907
FXUS63 KDVN 082321
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
621 PM CDT Tue Jul 8 2025

.KEY MESSAGES...

- There is a daily risk of isolated to scattered showers and
  thunderstorms (20-30%) that will be most favorable in the
  afternoon and early evening. Thunderstorms Thursday night will
  have the potential to be stronger as a cold front moves into
  the area.

- Seasonal temperatures and humidity levels will continue
  through the weekend and into early next week.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 228 PM CDT Tue Jul 8 2025

A weak swirl in satellite imagery denoting a low in eastern Iowa
will slowly exit the area tonight. The weak low should be enough to
generate a round of diurnal showers and storms with the better
coverage east of the Mississippi.

Convection that develops will slowly dissipate with sunset and leave
the area dry overnight. The light winds and low level moisture will
result in a conducive environment for patchy fog to develop. Cloud
cover will the key as to where and how large the areal coverage of
any fog will be.

After a dry Wednesday morning, isolated diurnal convection is
expected to develop during the afternoon with dissipation shortly
after sunset. Areal coverage of the diurnal convection will be low,
10% at best, so a vast majority of the area is expected to remain
dry.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Issued at 228 PM CDT Tue Jul 8 2025

Wednesday night/Thursday
Assessment...medium (40-60%) confidence on rain potential

Diurnal convection from Wednesday afternoon will dissipate after
sunset leaving much of Wednesday night dry. Internally, however, the
models are suggesting an organized storm complex developing in the
northern Plains that will move southeast through western and central
Iowa during the night. Although low, the potential is there for some
convection west of I-380/U.S. 218 toward sunrise Thursday. The model
consensus currently has a 20% chance of that occurring.

If convection does move into the area prior to sunrise Thursday,
which is dependent upon the timing of the decaying storm complex,
then areas generally south of an Independence, IA to Galva, IL line
would be favored for remnant isolated to scattered (20-35%)
convection during the morning.

Boundaries left over from the nocturnal convection will be the focus
for isolated to scattered (20-30%) diurnal convection Thursday
afternoon.

Thursday night through Friday night
Assessment...medium (40-60%) confidence for showers and storms

Strong convection is forecast to develop along a cold front in the
Plains into western Iowa Thursday afternoon. This convection will
move into eastern Iowa after midnight and will be in a weakening
phase. While there is a risk of severe storms late Thursday night,
it is currently a marginal risk (level 1 out of 5) with wind being
the primary risk.

The cold front will move through the area Friday into Friday
evening. Cloud cover will be a factor for the areal coverage on any
storms. Isolated to scattered (20-30%) coverage is expected Friday
morning from the decaying convection.

Boundaries from the overnight convection combined with the cold
front will develop a new round of storms Friday afternoon and
evening. Interestingly, CSU machine learning is depicting a severe
risk for Friday afternoon/evening for the area. The overall signal
is weak so it will be interesting to see how this will evolve over
the next few days. Given the weak signal, a potential marginal risk
(level 1 out of 5) may eventually be possible.

Saturday through Tuesday
Assessment...medium (40-60%) confidence for showers and storms

Typical mid-summer heat and humidity will be seen across the area
Saturday through Tuesday with a daily risk of showers and storms.
The model consensus has a distinct diurnal nature to the pops with
areal coverage being 20-30% for the area.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 616 PM CDT Tue Jul 8 2025

The vast majority of scattered thunderstorms have now moved east
towards central Illinois, while a few very isolated showers and
weak storms remain over northern Iowa and Wisconsin. These
isolated storms could move into eastern Iowa through sunset, but
coverage is so low (under 10%), that we`ll leave TAFs dry this
evening. Overnight and early Wednesday, shallow fog formation
appears to be the main concern, especially in areas that saw
recent rainfall, which is mostly Cedar Rapids and Dubuque. This
fog, should burn off quickly after sunrise, with VFR conditions
and light northwest winds returning to the area. For now, I`ve
gone with MVFR 5SM fog at MLI and BRL, and 3SM IFR at CID and
DBQ in a temporary condition from 10-13Z. If shallow dense fog
does form, an update for LIFR conditions would be warranted.

&&

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

&&

$$

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