995
FXUS63 KDMX 150855
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
255 AM CST Fri Nov 15 2024

.KEY MESSAGES...

- Patchy dense fog continues this morning.

- Spotty light rain possible (30% chance) on Saturday evening.

- Large system will bring widespread rain on Monday, followed
  by intermittent precipitation chances and cooler temperatures
  the rest of the week.

&&

.DISCUSSION...
Issued at 255 AM CST Fri Nov 15 2024

Patchy dense fog this morning is gradually becoming more widespread,
something that can be picked out on GOES nighttime microphysics
imagery early this morning. As is typical for this time of year,
this is expected to stick around through mid morning before
diminishing. With clearing skies and southerly flow into the area,
temperatures by this afternoon will warm into the 50s to near 60
degrees in southern Iowa.

Saturday will be another warm day with a wave passing to the north
inducing a strong pressure gradient across the area and elevated
south winds. Model soundings continue to show 25-35 kt winds through
the mixed layer on Saturday, and while a warm air advection pattern
may not be the most conducive to realizing those stronger gusts,
expect 25-30 mph gusts at times. Highest gusts are most likely over
northern Iowa in closer proximity to the surface low. At the same
time, the wave to the north will include a trailing boundary across
the area that ties back into an approaching low out over the Baja.
With the plume of moisture beginning to stream into the area,
models are becoming more consistent with the signal for light
rain on Saturday later afternoon and evening, mainly along and
south of a line from Creston to Ames to Mason City. While not a
washout, a few sprinkles or light showers are expected.

After a lull in activity on Sunday, the low across the Baja will
lift through the central US and into Iowa on Monday. With strong
deep moisture transport into the area, widespread soaking rains
are expected once again over most of the area. In fact, NAEFS
members max out pwats across the area through the period on
Monday compared to climatology. Models remain consistent with
over 90% chances for at least 0.5" areawide with at least an 80%
chance for 1+" west of I-35. Despite the wrapped up low, severe
chances are very low with CAPE under 50 J/kg through Monday
afternoon.

Beyond Monday the forecast becomes less certain. Recent runs of
both the GFS and Euro have trended towards a more progressive
pattern with this quickly deepening low. While a departure from
previous runs, this would keep the area drier for the middle to
end of next week while earlier runs indicated multiple
opportunities for precipitation. What we do know is that
temperatures will cooler significantly next week with highs in
the 30s to low 40s. Breezy winds can also be anticipated with
this large dynamic system. The forecast will continue to change
as new data is available so stay tune for updates.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1041 PM CST Thu Nov 14 2024

Areas of fog are expected to develop on the backside of the
retreating stratus deck over central Iowa early Friday morning.
MVFR to IFR conditions with restricted visibilities are expected
until mid morning Friday when increasing mixing helps the fog to
dissipate. The remainder of the forecast from midday Friday into
Friday night should see widespread VFR conditions. Surface winds
remain light and variable tonight becoming southeast with a
modest increase on Friday.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 9 AM CST this morning for IAZ004>007-
015>017-023>028-033>039-045>050-058>062-072>075-083>086-
095>097.

&&

$$

DISCUSSION...Hagenhoff
AVIATION...Cogil