677
FXUS63 KDMX 241150
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
550 AM CST Mon Nov 24 2025

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

.KEY MESSAGES...

- Dense Fog Advisory remains in effect for parts of northern,
  eastern, and southern Iowa this morning.

- Gray and soggy today, with fog giving way to light rain and
  thickening clouds.

- Much colder from around Tuesday night through the end of the
  week, with blustery winds Tuesday night through Wednesday.
  Precipitation chances return into Friday and the weekend,
  with a potential for accumulating snowfall but details of
  timing and magnitude still unclear.

&&

.DISCUSSION...
Issued at 357 AM CST Mon Nov 24 2025

Southerly flow continues to bring increasing moisture and warm air
advection into Iowa early this morning, with resulting advection fog
lifting northward across Iowa. This fog can be seen well on
satellite imagery, surging quickly ahead of the clouds that are
following it into Iowa, which has brought about widespread
patchy fog across much of Iowa, and areas of locally dense fog
in parts of northern, eastern, and southern Iowa. Overall,
expectations remain that this fog will continue to lift
northward through the morning, with dense fog expected to expand
over northern, eastern and parts of southern Iowa through
sunrise, with expected visibilities under a half to quarter
miles in these dense fog areas. Therefore, the Dense Fog
Advisory remains in effect for the aforementioned areas until
about 10am, but could be extended slightly if this fog were to
stick around longer, which will be dependent on the speed of
rainfall arriving over the state today. Please take it slow and
allow for extra time to arrive to your destination, especially
during the morning commute.

Otherwise, the system of interest today in terms of expected
rainfall gradually arriving today is currently over western
Kansas/Nebraska, which is slowly tracking east, and its deformation
band seen from very light returns on radar inching into southwest
Iowa so far. No rainfall is being reported at the surface yet, which
makes sense given more limited moisture aloft, but the expectation
is that towards sunrise, rain coverage will gradually expand north
and eastward, with the highest probabilities (60-70%) by late
morning to afternoon as the main moisture surge from the south
becomes more widespread into Iowa. Rainfall amounts are still
expected to be on the low side, with values around to less than a
few tenths by the end of the day. Highs are expected to remain more
mild with values in the 50s. Have continued to slowly exit the
rainfall from west to east tonight given trends in CAM guidance.
HREF guidance is showing a signal for another night of widespread
fog, this time from lingering moisture from the fresh rainfall over
Iowa, along with light winds. Therefore have added fog to the
forecast tonight into Tuesday, and like yesterday, will watch trends
over the next several hours to assess if another advisory is needed,
which at this time seems quite possible.

As this system departs into early Tuesday, a quickly moving
deepening trough to the northeast is expected to interact with this
first system and develop a defined low pressure system, dragging a
surface cold front into Iowa through Tuesday morning from west to
east before departing into the afternoon. Expectations remain
generally similar to previous thinking, with additional but low
chances for rain showers mainly over the eastern half of Iowa with
this, followed by wrap around precipitation in the form of light
snow over far northern Iowa Tuesday night into early Wednesday,
producing little if any accumulation. Besides the precipitation,
strong cold air advection with the elevated cold front, seen by
northwesterly flow with strong winds at 850mb up to 40-45+ knots
looks to lag a bit, arriving a bit later by Tuesday afternoon to
evening. Though widespread stratus is expected to remain overhead,
along with time of day at least somewhat limiting the better mixing
of these winds down to the surface, would still expect conditions to
be rather windy given the scope of this advection regime. Trends
therefore continue with this current forecast cycle to increase
winds a bit further Tuesday and Wednesday from the higher end
guidance to reflect these expectations. Winds gradually taper off
through later Wednesday and especially into Thursday as surface high
pressure settles overhead with highs expected in the 30s and lows in
the teens to 20s.

By Friday, long term guidance indicates the next system arriving
into the region that could introduce a more widespread winter
weather potential, but notable differences still remain that leave
more uncertainty at this time. Close monitoring will continue
over the coming days as more model members capture this specific
event and details become more clear. Stay tuned for updates.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 550 AM CST Mon Nov 24 2025

Widespread fog remains overhead this morning, with dense fog
across the eastern terminals causing reduced visibilities below
1 statute mile and LIFR conditions. These conditions are
expected to remain until about mid-morning before fog dissipates
as rain arrives into the state. The highest probabilities for
rain are generally expected late morning to afternoon, with
periods before and after handled with PROB30 groups, which will
also include low ceilings generally below MVFR/IFR. Low stratus
along with fog then returns this evening into Tuesday, which
will result in more significant restrictions.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 10 AM CST this morning for IAZ004>007-
015>017-023>028-035>039-047>050-061-062-074-075-083>086-
094>097.

&&

$$

DISCUSSION...Bury
AVIATION...Bury