451
FXUS63 KDVN 191116
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
616 AM CDT Sun Jul 19 2026

.KEY MESSAGES...

- Canadian wildfire smoke is forecast to spread across the area
  through tonight which will create hazy skies and poor air
  quality.

- Strong to severe storms are possible Monday and Monday night
  with potentially two rounds occurring. The Storm Prediction
  Center has an enhanced, level 3 out of 5, risk of severe
  storms along/north of I- 80. South of I-80 a slight, level 2
  out of 5, risk for severe storms exist.

- Hot and humid conditions will be seen across the area on
  Monday. Peak heat indices on Monday will depend upon which
  storm scenario occurs. If there are no storms during the
  morning, then heat headlines would be needed for parts of the
  area.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 149 AM CDT Sun Jul 19 2026

Slightly less humid conditions will be seen across the area today
but dew points will begin climbing again tonight. Canadian wildfire
smoke will create a hazy sky across the area with some minor
visibility reductions

The question tonight is when rain could move back into the area. Dry
conditions will be seen through midnight. After midnight the various
short term models have been showing a gradual backing off on the
potential for convection through sunrise. HOWEVER, internal signals
suggest something moving into the northern parts of the area shortly
after sunrise. Current data indicates that IF this scenario occurs
it would be in a decaying phase. This makes sense since the LLJ
would be rapidly decaying at this time.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 149 AM CDT Sun Jul 19 2026

Monday/Monday night
Assessment...medium (40-60%) confidence regarding heat headlines
and strong to severe storm potential.

Two scenarios are in play for Monday.

Scenario 1: morning storms then evening severe storms

Nocturnal storms move into the area in a decaying mode bringing
spotty rain to the area. Cloud cover from this convection helps
suppress temperatures and thus delays the development of diurnal
convection until close to sunset. The added cloud cover could keep
peak heat indices in the 95 to 100 degree range.

Around sunset convection develops rapidly. Storms would initially be
discrete and thus be capable of all severe hazards. However, storms
would rapidly grow upscale into one or more organized bowing storm
clusters.

Once the bowing storm clusters form, the potential for significant
damaging winds (>75 mph) would become the main severe risk. Brief
spin-up tornadoes in the bowing lines would also be possible.

Storms would be the most numerous during the evening hours but
boundaries from these storms would then provide numerous foci for
isolated to scattered storms that persist past midnight.

Scenario 2: a dry morning the severe storms developing mid to late
afternoon.

The nocturnal storms remain across Minnesota and Wisconsin keeping
the area dry. If this scenario occurs, the potential energy build-up
in the atmosphere would set the stage for strong to severe storms to
develop during the afternoon and continue into the evening hours.
Additionally, this scenario would result in a heat headline.

Under this scenario, discrete storms would develop mid to late
afternoon with all severe hazards possible. Like scenario 1, the
discrete storms would rapidly grow upscale into one or more
organized bowing storm clusters. Once this state occurs, the severe
risk would transition to damaging winds being the primary risk.
Brief spin-up tornadoes in the lines cannot be ruled out. Also like
scenario 1, significant damaging winds (>75 mph) would be possible.
Boundaries from these storms would provide numerous foci for
additional storms to develop during the late evening with convection
potentially ending after midnight.

Tuesday through Thursday
Assessment...a certainty (>98%) of cooler and much less humid
conditions after Tuesday

Tuesday will be dry as high pressure builds into the Midwest and the
flow aloft turns to the northwest. Heat indices will range from the
mid 80s to the low 90s due to lingering humidity until dew points
drop Tuesday night.

Wednesday through Thursday look to be banner days; daytime highs 80
to 85 and low humidity levels.

Thursday night through Friday night
Assessment...low (<25%) confidence regarding rain chances

Late Thursday night through Friday evening an upper level
respectable upper level disturbance in the northwest flow will be
paired with a weak surface low moving through Missouri.

The model consensus has 20-30% chances for rain centered mainly
around late Thursday night and Friday morning. Given the northwest
flow aloft across the area, moisture will be limited so it raises
questions on how much rain could occur and what the real areal
coverage of it will be.

The better moisture will run from the Plains into Missouri and there
will be a frontal boundary associated with the low as it moves from
Kansas across Missouri. I suspect the better rain chances will be
along the frontal boundary across Missouri.

Saturday
Assessment...a certainty (>95%) of humidity levels starting to rise

Return flow begins on Saturday as the heat dome builds north in the
Plains. While not the overly humid conditions earlier in the week,
dew points will start climbing into the low to mid 60s as
temperatures climb above normal again.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 614 AM CDT Sun Jul 19 2026

East to northeast low level flow will slowly advect in smoke
from wildfires which is creating areas of MVFR/IFR visibilities
this morning. I expect some improvement with daytime heating,
but occasional visibility around 3-5 miles can be expected at
times due to smoke. Winds of 10 knots or less will slowly
become easterly after sunrise with an eventual southeast flow
after 00z/20.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...Air Quality Alert until midnight CDT tonight for ILZ001-002-
     007-009-015>018-024>026-034-035.
MO...None.

&&

$$

SHORT TERM...08
LONG TERM...08
AVIATION...Ervin