811
FXUS63 KDMX 111135
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
535 AM CST Thu Dec 11 2025

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

.KEY MESSAGES...

- Band of snow passes over northwest into central and
  southeastern Iowa today into this evening with accumulation of
  1-3 inches possible. On the southwest side over portions of
  western and southern Iowa, light ice accumulations are
  possible.

- Accumulating snow Saturday with very cold air Saturday into
  Sunday. Cold weather headlines look increasingly likely early
  Sunday.

- Moderating temperatures and trending dry early next week.

&&

.DISCUSSION...
Issued at 242 AM CST Thu Dec 11 2025

High pressure across the area tonight has kept things quiet and
allowed for breaks in the cloud cover. Pull up GOES-east water vapor
imagery and look of to the west and see our next approaching system
reaching South Dakota early this morning. Precipitation will reach
northwest Iowa late morning and expand to central and southeast Iowa
through midday. This diagonal band bisecting the state from NW to SE
will produce a band of accumulating precipitation across the area
this afternoon into this evening. Most of the precipitation in the
band is expected to fall as snow with soundings showing deep
saturation through the dendritic growth zone paired with moderate
lift in this deformation zone. As the event progresses, the area of
best lift will shift lower in the atmosphere below the DGZ,
resulting in lower accumulation rates. Meanwhile, warm air advection
will be pushing into the state out of the southwest and into central
Iowa. This will result in a warm layer aloft. Models have trended
colder in the 00z and 06z runs, with less ice accumulation than
previous runs as the warm nose aloft does not quite exceed 0z
(or at least, not for as long or over as deep a layer). Have
trimmed down the ice accumulations to reflect recent trends,
however it is important to note that the potential for ice
accumulation has not gone away completely and event minor ice
can result in hazardous driving conditions. As the evening
update aptly noted, afternoon insolation should help to mitigate
slick spots early in the afternoon, however late afternoon and
through the evening conditions will likely worsen as the sun
goes down. Slack spots will likely make for hazardous travel
during the evening commute. As the event tapers off late
tonight, the HRRR has noted a brief period with lack of ice
introduction resulting in freezing drizzle. This should be
short lived and light, but would add to any earlier ice
accumulations. It is also worth noting that the synoptics
(GFS/Euro) have been further south with the band bisecting the
state practically corner to corner from NW to SE, the CAMs favor
a solution further northeast. With placement still uncertain,
have issued a winter weather advisory for areas expecting to see
2-3 inches of snow. These are marginal totals for an advisory,
but the the possibility of a wintry mix including ice
accumulation and the event occurring through the evening
commute, felt it would best convey potential impacts.
Adjustments may yet be needed if the band shifts or if higher
ice accumulations look possible.

There will be a lull in activity on Friday before the next wave in
this wave train in arrives on Saturday. As a fellow forecaster
noted, this should be the caboose in the wave train as the
following several days look to remain dry and warming back
towards seasonal temperatures for this time of year. Before
that, the Saturday system. This embedded shortwave passes
quickly across the area on Saturday the the deformation zone
passing over Iowa. Conditions are cold enough that snow is the
only precipitation type with 1-3 inches expected through the
day. Cold air pushes into the area on Saturday with morning lows
from the single digits above zero south to below zero north
(and wind chill from 0 south to -20 north). Reinforcing cold
air follows the Saturday snow and overnight lows thorugh Sunday
morning will be well below zero. Sunday morning wind chills
will be in the the -20 to -30s across most of Iowa. Cold
Weather Advisories and Extreme Cold Warnings are expected this
weekend. Dry conditions settle in Sunday through at least the
first half of next week with temperatures moderating back into
the 30s to low 40s.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 535 AM CST Thu Dec 11 2025

VFR conditions are in place across all site with patchy high
stratus across the state. MVFR stratus will move into the area
later this morning along with light snow that will impact all
sites from late morning into this evening. A wintry mix with
light ice accumulation is expected on the southern edge of the
snow band. This will mainly affect KDSM, but may come near
KOTM. Visibility in falling snow may drop to 1-2SM or lower.
Between falling snow and lowering ceilings, IFR conditions are
expected this afternoon through the end of the TAF period.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from noon today to midnight CST
tonight for IAZ004>006-015>017-023>027-035>039-048>050-062.

&&

$$

DISCUSSION...Hagenhoff
AVIATION...Hagenhoff