205
FXUS63 KDVN 150740
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
240 AM CDT Mon Sep 15 2025

.KEY MESSAGES...

- Unseasonably hot conditions will continue for much of this
  week before moderating some by Friday.

- Mostly dry conditions are expected through mid week, with
  increasing chances (30-50%) of showers and storms by Thursday
  night into Friday area-wide.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 230 AM CDT Mon Sep 15 2025

An upper level ridge will remain over eastern Iowa and northwest
Illinois today resulting in a continuation of the unseasonably
hot and humid conditions. It won`t be quite as hot as it was
over the weekend due to slightly cooler 850mb temperatures into
the upper teens (C). Forecast highs range from the mid/upper
80s north of Highway 30 to the lower 90s south. Dewpoints will
hold in the mid 60s to close to 70 degrees, but with the
slightly lower ambient temperatures peak heat indices should
not be as high as yesterday, reaching the upper 80s to mid 90s
for most areas today.

Isolated showers and thunderstorms could develop during peak
heating this afternoon and evening across portions of eastern
Iowa and west-central Illinois, mainly west and southwest of
the Quad Cities along a corridor of subtle low-level
convergence. Confidence is low on the areal coverage with the
CAMs showing a wide variety in solutions. Latest thinking is
for a lower coverage scenario due to limited forcing across the
area. If a few storms do manage to develop, moderate SBCAPE
(1500-2500 J/kg per HREF) and DCAPE (1000+ J/kg) could support
locally strong wind gusts.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 230 AM CDT Mon Sep 15 2025

Tuesday through Wednesday will continue to see the hot air mass in
place, although the 850 mb temperatures look to gradually decrease
from this weekend in both the ECMWF and GEFS ensembles. High
temperatures will generally be in the middle 80s to lower 90s per
the latest NBM, so a slight moderation expected. Humidity will also
remain elevated as well, with dew points during this period in the
lower to middle 60s.

One change in the extended forecast is for a slower arrival of
the trough late in the week. This translates to a continuation
of the hot conditions on Thursday with much of the area likely
to stay dry. The heat will eventually become scoured out by Friday
as a longwave upper-level trough is progged to slowly move into
the north-central CONUS region. Not only will this trough help
scour out the heat, but it will also bring our next widespread
chances of showers and storms to the area. The NBM has 20-50%
chances for showers/storms beginning Thursday night and lasting
into the weekend. There are no strong signals for severe weather
with latest machine learning guidance showing low end probabilities
(under 5% - 10%). High temperatures late in the period are
forecast in the 70s and 80s.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1240 AM CDT Mon Sep 15 2025

Quiet weather with VFR continues tonight into Monday AM. Low
coverage (10-30%) showers and storms may develop Monday
afternoon and evening over portions of eastern Iowa. Confidence
remains very low on the placement so have not mentioned
rain/thunder in the TAFs for now.

&&

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

&&

$$

SHORT TERM...Uttech
LONG TERM...Uttech/Schultz
AVIATION...Uttech

NWS DVN Office Area Forecast Discussion