819
FXUS63 KDMX 191746
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1146 AM CST Wed Nov 19 2025

 ...Updated for the 18z Aviation Discussion...

.KEY MESSAGES...

- Another cool and mostly cloudy day today. A few areas of fog
  and drizzle through mid morning.

- A few areas of fog possible tonight followed by a mild
  Thursday.

- Rain chances in far southern Iowa Thursday night into Friday
  and continue to trim NBM PoP south.

&&

.DISCUSSION...
Issued at 358 AM CST Wed Nov 19 2025

A large area of stratus extends from eastern Nebraska to western
Pennsylvania this morning. A ridge of high pressure through Iowa and
into the western Great Lakes is driving the low level steering flow
of this stratus. The current stratus level wind flow is mostly light
easterly across Iowa with some northeast component over southwest
Iowa. This flow continues to move stratus into the state and expand
it to the southwest into northeast Kansas. The steering flow will
turn light northerly this morning and remains around 5 to 10 kts
into the afternoon. This will lead to a slow lift of the clouds
northward and while some erosion on the southwest edge of the cloud
field may occur, central Iowa will remain mostly cloudy today.
Cumulus may develop in any clearing areas behind the stratus retreat
due to residual low level moisture rising and condensation. Lowered
high temperatures further today in response to the stratus with
highs in the 40s. The highest confidence of low stratus is over the
northeast and could see a repeat of Tuesday and only have a 2 to 4
degree diurnal rise.

A few items in the immediate term is fog and lingering drizzle.
Visibilities across most of the forecast area are below 3sm and
there have been brief periods of one quarter mile vsbys at times.
The lower vsbys are collocated with cloud bases in the 200-300 ft
range. This trend should stay status quo over the next several
hours, especially due to the stratus in place. A few patches of
light drizzle are occurring as well and roughly along the I80
corridor west of Des Moines. Turbulence within the saturated layer
remains minimal. Both the fog and drizzle may persist through mid
morning in some areas.

Fog could become possible again tonight, especially in any clearing
areas and lighter winds across the state. Thursday is expected to be
mild with some sunshine. High temperatures in the 50s to low 60s are
possible. Continue to monitor the system for the end of the week.
The NBM pops continue to be aggressive with precipitation chances
into central Iowa. This seems to be largely driven by the GFS and
some of its ensemble members of which even half of those are drier.
Followed a solution with a more pronounced high pressure system and
associated dry air moving into Iowa at this time and that is
represented well in the ECMWF/ECMWF ensembles and other
deterministics. A mild weekend will follow.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1137 AM CST Wed Nov 19 2025

Persistent stratus, fog and drizzle continue to impact all
sites today. LIFR to IFR ceilings around 300 to 600 ft have been
common, but southerly flow is advecting some drier air in
southwestern Iowa where ceilings are around 1000 to 1500 ft.
Expecting this to advect northward, helping to raise ceilings
and increase visibilities at times this afternoon. Regardless,
at least MVFR flight restrictions will continue through the
afternoon.

Tonight`s forecast becomes trickier, as stratus is eroding from
the southwest. If stratus does clear out, clear skies could
lead to more fog development by tomorrow morning. That said,
this erosion is quite slow and stratus is often stubborn this
time of year. Therefore, have written TAFs with the expectation
for low level moisture and stratus to linger through the night.
This keeps IFR ceilings continuing at all sites through tomorrow
morning, then improving Thursday. Also expecting a fog/mist to
continue at KMCW and KALO through this evening and overnight,
which may lead to occasional visibility reductions.

This forecast will likely change as conditions evolve, so
amendments are expected.

&&

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

&&

$$

DISCUSSION...Donavon
AVIATION...Dodson