741
FXUS63 KDVN 210655
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
155 AM CDT Tue Jul 21 2026

.KEY MESSAGES...

- Humid conditions will continue today until a secondary front
  moves through late this afternoon. Northwest winds gusting up
  to 30 mph should push most of the wildfire smoke out of the
  area.

- Much cooler and less humid conditions will be seen the
  remainder of the work week before heat and humidity return for
  the weekend.

- Mainly dry conditions over the next 7 days as rain chances are
  quite low.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 153 AM CDT Tue Jul 21 2026

Through sunrise, scattered showers and possibly a thunderstorm will
be seen as the cold front sweeps through the area.

Windy, cooler but humid conditions will be seen across the area
during the daylight hours. Deep mixing occurring behind the cold
front should allow winds to gust up to 30 mph. The strong northwest
winds should push most of the wildfire smoke out of the area.

Humidity levels will begin dropping around sunset as a secondary
front moves through the area. Winds will also diminish as the
boundary layer decouples.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 153 AM CDT Tue Jul 21 2026

Wednesday through Thursday night
Assessment...a certainty of cooler and less humid conditions

Wednesday and Thursday will be banner days with cooler temperatures
and dew points in the 50s.

The models have trended stronger with the high over the western
Great Lakes which has now resulted in Thursday night being dry. This
stronger high has ramifications for rain chances Friday

Friday
Assessment...low (<20%) confidence on rain chances

The global models have now confined any rain chances on Friday to
the morning hours. Dprog/Dt shows the system further south than
yesterday which is a result of the high in the western Great Lakes
being stronger.

The deterministic model runs (save the GFS) are dry for Friday.
However, there are some ensemble members from each global model that
have rain chances across the area Friday morning.

With the high stronger and the system further south in Missouri, the
prospects for rain are not good. A review of the Integrated Vapor
Transport shows the strongest values run from Oklahoma into
southeast Kansas and southern Missouri. Thus while the model
consensus currently has 15-35 percent rain chances Friday morning, I
suspect these values will slowly drop over the next two days.

Friday night through Monday
Assessment...medium to high (60-80%) confidence of rising humidity
levels

Return flow develops across the Midwest starting Friday night and
continues through the weekend as the heat dome builds north into the
Plains. Dew points will slowly increase back into the low to mid 60s
on Saturday with mid and upper 60 dew points Sunday into Monday. The
combination of rising temperatures and dew points will eventually
push heat indices into the 90s again.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1212 AM CDT Tue Jul 21 2026

Cold front to sweep through eastern Iowa and northern Illinois
through 15z/21. Prior to 12z/21 SHRA or even a TSRA will be
possible but coverage will be 10-30 percent. After 15z/21 deep
mixing will allow wind gusts up to 25 knots to occur. The winds
will subside with sunset as the boundary layer stabilizes and
high pressure builds into the Midwest.

&&

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

&&

$$

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