525
FXUS63 KDVN 141915
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
215 PM CDT Tue Jul 14 2026

.KEY MESSAGES...

- Slightly above average July heat is expected to persist into
  Saturday with highs in the upper 80s to mid 90s. Heat indices
  could exceed 100 degrees in some places (50-70% chance) on
  Wednesday, which is why a Heat Advisory has been issued for
  portions of northwestern Illinois and far eastern Iowa.

- The breakdown of the ridge on Thursday will lead to increased
  precipitation chances late week and beyond into next week
  with a return to more seasonable temperatures.

- Canadian wildfire smoke may potentially impact parts of the
  region late week and into the weekend as northwesterly flow
  returns aloft.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 214 PM CDT Tue Jul 14 2026

The warming trend continues as the near 600-dam 500 mb ridge camps
out to our north, keeping subsidence widespread across the area. A
surface high pressure over Iowa will limit any type of advection
into the CWA, so the air mass is expected to modify each day with
highs, lows, and dew points creeping up 1-2 degrees each day through
Thursday. Highs today are forecasted to be in the low 90s and inch
towards the mid-90s Wednesday and possibly Thursday. Lows
are expected to jump from the upper 60s tonight to the low-to-mid-70s
by Thursday morning. This will have heat indices teetering on
100 degrees on Wednesday, and a Heat Advisory has been issued
for portions of northwestern Illinois and far east-central Iowa
where those chances are the highest.

Besides the heat though, there is the potential (40-60% chance)
for patchy fog tonight as radiational cooling can maximize with
the clear skies. In addition, on Thursday, a weak backdoor cold
front across Wisconsin and a lake breeze off Lake Michigan
could enhance moisture convergence over northwestern Illinois,
west-central Illinois, and far eastern Iowa, spawning some
isolated showers and storms (20-30% coverage).

Looking further south, cut-off lobes of positive vorticity are
expected to weaken the center axis of the ridge by Thursday.
This could split the ridge into two segments: one over the
Mountain West and another over the Southeast, setting up the
potential for troughing and northwesterly flow to return by the
weekend.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Issued at 214 PM CDT Tue Jul 14 2026

Thursday night-Sunday...With the ridge weakening on Thursday, it
opens the door for a tropical moisture plume over the Gulf Coast to
move northward into our CWA with PWATs likely (60-100%) climbing
back above 1.5 inches by Friday morning ahead of the next
approaching shortwave on the backside of the longwave trough over
the eastern Canada and New England. A developing low pressure system
and cold front over the Northern Plains and Minnesota is forecasted
to introduce southerly flow near the surface by Friday which could
keep the heat around despite the lower heights aloft, but cloud
cover and PoPs (30-60%) should prevent heat headlines. By
Saturday, the cold front sinks into northern Iowa and Wisconsin,
keeping cloud cover and isolated PoPs (10-20%) around, before
reaching our CWA on Sunday where the lack of upper-level support
should dissolve the front as the next shortwave trough dives
into south-central Canada and the Northern Plains.

The northwesterly flow aloft developing late week and through
the weekend may also advect Canadian wildfire smoke into
portions of the area, per latest RRFS vertical smoke forecasts
and smoke forecast from the Canadian Wildland Fire Information
System (CWFIS). Trajectories place our region more on the
periphery at this time with the greater concentrations and
impacts being suggested across Minnesota/Wisconsin/Michigan,
but something to keep an eye on.

Monday-Tuesday...An 80+-knot jet streak over the Northern
Plains should deepen a low pressure system near the Minnesota-
Canada border, forcing another cold front to push into the
Central Plains and Midwest. This should boost PoPs and
thunderstorm chances on Monday before the front clears the area
by Tuesday. In terms of severe weather, it is difficult to speak
to the threat level, but the latest LREF guidance is showing a
30-40% chance of at least 500 J/kg of SBCAPE underneath 30+
knots of sfc-to-500 mb bulk shear. Northerly flow at the surface
should return for Tuesday behind the cold front, advecting in
some much needed cooler air.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1234 PM CDT Tue Jul 14 2026

VFR conditions are expected through this evening with mostly
clear skies and light, variable winds. Similar to last night,
the potential is there for fog development at the TAF sites.
Current forecast has MVFR visibilities developing around 3AM-4AM
with some areas seeing dense fog (less than a quarter mile
visibility) closer to sunrise. Since there is uncertainty in
the exact locations of the denser fog, TEMPOs for lower
visibilities were not included in this issuance. Any fog that
develops overnight is expected to start to mix out and clear the
TAFs sites by 9AM when VFR conditions will resume.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Heat Advisory from noon to 8 PM CDT Wednesday for IAZ042-054.
IL...Heat Advisory from noon to 8 PM CDT Wednesday for ILZ001-002-
     007.
MO...None.

&&

$$

SHORT TERM...Delaune
LONG TERM...Delaune/McClure
AVIATION...Delaune