Iowa City, Iowa 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

324
FXUS63 KDVN 261707
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1207 PM CDT Sat Jul 26 2025

.KEY MESSAGES...

- Storms at times today, especially south of Hwy 30, with the
  primary threat being torrential rainfall (rainfall rates
  2"+/hr possible) owing to a flash flood threat.

- Isolated strong to severe storms are also possible today with
  the primary threat being winds, and there is Marginal Risk or
  level 1 of 5 for severe weather for much of the area roughly
  south of Hwy 30.

- Heat builds back in Sunday through Tuesday, potentially
  dangerous, but there will also be episodes of storms making
  for a challenging temperature forecast and low confidence on
  the spatial extent and magnitude of the heat (day to day
  evaluation needed).

- Pattern change late week to usher in cooler, more seasonable
  and drier conditions.

&&

.UPDATE...
Issued at 1206 PM CDT Sat Jul 26 2025

Updated Aviation discussion for the 18z TAF issuance.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 308 AM CDT Sat Jul 26 2025

Showers and storms have blossomed across our southern counties
with ramping warm/moist advection atop a stationary front to
our south. Mid level water vapor imagery shows a few embedded
perturbations, some convectively enhanced, lifting ENE from
Kansas across far southern Iowa and northern Missouri. Just
eyeing satellite and radar trends would suggest potentially the
greater concentration of storms today being south of I-80, but
with any lull or breaks the warm advection could foster some
northward expansion through I-80. The continuous influx of
anomalously high PWATs (2-2.5 inches) will aid in potential high
rainfall rates (2"+/hr) at times and a continued threat for
flash flooding, particularly in areas that see repeated rounds,
which could exacerbate localized totals over 3-5+ inches as
suggested by 00z HREF localized probability matched mean 24 hr
QPF ending 00z Sunday. Needless to say the Flood Watch for the
threat for flash flooding will remain in effect through 00z
Sunday for the area mainly south of Hwy 30. Should this heavy
rain fall in areas that saw heavy rain/flash flooding on Friday
we would have concerns for significant flooding risk.

Aside from the primary flooding concerns, can`t also rule out
some isolated strong winds should we get sufficient diurnal
heating amidst strengthening deep layer shear 25-30+ kt.
SPC does have much of the area south of Hwy 30 in a Marginal
risk or level 1 of 5 risk for today.

Showers and storms should taper off to more low end scattered
to isolated coverage (20-30%) by tonight, as we see weak
mid level ridging build in but still some weak low level warm
advection atop the boundary to our south.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 308 AM CDT Sat Jul 26 2025

Sunday models support some amplification of the upper ridge
overhead. The building heights aloft and lack of any appreciable
forcing may limit storm coverage and support more diurnally
induced widely scattered activity. This upper ridge and
increasing heights aloft will also bring a return of the heat.
With corn sweat in prime-time, we`ll see some very humid to
oppressive conditions with dew points likely in the mid/upper
70s and possibly 80 in spots. This will bring the potential for
dangerous heat index readings exceeding 100 to around 105
degrees across much of the area, provided convection and cloud
cover stay limited to allow highs to top out in the upper 80s to
around 90.

Monday through Wednesday, the pattern looks to become quite
conducive for periodic storm complexes with an attendant heavy rain
and severe weather threat, as the ridge is suppressed further
to the south allowing our region to reside in the action zone or
`ring of fire` with main belt of westerlies strengthening and
shifting southward through the Northern Plains and Upper Midwest.
This timeframe will also hold the potential for a continuation
of dangerous heat and humidity, but this will likely be a day to
day evaluation because of the uncertainty with temperatures given
the active pattern and potential for rounds of convection.

Beyond mid-week though there are signs pointing to a cooler and
somewhat drier pattern for late next week, as we see a bout
of northwest flow attendant to an eastern Canada low.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1206 PM CDT Sat Jul 26 2025

In the wake of morning showers and convection, lingering MVFR
cigs will continue to impact CID and DBQ through 20-24z before
gradually lifting to VFR. Further south, have included PROB30
TSRA groups from 18-24z at MLI and BRL in case of convective
redevelopment this afternoon. Cigs/vsbys here this afternoon will
remain VFR outside of thunderstorm activity.

Clearing skies, calm winds, and a very saturated boundary layer
will promote fog development overnight. The most severe
restrictions will be at CID and DBQ where LIFR cigs/vsbys are
expected. At MLI and BRL, fog conditions will produce IFR and
MVFR vsby restrictions, respectively.

Winds through this afternoon will be steady from the south
around 6-10 kts, becoming calm overnight. After 13-15z Sunday,
winds will pick up again from south AOA 3-5 kts.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Flood Watch until 7 PM CDT this evening for IAZ063>068-076>078-
     087>089-098-099.
IL...Flood Watch until 7 PM CDT this evening for ILZ009-015>018-
     024>026-034-035.
MO...Flood Watch until 7 PM CDT this evening for MOZ009-010.

&&

$$

UPDATE...NWS Paducah
SHORT TERM...McClure
LONG TERM...McClure
AVIATION...NWS Paducah