025
FXUS63 KDMX 170724
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
224 AM CDT Fri Jul 17 2026

.KEY MESSAGES...

- Hot and humid weather continues today through the weekend.

- Isolated shower possible in the afternoon to early evening.

- Heat peaks on Monday, then a return to the low to mid 80s next
week.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 224 AM CDT Fri Jul 17 2026

The thermal ridge continues to dominate the near term pattern, with
a trough sitting to the northeast across the Great Lakes region. A
weak pseudo boundary stretches across northern Missouri with
scattered cloud cover in place there and into southern Iowa
early this morning. The rest of the area is clear, warm, and
humid this morning with temperatures in the low to mid 70s at 2
am. Patchy light fog is possible towards sunrise with plenty of
available moisture but widespread or dense fog is not
anticipated.

This afternoon will be hot and humid once again with highs in the
low 90s and dewpoints around 70. As was the case on Thursday,
an isolated shower is possible again this afternoon into the
evening mainly in the southern half of Iowa near that weak
boundary. There is very little shear to organize convection,
but with 1500+ J/kg of MLCAPE there will plenty of instability
to support short lived airmass showers. On Thursday these
collapse before even producing lightning and that will likely be
the case again today should any develop.

The Great Lakes area trough deepens on Saturday and pulls a cool
front across Iowa, keeping northern Iowa in the mid 80s while
central and southern Iowa warm into the low 90s once again. By
afternoon to evening a few thunderstorms are possible along the
weak front as it sinks south across southern Iowa. With little
to no shear, severe storms are not expected. Theta e advection
increases across the area on Sunday with low 90s areawide. As
that front is shoved back north and east a few thunderstorms
are possible, but there is uncertainty in the placement and
whether those may be east of the are on Sunday.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 208 PM CDT Thu Jul 16 2026

The high continues to be pinched off as an upper level ridge builds
over the western CONUS this weekend and early next week. Uncertainty
lies in how quickly this happens. LREF clusters hint that we could
be out from under the ridge as soon as Sunday night/Monday, although
it is most likely that we stay under it or on the edge through the
day Monday. A surge of warmer air enters the area this weekend just
before the ridge translates away from us, leading to the potential
for the highest temperatures of this stretch to end the weekend. The
Extreme Forecast Index (EFI) is keying in on this, highlighting part
of Iowa as having above normal temperatures. With this still being
several days out, it is a trend to monitor. Of note, long-term
deterministic models key in on this as well. In tandem,
uncomfortably warm low temperatures are being forecast for the same
time period.

Once we are out of the ridge`s area of influence, we get into a
northwesterly flow regime which leads to a change of pattern and
increased potential for shower and thunderstorm chances across the
region at times next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1043 PM CDT Thu Jul 16 2026

Minimal changes from the previous issuance. Monitoring shower
potential across southern Iowa after 20z, which is most likely
to affect KOTM. Thunderstorms will be possible, but are widely
scattered and small enough that confidence isn`t high enough to
include in the TAF. Their intensity and lightning production
will be reduced by their short lifespan.

&&

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

&&

$$

SHORT TERM...Hagenhoff
LONG TERM...67
AVIATION...Jimenez