451
FXUS63 KDVN 030645
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
145 AM CDT Thu Sep 3 2026

.KEY MESSAGES...

- Impactful heat will continue across the area today and Friday.
  Heat indices look to be 100 to 110. The heat headlines may
  need to be extended into Friday (advisory) and Saturday
  (warning) depending upon how convection develops/evolves over
  the next 48 hours.

- Isolated severe storms are possible today through Saturday
  mainly north of I-80. The primary risk is damaging winds with
  hail a secondary risk.

- There is a daily risk of showers and storms, mainly along and
  north of I-80. While there is a risk of rain, there will be
  plenty of dry hours.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 142 AM CDT Thu Sep 3 2026

Headlines...

Right now no changes have been made to the current heat headlines.
HOWEVER, the current heat advisory north of I-80 could be extended
into Friday and possibly Saturday depending upon how convection
evolves over the next 48 hours. Similar thoughts on the current
warning potentially needing to be extended into Saturday.

Discussion

A small persistent cluster of showers and a few rumbles of thunder
formed along a theta e gradient with some wind convergence aloft
north of Highway 30. That feature is exiting the area so mainly dry
conditions should be seen through sunrise.

New convection has developed along similar theta e gradients in
northwest Iowa but the overall wind convergence is weaker.
Internally the RAP generally moves those theta e gradients east
northeast from their current position which potentially could allow
some isolated showers or even a thunderstorm to get into the Highway
20 corridor prior to sunrise.

Impactful heat and humidity remains the key message for Thursday
with no rain for 95 percent of the area. The possible exception is
the Highway 20 corridor. The quasi-stationary frontal boundary is
just north of the area which will likely have some low end
convection festering along it all day.

Tonight there may or may not be some isolated convection in the
Highway 20 corridor during the evening that dissipates with sunset.

After midnight is where things become interesting. The better rain
chances are still across Minnesota and Wisconsin. However, with the
upper ridge slowly retrograding into the Plains, a weakness in the
heat dome develops which would place areas north and east of a line
from Independence, IA to Mt. Carroll, IL in a more favorable set up
for nocturnal convection.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 225 PM CDT Wed Sep 2 2026

Friday through Monday...With the latest medium range run of
ensembles continuing to show the brunt of the upper ridge axis
shunted back to the west acrs the MO RVR Valley and eastern
plains, Saturday may be a more optimum day of having a boundary
or two(such as a northeast flow LK MI enhanced front) for storms
to pop up on in the heating of the day. There also will be the
potentail for another day of 100+ degree heat indices especially
acrs the south half of the CWA and the need for heat headlines,
especially taking into account the accumulative days of heat
into account. Then hopefully the local area will become more
under the influence of western GRT LKS sfc ridging for cooler, a
bit less humid and mainly storm-free days for the second half
of the holiday weekend.

Mid next week...still signs of the thermal ridge temporally getting
shunted back up toward the region for an above normal temp surge Tue
into early Wed, before a bigger cool front push and pattern change
commences by Wednesday.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1212 AM CDT Thu Sep 3 2026

Winds around 5 knots will be seen through sunrise which should
keep most areas VFR across eastern Iowa and northern Illinois. A
couple of very short term models are attempting to push an
outflow boundary into the Highway 20 corridor after 14z/03
which may result in a period of variable winds for KDBQ.
Elsewhere southerly winds 5-10 knots will persist through
sunset. Probability of diurnal convection impacting a TAF site
is 10 percent. With sunset winds will again drop to around 5
knots.

&&

.CLIMATE...
Issued at 225 PM CDT Sun Aug 30 2026

Record Warm Low Temperatures:

September 3:
KDBQ: 73/1939
KMLI: 76/1939

September 4:
KDBQ: 71/1912
KMLI: 74/2018

September 5:
KDBQ: 76/1881
KMLI: 76/1925

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Heat Advisory until 7 PM CDT this evening for IAZ040>042-
     051>054-066.
     Extreme Heat Warning until 7 PM CDT Friday for IAZ063>065-067-
     068-076>078-087>089-098-099.
IL...Heat Advisory until 7 PM CDT this evening for ILZ001-002-007-
     009.
     Extreme Heat Warning until 7 PM CDT Friday for ILZ015>018-
     024>026-034-035.
MO...Extreme Heat Warning until 7 PM CDT Friday for MOZ009-010.

&&

$$

SHORT TERM...08
LONG TERM...12
AVIATION...08
CLIMATE...12

NWS DVN Office Area Forecast Discussion