349
FXUS63 KDMX 030321
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1021 PM CDT Sat Aug 2 2025

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

.KEY MESSAGES...

- Mild and smoky conditions continue today into Sunday, with
  diminishing smoke on Sunday.

- Light rain chances in far western Iowa tonight and Sunday
  night. Low risk for severe weather.

- Trending warmer with some shower and storm potential through
  mid-week.

&&

.DISCUSSION...
Issued at 134 PM CDT Sat Aug 2 2025

It`s been yet another quiet and pleasant day over central Iowa as
calm to light winds out of the east combine with mostly sunny skies
and comfortable temperatures that will reach the mid 70s this
afternoon. The main damper on today`s weather is the presence of
Canadian Wildfire smoke, which continues to filter sunshine and
produce poor air quality over Iowa today. These smoky conditions
will last through much of the day today and into Sunday.
Fortunately, conditions should begin to improve through the day
Sunday as smoke aloft drifts eastward and any surface smoke trapped
beneath the inversion mixes out. This improvement will be coincident
with a subtle shift in the pattern which will be evolving through
much of the work week, bringing the potential for showers and storms
to the area as well as warming temperatures.

The next chance for rainfall will move into the far western and
northwestern portions of Iowa overnight tonight into Sunday morning,
although this precipitation will encounter some fairly dry air in
the lowest levels, which will see them quickly dissipating as
they cross the Missouri River. However, those in the western
portions of the forecast area could certainly see a light shower
or few sprinkles by Sunday morning. Fortunately, the farther
east it goes, the less moisture it will have to work with,
limiting rainfall. Likewise, the better instability axis
remains just west of the state with only meager amounts of
MUCAPE (< 500 J/kg) into the west, squandering the potential for
strong storms tomorrow morning. Based on model soundings, even
getting lightning seems like a stretch, but certainly can`t
completely rule out a rogue strike before activity dissipates in
the late morning.

Conditions remain dry through the rest of Sunday and into Sunday
evening, then we rinse and repeat late Sunday night into Monday
morning. Storms will fire over the plains where the environment is
moist and unstable. These then track east to southeastward toward
the state, before meeting the drier, more stable environment
overhead and dissipating in western Iowa. Those in the western half
of the state could see lingering showers and potentially a few
storms as this activity persists into early Monday morning, but like
tonight, will lose steam as they progress eastward. That said, the
instability axis will be slightly farther into the state tomorrow
night and this convection may have a more prominent cold pool,
which both point towards a greater potential for showers or
storms to reach the area before dissipating. Even then, they
will still be on the downward trend as they lose access to the
better environment, keeping the potential for any strong to
severe weather low.

As we progress through the work week, the upper level ridge and
coincident warmer temperatures will build in from the west. As this
occurs, we will see chances for overnight storms move eastward,
roughly correlated with the nose of the elevated mixed layer. The
current progression of this warm nose puts it in the west on Tuesday
night into Wednesday, then roughly overhead Wednesday night into
Thursday, and finally to our east Thursday night into Friday. Given
this, both Tuesday and Wednesday seem to be days to watch for
potential rain and storms, as this will be when the main moisture
and instability axes are overhead prior to the arrival of the
EML/capping. That said, this morning`s guidance now suggests we
may get "jumped over" by rain and storm chances on Wednesday,
as the EML races overhead through the day. This is in contrast
to yesterday and last night`s progression which indicated storms
riding along the nose of the EM through central Iowa. Ensemble
and machine learning probabilities reflect this trend as well,
keeping the better rain and severe chances to our north where
temperatures aloft will be a bit cooler. All this to say, this
weeks precipitation forecast is far from being cut and dry, and
we will want to watch how models forecast the EML through the
coming days, using it and the moisture/instability axis as our
guide for thunderstorm potential. Of greater confidence this
week will be the return of warmer temperatures as the thermal
ridge builds in. High temperatures in the mid and upper 80s with
dewpoints in the upper 60s to low 70s will return by late this
week, becoming more reminiscent of what Iowans expect from the
weather in August.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1021 PM CDT Sat Aug 2 2025

Haze will continue to gradually exit the state through the day,
which will lead to further improvement to visibilities across
the state. Areas of clouds will pass through at times with VFR
conditions expected to prevail. Winds will be light out of the
northeast with gusts increasing to 15+ knots at times late
morning through the afternoon.

&&

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

&&

$$

DISCUSSION...Dodson
AVIATION...Bury