Flash Flood Warning 34, NWS Quad Cities, IA

Area Forecast Discussion
National Weather Service Quad Cities IA IL
306 AM CDT Fri Aug 14 2026

.KEY MESSAGES...

- Scattered to isolated storms this morning with continuing
  locally heavy rainfall threat, then potentially a more
  widespread storm cluster or MCS moving acrs the area late
  afternoon and tonight with a Slight Risk for severe weather.

- Active weather pattern to continue through the weekend, with
  greatest storm coverage at night into the morning. Due to
  successive rainfall events, additional totals of 2 to 4 inches
  by Saturday morning are favored with localized higher values
  likely(70%), continuing the flash flood threat.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 300 AM CDT Fri Aug 14 2026

LLJ fed lingering bands of mainly elevated sctrd storms will
continue into mid morning before diurnal processes allow them to
wane. Will have to watch  the banded storms in southwest to central
IA for trends trying to zipper more east or northeast and meet up
with the current activity in the local CWA over the next few hours
for a flooding axis. With the main boundary shunted for now to the
south of the CWA, again these storms should mainly elevated with
locally heavy rainfall(PWAT pool of 2 inches in place) and only an
isolated lower end severe potential through late morning. Then
expect a convective lull from late morning through mid afternoon
with just maybe a few rounds of passing debris or light high bases
showers. This will keep most temps in the 70s to low 80s except
maybe the far south heating up into the upper 80s if the boundary
can retreat some as a warm front into those areas...this front may
have better north push further to the west acrs western IA and the
MO RVR Valley by late afternoon to the lee of the next short wave.

Then attention turns to the next main upstream short wave/MCV now
seen on W/V imagery acrs far northeastern CO. This feature projected
to roll acrs central IA by midnight tonight, and with leeside LLVL
jet feed and shear will probably form another robust cluster of
storms/MCS. This is the main reason for SPC's upgrade to a Slight
Risk again, a daily occurrence. Still some uncertainty on how far
north or south the main storm complex will propagate acrs IA and the
local area, but many of the latest CAMs and 00z GFS suggest along
and north of I-80 from mid evening into the overnight.There may be
some precursor banded elevated WAA wings of showers/storms from late
afternoon and early evening, but the MCS will be the main show. As
has been all week, all types of severe modes possible with the prime
risk being bowing segments with damaging winds again. That and heavy
rainfall compounding the flash flooding and river/creek flooding
threat into Sat morning. Will of course keep the Flood Watch going
with storm chances CWA-wide tonight.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 300 AM CDT Fri Aug 14 2026

Saturday...Current ensemble handling the ridge periphery and short
wave timing suggest that most of Sat may be a lull window in the
convective onslaught. This may allow for a full on warm front
retreat back north bathing most of the cWA in a steamy warm sector
with highs in the upper 80s or near 90 with high sfc DPTs well up in
the 70s. If this scenario holds, Saturday may be a candidate for the
need of a heat headline. Then the nocturnal processes kick in for
more storm chances Sat night.

Sunday through Thursday...Medium range ensembles suggest an upper
pattern flux with brunt of the upper ridge retrograde and some
flattening and trending of the mid CONUS steering flow to a
northwesterly regime by early next week. This process may come at
the risk of shunting a cool font down through the area late Saturday
night or Sunday with an associated storm risk, but eventually lead
to a cooler and more settled weather regime for at least Monday into
Tuesday. But even west-northwesterlies usher acrs short waves and
MCV's and we may be due again for some convection by mid next
week.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1255 AM CDT Fri Aug 14 2026

Rounds of sctrd showers/thunderstorms will plague the area into
Friday morning, but are occurring in linear bands with coverage
and many of the TAF sites might not be affected til later Friday
morning. Best chance will be BRL overnight into Fri AM with
sctrd storms pushing that way for temporary bouts of MVFR to IFR
conditions. Ongoing general easterly sfc winds of 7-12 KTs north
of a boundary to the south should help prevent dense fog this
Friday morning, but there will be areas of lighter fog. Friday
morning expect sctrd storms to continue especially with the new
activity taking off acrs southwest IA into NE. Then maybe a
midday to mid afternoon lull before expect sctrd convection to
increases again into Friday evening. But MVFR clouds will look
to hang on for much of the afternoon and into the evening. The
active pattern and it's impacts to aviation unfortunately look
to continue.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Flood Watch through Saturday morning for IAZ040>042-051>054-
     063>068-076>078-087>089-098-099.
IL...Flood Watch through Saturday morning for ILZ007-009-015>018-
     024>026-034-035.
MO...Flood Watch through Saturday morning for MOZ009-010.

&&

SHORT TERM...12
LONG TERM...12
AVIATION...12

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