514
FXUS63 KDVN 100844
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
344 AM CDT Thu Jul 10 2025

.KEY MESSAGES...

- There is a daily risk of showers and thunderstorms through
  Saturday. As for severe weather, there is a Marginal Risk for portions
  of the local area today and tonight, and a Slight Risk for
  Friday.

- There is a signal suggesting a risk of heavy rainfall with any
  of this thunderstorm activity, which may compound on itself
  and lead to flooding, both flash and river. With several
  rivers already running above normal for mid summer, the risk
  of river flooding would increase if the heavy rainfall is
  realized.

- Seasonal temperatures and humidity levels will continue into next
  week.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 330 AM CDT Thu Jul 10 2025

Today...A MCV type feature was evident on water vapor imagery and
even regional RADAR loops rolling out of southeast SD into southwest
MN and northwest IA ATTM. Upstream linear MCS acrs western IA will
look to propagate eastward into the CWA this morning through midday,
assisted by the MCV and some cold pool kinematics. There may be some
isolated WAA wing elevated cells out ahead of the main system, but
extrapolate the main convective line into the western/northwestern
CWA after 7-8 AM, with decaying remnants and outflow reaching the
MS RVR by noon. These times may be rough, as also see the potential
of decaying remnants flaring up in the late morning into early
afternoon heating and MCV lift/shear to strong or even severe storm
cells acrs the MS RVR vicinity and moving acrs west/northwest IL
during the afternoon. Besides the threat of all type of severe
including a tornado on a boundary, A PWAT feed of 1.5 to 1.8 inches
will fuel locally heavy rainfall. Away from the MCV enhanced shear,
the ambient shear and vertical wind flow rather weak but may allow
for slower storms and higher residence times for very localized
flooding. High temps, DPTs and resultant SBCAPE/instability build up
again a challenge depending on the incoming MCS and convective
debris to deal with or erode. But not much of or any EML indicated
on the fcst soundings for today, and convective temps progged to be
in the mid to upper 80s. Many scenarios possible.

Tonight...After a potential convective lull during the late
afternoon into early evening(if earlier day storms are more vigorous
and don`t decay too early), another more subtle upper wave seen on
the WV imagery currently acrs southeast MT/far northeast WY will look
too roll acrs the area tonight. And with the models suggesting a
renewed southwesterly 25+ KT LLJ streaking up acrs the area and
impinging on lingering outflow boundaries, a main quasi-stationary
front or other thermal descrepancies, more storms should take off
tonight possibly developing overhead and/or just off to the west and
will move in later in the evening and overnight. Again, they will
pop earlier in the evening or late afternoon if the convection
coming in this morning just fades and doesn`t re-flare up.

SREF placement has this activity more likley occurring along and
north of the I-80 corridor, with rounds of convection lasting into
early Friday morning. Effective shear profiles not the strongest
tonight even with another wave aloft(25-30 KTs), but with ongoing
CAPE/THTA-e feed still see a potential damaging wind threat, and a
tornado on a lingering boundary with low LCL`s in place.  Of more of
a widespread concern will be the potential for training heavy rain
producing storms and eventual flash flooding this set-up could
produce. Still a lot of uncertainty on this storm axis placement and
maintenance/back-building potential and will hold of a Flood Watch
for now, but later shifts may have to consider one if the same area
looks to be indicated by the models and frontal placement lay out
after today`s convective activity.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 330 AM CDT Thu Jul 10 2025

Friday...Much of what occurs Thu night and lingers into Friday will
effect the convective scenario this day. But the most likely
scenario will be that as a more substantial upstream short wave
pushes acrs the MO RVR Valley, a high CAPE air mass of 3000-4000
J/kg in place locally if we get the heating and convective debris
decays fast enough, will be enough for effective shear profiles of
30-40 KTs for more strong to severe storm development Friday
afternoon and evening both locally and off to the southwest toward
northeast KS. Waves of strong to severe convection in clusters or
MCS form will move acrs the region into early Sat morning, again
with all modes of severe possible but large hail will have a melting
battle reaching the sfc. With a high Sigma, model indicated
PWAT feed of 2 to 2.3 inches, again flash flooding and areal
flooding becoming a concern where storms move acrs
repeatedly/train...especially acrs areas that get hit hard
today(Thursday). Definitely a messy fcst period with many
parameters to take into account.

Saturday through Wednesday...With the main short wave progression,
hopefully Sat storm chances will set up along and east of the local
area that will probably need a break in the action by that time.
Both sfc and upper ridging look on tap for a mainly dry and
seasonable Sunday into Monday, before precip chances start to
increase again toward mid next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1257 AM CDT Thu Jul 10 2025

Besides the chance for some patchy fog developing(not as much as
last night), and an isolated elevated shower or thunderstorm
developing out of the ACCAS wing in elevated warm air advection
acrs the area, generally a VFR fcst into Thu morning. Then will
have to watch how the remnants of the upstream MCS do as it
approaches from the west, if they continue to decay or re-
intensify by late morning into midday heating. Then there will
be lingering boundaries and convective debris for more storms to
fire on later this afternoon and tonight as the southwesterly
LLJ starts to increase again converging up and over these
features. This makes for a challenging TAF fcst trying to time
convective windows, with on and off chances for most of the
period after 14z. PROB30`s will have to be used until better
defined storm windows become evident.

&&

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

&&

$$

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