789
FXUS63 KDVN 171053
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
553 AM CDT Mon Aug 17 2026

.KEY MESSAGES...

- High pressure will remain draped over the region through the
  start of the work week, bringing seasonal temperatures and
  mostly clear skies.

- A storm system will pass through the area Tuesday into
  Wednesday, bringing the chance for thunderstorms. A few storms
  may be strong to severe.

- Another stretch of quieter weather returns late in the week
  and into the weekend, with limited precipitation chances.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 127 AM CDT Mon Aug 17 2026

The stretch of heavy rainfall and severe storms has finally come to
a close, as high pressure slides over the region today. We are
geared to have quite the beautiful start to the work week. Aside
from diurnal cumulus, mostly clear skies will be seen, with light
northwesterly winds and temperatures around 80. Tonight, high
pressure will be southeast of the area, with llvl winds shifting
southwesterly. An increase in llvl moisture will result, with
increasing mid-high clouds through the night. Dry conditions will
remain through much if not all of the night, with temperatures in
the low-mid 60s. The HRRR continues to bring in a decaying line of
showers/storms, largely impacting our northern counties and drying
up as it progresses through the area. Although, much of the short
term model suite keeps us dry through tonight.

A shortwave trof will approach the area later on Tuesday, with weak
bouts of energy passing out ahead of it. A 20-30 KT LLJ will also be
in place overhead, increasing moisture throughout. This will create
an environment favorable for showers and storms, which can be seen
as early as late morning. Although, forcing isn`t best until later
in the day, especially as a cold front crashes through the area.
Thus, any shower/storm activity should remain isolated to scattered
until the afternoon/evening hours. As the cold front approaches
Tuesday evening/night, we may have an environment favorable for some
organized convection. Deep-layer shear will largely remain in the 30-
40 KT range with sufficient instability, which would favor mixed-
mode convection that can grow upscale into a line of storms. The
environment in place would favor the chance for a few strong to
severe storms, with wind gusts being the main concern. Comparing to
previous forecast runs, the severe threat does seem to be decreasing
a little. This could be due to the aforementioned daytime
showers/storms, which may limit afternoon destabilization ahead of
the cold front, leading to a more conditional threat. This will be
something to continue monitoring as more short term guidance comes
in. SPC seems to have picked up on this trend, keeping much of the
area under a Marginal Risk, level 1/5, and trimming the Slight Risk,
level 2/5, to our far west.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Issued at 127 AM CDT Mon Aug 17 2026

Wednesday morning, we may continue to see residual showers/storms as
the cold front fully exits the area. At this point, the severe
threat will be quite limited. Thus, we are not expecting many
impacts at that point. Post-frontal airmass will kick in Wednesday,
with light northeasterly winds and decreasing cloud cover. The
remainder of the work week seems to be quiet, with a slightly cooler
airmass in place and much lower humidity. We will remain under weak
northwesterly flow aloft, with a few weak impulses in the flow.
Although, with low moisture and lacking return flow, we are not
expecting much rain for the rest of the week. As was mentioned
in the previous discussion, any precipitation will largely be
in the form of isolated instability showers. A few global models
indicate chances late Friday into Saturday morning, but
confidence is low on this. Will stick with what the NBM
initialized, introducing 15-30% PoPs Friday evening/night.
Otherwise, a much needed stretch of mostly-dry weather will be
seen, with comfortable humidity and temperatures largely in the
upper 70s.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 550 AM CDT Mon Aug 17 2026

Can`t rule out a very brief MVFR visibility reduction in mist at
a few of the terminals to start off the TAFs, but too low of
confidence and probability to mention. Lake stratus should not
impact the KMLI and KBRL terminals this morning with N/NE flow
in the cloud bearing layer steering them well to the east.
Otherwise, VFR conditions are expected to persist through the
period with diurnal cumulus 2500-3500 ft bases lifting and
decreasing with increased mixing, which will bump NW wind to
around 10+ kt before turning light while backing from the SSW
after sunset. There is a low chance for a shower or storm to
approach KCID and KDBQ terminals toward the end of the period,
but the probability (20%) is too low for any mention.

&&

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

&&

$$

SHORT TERM...Gunkel
LONG TERM...Gunkel
AVIATION...McClure