391
FXUS63 KDVN 272329
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
629 PM CDT Fri Jun 27 2025

.KEY MESSAGES...

- Hot and humid conditions return this weekend

- After a dry day Saturday, an active period begins Sunday into Monday,
  with an isolated strong to severe storm threat Sunday
  afternoon and evening

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 203 PM CDT Fri Jun 27 2025

A more seasonal day was seen across the area this afternoon, with
widespread temperatures hovering in the middle 70s north to the
lower 80s south. The relatively cooler conditions compared to the
last several days are due to a cool front that has cleared the area,
along with west to northwesterly flow. The low stratus deck from
earlier this morning will continue to dissolve as drier air filters
in from the west and high pressure develops overhead, leading to a
mostly clear night tonight. With the light winds and clear skies, we
will have to keep an eye on some fog potential, particularly after
midnight. Fog isn`t expected to reach the threshold for any
headlines, but certainly some widespread fog potential exists,
especially along the MS River. Lows tonight should dip to the lower
60s northeast to the upper 60s south.

We will warm up once again Saturday, thanks to southerly return flow
around the departing high pressure system. We appear to remain
between systems, with a threat for severe weather remaining north of
our region into Minnesota. We can`t rule out an isolated shower or
storm to pop up in the late afternoon and evening hours Saturday per
some of the CAMs, but again, coverage appears to be very limited, if
anything develops at all. With the enhanced theta-e advection, highs
should return to the 90 degree mark for most locations and heat
indices increasing to the middle to upper 90s. Saturday night should
remain dry, with milder overnight lows dipping only to the lower
70s.

&&

.LONG TERM /SATURDAY THROUGH FRIDAY/...
Issued at 203 PM CDT Fri Jun 27 2025

Sunday into Monday marks the return of active weather, with
increasing chances (50-70%) of thunderstorms across the area as a
longwave upper-level trough sweeps over the upper Plains region. The
morning looks likely to remain dry, but the afternoon and evening
hours will be a different story as a mid-level shortwave/attendant
cold front approaches the area near peak daytime heating.
Instability is progged to be pretty high, with MLCAPE values around
2000-3000 J/kg, along with steep low-level lapse rates. However,
deep-layer and low-level shear appears to be pretty weak, so
thinking that with high Pwat values (1.7 to 2.0 inches), some wet
microbursts/damaging winds will be the primary threat with any
strong to severe storms. SPC has maintained a Marginal Risk (level 1
of 5) for most of our CWA Sunday afternoon/evening. Convective
initiation should develop along the front Sunday afternoon farther
north, which will dive southward toward our region, so we will need
to watch conditions upstream as we would be impacted later in the
event.

Sunday will again be hot and humid, with slightly higher dew point
temperatures into the lower to middle 70s. High temperatures are
expected to warm into the upper 80s to lower 90s, with heat indices
in the upper 90s to near 100 degrees. Confidence remains lower that
we will need heat headlines, given the LREF ensemble exceedance
probabilities of triple-digit heat indices less than 10%, which is a
lower trend compared to this time 24 hours ago. Either way you
slice it, it should be a pretty hot and muggy day Sunday!

Some lingering chances (20-50%) of showers and storms will remain
into Monday morning before waning by the afternoon as drier air and
an area of high pressure builds in from the northwest. High pressure
ridging over the Intermountain West states should help maintain
mostly dry conditions Monday night through Wednesday before another
system moves in for Thursday. Temperatures will generally be
slightly above normal during this period, with daytime highs in the
middle to upper 80s.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 621 PM CDT Fri Jun 27 2025

High pressure is forecast to move across the area tonight with
winds switching to the south after 15 UTC on Saturday. This will
result in VFR conditions through the TAF period. There is the
potential for MVFR visibilities in fog at KBRL, KDBQ, and KMLI
between 09 and 12 UTC. Visibility below 1 mile is possible at
mainly KDBQ but confidence is low in that occurring at this
time.

&&

.HYDROLOGY...
Issued at 1055 AM CDT Fri Jun 27 2025

Forecast crests along portions of the Cedar River have continued
trend a bit lower into next week after assessing recent run-
off and a dry forecast over at least the next 24 hours. However,
additional rounds of heavy rainfall are possible on Sunday and
into early next week may result in changes to the timing and
magnitude of the forecast crests. The latest river level
forecasts are only accounting for forecast rainfall (QPF) over
the next 24 hours, again which is mainly dry. With run-off
uncertainty, flow attenuation, and the dry forecast through
Saturday, will maintain the River Flood Watches for now for the
Cedar River at Cedar Rapids and Conesville, and the Iowa River
at Marengo. Of the three sites, it appears Marengo has the
highest potential to rise above the flood stage Saturday night,
but how much higher than FS still at question. Thus, we will
continue the watches for now, but a warning may have to be
issued this evening or Sat morning if the projected upward
trends are close to what the forecast is. The Cedar River at
Cedar Rapids has been trended down and now has just one point
hitting flood stage during Tuesday evening July 1st, and
depending on rainfall on that basin Sunday into Monday, may fall
short of that 12 FT level.

&&

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

&&

$$

SHORT TERM...Schultz
LONG TERM...Schultz
AVIATION...Cousins
HYDROLOGY...12