361
FXUS63 KDVN 021058
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
558 AM CDT Tue Sep 2 2025

.KEY MESSAGES...

- The extent of the cool down the second half of the week is
  dependent upon cloud cover. Recent model trends are suggesting
  not much of a cool down.

- There are rain chances Wednesday and again on Thursday night.
  This will not be a widespread rain for either time frame but
  more likely scattered showers.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 233 AM CDT Tue Sep 2 2025

Quiet and seasonable temperatures will be seen today and into the
evening hours across the area. The questions start late tonight and
continue into Wednesday.

Late tonight the front approaches the area. Forcing along it is not
very strong and mid-level lapse rates are fairly stable. Thee is
some low level instability that may allow some isolated to low end
scattered (15-25% coverage) pops to move into the northwest areas
prior to sunrise Wednesday. Most of the area looks to remain
dry.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 233 AM CDT Tue Sep 2 2025

Wednesday/Wednesday night
Assessment...medium (40-60%) confidence regarding rain chances

The model suite moves the front through during the day which still
looks reasonable. The question is the rain chances along and behind
the front.

Overall the forcing is not real strong and mid-level lapse rates are
fairly stable. The rain chances appear to be tied to the low level
instability being generated by the models. The model consensus has
60-70 percent pops during the day and 15-35 percent pops Wednesday
evening.

As mentioned earlier, the models appear to be developing rain as a
result of the low level instability and moisture levels. Given the
known model biases, the amount of low level moisture may be overdone
which would bias rain chances higher. There will likely be pockets
of legit 60-70 percent rain coverage on Wednesday but given the weak
forcing and fairly stable mid-level lapse rates, an isolated to
scattered (20-50 percent) coverage may be more appropriate.

Cold advection behind the front should result in isolated to perhaps
scattered instability showers that lasts into the evening before
ending.

Overall, some localized areas may see 0.1 to 0.25 inches of rain.
Most areas will see 0.1 inch or less of rainfall.

Thursday
Assessment...medium (40-60%) confidence regarding temperatures

Thursday will be interesting regarding temperatures.

Consecutive runs of the models have done a slow backing off on the
amount of cold air moving into the area. As a result, the
temperature forecast, albeit cooler, has been gradually warming up.
How warm it gets will be dependent upon cloud cover. The models have
not been showing much in the way of clouds for days. However, there
will be cyclonic flow aloft which could induce diurnal cold weather
stratocumulus to develop during the day. IF cloud cover is more
extensive than what the models have been indicating then
temperatures could easily be 10 degrees colder on Thursday.

Thursday night
Assessment...low to medium (20-40%) confidence on rain

The models have a secondary front sweeping through the area Thursday
night with another potential chance for rain.

However, forcing is not overly strong and mid-level lapse rates are
fairly stable. Thus like Wednesday the rain chances are tied to the
low level instability and moisture. The current model consensus has
20-70 percent pops for the area with the higher pops north of I-80.

Like the Wednesday rain event, the overall scenario would be more
supportive of isolated to scattered (20-40%) pops given that the low
level moisture may be overdone.

Friday through Sunday night
Assessment...Low to medium (20-40%) confidence on Friday
temperatures. Medium to high (60-80%) confidence on a warming
trend.

After cyclonic flow aloft Friday into Friday night which should
generate diurnal stratocumulus clouds, a warming trend toward more
seasonable temperatures will be seen over the weekend. Like
Thursday, Friday temperatures will be dependent upon how much cloud
cover will be seen. Friday may have the better potential of more
widespread wrap around clouds across the northern half of the area.
If correct, temperatures across the northern half and especially
north of Highway 30 may struggle to get to 60 degrees.

Monday
Assessment...low (20-30%) confidence regarding rain

The model suite has a subtle but weak upper level disturbance moving
through the area in the flow aloft. Moisture is very limited so
there is a question on whether or not any rain would be seen. The
model consensus has 20 percent pops over the southwest half of the
area. While potentially high this far out, the pops are a reasonable
risk level for rain.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 550 AM CDT Tue Sep 2 2025

Night-time microphysics on satellite shows patchy fog has
developed in river valleys and low-lying areas that may
potentially impact TAF sites through 14z/02 with a period of
MVFR/IFR conditions with a 15% chance of LIFR conditions. Winds
will remain under 10 knots as high pressure slowly moves into
the eastern Great Lakes allowing southerly flow to develop ahead
of the approaching cold front.

&&

.CLIMATE...
Issued at 620 PM CDT Mon Sep 1 2025

RECORD COOL HIGH TEMPERATURES:
              September 4      September 5
Moline        61 in 1874       61 in 1876
Dubuque       58 in 1994       61 in 1920

RECORD LOW TEMPERATURES:
              September 4      September 5
Moline        39 in 1974       42 in 1974
Dubuque       38 in 1974       44 in 1988 and others
Cedar Rapids  38 in 1974       42 in 1974
Burlington    40 in 1974       44 in 1962

&&

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

&&

$$

SHORT TERM...08
LONG TERM...08
AVIATION...08
CLIMATE...NWS