945
FXUS63 KDMX 281942
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
242 PM CDT Wed Oct 28 2026

.KEY MESSAGES...

- Scattered showers and storms this afternoon (30% chance)
  mainly in northeast Iowa.

- Marginal Risk for severe storms later this afternoon, mainly
  in northern and northwestern Iowa. Large hail is the main
  threat followed by a very low chance of damaging winds.

- Rain returns Friday and chances remain for much of the
  remainder of the forecast. High temperatures challenged by
  rain and persistent cloud cover.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 238 PM CDT Wed Oct 28 2026

A closed midlevel low in southern Canada enhanced the synoptic winds
across the Upper Midwest this afternoon. The strongest flow is north
of Iowa, meaning deep-layer shear is lower compared to our neighbors
in Minnesota. Low-level moisture is increasing ahead of an
approaching cold front. Dew points in the low 60s were collecting in
western Iowa. Scattered showers and a few storms populated the state
ahead of the front. These reside along the instability axis, roughly
along the MUCAPE = 1000 J/kg contour.

For the severe weather risk today, the threat will be short lived
with most of the storm activity in Minnesota where the kinematic and
thermodynamic parameter spacing is better. Low level hodographs will
loop with the increasing LLJ, increasing SRH over Iowa. Northern
Iowa will have the highest severe risk this evening as they have
marginally better deep-layer shear and better convergence along the
front. Due to the presence of clouds today, capping looks to inhibit
storm development and reduce the wind and tornado threat in Iowa to
under 2%. The CAPE distribution is also elongated in the profile and
the lapse rates are weak (<7 C/km) so parcel acceleration and
updraft strength are slowed. The resultant storm mode will be a
broken line of storms with some of them early on (before sunset)
utilizing the SRH to become supercellular. Hail growth in
supercells will be most likely to become severe, aided by most
of the CAPE residing in the HGZ and minimal below. Can`t
completely rule out damaging winds in this early window,
especially close to the IA-MN state line. As we lose daytime
heating, the SRH will become inaccessible by storms with time
and the remnant scattered storms will have lightning and
isolated hail. Low freezing level heights make hail growth
easier to achieve, but the low deep-layer shear will make hail
growth and storm lifespan abbreviated.

The front will exit and sag south of the state through the night and
set up for a cooler Thursday. Lingering cloud cover in southern Iowa
will challenge the 70 degree highs locally forecasted. Southwest
flow recovers in the midlevels and a southern stream shortwave
in the Desert SW will negatively tilt into the Plains, ushering
in a return of rain for Friday.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Issued at 238 PM CDT Wed Oct 28 2026

A complex, amplified upper air pattern will dictate the extended
forecast. Rain chances will loom for much of the period, including
through the weekend to start. Timing differences still remain for
Saturday on when precipitation will pause, but for now, it appears a
warm front will lift northward towards Minnesota through the day,
but there is enough uncertainty in remaining moisture to warrant
keep a ~30% chance of rain in the area for Halloween night. Lee
cyclogenesis will temporarily pull away moisture from the area
Sunday, but it will return with a large closed system to start next
week. Location of the warm sector is still uncertain as the
formation of the closed low involves the combination of a couple
component waves merging together. What can be said is the resultant
feature will become wound up in the central US and will result in an
extended period of rain chances, cloud cover, and cooler
temperatures for the first week of November. It`s possible that
highs next week don`t reach 70 degrees for the area.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1242 PM CDT Wed Oct 28 2026

Main challenge in the short term is the scattered thunderstorms
that extend from SW to NE across the state. Right now, expecting
them to miss TAF sites, but will be closest to KALO. Then, a
line of thunderstorms will move across the state this evening.
Have added short TEMPO groups to reflect the highest impact
window, including vsby and cig restrictions. Hail will also be
possible with severe storms. Confidence in higher wind is lower
as storms will arrive after dark. MVFR/IFR stratus resides just
behind the wind shift which will hover for a few hours after the
wind shift. Eventually the stratus will mix out and become SCT
to FEW after 12z.

&&

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

&&

$$

SHORT TERM...Jimenez
LONG TERM...Jimenez
AVIATION...Jimenez