274
FXUS63 KDMX 192050
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
250 PM CST Wed Nov 19 2025

.KEY MESSAGES...

- Stratus and patchy fog/mist/drizzle today and tonight, cloud
  cover lingering into Thursday and Friday.

- Rain chances over far southern Iowa beginning Friday morning.

- Warmer and drier over the weekend

&&

.DISCUSSION...
Issued at 247 PM CST Wed Nov 19 2025

A stubborn stratus deck and saturated conditions continue to impact
much of the forecast area today. After seeing a range of fog, mist,
and drizzle through most of the morning and into mid-day,
visibilities are improving to various degrees over the area 2 pm.
That said, there remains a pocket of lower visibilities around 2 to
4 miles through central Iowa, including the Des Moines metro area
where a drizzle/mist continues. Steering flow is generally out of
the south to southwest, so theoretically drier surface conditions
should be advecting into the area, but this drizzle/mist has been
quite persistent under the roughly 4000 ft thick stratus deck.

Taking a look out west, we see surface low pressure building and
pressure gradients tightening with stratus slowly eroding from west
to east. However, this erosion has been a slow process, making it
less likely any sunshine will squeeze through this afternoon in our
area. In fact, the stratus will likely stick around through the much
night, with potentially a few breaks overnight in
western/southwestern Iowa by Thursday morning. If we do see clearing
overnight, light winds may lead to more fog development tomorrow
morning, some of which could be dense. For areas under the stratus,
patchy fog/mist may also occur as temperatures cool tonight,
although radiational cooling will be more limited under the cloud
cover, keeping widespread dense fog potential at bay in those areas.
In addition to the fog and stratus, a few short range models also
indicate the potential for showers in southern Iowa tonight, but
with relatively weak forcing and a stout dry layer in the mid-
levels, not expecting more than a few sprinkles or very light rain.

Unfortunately, relief from the gloomy, saturated conditions is
looking less likely on Thursday, as a boundary drops down into the
state tonight and pulls another plume of stratus down into the state
on Thursday. Optimistically, we could see some sunshine in the
morning over southwestern into central Iowa before the boundary
arrives and after today`s stratus erodes, but then cloud cover fills
in through the remainder of the day. As a result of this cloudier
trend, have dropped high temperatures on Thursday, as less of the
warm air aloft will be mixed down and weak cold air advection takes
over in the low levels. If no sun is seen tomorrow, highs may still
be slightly overdone.

Finally, we are still monitoring the system that will lift
northward early Friday morning, bringing rain potential to
southern Iowa through this period. The GFS and NAM deterministic
models are standing firm on precipitation making it as far north
as the interstate 80 corridor, while the ECMWF and Canadian
deterministic models keep it mostly along the Iowa/Missouri
border and south. High pressure filling in behind the Thursday
wave will bring a shot of dry mid-level air, that will work to
negate precipitation moving up into southern Iowa, so the
balance between these two systems will be the key factor for our
rainfall forecast on Friday. Initial CAM guidance shows the
influence of the dry air, with a fairly sharp northern edge to
the precipitation as it moves north, but most do eventually get
some rain at least into far southern Iowa. Therefore,
expectation is still that the highest chances for rain in our
area on Friday will be over southern Iowa, with greater
uncertainty farther north. As more short range guidance comes
in, a clearer picture will develop.


&&

.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...Dodson
AVIATION...Dodson