588
FXUS63 KDVN 060603
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
103 AM CDT Sun Sep 6 2026

.KEY MESSAGES...

- The break in the heat will last through Monday night, followed
  by hot weather Tuesday and Wednesday, with highs reaching the
  90s, but with substantially lower humidity values than recent
  weather.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 256 PM CDT Sat Sep 5 2026

The initial wind shift with the backdoor cool front has already
pushed southwest of our CWA, but there is little change in air mass
found until you look up near Highway 20 and into Wisconsin.  This
was largely the expectation leading into today, and is resulting in
another excessive heat afternoon for most locations along and south
of Highway 30.

CAPE remains plentiful along and south of the boundary, but modest
capping much like the past few days is combining with minimal
forcing. There has been an eastward progressing outflow boundary
across central Iowa late this morning and afternoon, and this will
intersect the backdoor front, but that intersection seems to be
occurring just west of our CWA border, in the Ottumwa area.  A few
runs of the HRRR have shown an isolated cell there at times this
evening, and I have introduced a narrow 15% pop for Keokuk county
this evening. Concerning that, SPC has introduced a Level 1 outlook
touching our west edge of Keokuk County. The probability of any
storm in our south remains 5-10%, below mention in grid
forecasts, but is being mentioned in the graphics for today.

Towards early evening, the increasing northeast wind will bring
lower dew point air to the region. This will be a slow transition to
drier air, but by morning, some 58-65 degree dew point air should be
in place over the CWA, helping it feel far better Sunday and Monday.

Skies Sunday do look to have some mid and high clouds, as convection
should be found over the west 1/2 of Iowa.  This should limit highs
to the upper 70s to mid 80s area-wide, and keep heat stress out of
the picture through Monday night.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Issued at 256 PM CDT Sat Sep 5 2026

Dry and seasonally warm conditions will continue through the
remainder of the holiday weekend before the upper level ridge begins
building back into the area. While LREF probabilities of heat
indices greater than 100 degrees are low (10-20%), high temperatures
on Tuesday will be around 5-10 degrees above normal. These high
temperatures will continue on Wednesday, though there is some
uncertainty due to the potential for a front to move through the
area Tuesday night into Wednesday morning, bringing in rain and
lingering cloud cover that could temper highs on Wednesday.

Wednesday night into Thursday, another boundary will sweep through
the area. Much of guidance keeps this boundary dry, owing in part to
the frontal passage on Wednesday sweeping out some of the moisture.
As northwest flow returns to the region, near-normal temperatures
will return through the end of the work week.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 101 AM CDT Sun Sep 6 2026

VFR to MVFR and potentially IFR conditions are possible during the
first half of the TAF period. Currently, a deck of mid to high
clouds is moving southward through the area, with a secondary deck
of low stratus developing westward from Lake Michigan with SCT to
BKN MVFR CIGs of 1500-2000 ft. After these CIGs move into the
DBQ/MLI/CID terminals early this morning, areas of fog with VFR to
MVFR VSBYs are expected from 06/10-14Z. Chances for IFR or lower
VSBYs (20-40%) are highest at DBQ, hence the inclusion of an IFR
TEMPO group, but low confidence in IFR VSBYS have excluded it from
MLI/CID at this issuance. Past 06/17Z, VFR conditions are expected
at all terminals through the remainder of the period.

&&

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

&&

$$

SHORT TERM...Ervin
LONG TERM...Ellingworth/Ervin
AVIATION...Ellingworth