Severe Thunderstorm Warning 63, NWS Quad Cities, IA

Area Forecast Discussion
National Weather Service Quad Cities IA IL
244 PM CDT Wed Jun 25 2025

.KEY MESSAGES...

- An upper level front will keep the heat and humidity across
  the area the remainder of the week along with a daily risk of
  showers and thunderstorms. Some relief may be seen next week.

- Brief funnel clouds will be possible this afternoon as diurnal
  convection develops along the many boundaries across the area.
  An isolated severe storm cannot be ruled out.

- With a wet pattern across the area and the potential for more
  heavy rainfall, area rivers are expected to see rises. Refer
  to the hydrology section for more information.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 230 PM CDT Wed Jun 25 2025

A hot and humid air mass resides over the Mid to Upper Mississippi
Valley region as the core of the Heat Dome continues to gradually
shift into the Ohio Valley to Southeast U.S.

After a fairly widespread rainfall over the past 24 hours, near
surface moisture has jumped up for portions of the area today with
dewpoints in the mid to upper 70s. This has pushed heat indices
into the upper 90s to lower 100s roughly south of Highway 30,
and have issued a Special Weather Statement to message the heat
impacts through this afternoon and evening. Isolated showers
have developed early this afternoon across southern counties and
were gradually tracking to the NNE toward the I-80 corridor. An
area of slightly stronger convection was ongoing northeast of
Quincy, IL and is set to shift into portions of Hancock and
McDonough Counties through the mid/late afternoon. The primary
concerns with any storms are lightning, brief torrential
rainfall (supported by ~2" PWATs), and gusty winds. Similar to
previous days, a few brief funnel clouds are possible due to the
slow storm motion, sufficient low-level CAPE (0-3 km), and
presence of near surface outflow boundaries. The overall threat
for severe weather is low through this period.

Additional scattered storm development is possible across the north
tonight (mainly north of Highway 30) as the nocturnal LLJ strengthens
out of the southwest. Otherwise, another muggy night is expected
with lows only in the low to mid 70s.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 230 PM CDT Wed Jun 25 2025

Thursday/Thursday night
Assessment...the heat and humidity is expected to continue with
medium to high (60-80%) confidence of storms.

Thursday morning may or may not see some lingering convection from
the previous night. However, there will be cold front that sweeps
through the area late Thursday afternoon and night.

Daytime heating ahead of the front will push afternoon heat indices
into upper 90s to lower 100s south of Highway 20 and a heat headline
may eventually be needed for portions of the area. The potential
energy that builds during the day will then go into feeding storm
development during the late afternoon and evening.

New storms look to initiate in central Iowa during the afternoon
that will grow upscale into a line that marches east and arrives in
eastern Iowa just before sunset. Ahead of this line scattered storms
are possible in eastern Iowa along a pre-frontal trof that will
dissipate with sunset. The model consensus has converged on this
scenario with the highest pops west of the Mississippi late Thursday
afternoon and night.

SPC has a marginal risk (level 1 out of 5) for severe storms for the
area. The primary risk looks to be damaging winds and heavy rainfall.
If severe storms were to develop, prime time looks to be 5 to 11 PM.

Friday through Sunday night
Assessment...high (>80%) confidence of heat and humidity continuing.
Medium (40-60%) confidence of a daily risk of rain.

The heat and humidity will continue through the weekend before a
pattern change shifts the upper flow to the west northwest.

Weak disturbances running around the edge of the heat dome are
expected to result in mainly diurnal convection developing during
the afternoon and evening. Areal coverage on this will be 20-40%.
The models are suggesting a better chance of rain Sunday/Sunday
night when a slightly stronger system and front moves through the
area.

That being said, there will be many hours of dry weather over the
weekend.

Monday through Tuesday
Assessment...medium to high (60-80%) confidence on temperatures
near normal with a continued risk of rain.

The heat dome will be pushed southward as a pattern change bring
west northwest flow into the area early next week.

A weak disturbance moving along in the flow aloft will bring a low
risk (20%) of diurnal showers and thunderstorms Monday/Monday night
to the area. Again, there will be many hours of dry weather on
Monday.

