012
FXUS63 KDMX 310536
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1236 AM CDT Sat May 31 2025

 ...Updated for the 06z Aviation Discussion...

.KEY MESSAGES...

- Temperatures warm into the upper 80s through the weekend with
  upper level smoke making for hazy skies.

- Thunderstorms return to the area on Tuesday and we continue to
  monitor the potential for severe storms.

&&

.DISCUSSION...
Issued at 229 PM CDT Fri May 30 2025

While most of Iowa is cloud free this afternoon, one cannot look up
into a blue sky. Smoke from wildfires across Canada has pushed
into Iowa today and satellite imagery shows this blanketing a
large swath of the midwest. This smoke has remained aloft with
no observational sites reporting reductions to visibility that
would indicate smoke making it to the ground. HRRR and RAP smoke
data continues to indicate that this will last through Saturday
as well. There is a chance with a passing shortwave on Saturday
that some of this smoke may be pulled down to the surface, and
this is indicated with slightly elevated concentrations in both
RAP and HRRR surface smoke variables. Any impacts to air quality
across Iowa will be monitored by the Iowa DNR. Aside from smoke
impacts, the passing shortwave should have little tangible
impact to Iowa weather with CAMs keeping the area dry. A stray
shower my be possible in the afternoon with marginal instability
in some HRRR soundings, however confidence to include this in
the forecast at this time is low.

Meanwhile, temperatures through the weekend and into Monday will
soar through the mid to upper 80s with theta e advection into
the area as the thermal ridge shifts east.

At the same time, a western US trough will dig across the Rockies
with an associated surface low ejecting across the midwest by Monday
into Tuesday. Impacts to Iowa look to arrive on Tuesday and this
will be the next window for thunderstorms. The current track
takes the low across Missouri and lifting into Illinois to
Wisconsin. That would keep the more robust impacts to the south,
however southern Iowa could see some triple point action as the
surface low skims southern Iowa. GFS soundings at Lamoni and
Des Moines indicate 1200-1500 J/kg surface based CAPE with
100-200+ m2/s2 0-1 km SRH and nicely curved hodographs through
roughly the lowest 3 km. While better deep layer shear lags the
instability axis in current model runs, this environment remains
more than sufficient for supporting organized convection. We`ll
continue to fine tune the forecast in the coming days, but this
will likely be the next window for severe storms in Iowa.
Another system will pass over the area late this week.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1229 AM CDT Sat May 31 2025

VFR conditions ongoing and expected to continue through the TAF
period. Lighter winds out of the west overnight will increase
again slightly Saturday shifting to be out of the northwest but
generally remain near to under 10 knots. Smoke will continue to
keep skies hazy and maintained some CIG coverage to account for
the smoke aloft. Will continue to evaluate the potential for any
smoke impacts making it to the surface but confidence in impacts
at any one TAF site remains too low for inclusion at this time.

&&

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

&&

$$

DISCUSSION...Hagenhoff
AVIATION...05