431
FXUS63 KDMX 250335
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1035 PM CDT Sun Aug 24 2025

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

.KEY MESSAGES...

- Quiet and comfortable weather through Tuesday.

- Only sporadic, low rain chances are forecast in the latter
  half of the coming week.

&&

.DISCUSSION...
Issued at 207 PM CDT Sun Aug 24 2025

A spell of cool, dry, and quiet weather will remain in place for
the next few days across Iowa. Persistent northwesterly steering
flow aloft, combined with a large surface high pressure area
building down over the region, will result in only few to
scattered clouds and very pleasant conditions for most outdoor
interests. Blended model guidance continues to be dragged warmer
by bias corrections which are largely based on the recent heat
wave. As a result, the distribution of temperature forecasts is
distinctly bimodal, with a cluster of bias corrected guidance
about 3-4 degrees warmer than a cluster of raw or blended raw
guidance for the next couple of days. Have continued the
practice of nudging the official forecast down into the upper
half of the raw guidance cluster, resulting in daily lows in the
mid to upper 40s and highs in the upper 60s to lower 70s
through Tuesday. With dewpoints only in the 40s to occasionally
lower 50s, this will provide the first hint of early autumn
flavor for Iowa residents.

By Tuesday night/early Wednesday the large gyre over eastern
Canada responsible for our early-week northwesterly flow will
finally move off farther east. Concurrently, a western U.S. 500
MB ridge will flatten out and slide into the southern Plains.
The combined effect will be to place Iowa beneath weaker and
more nebulous steering flow. This will have three primary
impacts on the forecast for the latter half of the coming week:

 1. A lower degree of predictability.
 2. A modest warming and moistening trend, but still remaining
seasonally mild.
 3. A return of low rain chances at times.

The details of timing and location for any rain chances are a
low confidence prospect at this range. However, no major storm
systems are foreseen this week, and in general rain chances
should remain low (around 20%) and spotty.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1033 PM CDT Sun Aug 24 2025

VFR conditions to prevail. Have added a SCT deck to MCW and ALO
as a VFR stratus deck may graze the sites overnight. Could see
periods of BKN to OVC in the next 6 hours. Coverage becomes FEW
after sunrise for all sites.

&&

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

&&

$$

DISCUSSION...Lee
AVIATION...Jimenez