811
FXUS63 KDMX 012025
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
225 PM CST Mon Dec 1 2025

.KEY MESSAGES...

- Light snow ending over the south by early this evening.

- Local fog possible overnight with some clearing into Tuesday.

- A strong cold front arrives late Tuesday night into Wednesday
  morning with falling temperatures and gusty winds. Very cold
  Wednesday night with all locations well below zero and wind
  chill values approaching 20 below over northern Iowa.

&&

.DISCUSSION...
Issued at 221 PM CST Mon Dec 1 2025

Light snow band is moving across the southeast half of Iowa this
afternoon though it is already beginning to diminish over parts of
southwest Iowa. A few inches of accumulation remains possible over
the far south central and southeast sections of the forecast area.
Road conditions this far have remained only partly snow covered
though some refreezing has been evident due to some melting and
refreeze due to some solar radiation warming road surfaces enough or
residual road treatments. This refreeze process likely will become
more common after 4 pm as we move closer to sunset. A Winter Weather
Advisory remains in effect for the southern area with the main
accumulations. Will be removing counties as the event ends from west
to east.

Once the snow ends, the forecast challenge for the overnight is
cloud cover and low temperatures. Light south to southwest wind will
develop overnight as the surface high pressure moves to the east
with gradual warm advection developing. Clearing in the sky cover
has been occurring this afternoon into northwest Iowa and over all
of South Dakota and much of Nebraska. The stratus level steering
flow will become more west to east overnight and that should lead to
some clearing. That should lead to some cooling with the release of
the cloud blanket but that will be minimized to some degree to the
light southwest winds. It will be cold with many locations falling
into the single digits to perhaps some low teens southeast where the
clouds will linger the longest. Several raw guidance output suggest
some reduced visibilities in fog late tonight into Thursday morning.
A southwest wind of 5 mph or greater wouldn`t support this so it
will depend if the wind falls off with a brief weakness in the
pressure gradient.

The next system to monitor is the Arctic cold front that will arrive
late Tuesday night over northwest Iowa and through the rest of the
area Wednesday morning. A period of light snow may occur as the
boundary passes through with minor accumulations possible. High
temperatures will be early in the morning then falling temperatures
and gusty northwest winds of 25 to 35 mph will occur the remainder
of the day. This wind may lead to enough blowing snow of the
existing snow cover to lead areas with snow cover on roads again.
The winds will subside Wednesday night as high pressure arrives.
Very cold temperatures are forecast for Wednesday night and Thursday
morning with lows of 5 below to 15 below. Some locations could
bottom out and be colder than this where radiational cooling is
maximized. Wind chills may be near 20 below over northern Iowa.
Beyond this, some minor warming returns but we are in a winter type
pattern so temperatures will remain below normal for the foreseeable
future. Another change for snow may arrive this weekend as another
wave drops southeast through the northwest flow.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1131 AM CST Mon Dec 1 2025

Several challenges in this forecast period. Light snow will
continue over parts of central and southern Iowa with main
impacts at KDSM/KOTM. Reduced vsbys in fog and some light
snow may occur elsewhere. KFOD and KMCW are near an edge of
IFR cigs with VFR just west/northwest of those location. A
period of VFR could occur at those sites. Cigs will likely
return for all areas tonight along with more vsby restrictions
with developing fog. Cigs should begin to scatter Tuesday
morning. The wind will be mostly light and less than 10 kts
during the period.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 9 PM CST this evening for IAZ074-
075-084>086-095>097.
Winter Weather Advisory until 6 PM CST this evening for IAZ083-
092>094.

&&

$$

DISCUSSION...Donavon
AVIATION...Donavon