589
FXUS63 KDMX 161137
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
637 AM CDT Sun Aug 16 2026

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

.KEY MESSAGES...

- Lingering convection over far southern Iowa early this morning
  then drier the rest of today through the daytime Monday.

- Fog is possible early this morning.

- Strong storms and potentially heavy rainfall is possible
  Tuesday/Tuesday night.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 253 AM CDT Sun Aug 16 2026

Patchy to areas of fog have developed this morning but thus far, the
fog has been mostly transient over central Iowa with lower
visibilities not sustaining. Drier air is finally beginning to
filter south into Iowa early this morning as a broad areas of high
pressure is moving into the Upper Midwest. The switch to northerly
wind and lowering dew points should help diminish any fog over
northern Iowa early this morning. Deeper moisture and the 2+ inch
PWATs remain over far southern Iowa while the main surface warm
front continues to retreat south and deeper into central Missouri.
Thunderstorms are ongoing over northern Missouri but the main focus
this morning is the complex of storms lifting northeast out of north
central Kansas. This complex is lifting northeast along the MUCAPE
axis, which still extends north into southern Iowa. As the complex
moves northeast, the MUCAPE axis will settle slowly south, but will
remain long enough for some of the convection to reach the far
southern Iowa today and there is a possibility that renewed
convection develops this afternoon. High pressure will continue
to settle into Iowa today resulting in less humid conditions
and drier conditions. Those drier conditions will persist into
much of Monday, however, return flow on the back side of the
high pressure and an approaching boundary will bring renewed
thunderstorm chances to northern Iowa by Monday evening and
night. High temperatures today and Monday will be pleasant and
in the upper 70s to low 80s.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Issued at 246 PM CDT Sat Aug 15 2026

Shower and thunderstorm potential returns area-wide again
Tuesday into Wednesday. Given this will be another northwest
flow regime, it`s tough to get too involved in the details. That
said, the Tuesday storms do seem to have a rather healthy
environment with increasing instability and modest deep layer
shear supportive of more organized convection. SPC does have a
day 4 15% risk for most of Iowa and WPC has put out a slight
risk for excessive rainfall for Tuesday. The pattern remains
relatively active through mid- week and then ridging begins to
build through the second half of this week.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 633 AM CDT Sun Aug 16 2026

LIFR to IFR stratus and fog is ongoing over parts of northeast
and eastern Iowa. The fog will continue to improve but IFR
stratus may linger for a few hours. In addition, MVFR cumulus
may develop in this area as low level moisture lifts this
morning. A MCS is moving into southwest Iowa early in the
period. There is a chance that showers or an isolated storm
impacts KDSM or KOTM but the potential remains low enough to
keep out of the forecast at this time. VFR conditions are
expected be widespread overnight outside of localized fog
development.

&&

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

&&

$$

SHORT TERM...Donavon
LONG TERM...Dodson
AVIATION...Donavon