDATE...Friedlein
SHORT TERM...12
LONG TERM...12
AVIATION...NWS

Hazardous Weather Outlook
National Weather Service Quad Cities IA IL
105 PM 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-MOZ009-010-180515-
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-
105 PM 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...THIS AFTERNOON AND TONIGHT

Another round of strong to severe thunderstorms will be possible
through this evening as a cold front pushes through the region.
Most of the Outlook Area is in a Slight Risk, level 2 out of 5,
for severe weather. However west central Illinois is in an
Enhanced Risk, level 3 of 5. All severe weather hazards will be possible,
including tornadoes. Withe heavy rainfall already fallen from this
morning's storm activity, localized flash flooding will also be a
threat, especially in areas that see multiple rounds of storms on
soaked ground. A Flood Watch is in effect for areas generally
along and south of the Highway 30 corridor through this evening.

A few tributary rivers will experience flooding or at least
within bank rises through the end of the week.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

The next main chance for thunderstorms will be Sunday and Sunday
night.There is still some uncertainty if these storms will have
the capability to be strong or severe.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this afternoon into the evening.

12

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

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

0230 PM     Rain             3 ESE Davenport         41.55N 90.54W
06/17/2026  M2.20 Inch       Scott              IA   Trained Spotter

            12-hour rainfall accumulation.

&&

CMD

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

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

0235 PM     Rain             1 ENE Green River       41.47N 90.32W
06/17/2026  M1.80 Inch       Henry              IL   Trained Spotter

            12-hour rainfall accumulation.

&&

CMD

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

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

0240 PM     Rain             1 ENE North English     41.52N 92.06W
06/17/2026  M2.82 Inch       Iowa               IA   CO-OP Observer

            12-hour rainfall accumulation.

&&

CMD

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

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

1254 PM     Flash Flood      3 SSE Ely               41.83N 91.56W
06/17/2026                   Johnson            IA   Emergency Mngr

            Roads closed due to high water - 140th St
            between Ely Rd and Naples, Sandy Beach Rd at
            the Beach, and Chambers Ave at posted low
            water crossing. Time estimated.

&&

MBS

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

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

0257 PM     Rain             3 NNE Cedar Rapids      42.01N 91.66W
06/17/2026  M2.04 Inch       Linn               IA   Trained Spotter

            12-hour rainfall accumulation.

&&

CMD

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

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

1244 PM     Rain             Parnell                 41.59N 92.01W
06/17/2026  M2.15 Inch       Iowa               IA   Trained Spotter

1208 PM     Rain             1 N Williamsburg        41.68N 92.01W
06/17/2026  M1.80 Inch       Iowa               IA   Trained Spotter

0100 PM     Rain             2 W Bettendorf          41.57N 90.51W
06/17/2026  M1.74 Inch       Scott              IA   Trained Spotter

            began around 7 am.

1200 PM     Rain             Shellsburg              42.09N 91.87W
06/17/2026  M1.68 Inch       Benton             IA   Trained Spotter

            storm total.

0207 PM     Rain             2 W Downey              41.61N 91.39W
06/17/2026  M1.60 Inch       Johnson            IA   Trained Spotter

            since 7 am.

0216 PM     Rain             2 NW Mc Nabb            41.19N 89.23W
06/17/2026  M1.37 Inch       Putnam             IL   Cocorahs

            rainfall since 840am.

0242 PM     Rain             1 N Lombardville        41.24N 89.66W
06/17/2026  M1.27 Inch       Bureau             IL   Trained Spotter

            storm total.

&&