548
FXUS63 KDMX 120357
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1057 PM CDT Sat Oct 11 2025

 ...Updated for the 06z Aviation Discussion...

.KEY MESSAGES...

- Highs near 80 degrees Sunday. Rain chances have trended down
  during the day. Highest chances in northern Iowa (<20%).

- Rain increases in coverage Sunday night (30-40% chance) and
  lingers near southern Iowa Monday.

- Rain chances commonplace next week, mainly on Tuesday and
  Friday.

&&

.DISCUSSION...
Issued at 241 PM CDT Sat Oct 11 2025

The beginnings of moisture advection could be seen over Iowa today,
but moisture resides up high for now. Cloud bases are around 20kft,
moisture originating from the monsoonal flow over the eastern
Pacific. The low level moisture fetch is locked in step with the
cyclone over Colorado. The feature will be ushered northeast along
the strong 500mb flow that will round the trough base, placing the
main area of forcing in the Dakotas for Sunday. The pressure
gradient will tighten over Iowa during the day Sunday with gusts
over 30mph likely (70% confidence) over portions of western and
northern Iowa. Wind maxes will be spurious through the afternoon as
WAA and synoptic lift will limit momentum transfer to the surface.
It will also be warm with highs again approaching 80 degrees. Fire
weather conditions will be dampened by increasing dew points,
holding RH values in the 40s.

Theta-e advection picks up ahead of the front, but profiles continue
to fight a lot of dry air. Precip output in models has an eastern
flank of precip along the theta-e gradient and a western counterpart
on the synoptic front. A look at profiles on the eastern flank shows
that moisture will be anchored at around 700mb and above, meaning
that if there was rain associated with it, it will be very light.
This is why rain chances south of Highway 20 are below 25%, and near
0% in southern Iowa. Better saturation, albeit for a short duration,
will come Sunday night along the synoptic front. The chance for
thunderstorms overnight is low (~15% in the south) as MUCAPE values
are under 200 J/kg.

Monday will bring a welcomed change to temperatures as highs in the
60s return for a short increment. Our front won`t be far away as it
stalls near the IA-MO state line. Its 850mb reflection looks to stay
right over the state, hence the increase in PoPs Tuesday and
Wednesday. Forcing and instability will be at a minimum, but
wherever the front sets up, it will produce light rain and cloud
cover for an extended period. A deep trough from the west will
grab a hold of it in the second half of the week and it remains
to be seen what dynamics will be in play for Iowa this far out.
WPC cluster analysis shows that around 60% of members favor a
northern stream track for the deepest height falls, but a look
at both deterministic GFS and ECMWF give credence for some
leakage deeper into the CONUS.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1052 PM CDT Sat Oct 11 2025

VFR conditions prevail this evening and through much of the
forecast period. Winds will be increasing over western Iowa
through the morning hours, with occasional breezy winds already
being seen at KFOD and even near KDSM. Winds and wind gusts overnight
should only be around 15 to 20 kts, but will increase through
the day on Sunday where gusts up to 30 kts are possible. In
addition to breezy southerly winds, light showers are also
possible toward the end of the TAF period. Have begun some
mention of showers at KFOD, KMCW, and KALO where confidence is
higher. A front then passes at the end of the period, flipping
winds to more northwesterly and diminishing wind speeds.

&&

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

&&

$$

DISCUSSION...Jimenez
AVIATION...Dodson