Des Moines, Iowa 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

321
FXUS63 KDMX 201125
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
525 AM CST Sat Dec 20 2025

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

.KEY MESSAGES...

- Seasonal highs this weekend with a cold Sunday morning and mainly
  dry conditions.

- Turning warmer from Sunday into Christmas Day with high
  confidence in above normal temperatures. Limited
  precipitation chances as well.

- Will need to monitor for possible fog development next week
  over areas that have melting snowpack.

&&

.DISCUSSION...
Issued at 240 AM CST Sat Dec 20 2025

Fast, zonal flow is readily identified on early morning GOES-
East upper level water vapor imagery with a stream of moisture
from the central West Coast into the central US. Less apparent
in this imagery is a shortwave trough over the Manitoba province
with a surface low pressure pushing into the Ontario province
and a cold front draped to the southwest into the Dakotas. Over
Iowa at this hour, breezy southwesterly or southerly surface
flow and strong low level warm air advection is ongoing, which
has resulted in steady if not rising temperatures overnight. As
of 2am, the cold front is just entering the northwest corner of
the state and will swing through the rest of the state this
morning. Cross sections look drier than last night, but have
maintained spurious flurry mentions over northern Iowa for a few
hours around and shortly after sunrise. Behind the front, there
will be cold air advection with breezy winds becoming from the
northwest. These winds will diminish into tonight as surface
high pressure slides through the state into Sunday with a cold
Sunday morning, especially over northern Iowa where lows will be
in the single digits above zero. While the setup is favorable
for fog Sunday morning (light to calm winds, clear sky),
Saturday snowmelt looks to be limited with dewpoints in the low
20s. High pressure will depart through the day as waves of low
level thermal lift spread over the state once again into Sunday
night and Monday. Deterministic and ensemble data continues to
point to precipitation, likely light snow, developing over far
northeastern Iowa or more likely points northeast of the state
into Monday.

The Christmas holiday week looks to be one filled with overall
favorable ground transportation weather with confidence remaining
high in above normal conditions, no strong systems, and limited
precipitation chances through at least Christmas Day if not Friday.
The zonal flow will evolve into mid-level ridging into the middle
and late part of next week with the peak of the thermal ridge over
Iowa Wednesday into Friday. This will result in high temperatures
trending upward from the upper 30s to low 50s on Monday to well into
the 40s and 50s with some low 60s peeking into southern Iowa on
Christmas Day. Record highs may be challenged on Christmas Day,
especially over southern Iowa, and most days next week temperatures
(highs and lows) will be 10 to 20 degrees above normal. With the
warm pattern, remaining snowpack over northern Iowa should largely
melt with the areas from around Fort Dodge to around Webster City
holding on the longest to the snow due to their deeper snow depths
per NOHRSC analysis and COOP/CoCoRaHS observed snow depths. Models
are likely struggling to resolve temperatures over northern Iowa as
they model the melting snow so upward adjustment in temperatures is
possible in these areas early next week. In addition, will have to
keep an eye on possible fog development where snow is melting if sky
and wind conditions align favorably. Finally, there is a subtle
shortwave trough scooting through the flow Wednesday and the
Canadian and ECMWF continue to advertise light QPF. Looking at ECMWF
ensemble sounding, it looks to be cloudy and the moisture depth may
be sufficient for drizzle, but that will be something to evaluate in
the coming days.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 525 AM CST Sat Dec 20 2025

Period of low level wind shear will come to an end in the next
few hours as a cold front causes the low level flow to become
more unidirectional from the northwest. VFR conditions will
prevail as mid-level clouds accompany the passing front.
Surface winds will average 10 to 15 knots with gusts of 20 to 25
knots through much of the day before diminishing into tonight.

&&

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

&&

$$

DISCUSSION...Ansorge
AVIATION...Ansorge