985
FXUS63 KDVN 151630
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1130 AM CDT Sun Jun 15 2025

...Updated for 18z Aviation...

.KEY MESSAGES...

- Well advertised active pattern is expected to ramp up each day
  until Tuesday and Wednesday when strong to severe storms are
  possible across the area.

- Current weather pattern makes for difficult forecasting as
  each day`s chances for storms are not necessarily tied to
  distinct weather systems.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 319 AM CDT Sun Jun 15 2025

Rain continues to overspread eastern Iowa this morning. Easterly
flow off of Lake Michigan, that lead to a very pleasant evening
last night, continues to bring drier air into our area. We find
ourselves wedged between the warmer moist airmass and cooler
`drier` airmass to the east. This means that most of the
thunderstorms that formed last night have weakened as they try
pushing towards the radar. Today, the upper level ridge will
push further east as the better moisture overspreads more of our
area. This airmass won`t fully be in place across our entire
area until tomorrow, nonetheless we should see better coverage
of showers and storms today into tonight than yesterday.

CAMs are not all that useful in this pattern other than
potential storm mode. The CAMs continue to try and produce MCSs
that move into our area today. Each of them have different
timing. There is a better wave moving into the area later today,
however, shear associated with this wave does not seem that
impressive. As a result think that we could see MCSs form that
quickly gust out. When this occurs, is uncertain. Especially
with the ongoing precip that was not forecast like this 24 hrs
ago. The question is whether we see a MCV or boundaries from the
precip this morning setup across the area. These could be focal
points for better convection this afternoon. CAPE still looks to
be maximized west of the area, so better chances for strong to
severe storms out there. The other thing CAMs are good for are
wind gusts from any convection. We do see wind gusts from storms
today, but again the stronger/severe gusts are well west of the
area today and tonight. So while I can`t rule out a near severe
wind gust or even localized severe gust, the better chance is to
the west where SPC has a risk area.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 319 AM CDT Sun Jun 15 2025

More of the same in the long term as we continue to build
instability as the heat dome shifts east through the period.
This coupled with a series of shortwaves moving through the flow
are expected to bring daily thunderstorm chances through early
Thursday. There is a better wave Tuesday into Wednesday that
increases deep layer shear. This will help to support a more
balanced shear/cold-pool interaction that could lead to
sustained MCSs with damaging winds. Tuesday looks like best day
for us to see strong to severe weather with that wave moving
through. However, with this environment, it is important to
remember that convection driven in a summer time pattern really
depends on what is going on in the morning of that day. Will we
see cloud cover and keep the area cooler with the wave moving
through, decreasing a severe weather threat? Or will overnight
storms leave a boundary that could enhance local shear and add a
tornado threat to the event? All of these questions are hard to
nail down even 12 hours out. So it remains, thermodynamic
environment supports strong to severe storms and increasing
shear will lead to updraft longevity. The main question is, do
we get storms that can tap into this environment. SPC has severe
risks on Monday and Tuesday and these seem like good forecasts
at the current time.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1125 AM CDT Sun Jun 15 2025

Precipitation chances/timing is the primary concern during the
period.

A well defined convectively enhanced shortwave /MCV/ was nearly
stationary just north of DBQ late this morning. This is forecast
to further weaken while shifting eastward over the next 12+
hours, and will keep scattered showers around for at least the
northern terminals (CID, DBQ) into this afternoon, with
isolated (20%) diurnally driven activity possible further south
toward MLI possible into this evening. Otherwise, an approaching
upper level disturbance from SD will foster another chance for
showers and some storms mainly overnight/early Monday AM. This
potential will be handled with PROB30 mention due to uncertainties
on spatial extent. Brief MVFR conditions are likely with any
precipitation with isolated IFR in any storms. Aside from the
precipitation, pooling moisture and some elevated smoke will
bring potential for some bouts of light HZ or BR at times with
weak surface winds in an otherwise VFR forecast outside of any
convection.

&&

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

&&

$$

SHORT TERM...Gibbs
LONG TERM...Gibbs
AVIATION...McClure