987
FXUS63 KDVN 110743
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
243 AM CDT Thu Jun 11 2026

.KEY MESSAGES...

- Today will see more severe storms. There is an Enhanced, level
  3 out of 5, risk for severe storms that look to occur in two
  rounds. All modes of severe weather will be possible.

- Storms will be moving at 50-60 mph so there will be less time
  than normal to react when a storm approaches. Additionally,
  storms will be prolific heavy rain producers that may cause
  flash flooding.

- Strong gradient winds of 30 mph with gusts to 45 mph will be
  seen today ahead of the front. Behind the front winds may gust
  up to 50 mph for a period of a few hours.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 241 AM CDT Thu Jun 11 2026

The next 24 hours will consist of multi-faceted weather risks with
several having the potential of being high impact. That being severe
storms, fast moving storms, flash flooding and non-thunderstorm
winds.

Headlines changes...

The flash flood watch has been extended to the entire area and
extended until 7 PM.

Discussion...

The LLJ and moisture transport will continue to strengthen through
sunrise. This will allow elevated storms to develop from southeast
Nebraska into southwest Iowa and possibly northwest Missouri. The
very short term models show this growing upscale into an organized
MCS that will move east across Iowa. The arrival in eastern Iowa
will be after sunrise and the MCS will begin a transition from
elevated to surface based.

Like yesterday there will be a risk of damaging winds this morning
through about mid-day. The very short term models differ on when the
complex becomes surface based but it will be across eastern Iowa.

Initially the damaging winds may be limited to 55 to 65 mph with
large hail. However, once the complex becomes surface based, much
higher severe winds become more likely. Indeed, some of the CAMs are
starting to suggest small corridors of 70 to 80+ mph winds as the
system bows out (indicating the system is surface based). At the
same time, brief spin-up tornadoes would also be possible.

Normally the severe risk would go down after the atmosphere gets
worked over so thoroughly in the morning.

However, the LLJ will increase through late morning and into the
afternoon with the approach of the surface low. Integrated Vapor
Transport is progged to increase to over 1200 kg/m/s. The very
strong IVT combined with an upper jet of 100+ knots will result in
rapid recovery of the atmosphere behind the departing morning storm
complex and also promote broad lift for new storm development.

The passage of the surface low from late morning through mid-
afternoon will be the time when the tornado risk will be the highest.

All the CAMs develop supercells by mid-day and continue that through
mid-afternoon. The position of the warm front across the area will
maximize low level turning in the atmosphere and will be key as to
where the greatest tornado risk will be located. Any storm riding on
or near the warm front will be most at risk for producing tornadoes.

During the supercell phase the primary severe risks will be very
large hail and tornadoes. The CAMs are indicting upscale growth
occurring into a broken line of storms. One CAM solution suggests
two broken lines of storms; one along the cold front and the other
along a pre-frontal trof. Once the upscale growth into lines occurs,
the severe risk will transition to damaging winds and spin-up
tornadoes.

On top of all this, storms will be moving at 50-60 mph so there will
be less time that normal to react when a storm approaches. In spite
of the fast storm movement, high atmospheric moisture means storms
will be prolific heavy rain producers. If storms stall or repeat
over the same area due to fronts or boundary interactions, high
rainfall rates will create flash flooding due to already wet ground.

In addition to the severe risk will be strong gradient winds. Model
soundings are showing 35-40 knots through the mixed layer with 50-55
knots on top. This suggests the potential for sustained gradient
winds during the late morning and afternoon of around 30 mph with
gusts up to 45 mph...on the cusp of wind advisory. Likewise, the
models are showing several hours of wind gusts approaching 50 mph
behind the front.

The cold front and severe storms will clear areas east of the
Mississippi by mid-evening. The strong gradient winds will slowly
decrease the remainder of the night resulting in much cooler and
quieter conditions.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 248 PM CDT Wed Jun 10 2026

Quick look at the longer range, a quiet, cooler and tranquil Friday
looks in store, then another frontal system takes aim at the region
on Saturday with potentially enough forcing to support some strong
storms. After that, a well needed reprieve as the storm track gets
shunted south and below normal temps infiltrate the area for highs
in the 70s Sunday and into early next week. Will have to watch for
nuisance clipper like systems for spotty precip chances in the
northwesterly steering flow next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1229 AM CDT Thu Jun 11 2026

The next 24 hours will have the potential of seeing high impact
weather across eastern Iowa and northern Illinois. Two rounds
of convection should be seen; one during the morning and the
other in the afternoon to early evening. Numerous TSRA will be
seen. The morning storms may produce wind gusts up to 45 knots;
the afternoon storms may see wind gusts well over 50 knots and
hail. Cold front to be along the Mississippi by 00z/12 with
rapidly improving conditions behind it and slowly decreasing
winds.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Flood Watch through this evening for IAZ040>042-051>054-
     063>068-076>078-087>089-098-099.
IL...Flood Watch through this evening for ILZ001-002-007-009-
     015>018-024>026-034-035.
MO...Flood Watch through this evening for MOZ009-010.

&&

$$

SHORT TERM...08
LONG TERM...12
AVIATION...08