396
FXUS63 KDMX 261111
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
611 AM CDT Sun Jul 26 2026

 ...Updated for the 12z Aviation Discussion...

.KEY MESSAGES...

- Dying showers over northern Iowa early this morning.

- Dangerously hot conditions persist through Monday.

- Severe weather potential remains tonight, but there is high
  uncertainty in location and timing of storms.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 1239 AM CDT Sun Jul 26 2026

The remnants of the mesoscale convective system (MCS) is
pushing through northern Iowa after blasting the Sioux Falls
metro with severe winds earlier this evening. Intensity has
waned significantly with no lightning now as the outflow
boundary has pushed far ahead of the rain. As this rain
continues to diminish across the area, there may be lingering
clouds in the morning, which should scattered into the
afternoon. With mid-level heights persisting or slightly
higher, it will be a sultry day. Forecast soundings show
boundary layer mixing that results in higher temperatures and
lower dewpoints, especially over western into portions of
central Iowa. This has been accounted for in the current
forecast. The net result is similar heat index values, which are
plus or minus five degrees of 110. Thus, the extreme heat
warning for Sunday afternoon continues to look warranted.
Additional nudgers is the experimental NWS HeatRisk, which is
in the high/level 3 of 4 category over much of our area. Adding
to the hot day will be a bit of haziness to the sky due to high
level wildfire smoke that will be drifting overhead.

As the sun sets Sunday evening, attention will turn to the high
reservoir of instability over the region, especially over
eastern Iowa and points east. Deterministic models and CAMs show
a variety of solutions with their placement and timing of
storms as the low level jet ramps up into Iowa during the
evening. Trying to cluster these into similar placement camps,
models are trying to have one MCS push south-southeastward
through the Mississippi River Valley of eastern
Iowa/Wisconsin/Illinois overnight while perhaps another MCS
pushes southward through the Missouri River Valley of western
Iowa/eastern Nebraska overnight. While none of these peg central
Iowa at the moment, the take home point here is the atmosphere
can support thunderstorms, which could be severe wherever they
track with the main hazard being damaging wind gusts.

With the convective evolution of storms Sunday night still
uncertain, this lends to uncertainty in where and how hot the
conditions will be on Monday. Looking at mid-level heights, they
look to be similar to Sunday if not perhaps a bit less in the global
models for Monday. So, right now temperatures and heat index
values are a bit lower than Sunday on Monday. Thus, will be
looking to adjust the watch to an advisory and perhaps a warning
in the coming hours.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Issued at 301 PM CDT Sat Jul 25 2026

As the aforementioned trough deepens as it tracks over the
Great Lakes into the Ohio valley late Monday into Tuesday, will
see a push of cool air advection into Iowa that will end the
stretch of sweltering heat. While temperatures will only be a
touch cooler in the upper 80s to low 90s Tuesday, drier air from
this shift in low level flow turning northwesterly will allow
for slightly lower dewpoints in the upper 60s for most areas.
The western thermal ridge overall will move very little through
much of the work weak, with any precipitation chances signaled
to largely remain west of Iowa until around Thursday, when a
more potent shortwave dives southeast on the eastern fringe of
this ridge from the Dakotas into Iowa. Certainly room for slight
shifts in these larger scale features to occur in the coming
days given this being further out in the forecast period, so
stay tuned for updates. Highs through the rest of the week
remain generally in the upper 80s to low 90s, paired with
dewpoints in the 60s, more towards normal summertime averages.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 606 AM CDT Sun Jul 26 2026

Patchy, light fog is lingering over the eastern half of the
state early this morning, but should burn off by mid-morning. Mid-
level clouds overhead will become more scattered through the
day, allowing for broken sunshine. A few light showers are
intermingled with this cloud deck, but any impacts at TAF sites
will be minimal. Wildfire smoke will also be in place aloft,
leading to a slightly filtered sunshine. Tonight, thunderstorms
may return to the area, but confidence is low in exact location
of these storms. Therefore, have left out of TAFs with this
issuance.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until noon CDT today for IAZ004>007-015>017-
023>026-033>037-044>048-057>060-070>073-081-082-092-093.
Extreme Heat Warning from noon today to 9 PM CDT this evening
for IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-
081>086-092>097.
Extreme Heat Watch from this evening through Monday evening
for IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-
081>086-092>097.

&&

$$

SHORT TERM...Ansorge
LONG TERM...Bury
AVIATION...Dodson