847
FXUS63 KDMX 281137
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
637 AM CDT Tue Apr 28 2026

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

.KEY MESSAGES...

- Showers possible this afternoon and tonight. Expected to be
  light.

- Seasonal to cool much of this week with a few chances for
  precipitation on Wednesday and late Thursday.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 345 AM CDT Tue Apr 28 2026

Stratus that was over much of the state last evening is beginning to
clear over the northwest third of the state and that trend will
continue through this morning as northwest steering flow continues
to usher it out of the area. Light drizzle that was occurring with
this stratus has mostly ended as the weak vertical ascent within the
stratus layer has further stabilized.

The challenge for today is precipitation chances later this
afternoon and overnight. Two PV anomalies are being highlighted on
the PV 1.5 pressure surface and water vapor imagery. The first
anomaly is over southern Utah while the other over southern Idaho.
Those two pieces of energy will move towards Iowa today and will
bring kinematic forcing aloft this afternoon over the south and
farther north into the evening as the second system arrives. This
system does have attendant mid-level Pacific moisture advecting in
to the state that will help saturate profiles aloft. Therefore, have
increased PoPs over the area. PoPs may need to be trended even
higher if confidence in saturation increases.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 345 AM CDT Tue Apr 28 2026

The rest of the week forecast is tracking low precipitation chances
at times. A robust short wave moving over south central Canada will
evolve in a closed upper low over the Great Lakes on Wednesday that
will lead to troughing over the Upper Midwest followed by northwest
flow. This flow along with broad high pressure will effectively
close off any northward flow of Gulf moisture through this week. Any
mid-level moisture contributions will be quite limited so systems
will be reliant on attendant residual moisture. Two more short waves
will be moving thorugh this flow, with one arriving on Wednesday and
another late Thursday. Therefore, low PoPs have been assigned to
each period for now and will continue to assess moisture availability
and dry air impacts. Temperatures will be seasonal to cool this week
and there may be a few opportunities for frost/freeze, especially
over northern Iowa. A bit warmer temperatures for the weekend as the
steep northern flow relaxes.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 636 AM CDT Tue Apr 28 2026

Widespread MVFR stratus is currently clearing out of the state but
may linger around KOTM through 13z. VFR CIGs are currently expected
to prevail through the period, but some signal exists for near-MVFR
CIGs this evening in the central part of the state. There is a
chance for showers after 00z at KDSM/KFOD but probs are too low to
include.

&&

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

&&

$$

SHORT TERM...Donavon
LONG TERM...Donavon
AVIATION...Donavon/De Bruin