097
FXUS63 KDMX 242338
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
638 PM CDT Mon Aug 24 2026

 ...Updated for the 00z Aviation Discussion...

.KEY MESSAGES...

- Multiple low (20%) storm chances through the day tomorrow. A
  Marginal (Level 1 of 5) Risk for severe weather is in place
  for northwestern Iowa where storms have the potential to be
  strongest.

- A cold front will clear the area by Wednesday morning,
  leading to dry conditions through the rest of the workweek.

- The next disturbance will move through this weekend, followed
  by a pattern change next week.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 225 PM CDT Mon Aug 24 2026

Showers which have well overstayed their welcome across southern
Iowa are currently clearing the area. The showers were covering much
more of Iowa than originally forecast due to influences from the low
level jet this morning and a decent pool of moisture that extended
through much of central Iowa. Due to the temporal extent of the
showers this morning, highs have been nudged down a couple of
degrees. The rest of today should remain shower-free as dry air
advects in from the north.

Tomorrow brings the potential for more active weather to the area.
Yet, high uncertainty is caused because of several factors
relating to timing, placement of features, and dry air. This
evening, a complex of storms should form in the Dakotas and move
east/southeast through the night. The split in guidance puts a
kink in how things should pan out. CAMs are currently in two
camps with the evolution of this complex. The first camp is that
storms will follow the mean flow across Minnesota and
completely miss our area. The second camp is that storms become
rooted into the boundary layer and follow the gradient of CAPE
into northern Iowa. This would be more impactful to our area,
however, confidence is still low. The environment in Iowa is
lacking in moisture and, should the complex take a southerly
track towards Iowa, they will outrun the available instability.
Furthermore, soundings show a dry layer in the low levels, which
would continue to limit storm coverage in Iowa. If storms
sustain themselves and make it to Iowa, the timing would be
between sunrise and noon, and spatial coverage would be north of
Highway 20. As these storms decay, severe weather is not
expected, but gusty winds are still possible due to the dry air
at the surface.

The next window for severe weather comes tomorrow afternoon. A
shortwave is progged to move through the Great Lakes region and the
periphery of it will be over northern Iowa. This lines up with a
brief window where mixed-layer instability in northern Iowa peaks
between 1000 and 2000 J/kg and 30-35kts of shear are available. A
cold front is also expected to pass with this system as it passes.
This will help provide some amount of forcing to the area. While
there is plenty of CAPE and shear present, forcing looks pretty
limited and lapse rates hardly exceed 7 degC/km. If an updraft is
able to sustain itself, it could pose a risk for gusty winds and
hail, although it would also have to fight a stout EML and dry air
at the surface.

Late tomorrow night, showers and storms are possible again, mainly
across southern Iowa. A plume of better moisture sets up in the
southern and eastern portions of the state, and there is limited
instability available. Limited forcing once again makes the chances
of storms developing fairly slim. The rest of the day Wednesday
looks to be fairly dry with temperatures in the low to mid 80s
across the state. Dewpoints will be in the low to mid 60s for the
most part, leading to fairly pleasant conditions outside. As
northwest flow continues, temperatures overnight Wednesday will stay
in the upper 50s to mid 60s.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 225 PM CDT Mon Aug 24 2026

Conditions are expected to remain unchanged as Iowa stays in a
pattern of northwest flow. The next disturbance moves through
sometime Friday evening into Saturday morning. Beyond that the
pattern looks to change as the high that has been pancaked over the
Four Corners region begins to break down, leading to a return of
warmer temperatures.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 638 PM CDT Mon Aug 24 2026

Generally VFR conditions are forecast for the next 24 hours,
with some mid-level ceilings around FL060-080 gradually lifting
and/or breaking up later tonight or Tuesday morning. There is a
very low (less than 20%) chance of thunderstorms at times during
the day Tuesday, but with such low confidence in occurrence or
timing, they are not mentioned in the 00Z TAFs and any
potential will be reassessed in later issuances.

&&

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

&&

$$

SHORT TERM...67
LONG TERM...67
AVIATION...Lee