Ottumwa, Iowa 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

978
FXUS63 KDMX 221105
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
505 AM CST Mon Dec 22 2025

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

.KEY MESSAGES...

- Confidence remains high in above normal temperatures this week.

- Monitoring fog potential over melting snowpack tonight into the
  middle part of this week.

- Limited sunshine Wednesday and Thursday may limit the degree
  of warming, but still a mild Christmas. Low chances for
  precipitation (<15%).

&&

.DISCUSSION...
Issued at 214 AM CST Mon Dec 22 2025

Early morning radar shows light returns over far northern Iowa, but
no precipitation has been reported over this area with cloud bases
around 9kft. There was a recent mPING near Austin, MN of freezing
rain and about an hour ago Fairmont, MN near I-90 reported light
rain with a 10 mile visibility so whatever may be falling is
extremely light. All of this precipitation is within the strong low
level warm air advection (WAA) wing and will be pushing away from
our forecast area in the next few hours. Turning attention to the
upper level pattern, the ridge can be seen in the plume of water
vapor in GOES-East imagery arcing from California into the Montana
and then downward into the western Great Lakes. This ridge will be
building a bit more poleward and moving eastward through this week
with the ridge axis over Iowa on Christmas Day. Confidence continues
to remain very high in temperatures being above normal this week in
this pattern, though how far above normal is more in question on
Christmas Eve and even more so on Christmas itself. Before we get to
later this week, today will have breezy winds from the south with
gusts between 15 and 25 mph, which will be strongest this morning
with the highest gusts in southwest Iowa. Spread in temperatures
today remains tight and did increase highs upward given the WAA
regime. Wet bulb temperatures should be above freezing for around 12
hours from later today into tonight and this will help to melt the
snowpack over northern Iowa. Soundings show an inversion setting up
and winds do lessen raising concerns for fog potential over the
snowpack after midnight tonight.

Tuesday will have highs several degrees lower as high pressure
passing north of the state causes northerly flow and cooler air to
arrive. This will be short-lived as the next round of low level WAA
surges over Iowa Tuesday night into Wednesday helping to create a
low level inversion. Checking around different central Iowa
locations, forecast soundings show the depth of moisture trapped
beneath this inversion generally a bit less than yesterday at this
time with perhaps the exception over our eastern forecast area (e.g
GGI). This is where drizzle may still be possible given the weak
omega and directional shear as a filament of vorticity passes over
the state. Overall though, drizzle chances are looking less likely
on Christmas Eve with a cloudy sky across much of Iowa. This cloud
cover is looking to linger into Christmas Day, especially over
northern and eastern Iowa. This is where soundings show a saturating
profile that may allow for light rain later on Christmas as another
round of WAA occurs ahead of a weak surface low that will move
across the region Thursday night into Friday. The clouds will have
an impact on temperatures with the spread between the 25th and 75th
percentile growing from 5 to 9 degrees on Wednesday to 6 to 11
degrees on Thursday. Spreads do remain smaller in far southern Iowa
on Thursday so temperatures may rise to near 60 degrees, but the
ceiling on highs is lowering the longer the clouds linger on
Thursday. In the wake of the low on Friday, winds from the northwest
will usher in less warm air, but it will still be mild for late
December.

While models start to diverge in their evolution of the upper air
pattern next weekend, there is a general consensus that a more
amplified trough sends a cold front through the state later Saturday
or Sunday. There is not much agreement on whether there will be any
precipitation with this, but temperatures do look to move back
closer to normal and winds could be breezier on Sunday.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 506 AM CST Mon Dec 22 2025

A period of low level wind shear is coming to an end this
morning, but surface winds from the south will remain breezy
with gusts of 15 to 25 knots common this morning into early this
afternoon before winds diminish into tonight. Stratus straddling
low end VFR/high end MVFR are lifting northeastward and look to
have reached DSM and OTM with ~BKN040. Have prevailed VFR
conditions, though do show SCT028 at OTM later this morning and
will monitor trends for any prevailing MVFR restrictions and
possible AMD. Will also be monitoring possible fog development
late in the period over northern Iowa, but confidence way too
low to include anything at this point.

&&

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

&&

$$

DISCUSSION...Ansorge
AVIATION...Ansorge/Lee