087
FXUS63 KDVN 040020
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
720 PM CDT Wed Sep 3 2025

.KEY MESSAGES...

- Widespread chances (40-70%) of light to moderate showers will continue
  this afternoon into the early evening today, with some
  embedded thunderstorms, most likely along and south of Highway
  92

- Another chance of showers is possible Thursday night, but we
  should see dry conditions Friday through Tuesday next week

- Another taste of fall-like conditions are on the way for late
  this week, with overnight lows in the 40s likely for tonight,
  and again Friday night and Saturday night, although no record
  lows are expected

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 232 PM CDT Wed Sep 3 2025

Early this afternoon, we continue to see some widespread light
showers over our far southeast, which had developed along a surface
cold front that will sweep southeastward through the CWA. Aloft,
GOES-East mid-level water vapor imagery shows an attendant shortwave
diving southeastward through southeastern Iowa into west-central
Illinois embedded within a longwave upper-level trough that will
stick around this part of the CONUS through the weekend. A secondary
cold front is following right behind from the northwest which will
support widespread chances (40-70%) of showers and a few embedded
thunderstorms through the afternoon hours before shifting off to the
south and east by the early evening. Indeed, we are already seeing a
line of activity forming from Delta, IA to DeWitt, IA. The 03.12z
HREF ensemble 1-hr probability of lightning keeps the highest
chances (40-50%) along and south of the Highway 92 corridor late
this afternoon. SPC continues to keep any severe outlook outside of
our forecast area to the south deeper into Missouri. In terms of the
convective parameter space, instability does appear to be quite
sparse, with MUCAPE progged only around 500 to 1000 J/kg, along with
pretty meager mid-level lapse rates. Deep-layer shear appears a bit
stronger, with values of around 40 knots as 500 mb level flow
strengthens slightly to around 40 to 50 knots per the 03.12z HREF.
In terms of rainfall, the 03.12z HREF PMM QPF fields show most
locations the possibilty of up to a tenth of an inch of rainfall,
with some isolated locations possibly seeing up to around a quarter
of an inch.

Eventually, the activity this afternoon should diminish by the
evening as the secondary boundary passes through. The main focus for
tonight will be on temperatures as 850 mb temperatures fall to
around 3 to 5 degrees C per the GEFS and ECMWF ensemble means. Skies
could also clear out for a time before higher level clouds build
back in, so overnight lows in the middle to upper 40s will be in
play.

Surface high pressure should take hold for Thursday, leading to a
partly to mostly sunny day. There could be some smoke filtering in
behind the incoming front, so there could be some haziness to the
skies for Thursday. Insolation and southerly flow behind the high
pressure system should help temperatures warm to the middle 60s
northeast to the lower 70s southwest. Another mid-level shortwave
trough embedded within the upper trough is progged to sweep across
the northern portions of the region Thursday night, which will
result in another chance of showers (20-50%), most likely along and
north of Highway 30. Instability appears to be lacking, so
thunderstorms appear unlikely with this shortwave. Overnight lows
Thursday night will be a little warmer than tonight, dipping only to
the upper 40s north to the middle 50s south.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 232 PM CDT Wed Sep 3 2025

Overall, a drier and cooler stretch of weather is expected Friday
through Tuesday. The main focus in the long-term period will be on
some gusty northwest winds Thursday night through Friday as cold air
advection should help maintain strong momentum transport via steep
low-level lapse rates. Wind gusts during this period could be as
strong as 25 to 35 mph, strongest across our north. Additionally,
the cold air advection should lead to some chilly nights, especially
Friday night and Saturday night. Overnight lows are forecast to fall
to the lower to middle 40s each night, which will feel more like
early October than early September! It doesn`t appear likely that we
would break any record lows, although some record cool high
temperatures will be in play for Friday. See our Climate section
below for the records list. Temperatures do look to rebound for
Monday and Tuesday as southerly flow returns, with highs both days
back into the 70s.

Despite a few mid-level shortwaves passing through over the weekend,
dry conditions should prevail given a lack of moisture through the
column to generate precipitation.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 659 PM CDT Wed Sep 3 2025

VFR conditions are expected to last through the period as cold
front continues to have gusty winds through the evening.
Eventually winds will decrease and become light. Mo sig wx
impacts to aviation expected.

&&

.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...Schultz
LONG TERM...Schultz
AVIATION...Gibbs
CLIMATE...NWS