Severe Thunderstorm Warning 210, NWS Quad Cities, IA

Area Forecast Discussion
National Weather Service Quad Cities IA IL
210 PM CDT Thu Jul 2 2026

.KEY MESSAGES...

- Extreme Heat Warning continues through Friday evening for
  areas along/south of an Ottumwa, IA to Galesburg, IL line from
  the prolonged hot and very humid conditions. The humid
  conditions will continue into the holiday weekend, but cloud
  cover and rounds of thunderstorms make for great uncertainty
  if there will be the need for additional heat headlines.

- With the storm track edging closer in from the west/northwest,
  the local area will be more susceptible to occasional rounds
  of thunderstorms into the Holiday weekend. Strong to severe
  storms will be possible, as well as locally heavy rainfall.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 204 PM CDT Thu Jul 2 2026

The heat headlines have been extended until 10 PM Friday for areas
along and south of an Ottumwa, IA to Galesburg, IL line. It will be
another very warm night for this area. Although heat indices Friday
may only around 100, heat affects are cumulative and this would be
day five for this area.

The outflow boundary from the nocturnal storms across Wisconsin has
stalled from roughly a KALO to KDKB line and is now slowly moving
north. Storms have initiated along this line and will likely be
confined to this area through late afternoon. However, the 18z
sounding has a very weak cap and minimal inhibition. Thus a few
rogue isolated storms cannot be fully ruled out through sunset along
and south of Highway 30.

There is a respectable upper level disturbance moving east northeast
out of eastern Nebraska which will likely initiate new storms in
central Iowa this afternoon. These storms will grow upscale
overnight into an organized storm complex that will generally move
east northeast as a weak LLJ develops.

Corfidi vectors become perpendicular to each other suggesting the
potential for slow storm movement and for storms to repeat over the
same areas. Given the very high moisture levels in the atmosphere,
heavy rain is a given.

The HREF and REFS probability matched means are painting a fairly
large area of northeast Iowa with 2+ inches of rain. The HREF LPMM
is even more disturbing suggesting smaller areas of 4+ inches.

If the storm complex tonight would latch onto the outflow boundary
then rainfall would have a high probability of being excessive. Due
this possibility, a flood watch has been issued for the Highway 20
corridor from Dubuque on west.

Most storms overnight should remain below severe limits. However,
localized severe downbursts due to precipitation loading in the
downdrafts cannot be ruled out.

Outflow boundaries from the nocturnal convection will push south
across the area and help initiate additional convection. Areas along
and north of the I-80 corridor have the better chances for rain.

Friday will be yet another humid day. However, clouds and residual
convection should keep heat indices in the 95 to 100 range for the
northern two thirds of the area. Boundaries from the overnight
convection should initiate new diurnal convection across the entire
area, especially the south third during the afternoon.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 245 AM CDT Thu Jul 2 2026

Friday night through Sunday

Model ensembles and mid to upper jet progs(which generally do
well at this range) show the continued southeast upper ridge de-
amplify to allow flattened progressive flow to press acrs the
upper Midwest into Saturday. This flow embedded with short waves
and MCVs means the adjustment of the main storm track from the
north half of the plains through the GRT LKS and on into the
northeast CONUS. This will open up the local area for more
direct hits by storm clusters through at least early Sunday. The
oppressive humidity will still be here(aided by crop evapo-
transpiration) through the weekend, but convective debris and
outflow between the episodes of storms should help reduce the
need for additional heat headlines. A damaging wind producing
MCS may move acrs IA and then effect the local area later Friday
night into early Sat morning. Besides an almost daily chance
for strong to severe storms through at least Saturday, swaths of
heavy rainfall may really add up through Sunday especially acrs
the northwest half of IA, southern MN, and into WI.

Longer range progs and upper jet patterns suggest a good bout of
ridging to unfold acrs the upper Midwest for a reprieve from the
storms by early next week. Temps may be more seasonable and not as
hot early next week as well.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1222 PM CDT Thu Jul 2 2026

Outflow boundary from the WI convection runs from about KALO to
KDKB. Isolated convection has initiated along it and will likely
persist through the afternoon. More convection will initiate
after 21z/03 across northeast Iowa and grow upscale into another
TSRA complex overnight. Probability of IFR impacts is better
than 50 percent for KDBQ. Outflow boundaries from the storm
complex will be the foci for isolated to scattered convection
across eastern Iowa and northern Illinois after 12z/03.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Flood Watch through Friday morning for IAZ040>042.
     Extreme Heat Warning until 10 PM CDT this evening for
     IAZ063>068-076>078.
     Extreme Heat Warning until 10 PM CDT Friday for IAZ087>089-098-
     099.
IL...Extreme Heat Warning until 10 PM CDT this evening for ILZ009-
     015>018-024.
     Extreme Heat Warning until 10 PM CDT Friday for ILZ025-026-034-
     035.
MO...Extreme Heat Warning until 10 PM CDT Friday for MOZ009-010.

&&

SHORT TERM...08
LONG TERM...12/08
AVIATION...08

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