901
FXUS63 KDVN 221030
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
530 AM CDT Fri Aug 22 2025

...Updated for 12z Aviation...

.KEY MESSAGES...

- Patchy fog early this morning.

- A dry forecast is largely in place, with very pleasant
  temperatures from Sunday onward. The only chance for
  rain/storms (20-40%) is Friday night into Saturday morning
  with a cold front.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 131 AM CDT Fri Aug 22 2025

Clear skies were found across the area this morning as high
cirrus from convection near the IA/MN/SD borders bleeds into the
area. These clouds could affect the fog potential tonight. As
they move south into the area, they are starting to thin. This
means I really don`t have much confidence in the forecast for
fog tonight. Remove the cirrus cloud deck and I think we end up
seeing across most of the area tonight. CAMs have widespread
dense fog developing tonight across the area. Some of the time
lagged guidance has been backing off of the fog potential. So
guidance doesn`t really have an idea either. If we were to see
dense fog it would likely be south of I80. That said, think we
are in a wait and see approach for any fog tonight.

Today, a pleasant late summer day is forecast, with winds
shifting towards the south/southwest during the day. and
Temperatures in the upper 70s to low 80s seem on target for
today in the "warm sector" ahead of the cold front late tonight.

A cold front is forecast to move through the area later this
evening into the overnight. Overall CAPE looks rather low with
MUCAPE values <1000 J/kg. CAMs have cellular convection, this
with the low CAPE suggests showers with some isolated
thunderstorms are possible with the fropa. Do not see a
potential for strong/severe storms with this setup. Signal for
convection weakens overnight and as the front moves through the
area overall coverage of rain showers will diminish south of
I80.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Issued at 234 AM CDT Fri Aug 22 2025

High pressure surges into the area to start the period as CAA
brings in some of the coolest air this summer. This airmass will
be in place through at least the middle of next week, bringing
a beautiful start to the last full week of August. Highs in the
60s and 70s with lows in the upper 40s to low 50s means you can
give the A/C some rest and open the windows. The first surge of
cold air Saturday does not look like there will be any wildfire
smoke with it. Will need to keep an eye upstream to see if any
does trickle down into the area during our cool snap.

While expectations are for dry conditions at nearly all extended
forecast days, the cool air aloft may allow for some diurnally
driven cumulus and sprinkles/showers at times, and any embedded
short wave in this cyclonic flow could provide forcing for a brief
wetting rain in this pattern ahead.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 525 AM CDT Fri Aug 22 2025

Patchy fog, dense in river valleys and other low lying areas,
will burn off quickly after sunrise with predominantly VFR
conditions the rest of the period. A cold front will move through
overnight (06z-12z) shifting winds to the northwest. A few
showers will be possible along the front, but CAMs generally
weaken any activity as it approaches encountering drier sub-
cloud air, and weakening low level convergence. Thus, probabilities
for any impacts (reduced visibilities) appear too limited (20 percent)
for any mention.

&&

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

&&

$$

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