987
FXUS63 KDVN 041729
AFDDVN
Area Forecast Discussion
National Weather Service Quad Cities IA IL
1229 PM CDT Sat Jul 4 2026
.KEY MESSAGES...
- Scattered storms possible today. Heavy rain and gusty winds
up to 50 mph will be the primary threats.
- Humid but not as hot today, with highs only in the 80s. There
will be dry periods as well, with lower coverage of storms
expected for evening fireworks displays.
- Additional showers/storms Sunday, before drying out early
next week.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 245 AM CDT Sat Jul 4 2026
Morning water vapor imagery shows two distinct shortwaves, one
over southeast NE and another one over eastern SD. Ahead of
these waves, strong upper level divergence along a 850mb
moisture gradient brought more storm development over central
IA, especially over Story county where another 4+ inches has
fallen in just 3 hrs.
A rather challenging forecast continues today, with regards to
storm timing and evolution. Most CAMs have not been helpful and
have relied heavily on observational trends and SPC mesoanalysis
for the near-term forecast. Current thinking is the storms over
central IA will make their way into eastern IA by daybreak in a
decaying mode, as the LLJ weakens. Some dry hours is certainly
possible for 4th of July activities mid-late morning from west
to east across the region. This afternoon, additional storms are
expected to develop primarily from the outflow boundaries from
last evening`s storms. A similar environment will be in place
from last evening (moist BL, favorable thermodynamics, weak
deep layer shear) leading to slow storm motions. Where exactly
these storms fire and linger is still uncertain and for this
reason, opted to expand and extend the Flood Watch for flash
flooding until 00z. While recent CAM trends seem to suggest a
lower coverage of storms this afternoon/evening still felt it
prudent to keep the watch going during the holiday. The 00z REFS
24-hr QPF PMM has 2-4 inch stripes falling roughly between the
Hwy 20 and I-80 corridors. In addition to a flash flood threat,
this will likely lead to renewed rises on tributary rivers.
Please see latest flood statements and forecasts for details.
Some good news though, is the overall coverage of storms after
7pm is looking much lower than last evening resulting in a
higher confidence dry forecast for most late evening for
fireworks displays! Overnight lows to drop into the upper 60s.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 245 AM CDT Sat Jul 4 2026
Sunday...shortwave trof to move through in the morning, bringing
chance PoPs for scattered showers and storms through the
afternoon hours. Dewpoints in the upper 60s/low 70s will keep
humid conditions around through the rest of the weekend.
However, it will not be as hot, with highs in the low to mid
80s.
Next week...broad ridging aloft over the central CONUS to bring
mainly dry and seasonable conditions. Active storm track appears
to be just to our north over the Dakotas and MN until Wednesday
night/Thursday when a cold front will bring us our next chance
for widespread precipitation.
&&
.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1224 PM CDT Sat Jul 4 2026
Convectively induced vort max will initiate SHRA/TSRA along and
east of the Mississippi this afternoon/evening. Overall
environment suggests a low probability of a TAF site being
impacted. However, a prob30 was included for all TAF sites this
afternoon and into the evening. CAMs are struggling to handle
the weak forcing but appear to be keying in on areas east of the
Mississippi as the primary focus for storms. After 03z/05
isolated SHRA/TSRA will be possible through the night and into
Sunday morning.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Flood Watch until 10 PM CDT this evening for IAZ040>042-
051>054-063>068-076>078-087>089.
IL...Flood Watch until 10 PM CDT this evening for ILZ009-015>018-
024.
MO...None.
&&
$$
SHORT TERM...Gross
LONG TERM...Gross/12/08
AVIATION...08