796
FXUS63 KDMX 192340
AFDDMX

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

 ...Updated for the 00z Aviation Discussion...

.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 /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 540 PM CST Wed Nov 19 2025

Stratus with occasional drizzle and fog remains persistent
across the area this evening with widespread IFR to LIFR
conditions across the northern half of Iowa with MVFR conditions
are prevalent across the southern half. Stratus has begun to
erode in parts of western Iowa and this may expand towards TAF
sites overnight. Any loss of cloud cover would likely result in
a higher likelihood of fog development. Given the clearing in
far western Iowa already this evening, have increased the
visibility reductions within TAFs for Thursday morning.
Uncertainty remains in how readily morning fog may develop,
hinging on how persistent the stratus is. As such, amendments
are likely as conditions evolve.

&&

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

&&

$$

DISCUSSION...Dodson
AVIATION...Hagenhoff