High pressure building into the area on Tuesday looks to bring the
first chance of a dry day across the area.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1210 PM CDT Wed Jun 25 2025

Mainly anticipate VFR to prevail today into tonight with low
chances (10-30%) for an isolated shower or storm to impact the
terminals. Slightly higher chances (20-40%) near DBQ tonight so
have included a PROB30 for thunder there. Brief MVFR/IFR is
possible in the vicinity of any showers/storms that develop.

&&

.HYDROLOGY...
Issued at 1138 AM CDT Tue Jun 24 2025

     RIVER FLOOD WATCHES HAVE BEEN ISSUED FOR THE CEDAR RIVER AND
PORTIONS OF THE IOWA RIVER...

Heavy rainfall of 1 to 3 inches fell across portions of central and
eastern Iowa Monday evening, June 21. The combination of heavy rain
this past week, and potentially heavy rains across Iowa and southern
Minnesota in the next 3 days has brought the potential for
significant river flooding on the Cedar River and Iowa River. As
this rainfall materializes the next few days, forecasts for rivers
will become more confident, and flood warnings may be required.

HEFS guidance continues to show a wide spread at the upper end
of forecasts for many Iowa tributary rivers, especially the
Cedar River, including Cedar Rapids. There is a 10-25% chance of
exceeding major flood stage on the Cedar River at Cedar Rapids
early next week. Other points along the Cedar River have similar
potential in the 5-10% range of exceeding major FS. The Iowa
River also continues to see a forecast for potential flooding,
with 10-25% chance for exceeding moderate levels of flooding at
Marengo.

All of this information is 4+ days away from reaching flood
stage, and models are not greatly skilled at determining the
exact latitude/location of heavy rainfall events. However, due
to the potential significant impact of forecast rainfall on
rivers, the RFC is using a 72 hour forecast rainfall amount,
rather than the normal 24 hour amount (QPF). As this rainfall
verifies, or falls into another basin rather than the
Iowa/Cedar, these forecasts are subject to considerable change.

&&

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

&&

SHORT TERM...Uttech
LONG TERM...08/Uttech
AVIATION...Uttech
HYDROLOGY...Ervin

Hazardous Weather Outlook
National Weather Service Quad Cities IA IL
249 PM CDT Wed Jun 25 2025

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-262000-
Buchanan-Delaware-Dubuque-Benton-Linn-Jones-Jackson-Iowa-Johnson-
Cedar-Clinton-Muscatine-Scott-Keokuk-Washington-Louisa-Jefferson-
Henry IA-Des Moines-Van Buren-Lee-Jo Daviess-Stephenson-Carroll-
Whiteside-Rock Island-Henry IL-Bureau-Putnam-Mercer-Henderson-
Warren-Hancock-McDonough-Scotland-Clark-
249 PM CDT Wed Jun 25 2025

This Hazardous Weather Outlook is for portions of north central
Illinois...northwest Illinois...west central Illinois...east
central Iowa...northeast Iowa...southeast Iowa and northeast
Missouri.

.DAY ONE...THIS AFTERNOON AND TONIGHT

Peak afternoon and early evening heat indices in the upper 90s to
lower 100s are expected south of Highway 30.

Scattered thunderstorms are expected today and tonight. There is
a marginal (level 1 out of 5) risk of severe storms this afternoon
and evening. The primary risks are lightning, isolated damaging
winds, and brief torrential rainfall.

There is also a risk of brief funnel clouds this afternoon
associated with the showers and thunderstorms.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

Heat and humidity will continue Thursday through Sunday with
afternoon heat indices around 100 degrees.

A near daily risk of showers and thunderstorms is expected
through Monday. A severe risk in the form of damaging winds and
heavy rainfall is possible at times.

Heavy rainfall could lead to a risk of flooding for some area
rivers due to repeated heavy rainfall in the headwaters. River
flood watches continue for portions of the Cedar, Iowa and
Wapsipinicon Rivers. Please refer to the latest statement for
details.

.SPOTTER INFORMATION STATEMENT...

There is a low risk of spotter activation this afternoon and
evening. Reports of rainfall amounts over 1 inch will be
appreciated.

Uttech

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