245
FXUS63 KDVN 182300
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
600 PM CDT Tue Aug 18 2026

.KEY MESSAGES...

- A storm system will drag a cool front through the area tonight
  into Wednesday, bringing some showers and thunderstorms. A
  couple of storms may be strong to severe but confidence is
  low.

- Outside of another front bring a shower and thunderstorm risk
  to the area late Thursday night into Friday evening,
  precipitation chances look to be very limited over the next 7
  days.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 147 PM CDT Tue Aug 18 2026

Satellite trends show clearing occurring ahead of the approaching
cool front. The overall forcing is weak as is the convergence along
the front. Thus there are questions regarding the potential for rain.

Based on radar/satellite trends through early afternoon, prudence
dictates going with a 15-50 percent chance of rain late this
afternoon with the better chances north of Highway 30.

The cloud cover and relatively cooler temperatures will result in
limited instability for storms. However, progged soundings of the
atmosphere do give weak support that a couple of storms could be
strong to severe. IF this scenario does occur, the primary risk
would be hail for areas along/north of Highway 30.

Once sunset occurs the overall coverage of convection will drop with
some weak but isolated convection festering the remainder of the
night.

On Wednesday there should be some lingering convection south of I-80
during the morning that slowly dissipates. If diurnal convection
develops Wednesday afternoon, it would be isolated due to the lack
of upper air support and would be confined to areas south of
I-80.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Issued at 147 PM CDT Tue Aug 18 2026

Wednesday night through Tuesday...
Assessment...low (20-30%) confidence on late week rain chances

The models have another front moving through the area in the late
Thursday night through Friday evening time frame. Northwest flow
aloft dominates well into next week so the overall moisture
available for rain will be limited. The current model consensus is
at a 20-35% chance of rain with the better chances generally along
and north of I-80.

Outside of this time period, the prospects for rain is very limited
with temperatures near normal.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 600 PM CDT Tue Aug 18 2026

Isolated showers and thunderstorms to track southeast across
northeast IA and southern WI over the next 2-3 hours along and
ahead of a weak cold front. Confidence in another thunderstorm
reaching DBQ remains too low for a prevailing group and thus
have just included a PROB30 mention for this occurrence at this
time. Storm coverage to decrease with a few hours after sunset.
Winds to become light/calm overnight allowing for some MVFR/IFR
fog to develop at the terminals. Some guidance even has LIFR
conditions occurring at DBQ, but left out with this issuance
due to low confidence.


&&

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

&&

$$

SHORT TERM...08
LONG TERM...08
AVIATION...Gross