336
FXUS63 KDVN 231028
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
528 AM CDT Wed Sep 23 2026

...Updated for 12z Aviation...

.KEY MESSAGES...

- A break from the recent rainy pattern still looks on track for
  the second half of the week but some isolated showers cannot
  be ruled out. There are indications another rainy pattern may
  return early to mid next week influenced by tropical moisture.

- The cooler than normal trend, especially with daytime
  temperatures, will continue with some moderation by the
  weekend.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 240 AM CDT Wed Sep 23 2026

Complex blocked upper air pattern continues to reign acrs much of
the CONUS for the mid week. Both sfc and upper level ridge lobing
will make for a fair weather day today, but east to northeasterly
flow under a sharp H85 to H7 MB inversion will try to advect rounds
of stratocu decks in acrs the local area from the east(large decks
currently acrs the northeast half of IL and IN). Also if some breaks
are able to maintain, Cu Rule parameters suggest that ambient cumulus
may form into a heavy broken sky coverage in the diurnal heating of
the day. So partly to mostly cloudy skies seem more likley than
large amounts of sunshine. Also several CAMs want to break out
isolated to sctrd light showers or sprinkles acrs the heart of the
DVN CWA in the afternoon heating. Am not confident in this ATTM and
will just raise non-mentionable POPs acrs the area for now.

With the clouds in mind, the advertised mid 60s to near 70 seem
okay as long as we get a few breaks in the clouds at times.
Otherwise there may be more low to mid 60s. Tonight with a few
patches of lingering clouds and northeast sfc winds maintaining
around 5 KTs, will keep overnight lows in the upper 40s to mid
50s for much of the area but some worry that a few cool air
drainage locations could push the mid 40s.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 240 AM CDT Wed Sep 23 2026

Thursday and Friday...Several of the latest models try to propagate
the upstream upper trof seen currently on water vapor imagery acrs
eastern ID, toward the upper MS RVR Valley by Thu evening battling
ridge complex along the way. This wave will try to sweep in a band
of showers from the west Thu and into Thu night, but lingering ridge
effects and dry air in place should erode most of the precip as it
tries to enter the western CWA. We may just have debris clouds
spilling in from the west off this process ruining a mostly sunny
forecast for the day. If the clouds arn`t too thick, Thu highs may
be a degree or two milder than Wednesday. Low temps Thu night
generally in the 50s with a few upper 40s possible. Friday will look
to be similar to Thursday or maybe continuing to trend a bit warmer
if we get the cloud breaks and some insolation. But the next salvo
of upper trof energy from the southwestern U.S. will pummel it`s way
northeastward and take aim at the ridging in place. Moisture
advecting processes although not great, are there a little bit more
for the synoptic scale forcing to try and bring in at least a few
light showers from the west either late Friday night or Saturday,
especially along and west of the MS RVR.

Saturday through Tuesday...Part of the incoming trof overhead may
translate to more clouds and a few showers acrs the area Saturday
putting a damper on high temp potential and they may be held well
down in the 60s. The latest medium range ensembles then suggest the
upper system to erode/fill in enough for less impact and more
sunshine/drier conditions to allow for a warming Sunday with more
areas in the 70s. Lingering ridging and some LLVL return flow should
keep the dry and warming trends going into Monday, while an inland
striding longer wave trof drawing western Gulf moisture looms off to
the west. Thus another wet system may be eventually on tap acrs the
mid CONUS by early to mid next week.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 525 AM CDT Wed Sep 23 2026

MVFR to VFR conditions (ceilings) are expected during the TAF period.

Early morning satellite shows a large expanse of VFR stratus over
Illinois moving westward toward the Mississippi River. In advance
a band of lower VFR to at times MVFR ceilings has developed in
vicinity of DBQ down through CID to FFL. In general, the
expectation is for the stratus to lower to MVFR while continuing
to slowly advance toward the river terminals. Surface heating
ahead of this advancing cloud deck this morning should promote
a broken coverage of CU/SC with initial bouts of MVFR ceilings.
The ceilings should then lift to VFR this afternoon with scattered
to broken VFR clouds into tonight. In addition to the clouds there
may also be some sprinkles and isolated light showers today.
If they occur there should be little in the way of impacts and
will continue to leave out any mention. East to northeast winds
will generally range from 5-15 kt throughout the period.

&&

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

&&

$$

SHORT TERM...12
LONG TERM...12
AVIATION...McClure

NWS DVN Office Area Forecast Discussion