476
FXUS63 KDMX 240704
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
204 AM CDT Thu Sep 24 2026

.KEY MESSAGES...

- Cloudy today with rain beginning in northwest Iowa this
  morning, then moving southeast through the day.

- Showers and a few rumbles of thunder expand across Iowa on
  Friday and Saturday, tapering off on Sunday. Severe storms are
  not anticipated but pockets of heavier rain are possible.

- Another strong system will arrive Tuesday next week.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 204 AM CDT Thu Sep 24 2026

Cloud cover is increasing across Iowa early this morning with light
showers west of the state across South Dakota and Nebraska. Zooming
out for a wider view, the trough pushing across the northern plains
early this morning is squashing the central US ridge and tilting it
to the east. This has induced an elongated area of convergence for
shower development with increasing moisture transport. This axis
will gradually move into Iowa with showers reaching northwest Iowa
later this morning and sinking southeast across the state through
the day. There is very little instability available today, so while
a rumble of thunder is possible severe weather is not expected. This
convergent axis shifts across Iowa Friday with continued showers and
isolated thunderstorms across the state throughout the day. PWAT
values reach around 1.7-1.8" on Friday with warm cloud depths of
3500-4000m, allowing for more efficient rainfall. Even so, the lack
of convective processes limited by meager instability will help
to mitigate more widespread heavy rain. Amounts of 0.5-1.0" are
expected through Friday evening, though rain continues on
Saturday as the pattern moves very little.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 233 PM CDT Wed Sep 23 2026

Numerous waves of theta-e advection will occur into Friday with
precipitation chances increasing further east into central Iowa as
Lee side cyclogenesis occurs over eastern Colorado to Wyoming. The
cyclogenesis will push additional moisture into Iowa and bring more
widespread potential for showers and a few non-severe thunderstorms.
PWAT values Friday night and Saturday will be over 1.5 inches over
Iowa along with 850 mb dew points near 12C and warm cloud depths
near 13 kft. These parameters will be favorable for warm rain
processes and a efficient rain producing system. Deep convection
will be lacking, which in this case, maximum rainfall rates are not
expected. The deep layer moisture will diminish on Sunday but
stratus may linger over parts of Iowa into early next week. A potent
upper level system remains on track to impact Iowa Tuesday and
Tuesday night. Locally heavy rainfall and perhaps a few strong
storms will be possible.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1041 PM CDT Wed Sep 23 2026

VFR conditions are expected to continue throughout the morning,
with cloud cover gradually increasing and ceilings lowering
through the day. MVFR conditions become possible for most areas
into the afternoon and especially into the evening from low
ceilings. Otherwise, PROB30s are now introduced across all
sites except KOTM, given an increased signal for light rain to
spread across the forecast area in the afternoon to evening.
Will continue to refine timing and probabilities with future
forecast updates. Winds will generally remain out of the
southeast, with daytime gusts occasionally reaching up to 15-20
knots, highest over northwest Iowa.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SHORT TERM...Hagenhoff
LONG TERM...Donavon
AVIATION...Bury